sabir khan | Universidade Estadual de Campinas (original) (raw)
Papers by sabir khan
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Water Science and Technology, 2017
A chitosan magnetic membrane was prepared in order to confer magnetic properties to the membrane,... more A chitosan magnetic membrane was prepared in order to confer magnetic properties to the membrane, which could be used for the removal of cations from aqueous solution. The crosslinked magnetic membrane was compared with pristine chitosan membrane in term of stability, morphology and cation adsorption capacity. The fabricated magnetic materials are thermally stable as shown by thermogravimetric curves. The membrane containing nickel magnetic particles (CHNiF-G) shows high thermal stability compared to the other membranes. The Fourier transform infrared spectroscopy showed successful preparation of chitosan magnetic membrane. Scanning electron microscopy micrographs showed the rough surface of the membrane with increased porosity. The prepared chitosan membranes were applied to cations of copper, nickel and lead in dilute aqueous solution. The chitosan membrane showed the following adsorption order for metallic cations: Cu(2+) > Ni(2+) > Pb(2+), while CHNiF-G showed higher capacity, 3.51 mmol g(-1) for copper, reflecting the improvement in adsorption capacity, since the amount of copper on pristine chitosan gave 1.40 mmol g(-1). The time required for adsorption to reach to the equilibrium was 6 h for the selected cations using different chitosan membranes. The kinetic study showed that adsorption followed pseudo-second order kinetics. The most commonly used isotherm models, Freundlich, Langmuir and Temkin, were applied to experimental data using linear regression technique. However, The Temkin model fits better to experimental data.
Journal of Nuclear Medicine, Apr 30, 1994
There is limited information regarding the incidence of post-I-131 therapeutic side effects in pt... more There is limited information regarding the incidence of post-I-131 therapeutic side effects in pts. undergoing high-dose I-131 therapy for DTC. The purpose of the current study is to characterize side effects experienced by patients following 150 mCi.
Journal of the Pakistan Medical Association, Feb 1, 2011
To assess the in vivo efficacy and adverse effects of Artemether-lumefantrine combination in acut... more To assess the in vivo efficacy and adverse effects of Artemether-lumefantrine combination in acute uncomplicated falciparum malaria. A prospective, observational study was conducted at Department of Medicine and Pathology, Pakistan Medical level II hospital, Tubmanburg and Harper from March 2009 to September 2009. One hundred subjects with positive Plasmodium falciparum rings on malaria slide fulfilled the selection criteria and were included in the study. Mean, minimum and maximum values along with standard deviation of age, malarial parasite index, fever clearance time and parasite clearance time were calculated. A 28 day parasitological cure rate was determined. Frequency of various adverse events observed during this study were also noted. Of 100 subjects, 70 wereAfricans while remaining were Asians. Mean fever clearance time in Africans and Asians were 18.9 +/- 11.5 and 27.9 +/- 14.3 hours respectively. The mean parasite clearance time was almost similar in both races ranging from 28 to 31 hours. A 28 day parasitological cure rate was found to be 100%. About 10% of the subjects developed mild to moderate side effects including headache, vomiting, loss of sleep, vertigo and diarrhoea. There was no mortality during the study. Artemether Lumefantrine combination therapy may be used safely and effectively in the management of acute uncomplicated falciparum malaria.
Food Chemistry, 2016
This work presents an efficient method for the preparation of magnetic nanoparticles modified wit... more This work presents an efficient method for the preparation of magnetic nanoparticles modified with molecularly imprinted polymers (Mag-MIP) through core-shell method for the determination of biotin in milk food samples. The functional monomer acrylic acid was selected from molecular modeling, EGDMA was used as cross-linking monomer and AIBN as radical initiator. The Mag-MIP and Mag-NIP were characterized by FTIR, magnetic hysteresis, XRD, SEM and N2-sorption measurements. The capacity of Mag-MIP for biotin adsorption, its kinetics and selectivity were studied in detail. The adsorption data was well described by Freundlich isotherm model with adsorption equilibrium constant (KF) of 1.46 mL g(-1). The selectivity experiments revealed that prepared Mag-MIP had higher selectivity toward biotin compared to other molecules with different chemical structure. The material was successfully applied for the determination of biotin in diverse milk samples using HPLC for quantification of the analyte, obtaining the mean value of 87.4% recovery.
