Jackson Gurung | NIT Mizoram (original) (raw)
articles by Jackson Gurung
Chemistryselect, 2022
Abstract Gemini surfactants are advantageous over conventional surfactants as they find applicati... more Abstract Gemini surfactants are advantageous over conventional surfactants as they find applications as antimicrobial agents, corrosion inhibitors, enhanced oil recovery, capping agents for nanoparticle synthesis, drug delivery agents, etc. This article provides a detailed overview of synthetic procedures for various types of geminis and the fundamental physicochemical parameters of these systems. This includes a discussion on the cationic geminis based on various groups such as biphenyl, amide (with/without alkane tail), binol, quaternary ammonium (with/without hydroxyl group as a spacer), morpholinium, pyridinium, amide (with/without alkane tail), ester quaternary ammonium, and imidazolium (spacer with/without hydroxyl group and thioether/ester) types. Further, it is focused on anionic geminis with carboxylate, borate, and sulfonate head groups. Zwitterionic geminis such as betaine surfactants, cocogem surfactants based on dodecylisopropylol amine and dicarboxylic acid, diester type, sulphobetaine gemini based on S-triazine, zwitterionic hetero gemini containing ammonium and carboxylate head groups, zwitterionic gemini containing quaternary ammonium and a sulfate group, gemini containing phosphodiester anion and quaternary ammonium salt are also reviewed. Lastly, synthesis of nonionic geminis from sunflower oil, amide-based nonionic, sulfonamide nonionic, N,N’-diethylaminedialkyldiamide nonionic gemini, sugar-based gemini, and nonionic gemini with sulfonate spacer have been discussed.
Journal of Molecular Liquids, 2022
Conductometric and spectroscopic methods were used to examine the interactions among the cationic... more Conductometric and spectroscopic methods were used to examine the interactions among the cationic surfactants, tetradecyltrimethylammonium bromide (TTAB) and cetylpyridinium chloride (CPC), and the anionic azo dye metanil yellow (MY) in an aqueous solution. The standard Gibb’s energy (ΔGm0), enthalpy (ΔHm0), and entropy (ΔSm0) of micellization were determined with the help of the equilibrium model. With temperature rise, the critical micelle concentration (cmc) increases because of the interruption of the organized water (WR) molecules enclosing the surfactant’s hydrophobic groups. As the total carbon atoms of the hydrophobic group are more in CPC than TTAB, a considerable fall in cmc value was observed. The presence of MY caused a higher degree of ionization (α) of micelles of TTAB and CPC. The negative values of ΔGm0 and ΔHm0 for both the surfactants in WR and aqueous MY solution (WR-MY) show that the micellization process is spontaneous and exothermic. As indicated by the -TΔSm0 values, which were found to be greater than ΔHm0 values, the entropy gain is typically what regulates the micellization process and the micellization was found to have a negative heat capacity (ΔCp,m0). UV–Visible spectra show that CPC has a higher binding constant (Kb) value as compared to TTAB implying that CPC has a comparatively greater binding affinity with MY dye in aqueous media (WR). The decreasing value of ΔGb for CPC indicates that the chance for the MY–CPC complex formation is more than that of the MY–TTAB complex. As shown by the rise in absorbance values as surfactant concentrations increase, a large number of the MY molecules are attracted to TTAB and CPC micelles.
Journal of Molecular Liquids, 2022
This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide... more This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide (TTAB), hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB) and sodium dodecylsulphate (SDS) in presence of poorly soluble drug phenothiazine (PTZ) in triton X-100 (TX-100) micellar aqueous media through the investigation of different physicochemical parameters. The interaction of surfactants in PTZ–TX-100 media has been studied using conductometric technique at pH 7.4 (SP buffer) and at three temperatures. The conductometric results reveal the sequence of critical micelle concentration (CMC) values of surfactants as SDS > TTAB > CPC > CPB > CTAB. UV–vis spectroscopy studies were used to learn the interactions of surfactants with the drug PTZ in TX-100 aqueous media (at 303.15 K and pH 7.4) which suggest the interactions are highly feasible (change of Gibbs energy; DGb < 0) and greatly improve beyond the CMC values of corresponding surfactants. The estimated parameters using the Benesi–Hildebrand equation indicate higher binding constant (Kb) for cetylpyridinium surfactants and least for SDS and the drug–surfactant complex formations are found to be in 1:2 stoichiometric ratios. Fluorescence technique has also been employed to study the aggregation number (Nagg), Stern-Volmer constant (KSV) and micro-polarity of TTAB/CTAB/SDS in PTZ–TX-100 systems at 303.15 K. The evaluated thermodynamic parameters such as change in Gibbs energy (DG0m), enthalpy (DH0m) and entropy (DS0m) of micellization show the process of micellization of all studied surfactants in PTZ–TX-100 aqueous media are spontaneous and exothermic.
Journal of Chemical & Engineering Data, 2020
Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several i... more Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several industrial and pharmaceutical applications. This article emphasizes the role of 2-propanol (PrOH) as a cosolvent in the micellization of cetylpyridinium chloride (CPCl) and cetylpyridinium bromide (CPBr) surfactants at different temperatures (293.15−308.15 K) studied through the conductometric technique. The results show an enhancement in CMC values for both the surfactants with an increase in volume percentage (vol %) of PrOH (from 0 up to 20 vol %) as well as temperature. The CPBr shows distinct behavior in the lower composition of PrOH−WR (0 and 2.5%) at a higher temperature (308.15 K). The rise in the CMC values depends on lowering of permittivity of the mixed media caused by change in compositions of PrOH−WR mixed media. A similar effect is also seen on the degree of counterion dissociation (α) values with an exception to a few compositions. The increase in α values is found to be relatively less for CPBr as compared to CPCl. Temperature dependency of CMC values has been used to calculate thermodynamic parameters such as the change in Gibbs energy (ΔGm 0 ), enthalpy (ΔHm 0 ), and entropy (ΔSm 0 ) of micellization, and their values were used to analyze the effect of various compositions of PrOH−WR mixed media. The ΔGm 0 values indicate that micellization is spontaneous and becomes less favorable with the inclusion of PrOH. The values of ΔHm 0 (<0) and ΔSm 0 (>0) affirm that the process of micellization is entropically driven within the scope of the studied temperature. Overall results have been analyzed based on the interactions between the solute and solvent, counterions and aggregates, and solvation/desolvation of counterions.
Applied Nanoscience, 2020
The development of effective photocatalyst through green and eco-friendly approach has become a g... more The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei, a plant extract with three different concentrations of AgNO3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV–Vis spectroscopy confirmed the reduction of Ag+ ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states’ binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei; plant extract can be used to modify and develop more efficient nano-photocatalyst for other application.
Journal of Molecular Liquids (Elsevier), 2020
The physicochemical properties of drugs and drug–additive interactions have great importance to e... more The physicochemical properties of drugs and drug–additive interactions have great importance to elucidate the pharmacological effect of the drug formulations. Plentiful pharmacologically active molecules are amphiphilic in nature. Knowledge about self-assembly, aggregate morphology as well as size and interfacial/micellar properties of such drugs in presence of pharmaceutical excipients (surfactants, electrolytes, polymers, hydrotropes, etc.) is vital from the fundamental and practical point of view. This article reviews the micellar properties and phase separation of drugs as well as drug–additive systems in aqueous and organic solvent–water mixed media. Results of several pharmaceutical excipients/surfactants assisted drug mixed systems have been analyzed through thermodynamic parameters which provide a comprehensive account on the physicochemical aspects of drug/drug–additives systems. Along with amphiphilic drugs, studies of a few non surface-active drugs have also been reviewed.
Engineering Reports (Wiley), 2019
Schedule maintenance programs rely on the analysis of collected data during running and shut down... more Schedule maintenance programs rely on the analysis of collected data during running and shut down time. In a preventive maintenance program, it is difficult to a priori determine the time limit or set an alarm indicating the failure time of a specific component. To this end, a Visual Basic 6.0–based software program is here proposed for a comprehensive running and maintenance database management. The developed software is capable of storing all relevant data related to parts, equipment, personnel, spares, failures, costs, etc, and displays a warning message when the expected life of a particular component has been reached. An unscheduled outage heavily impacts on the production cycle costs, depending on the nature of the failure and the damaged part. Since the variation of the used parts and equipment is high, it is not possible to have an all-encompassing maintenance guide, which is applicable to all equipment. A successful program of preventive and routine maintenance may hence decrease equipment failures rates, extend equipment life, and drastically reduce the overall operating costs. Therefore, the present work can help in preventing unscheduled breakdown of operating systems due to a failure in a component.
Chemical Engineering Communications (Taylor & Francis), 2019
Addition of organic solvents is known to change the properties of amphiphiles through modificatio... more Addition of organic solvents is known to change the properties of amphiphiles through modification of bulk phase. Amitriptyline hydrochloride (AMT) is a tricyclic amphiphilic drug which is usually used as an antidepressant. In drug delivery, the cloud point (CP) of the drug is an important parameter. This article discusses the effects of ethanol–water (EtOH–WR) compositions on the energetic parameters, such as changes in Gibbs energy of clouding (ΔsG0), enthalpy of clouding (ΔsH0), and entropy of clouding (TΔsS0) of AMT-additive systems. Monovalent alkali halide salts, cationic conventional surfactants, and gemini surfactants were used as additives in the EtOH–WR mixed media whose compositions were varied between 0 and 15% (w/w). The ΔsG0 values are positive for all the additives and the values decrease with the rise in mole fractions of the additives. The ΔsH0 and TΔsS0 were noted to be positive except for KF in 15% EtOH–WR mixed media.
Journal of Chemical & Engineering Data (ACS), 2019
Journal of Chemical & Engineering Data (ACS), 2018
In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and ... more In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30 °C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH–WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH–WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. For up to 10 wt % EtOH–WR mixed media, the effect of anionic and cationic co-ions on the CP is found to follow the order Br– > Cl– > F– and NH4+ > Li+ > Na+ > K+, respectively. When surfactants were used as additives, the hydrophobicity was found to be responsible for higher CP values and follow the order TTAB < CTAB < 14-m-14, where m is the length of the spacer.
New Journal of Chemistry (RSC), 2018
The influence of ethylene glycol (EG)/glycerol(GL)–water mixed media on clouding action of an amp... more The influence of ethylene glycol (EG)/glycerol(GL)–water mixed media on clouding action of an amphiphilic drug{,} amitriptyline hydrochloride (AMT) at pH 6.7 with inorganic salts (KF{,} KCl{,} KBr{,} LiCl{,} NaCl{,} and NH4Cl) in selected compositions of EG–WR and GL–WR mixed media (0%{,} 5%{,} 10%{,} 15%{,} and 20% of EG/GL{,} w/w) and their thermodynamic parameters at cloud point (CP) were studied. Experimentally determined critical micellization concentration (cmc) values (up to 25% w/w with an increment of 5% w/w) by conductivity measurements and results of dye solubilization by a UV-visible spectroscopic technique show that the micellization of AMT drug molecules is affected by an indirect{,} solvent-mediated mechanism with increasing weight% of EG and GL in their binary mixture due to a diminution in the dielectric constant of mixed media. A rise in CP of the AMT solution was observed with an increase in weight% of organic solvent in the mixed media in the absence and presence of the salts. The results demonstrated that CP behavior depends on the interaction of solvent with the drug micelles as well as with the hydrated/solvated radii of these ions. F− and Br− co-ions show a prominent effect in higher weight% of the binary mixtures. ΔsG0 values were found to be positive for all the additives whereas ΔsH0 and TΔsS0 were positive except in presence of KF in 20% EG–WR mixed media. The results are discussed by considering the solvent effect on electrostatic interaction and based on hydrated/solvated sizes of the ions.