International Journal of Vegetable Science, 2010
Page 1. International Journal of Vegetable Science, 16:278286, 2010 Copyright © Taylor &... more Page 1. International Journal of Vegetable Science, 16:278286, 2010 Copyright © Taylor & Francis Group, LLC ISSN: 1931-5260 print / 1931-5279 online DOI: 10.1080/19315261003707492 WIJV1931-5260 1931-5279 International Journal of Vegetable Science, Vol. 16, No. ...
Ethnomusicology, 2001
... K. Shridar, sarod, with NV Murthy, tabla ... Reflecting the prodigious rig repertoire of his ... more ... K. Shridar, sarod, with NV Murthy, tabla ... Reflecting the prodigious rig repertoire of his guru, Das Gupta here pre-sents an expansive treatment of the seldom-heard rig ... predominance of this and other as-pects of Vilayat Khan's style-in contrast, for example, to that of Ravi Shan-kar ...
Clinical Nuclear Medicine, 1992
British Journal of Dermatology, 2010
Desalination and Water Treatment, Jan 12, 2015
ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution u... more ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution using brick kiln chimney waste as adsorbent, Desalination and Water Treatment, makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Heavy metals are toxic to aquatic flora and fauna even in relatively low concentrations. Chromium is a commonly occurring toxic metal in ecosystems. This study aims the adsorption of Cr(VI) on a novel low-cost carbonaceous material under different experimental conditions such as contact time, initial concentration of metal ions, pH, and temperature. The adsorbent was characterized by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The equilibrium data were fitted well with Langmuir and Freundlich isotherms. Adsorption kinetics of Cr(VI) ions onto chimney waste adsorbent were analyzed by pseudo-first-order and pseudo-second-order models. The adsorption process is favored by acidic pH and followed the second-order kinetics. Various thermodynamic parameters like activation energy (E a), Gibbs free energy change (DG o), enthalpy change (DH o), and entropy change (DS o) were calculated. The results showed that the carbonaceous material obtains from bricks kiln chimneys can be efficiently used for Cr(VI) removal from wastewater.
Desalination and Water Treatment, 2015
ABSTRACT The adsorption of Acid Blue 129 (AB129) from aqueous solution onto hydrochloric acid-act... more ABSTRACT The adsorption of Acid Blue 129 (AB129) from aqueous solution onto hydrochloric acid-activated montmorillonite clay (HCl-bentonite) was investigated. The activated clay was characterized by scanning electron microscopy, energy dispersive spectroscopy, and Brunauer-Emmett-Teller surface area. Batch adsorption experiments were performed to investigate the effects of pH, contact time, initial dye concentration, and temperature (10, 20, 30, and 40°C). Acidic conditions was suitable for higher adsorption of AB129, and kinetic studies demonstrate that the process followed a pseudo-second-order model. An activation energy of 23.858 kJ mol−1 was obtained for adsorption process. Adsorption data were fitted to Freundlich and Langmuir isotherms and various adsorption parameters have been calculated. Standard enthalpy (ΔH°) and standard entropy (ΔS°) were −44.90 kJ mol−1 and −68.44 kJ mol−1 K−1, respectively, showing that overall adsorption process was exothermic and is spontaneous in nature with a decrease in the disorder of the system at the dye/adsorbate interface. However, the mechanism of the dye-Bentonite interaction is likely to be very complicated, involving a wide range of sites having different energy considerations. The activated clay was effective toward adsorption of AB129. The results show that activated bentonite clay could be employed as low-cost materials for the removal of acid dyes from colored effluents.