ChemistrySelect (ChemPubSoc Europe, Wiley), 2017
Abstract The cloud point (CP) and thermodynamic parameters at cloud point viz., ΔsG0, ΔsH0and TΔs... more Abstract The cloud point (CP) and thermodynamic parameters at cloud point viz., ΔsG0, ΔsH0and TΔsS0 of an amphiphilic drug amitriptyline hydrochloride (AMT) at several compositions of organic solvent-water namely, ethylene glycol (EG) / glycerol (GL) - water (WR) (0\%, 5\%, 10\%, 15\%, 20\%, 25\%, 30\%, 35\% and 40\% w/w) mixed media and the effects of addition of conventional hexadecyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and gemini (14-4-14, 14–5-14 and 14–6-14) surfactants at selected compositions of organic solvent-water media (0\%, 5\%, 10\%, 15\% and 20\%, w/w) have been studied at a pH 6.7. Conductivity measurements were done to determine the critical micelle concentration (cmc) and degree of counterion dissociation (α) of AMT in water and different weight\% of binary mixture ranging from 0\% to 25\% of EG/GL at 30 °C. It is observed that the micellization of AMT molecules is affected through an indirect, solvent-mediated mechanism with the increase in their binary mixture due to lowering of dielectric constant of the mixed media. As a result, inter / intra electrostatic repulsion in the drug-micellar head groups increases raising the cmc values of AMT. The study reveals that the inclusion of EG and GL to the AMT drug solution with/without additives modifies the interactions of the drug molecules due to a decrease in dielectric constant of resultant mixed media.
Papers by Jackson Gurung
Journal of Molecular Liquids, Jan 31, 2024
Inorganic Chemistry Communications, Dec 31, 2023
Journal of Molecular Liquids, May 1, 2022
This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide... more This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide (TTAB), hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB) and sodium dodecylsulphate (SDS) in presence of poorly soluble drug phenothiazine (PTZ) in triton X-100 (TX-100) micellar aqueous media through the investigation of different physicochemical parameters. The interaction of surfactants in PTZ–TX-100 media has been studied using conductometric technique at pH 7.4 (SP buffer) and at three temperatures. The conductometric results reveal the sequence of critical micelle concentration (CMC) values of surfactants as SDS > TTAB > CPC > CPB > CTAB. UV–vis spectroscopy studies were used to learn the interactions of surfactants with the drug PTZ in TX-100 aqueous media (at 303.15 K and pH 7.4) which suggest the interactions are highly feasible (change of Gibbs energy; DGb < 0) and greatly improve beyond the CMC values of corresponding surfactants. The estimated parameters using the Benesi–Hildebrand equation indicate higher binding constant (Kb) for cetylpyridinium surfactants and least for SDS and the drug–surfactant complex formations are found to be in 1:2 stoichiometric ratios. Fluorescence technique has also been employed to study the aggregation number (Nagg), Stern-Volmer constant (KSV) and micro-polarity of TTAB/CTAB/SDS in PTZ–TX-100 systems at 303.15 K. The evaluated thermodynamic parameters such as change in Gibbs energy (DG0m), enthalpy (DH0m) and entropy (DS0m) of micellization show the process of micellization of all studied surfactants in PTZ–TX-100 aqueous media are spontaneous and exothermic.
Chemical Engineering Communications, Sep 11, 2019
Addition of organic solvents is known to change the properties of amphiphiles through modificatio... more Addition of organic solvents is known to change the properties of amphiphiles through modification of bulk phase. Amitriptyline hydrochloride (AMT) is a tricyclic amphiphilic drug which is usually used as an antidepressant. In drug delivery, the cloud point (CP) of the drug is an important parameter. This article discusses the effects of ethanol-water (EtOH-WR) compositions on the energetic parameters, such as changes in Gibbs energy of clouding (D s G 0), enthalpy of clouding (D s H 0), and entropy of clouding (TD s S 0) of AMT-additive systems. Monovalent alkali halide salts, cationic conventional surfactants, and gemini surfactants were used as additives in the EtOH-WR mixed media whose compositions were varied between 0 and 15% (w/w). The D s G 0 values are positive for all the additives and the values decrease with the rise in mole fractions of the additives. The D s H 0 and TD s S 0 were noted to be positive except for KF in 15% EtOH-WR mixed media.
Clean Technologies and Environmental Policy, Mar 15, 2022
The widespread usage of plastic grocery bags, as well as their non-biodegradability, has turned o... more The widespread usage of plastic grocery bags, as well as their non-biodegradability, has turned out to be a stern reason for waste generation. With regard to plastic grocery bag disposal, pyrolysis is an encouraging solution that addresses the energy crisis issue as well. This study examined the interactive influences of pyrolysis temperature, residence time, and nitrogen flow for plastic grocery bag pyrolysis to optimize waste plastic oil yield by the Grey–Fuzzy–Taguchi method. Additionally, mass–energy assessment and characterization were done for the waste plastic oil, extracted at the optimal parametric condition. The optimal parametric combination was: temperature 400 °C, time 360 min, and nitrogen flow rate 20 ml/min. The liquid yield at optimal condition was 78.57%, and a minimal error (2.53%) between the predicted and experimental grey fuzzy grade was observed. The oil achieved at optimal condition showed a high hydrocarbon content with a higher heating value of 46,685 kJ/kg. The values of mass ratio, energy ratio, energy efficiency, and energy consumption ratio for the liquid oil were 0.79, 0.89, 0.63, and 0.47, respectively, which indicate the energy favorability for plastic grocery bag pyrolysis. FT-IR results demonstrated mainly the existence of alkene and alkane functional groups in the waste plastic oil. GC–MS results revealed that the oil contains mainly light and middle fractions of 26.4% and 62.7%, respectively, with a smaller proportion (10.9%) of heavy fraction. Finally, the optimum parametric combination can be considered a useful condition for extracting quality fuel from plastic grocery bags.
Applied Nanoscience, Nov 9, 2020
The development of effective photocatalyst through green and eco-friendly approach has become a g... more The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei, a plant extract with three different concentrations of AgNO 3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet-visible spectroscopy (UV-Vis), Fouriertransform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV-Vis spectroscopy confirmed the reduction of Ag + ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states' binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei; plant extract can be usto modify and develop more efficient nano-photocatalyst for other application.
Journal of Chemical & Engineering Data, Sep 5, 2018
In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and ... more In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30°C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH−WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH−WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. For up to 10 wt % EtOH−WR mixed media, the effect of anionic and cationic co-ions on the CP is found to follow the order Br − > Cl − > F − and NH 4 + > Li + > Na + > K + , respectively. When surfactants were used as additives, the hydrophobicity was found to be responsible for higher CP values and follow the order TTAB < CTAB < 14-m-14, where m is the length of the spacer.
New Journal of Chemistry, 2018
Chemistryselect, 2022
Abstract Gemini surfactants are advantageous over conventional surfactants as they find applicati... more Abstract Gemini surfactants are advantageous over conventional surfactants as they find applications as antimicrobial agents, corrosion inhibitors, enhanced oil recovery, capping agents for nanoparticle synthesis, drug delivery agents, etc. This article provides a detailed overview of synthetic procedures for various types of geminis and the fundamental physicochemical parameters of these systems. This includes a discussion on the cationic geminis based on various groups such as biphenyl, amide (with/without alkane tail), binol, quaternary ammonium (with/without hydroxyl group as a spacer), morpholinium, pyridinium, amide (with/without alkane tail), ester quaternary ammonium, and imidazolium (spacer with/without hydroxyl group and thioether/ester) types. Further, it is focused on anionic geminis with carboxylate, borate, and sulfonate head groups. Zwitterionic geminis such as betaine surfactants, cocogem surfactants based on dodecylisopropylol amine and dicarboxylic acid, diester type, sulphobetaine gemini based on S-triazine, zwitterionic hetero gemini containing ammonium and carboxylate head groups, zwitterionic gemini containing quaternary ammonium and a sulfate group, gemini containing phosphodiester anion and quaternary ammonium salt are also reviewed. Lastly, synthesis of nonionic geminis from sunflower oil, amide-based nonionic, sulfonamide nonionic, N,N’-diethylaminedialkyldiamide nonionic gemini, sugar-based gemini, and nonionic gemini with sulfonate spacer have been discussed.
Journal of Molecular Liquids, 2022
Conductometric and spectroscopic methods were used to examine the interactions among the cationic... more Conductometric and spectroscopic methods were used to examine the interactions among the cationic surfactants, tetradecyltrimethylammonium bromide (TTAB) and cetylpyridinium chloride (CPC), and the anionic azo dye metanil yellow (MY) in an aqueous solution. The standard Gibb’s energy (ΔGm0), enthalpy (ΔHm0), and entropy (ΔSm0) of micellization were determined with the help of the equilibrium model. With temperature rise, the critical micelle concentration (cmc) increases because of the interruption of the organized water (WR) molecules enclosing the surfactant’s hydrophobic groups. As the total carbon atoms of the hydrophobic group are more in CPC than TTAB, a considerable fall in cmc value was observed. The presence of MY caused a higher degree of ionization (α) of micelles of TTAB and CPC. The negative values of ΔGm0 and ΔHm0 for both the surfactants in WR and aqueous MY solution (WR-MY) show that the micellization process is spontaneous and exothermic. As indicated by the -TΔSm0 values, which were found to be greater than ΔHm0 values, the entropy gain is typically what regulates the micellization process and the micellization was found to have a negative heat capacity (ΔCp,m0). UV–Visible spectra show that CPC has a higher binding constant (Kb) value as compared to TTAB implying that CPC has a comparatively greater binding affinity with MY dye in aqueous media (WR). The decreasing value of ΔGb for CPC indicates that the chance for the MY–CPC complex formation is more than that of the MY–TTAB complex. As shown by the rise in absorbance values as surfactant concentrations increase, a large number of the MY molecules are attracted to TTAB and CPC micelles.
Journal of Molecular Liquids, 2022
This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide... more This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide (TTAB), hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB) and sodium dodecylsulphate (SDS) in presence of poorly soluble drug phenothiazine (PTZ) in triton X-100 (TX-100) micellar aqueous media through the investigation of different physicochemical parameters. The interaction of surfactants in PTZ–TX-100 media has been studied using conductometric technique at pH 7.4 (SP buffer) and at three temperatures. The conductometric results reveal the sequence of critical micelle concentration (CMC) values of surfactants as SDS > TTAB > CPC > CPB > CTAB. UV–vis spectroscopy studies were used to learn the interactions of surfactants with the drug PTZ in TX-100 aqueous media (at 303.15 K and pH 7.4) which suggest the interactions are highly feasible (change of Gibbs energy; DGb < 0) and greatly improve beyond the CMC values of corresponding surfactants. The estimated parameters using the Benesi–Hildebrand equation indicate higher binding constant (Kb) for cetylpyridinium surfactants and least for SDS and the drug–surfactant complex formations are found to be in 1:2 stoichiometric ratios. Fluorescence technique has also been employed to study the aggregation number (Nagg), Stern-Volmer constant (KSV) and micro-polarity of TTAB/CTAB/SDS in PTZ–TX-100 systems at 303.15 K. The evaluated thermodynamic parameters such as change in Gibbs energy (DG0m), enthalpy (DH0m) and entropy (DS0m) of micellization show the process of micellization of all studied surfactants in PTZ–TX-100 aqueous media are spontaneous and exothermic.
Journal of Chemical & Engineering Data, 2020
Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several i... more Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several industrial and pharmaceutical applications. This article emphasizes the role of 2-propanol (PrOH) as a cosolvent in the micellization of cetylpyridinium chloride (CPCl) and cetylpyridinium bromide (CPBr) surfactants at different temperatures (293.15−308.15 K) studied through the conductometric technique. The results show an enhancement in CMC values for both the surfactants with an increase in volume percentage (vol %) of PrOH (from 0 up to 20 vol %) as well as temperature. The CPBr shows distinct behavior in the lower composition of PrOH−WR (0 and 2.5%) at a higher temperature (308.15 K). The rise in the CMC values depends on lowering of permittivity of the mixed media caused by change in compositions of PrOH−WR mixed media. A similar effect is also seen on the degree of counterion dissociation (α) values with an exception to a few compositions. The increase in α values is found to be relatively less for CPBr as compared to CPCl. Temperature dependency of CMC values has been used to calculate thermodynamic parameters such as the change in Gibbs energy (ΔGm 0 ), enthalpy (ΔHm 0 ), and entropy (ΔSm 0 ) of micellization, and their values were used to analyze the effect of various compositions of PrOH−WR mixed media. The ΔGm 0 values indicate that micellization is spontaneous and becomes less favorable with the inclusion of PrOH. The values of ΔHm 0 (<0) and ΔSm 0 (>0) affirm that the process of micellization is entropically driven within the scope of the studied temperature. Overall results have been analyzed based on the interactions between the solute and solvent, counterions and aggregates, and solvation/desolvation of counterions.
Applied Nanoscience, 2020
The development of effective photocatalyst through green and eco-friendly approach has become a g... more The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei, a plant extract with three different concentrations of AgNO3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV–Vis spectroscopy confirmed the reduction of Ag+ ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states’ binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei; plant extract can be used to modify and develop more efficient nano-photocatalyst for other application.