Biosensors and Bioelectronics, 2006
... concentration that yields a signal-to-noise (S/N) ratio of 3, the LOD of the sensor with opti... more ... concentration that yields a signal-to-noise (S/N) ratio of 3, the LOD of the sensor with optimal immobilization is 0.234 ppb, which is lower than the LOD of 0.3 and 0.4 ppb by an amperometric biosensor (Jeanty and Marty, 1998) and an optical fiber biosensor (Xavier et al., 2000 ...
Arabian Journal of Geosciences, 2014
ABSTRACT The purpose of the present study was to investigate the effects of brick kiln exhaust on... more ABSTRACT The purpose of the present study was to investigate the effects of brick kiln exhaust on the quantity of polycyclic aromatic hydrocarbons in surrounding soils and plants. In Pakistan, a big problem is the rapid conglomeration of the brick kilns in out skirt of nearly all urban centers to cope with the rapid construction work in big cities. A huge amount of low-grade coal, rubber, tires is used in non-scientific manner. The study was conducted in the City of Peshawar the capital of Kyber Pakhtunkhwa where many brick kilns are located in the periurban areas. Soil and medicinal plants samples were collected from different locations around the bricks kiln and were analyzed for selected polycyclic aromatic hydrocarbons (PAHs), i.e., benzo(a)pyrene, anthracene, chrysene, flourene, flouranthene, phenanthrene, naphthalene, and acenapthylene. Quantitative and qualitative analysis was carried out by UV spectrophotometer and high-performance liquid chromatography. Benzo[a]pyren and Chrysene were found to be the most abundant compounds. The total load of PAHs in the central location was found to be 0.4014 mg/kg. General trend of PAHs distribution was such that the concentration of individual PAHs was found to increase with depth clearly indicating their absorption in the soil. PAHs concentration increased with the distance up to 300 m and then gradual decreased which showed their movement with the water and air. The PAHs load was found high in the leaves as compared to stem and roots. This high load in the aerial parts indicated their excretion route as well as air deposition.
Desalination and Water Treatment, 2013
ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution u... more ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution using brick kiln chimney waste as adsorbent, Desalination and Water Treatment, makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Heavy metals are toxic to aquatic flora and fauna even in relatively low concentrations. Chromium is a commonly occurring toxic metal in ecosystems. This study aims the adsorption of Cr(VI) on a novel low-cost carbonaceous material under different experimental conditions such as contact time, initial concentration of metal ions, pH, and temperature. The adsorbent was characterized by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The equilibrium data were fitted well with Langmuir and Freundlich isotherms. Adsorption kinetics of Cr(VI) ions onto chimney waste adsorbent were analyzed by pseudo-first-order and pseudo-second-order models. The adsorption process is favored by acidic pH and followed the second-order kinetics. Various thermodynamic parameters like activation energy (E a), Gibbs free energy change (DG o), enthalpy change (DH o), and entropy change (DS o) were calculated. The results showed that the carbonaceous material obtains from bricks kiln chimneys can be efficiently used for Cr(VI) removal from wastewater.
Magnetic molecularly imprinted polymer (mag-MIP) were developed for the analysis of ametryn (4-N-... more Magnetic molecularly imprinted polymer (mag-MIP) were developed for the analysis of ametryn (4-N-ethyl-6-methylsulfanyl-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine), a popular triazine herbicide. Iron oxide (Fe3O4) nanoparticles were synthetized, and then modified with tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPS). Then MIPs' polymerimerization occurred in the nanoparticles' surface, using ethylene-glycol-dimethacrylate (EGDMA) as the building monomer, 2,2′-azobis(2-methylpropionitrile) (AIBN) as the radical initiator, and 2-vinylpyridine as the functional monomer. The functional monomer was previously chosen by computational simulation. The mag-MIPs' adsorption behavior well-fitted a Langmuir model (qm of 8.6 mg g− 1, KL of 5.2 L mg− 1) and pseudo first order kinetics (k1 of 2.5 × 10− 4 s− 1). The developed analytical methodology, using high-performance liquid chromatography with UV detection (HPLC-UV), showed suitable selectivity and had a limit of detection (LOD) and quantification (LOQ) of 25 and 82 nmol L− 1, respectively.