Journal of Molecular Liquids (Elsevier), 2020
The physicochemical properties of drugs and drug–additive interactions have great importance to e... more The physicochemical properties of drugs and drug–additive interactions have great importance to elucidate the pharmacological effect of the drug formulations. Plentiful pharmacologically active molecules are amphiphilic in nature. Knowledge about self-assembly, aggregate morphology as well as size and interfacial/micellar properties of such drugs in presence of pharmaceutical excipients (surfactants, electrolytes, polymers, hydrotropes, etc.) is vital from the fundamental and practical point of view. This article reviews the micellar properties and phase separation of drugs as well as drug–additive systems in aqueous and organic solvent–water mixed media. Results of several pharmaceutical excipients/surfactants assisted drug mixed systems have been analyzed through thermodynamic parameters which provide a comprehensive account on the physicochemical aspects of drug/drug–additives systems. Along with amphiphilic drugs, studies of a few non surface-active drugs have also been reviewed.
Engineering Reports (Wiley), 2019
Schedule maintenance programs rely on the analysis of collected data during running and shut down... more Schedule maintenance programs rely on the analysis of collected data during running and shut down time. In a preventive maintenance program, it is difficult to a priori determine the time limit or set an alarm indicating the failure time of a specific component. To this end, a Visual Basic 6.0–based software program is here proposed for a comprehensive running and maintenance database management. The developed software is capable of storing all relevant data related to parts, equipment, personnel, spares, failures, costs, etc, and displays a warning message when the expected life of a particular component has been reached. An unscheduled outage heavily impacts on the production cycle costs, depending on the nature of the failure and the damaged part. Since the variation of the used parts and equipment is high, it is not possible to have an all-encompassing maintenance guide, which is applicable to all equipment. A successful program of preventive and routine maintenance may hence decrease equipment failures rates, extend equipment life, and drastically reduce the overall operating costs. Therefore, the present work can help in preventing unscheduled breakdown of operating systems due to a failure in a component.
Chemical Engineering Communications (Taylor & Francis), 2019
Addition of organic solvents is known to change the properties of amphiphiles through modificatio... more Addition of organic solvents is known to change the properties of amphiphiles through modification of bulk phase. Amitriptyline hydrochloride (AMT) is a tricyclic amphiphilic drug which is usually used as an antidepressant. In drug delivery, the cloud point (CP) of the drug is an important parameter. This article discusses the effects of ethanol–water (EtOH–WR) compositions on the energetic parameters, such as changes in Gibbs energy of clouding (ΔsG0), enthalpy of clouding (ΔsH0), and entropy of clouding (TΔsS0) of AMT-additive systems. Monovalent alkali halide salts, cationic conventional surfactants, and gemini surfactants were used as additives in the EtOH–WR mixed media whose compositions were varied between 0 and 15% (w/w). The ΔsG0 values are positive for all the additives and the values decrease with the rise in mole fractions of the additives. The ΔsH0 and TΔsS0 were noted to be positive except for KF in 15% EtOH–WR mixed media.
Journal of Chemical & Engineering Data (ACS), 2019
Journal of Chemical & Engineering Data (ACS), 2018
In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and ... more In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30 °C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH–WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH–WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. For up to 10 wt % EtOH–WR mixed media, the effect of anionic and cationic co-ions on the CP is found to follow the order Br– > Cl– > F– and NH4+ > Li+ > Na+ > K+, respectively. When surfactants were used as additives, the hydrophobicity was found to be responsible for higher CP values and follow the order TTAB < CTAB < 14-m-14, where m is the length of the spacer.
New Journal of Chemistry (RSC), 2018
The influence of ethylene glycol (EG)/glycerol(GL)–water mixed media on clouding action of an amp... more The influence of ethylene glycol (EG)/glycerol(GL)–water mixed media on clouding action of an amphiphilic drug{,} amitriptyline hydrochloride (AMT) at pH 6.7 with inorganic salts (KF{,} KCl{,} KBr{,} LiCl{,} NaCl{,} and NH4Cl) in selected compositions of EG–WR and GL–WR mixed media (0%{,} 5%{,} 10%{,} 15%{,} and 20% of EG/GL{,} w/w) and their thermodynamic parameters at cloud point (CP) were studied. Experimentally determined critical micellization concentration (cmc) values (up to 25% w/w with an increment of 5% w/w) by conductivity measurements and results of dye solubilization by a UV-visible spectroscopic technique show that the micellization of AMT drug molecules is affected by an indirect{,} solvent-mediated mechanism with increasing weight% of EG and GL in their binary mixture due to a diminution in the dielectric constant of mixed media. A rise in CP of the AMT solution was observed with an increase in weight% of organic solvent in the mixed media in the absence and presence of the salts. The results demonstrated that CP behavior depends on the interaction of solvent with the drug micelles as well as with the hydrated/solvated radii of these ions. F− and Br− co-ions show a prominent effect in higher weight% of the binary mixtures. ΔsG0 values were found to be positive for all the additives whereas ΔsH0 and TΔsS0 were positive except in presence of KF in 20% EG–WR mixed media. The results are discussed by considering the solvent effect on electrostatic interaction and based on hydrated/solvated sizes of the ions.
ChemistrySelect (ChemPubSoc Europe, Wiley), 2017
Abstract The cloud point (CP) and thermodynamic parameters at cloud point viz., ΔsG0, ΔsH0and TΔs... more Abstract The cloud point (CP) and thermodynamic parameters at cloud point viz., ΔsG0, ΔsH0and TΔsS0 of an amphiphilic drug amitriptyline hydrochloride (AMT) at several compositions of organic solvent-water namely, ethylene glycol (EG) / glycerol (GL) - water (WR) (0\%, 5\%, 10\%, 15\%, 20\%, 25\%, 30\%, 35\% and 40\% w/w) mixed media and the effects of addition of conventional hexadecyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and gemini (14-4-14, 14–5-14 and 14–6-14) surfactants at selected compositions of organic solvent-water media (0\%, 5\%, 10\%, 15\% and 20\%, w/w) have been studied at a pH 6.7. Conductivity measurements were done to determine the critical micelle concentration (cmc) and degree of counterion dissociation (α) of AMT in water and different weight\% of binary mixture ranging from 0\% to 25\% of EG/GL at 30 °C. It is observed that the micellization of AMT molecules is affected through an indirect, solvent-mediated mechanism with the increase in their binary mixture due to lowering of dielectric constant of the mixed media. As a result, inter / intra electrostatic repulsion in the drug-micellar head groups increases raising the cmc values of AMT. The study reveals that the inclusion of EG and GL to the AMT drug solution with/without additives modifies the interactions of the drug molecules due to a decrease in dielectric constant of resultant mixed media.
Journal of Molecular Liquids, Jan 31, 2024
Inorganic Chemistry Communications, Dec 31, 2023
Journal of Molecular Liquids, May 1, 2022
This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide... more This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide (TTAB), hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB) and sodium dodecylsulphate (SDS) in presence of poorly soluble drug phenothiazine (PTZ) in triton X-100 (TX-100) micellar aqueous media through the investigation of different physicochemical parameters. The interaction of surfactants in PTZ–TX-100 media has been studied using conductometric technique at pH 7.4 (SP buffer) and at three temperatures. The conductometric results reveal the sequence of critical micelle concentration (CMC) values of surfactants as SDS > TTAB > CPC > CPB > CTAB. UV–vis spectroscopy studies were used to learn the interactions of surfactants with the drug PTZ in TX-100 aqueous media (at 303.15 K and pH 7.4) which suggest the interactions are highly feasible (change of Gibbs energy; DGb < 0) and greatly improve beyond the CMC values of corresponding surfactants. The estimated parameters using the Benesi–Hildebrand equation indicate higher binding constant (Kb) for cetylpyridinium surfactants and least for SDS and the drug–surfactant complex formations are found to be in 1:2 stoichiometric ratios. Fluorescence technique has also been employed to study the aggregation number (Nagg), Stern-Volmer constant (KSV) and micro-polarity of TTAB/CTAB/SDS in PTZ–TX-100 systems at 303.15 K. The evaluated thermodynamic parameters such as change in Gibbs energy (DG0m), enthalpy (DH0m) and entropy (DS0m) of micellization show the process of micellization of all studied surfactants in PTZ–TX-100 aqueous media are spontaneous and exothermic.
Chemical Engineering Communications, Sep 11, 2019
Addition of organic solvents is known to change the properties of amphiphiles through modificatio... more Addition of organic solvents is known to change the properties of amphiphiles through modification of bulk phase. Amitriptyline hydrochloride (AMT) is a tricyclic amphiphilic drug which is usually used as an antidepressant. In drug delivery, the cloud point (CP) of the drug is an important parameter. This article discusses the effects of ethanol-water (EtOH-WR) compositions on the energetic parameters, such as changes in Gibbs energy of clouding (D s G 0), enthalpy of clouding (D s H 0), and entropy of clouding (TD s S 0) of AMT-additive systems. Monovalent alkali halide salts, cationic conventional surfactants, and gemini surfactants were used as additives in the EtOH-WR mixed media whose compositions were varied between 0 and 15% (w/w). The D s G 0 values are positive for all the additives and the values decrease with the rise in mole fractions of the additives. The D s H 0 and TD s S 0 were noted to be positive except for KF in 15% EtOH-WR mixed media.
Clean Technologies and Environmental Policy, Mar 15, 2022
The widespread usage of plastic grocery bags, as well as their non-biodegradability, has turned o... more The widespread usage of plastic grocery bags, as well as their non-biodegradability, has turned out to be a stern reason for waste generation. With regard to plastic grocery bag disposal, pyrolysis is an encouraging solution that addresses the energy crisis issue as well. This study examined the interactive influences of pyrolysis temperature, residence time, and nitrogen flow for plastic grocery bag pyrolysis to optimize waste plastic oil yield by the Grey–Fuzzy–Taguchi method. Additionally, mass–energy assessment and characterization were done for the waste plastic oil, extracted at the optimal parametric condition. The optimal parametric combination was: temperature 400 °C, time 360 min, and nitrogen flow rate 20 ml/min. The liquid yield at optimal condition was 78.57%, and a minimal error (2.53%) between the predicted and experimental grey fuzzy grade was observed. The oil achieved at optimal condition showed a high hydrocarbon content with a higher heating value of 46,685 kJ/kg. The values of mass ratio, energy ratio, energy efficiency, and energy consumption ratio for the liquid oil were 0.79, 0.89, 0.63, and 0.47, respectively, which indicate the energy favorability for plastic grocery bag pyrolysis. FT-IR results demonstrated mainly the existence of alkene and alkane functional groups in the waste plastic oil. GC–MS results revealed that the oil contains mainly light and middle fractions of 26.4% and 62.7%, respectively, with a smaller proportion (10.9%) of heavy fraction. Finally, the optimum parametric combination can be considered a useful condition for extracting quality fuel from plastic grocery bags.
Applied Nanoscience, Nov 9, 2020
The development of effective photocatalyst through green and eco-friendly approach has become a g... more The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei, a plant extract with three different concentrations of AgNO 3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet-visible spectroscopy (UV-Vis), Fouriertransform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV-Vis spectroscopy confirmed the reduction of Ag + ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states' binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei; plant extract can be usto modify and develop more efficient nano-photocatalyst for other application.
Journal of Chemical & Engineering Data, Sep 5, 2018
In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and ... more In this work, the effect of ethanol (EtOH) at different weight percentages (wt %) (0, 5, 10, and 15% w/w) is accounted for in the clouding phenomena of the AMT drug with/without additives (inorganic salts and conventional and gemini surfactants). The critical micelle concentration (cmc) and degree of counterions dissociation (α) of AMT solution at 30°C in SP buffer (pH 6.7), studied through conductometric studies, are found to be enhanced with the increase in ethanol content due to the reduction in the dielectric constant of mixed media. A dye solubilization study performed under identical physicochemical conditions exhibited supporting results. Clouding could not be observed in 20 wt % EtOH−WR mixed media at pH 6.7. The effects of additives on the CP in 15 wt % EtOH−WR at a pH of 6.95 were also studied. Furthermore, the effect of pH (range 6.7 to 7.15) on the CP in the presence of KCl at the same composition of the mixed media reduce the clouding temperature due to the deprotonation of AMT headgroups. For up to 10 wt % EtOH−WR mixed media, the effect of anionic and cationic co-ions on the CP is found to follow the order Br − > Cl − > F − and NH 4 + > Li + > Na + > K + , respectively. When surfactants were used as additives, the hydrophobicity was found to be responsible for higher CP values and follow the order TTAB < CTAB < 14-m-14, where m is the length of the spacer.
New Journal of Chemistry, 2018
Engineering reports, Oct 1, 2019
Schedule maintenance programs rely on the analysis of collected data during running and shut down... more Schedule maintenance programs rely on the analysis of collected data during running and shut down time. In a preventive maintenance program, it is difficult to a priori determine the time limit or set an alarm indicating the failure time of a specific component. To this end, a Visual Basic 6.0-based software program is here proposed for a comprehensive running and maintenance database management. The developed software is capable of storing all relevant data related to parts, equipment, personnel, spares, failures, costs, etc, and displays a warning message when the expected life of a particular component has been reached. An unscheduled outage heavily impacts on the production cycle costs, depending on the nature of the failure and the damaged part. Since the variation of the used parts and equipment is high, it is not possible to have an all-encompassing maintenance guide, which is applicable to all equipment. A successful program of preventive and routine maintenance may hence decrease equipment failures rates, extend equipment life, and drastically reduce the overall operating costs. Therefore, the present work can help in preventing unscheduled breakdown of operating systems due to a failure in a component. KEYWORDS coal-handling plant, preventive maintenance, reduced breakdown time, scheduling program, Visual Basic This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Journal of Molecular Liquids, Nov 1, 2020
Abstract The physicochemical properties of drugs and drug–additive interactions have great import... more Abstract The physicochemical properties of drugs and drug–additive interactions have great importance to elucidate the pharmacological effect of the drug formulations. Plentiful pharmacologically active molecules are amphiphilic in nature. Knowledge about self-assembly, aggregate morphology as well as size and interfacial/micellar properties of such drugs in presence of pharmaceutical excipients (surfactants, electrolytes, polymers, hydrotropes, etc.) is vital from the fundamental and practical point of view. This article reviews the micellar properties and phase separation of drugs as well as drug–additive systems in aqueous and organic solvent–water mixed media. Results of several pharmaceutical excipients/surfactants assisted drug mixed systems have been analyzed through thermodynamic parameters which provide a comprehensive account on the physicochemical aspects of drug/drug–additives systems. Along with amphiphilic drugs, studies of a few non surface-active drugs have also been reviewed.
ChemistrySelect, Sep 29, 2017
The cloud point (CP) and thermodynamic parameters at cloud point viz., D s G 0 , D s H 0 and TD s... more The cloud point (CP) and thermodynamic parameters at cloud point viz., D s G 0 , D s H 0 and TD s S 0 of an amphiphilic drug amitriptyline hydrochloride (AMT) at several compositions of organic solvent-water namely, ethylene glycol (EG) / glycerol (GL)water (WR) (0%, 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% w/w) mixed media and the effects of addition of conventional hexadecyltrimethylammonium bromide (CTAB), tetradecyltrimethylammonium bromide (TTAB) and gemini (14-4-14, 14-5-14 and 14-6-14) surfactants at selected compositions of organic solvent-water media (0%, 5%, 10%, 15% and 20%, w/w) have been studied at a pH 6.7. Conductivity measurements were done to determine the critical micelle concentration (cmc) and degree of counterion dissociation (a) of AMT in water and different weight% of binary mixture ranging from 0% to 25% of EG/GL at 30 8C. It is observed that the micellization of AMT molecules is affected through an indirect, solvent-mediated mechanism with the increase in their binary mixture due to lowering of dielectric constant of the mixed media. As a result, inter / intra electrostatic repulsion in the drug-micellar head groups increases raising the cmc values of AMT. The study reveals that the inclusion of EG and GL to the AMT drug solution with/without additives modifies the interactions of the drug molecules due to a decrease in dielectric constant of resultant mixed media.
Journal of Chemical & Engineering Data, Sep 9, 2019
Organic solvent−water mixed media find applications in industrial, chemical, and pharmaceutical a... more Organic solvent−water mixed media find applications in industrial, chemical, and pharmaceutical areas. This work discusses the micellization and related parameters such as degree of counterion dissociation (α), change in Gibbs energy of micellization (ΔG m 0) of an amphiphilic drug amitriptyline hydrochloride (AMT), and Gordon parameter (G p) in three polar organic solvents, viz., ethanol (EtOH), ethylene glycol (EG), and glycerol (GL)−water mixed media, with a special focus on the effects of a wide range of polarity changes. A decrease in conductivity of the solution and an enhancement of critical micelle concentration (cmc) of AMT are found with the increase in weight percentage (wt %) of the organic solvents in their mixed media at a pH of 6.7 and a temperature of 303.15 K. The cmc and absorbance values evaluated from conductivity and dye solubilization measurements, respectively, reveal that the GL−water mixed media behave as a better system for AMT compared to the EG−water and EtOH−water mixed media. The calculated values for ΔG m 0 in all the compositions of the mixed media were negative, which increase with the increase in wt % of the studied organic solvents.
Journal of Molecular Liquids
ChemistrySelect
Abstract Gemini surfactants are advantageous over conventional surfactants as they find applicati... more Abstract Gemini surfactants are advantageous over conventional surfactants as they find applications as antimicrobial agents, corrosion inhibitors, enhanced oil recovery, capping agents for nanoparticle synthesis, drug delivery agents, etc. This article provides a detailed overview of synthetic procedures for various types of geminis and the fundamental physicochemical parameters of these systems. This includes a discussion on the cationic geminis based on various groups such as biphenyl, amide (with/without alkane tail), binol, quaternary ammonium (with/without hydroxyl group as a spacer), morpholinium, pyridinium, amide (with/without alkane tail), ester quaternary ammonium, and imidazolium (spacer with/without hydroxyl group and thioether/ester) types. Further, it is focused on anionic geminis with carboxylate, borate, and sulfonate head groups. Zwitterionic geminis such as betaine surfactants, cocogem surfactants based on dodecylisopropylol amine and dicarboxylic acid, diester type, sulphobetaine gemini based on S-triazine, zwitterionic hetero gemini containing ammonium and carboxylate head groups, zwitterionic gemini containing quaternary ammonium and a sulfate group, gemini containing phosphodiester anion and quaternary ammonium salt are also reviewed. Lastly, synthesis of nonionic geminis from sunflower oil, amide-based nonionic, sulfonamide nonionic, N,N’-diethylaminedialkyldiamide nonionic gemini, sugar-based gemini, and nonionic gemini with sulfonate spacer have been discussed.
Journal of Molecular Liquids
Clean Technologies and Environmental Policy, 2022
Journal of Molecular Liquids, 2022
This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide... more This article discusses the interaction of surfactants such as tetradecyltrimethylammonium bromide (TTAB), hexadecyltrimethylammonium bromide (CTAB), cetylpyridinium chloride (CPC), cetylpyridinium bromide (CPB) and sodium dodecylsulphate (SDS) in presence of poorly soluble drug phenothiazine (PTZ) in triton X-100 (TX-100) micellar aqueous media through the investigation of different physicochemical parameters. The interaction of surfactants in PTZ–TX-100 media has been studied using conductometric technique at pH 7.4 (SP buffer) and at three temperatures. The conductometric results reveal the sequence of critical micelle concentration (CMC) values of surfactants as SDS > TTAB > CPC > CPB > CTAB. UV–vis spectroscopy studies were used to learn the interactions of surfactants with the drug PTZ in TX-100 aqueous media (at 303.15 K and pH 7.4) which suggest the interactions are highly feasible (change of Gibbs energy; DGb < 0) and greatly improve beyond the CMC values of corresponding surfactants. The estimated parameters using the Benesi–Hildebrand equation indicate higher binding constant (Kb) for cetylpyridinium surfactants and least for SDS and the drug–surfactant complex formations are found to be in 1:2 stoichiometric ratios. Fluorescence technique has also been employed to study the aggregation number (Nagg), Stern-Volmer constant (KSV) and micro-polarity of TTAB/CTAB/SDS in PTZ–TX-100 systems at 303.15 K. The evaluated thermodynamic parameters such as change in Gibbs energy (DG0m), enthalpy (DH0m) and entropy (DS0m) of micellization show the process of micellization of all studied surfactants in PTZ–TX-100 aqueous media are spontaneous and exothermic.
Applied Nanoscience, 2020
Abstract The development of effective photocatalyst through green and eco-friendly approach has b... more Abstract The development of effective photocatalyst through green and eco-friendly approach has become a great concern for the light-induced degradation of organic pollutant dyes. This article reports a simple, cost-effective, and a benign environmental biosynthesis of Ag nanoparticles (NPs) using Cyperus pangorei , a plant extract with three different concentrations of AgNO 3 in aqueous media. The synthesized silver nanoparticles were performed ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) peak at 437 nm in UV–Vis spectroscopy confirmed the reduction of Ag + ions into Ag nanoparticles. FTIR spectra revealed that plant extract could reduce/stabilize/capping to form Ag nanoparticles, and strong PL emission spectra tend to exhibit higher photocatalytic activity. The structural information is derived from XRD and TEM, which can exhibit the FCC structure and polydisperse with the spherical shape. EDX addresses the presence of Ag constitute. XPS confirmed the Ag nanoparticles in characteristic silver peaks, plant extract derivatives, and their oxidative states’ binding energy. The photocatalytic activity of Ag nanoparticles against dye Rhodamine B (Rh-B) under ultraviolet irradiation with periodic interval and pseudo-first-order kinetics were also studied. The obtained results show that the synthesized Ag nanoparticles can degrade dye (Rh-B) up to 86% within 2 h of irradiation time. Furthermore, the present study suggests that the biosynthesized Ag nanoparticles could be potential photocatalysts against various industrial dyes as well as C. pangorei ; plant extract can be usto modify and develop more efficient nano-photocatalyst for other application.
Journal of Chemical & Engineering Data, 2020
Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several i... more Self-assembly of surfactant systems in organic solvent−water mixed media is relevant in several industrial and pharmaceutical applications. This article emphasizes the role of 2-propanol (PrOH) as a cosolvent in the micellization of cetylpyridinium chloride (CPCl) and cetylpyridinium bromide (CPBr) surfactants at different temperatures (293.15−308.15 K) studied through the conductometric technique. The results show an enhancement in CMC values for both the surfactants with an increase in volume percentage (vol %) of PrOH (from 0 up to 20 vol %) as well as temperature. The CPBr shows distinct behavior in the lower composition of PrOH−WR (0 and 2.5%) at a higher temperature (308.15 K). The rise in the CMC values depends on lowering of permittivity of the mixed media caused by change in compositions of PrOH−WR mixed media. A similar effect is also seen on the degree of counterion dissociation (α) values with an exception to a few compositions. The increase in α values is found to be relatively less for CPBr as compared to CPCl. Temperature dependency of CMC values has been used to calculate thermodynamic parameters such as the change in Gibbs energy (ΔGm 0 ), enthalpy (ΔHm 0 ), and entropy (ΔSm 0 ) of micellization, and their values were used to analyze the effect of various compositions of PrOH−WR mixed media. The ΔGm 0 values indicate that micellization is spontaneous and becomes less favorable with the inclusion of PrOH. The values of ΔHm 0 (<0) and ΔSm 0 (>0) affirm that the process of micellization is entropically driven within the scope of the studied temperature. Overall results have been analyzed based on the interactions between the solute and solvent, counterions and aggregates, and solvation/desolvation of counterions.
Journal of Molecular Liquids, 2020
Abstract The physicochemical properties of drugs and drug–additive interactions have great import... more Abstract The physicochemical properties of drugs and drug–additive interactions have great importance to elucidate the pharmacological effect of the drug formulations. Plentiful pharmacologically active molecules are amphiphilic in nature. Knowledge about self-assembly, aggregate morphology as well as size and interfacial/micellar properties of such drugs in presence of pharmaceutical excipients (surfactants, electrolytes, polymers, hydrotropes, etc.) is vital from the fundamental and practical point of view. This article reviews the micellar properties and phase separation of drugs as well as drug–additive systems in aqueous and organic solvent–water mixed media. Results of several pharmaceutical excipients/surfactants assisted drug mixed systems have been analyzed through thermodynamic parameters which provide a comprehensive account on the physicochemical aspects of drug/drug–additives systems. Along with amphiphilic drugs, studies of a few non surface-active drugs have also been reviewed.