This article reveals the qualitative analysis of different metabolites, seven heavy metals concen... more This article reveals the qualitative analysis of different metabolites, seven heavy metals concentration and antioxidant activity of the fruit of Solanum nigrum (L). Qualitative analysis is very essential for identifying the various classes of compounds present in the medicinal plants. Solanum nigrum (L) is an important herbaceous medicinal plant belongs to Solanacae family. Phytochemical screening of the crude extracts revealed the presence of secondary compounds such as alkaloids, flavonoids, steroids and tainns. Also the concentration of seven heavy metals Zinc (Zn), Cobalt (Co), Lead (Pb), Nickle (Ni), Cadmium (Cd), Iron (Fe) and Copper (Cu) were determined. On comparison the concentration of all metals were high in Solanum nigram. The iron was in high amount 46.46 mg/L, while cobalt was in less amount 0.082 mg/L in Solanum nigram. The fruit extract show a good antioxidant activity at low concentration at 20 and 40 ppm.
Application of ultrasonically modified cloud point extraction method for simultaneous enrichment ... more Application of ultrasonically modified cloud point extraction method for simultaneous enrichment of cadmium and lead in sera of different types of gallstone patients, Ultrasonics Sonochemistry (2017), doi: http://dx.
O metóxido de sódio é usado como reagente ou como catalisador em muitos processos industriais com... more O metóxido de sódio é usado como reagente ou como catalisador em muitos processos industriais como, por exemplo, na síntese de fármacos e de biodiesel. O presente trabalho apresenta um novo e seletivo método analítico quantitativo termométrico para a determinação de metóxido de sódio em soluções de metanol na presença de íons hidróxido. Para fins de comparação com o método Karl-Fischer, os dois procedimentos foram aplicados a quatro diferentes soluções de metóxido de sódio em metanol, inclusive em presença de hidróxido de sódio, e os resultados foram comparados estatisticamente mostrando total concordância. Sodium methoxide is used as a reagent or a catalyst in many industrial processes such as, for example, pharmaceuticals and biodiesel syntheses. This work presents a new and selective quantitative analytical thermometric method for sodium methoxide determination in methanol solutions in the presence of hydroxide ions. For comparative purposes with the Karl-Fischer procedure, these two methods were applied to four different solutions of sodium methoxide in methanol, including in presence of sodium hydroxide, and the results were compared statistically showing total agreement.
A simple, low-cost, sensitive and selective method for the determination of trace quantities of n... more A simple, low-cost, sensitive and selective method for the determination of trace quantities of nitrite in foods such as cheese and cured meat using diffuse ultraviolet-visible reflectance was developed. It is based on the reaction of nitrite with sulphadiazine and -naphthol, which produces a coloured product in basic medium. The reaction is carried out directly in the measuring cell. For cheese the limit of detection (LOD), expressed as NaNO 2 , was estimated to be about 2.0 Â 10 À2 mg l À1 (2.9 Â 10 À7 mol l À1 ) in the final measuring solution and 0.17 mg kg À1 in cheese (2.5 Â 10 À6 mol kg À1 ). The relative standard deviation (RSD) varied from 5% to 8% depending on the sample. For meat the LOD was estimated to be about 2.0 Â 10 À2 mg l À1 (2.9 Â 10 À7 mol l À1 ) in the final measuring solution and 0.13 mg kg À1 in meat (1.9 Â 10 À6 mol kg À1 ). The RSD varied from 3% to 6% depending on the sample. The results of the proposed method were also compared with those obtained with the official method using the statistical Student's t-test and F-test procedures.
International Journal of Pharmacy and Pharmaceutical Sciences, 2014
Water Science and Technology, 2017
A chitosan magnetic membrane was prepared in order to confer magnetic properties to the membrane,... more A chitosan magnetic membrane was prepared in order to confer magnetic properties to the membrane, which could be used for the removal of cations from aqueous solution. The crosslinked magnetic membrane was compared with pristine chitosan membrane in term of stability, morphology and cation adsorption capacity. The fabricated magnetic materials are thermally stable as shown by thermogravimetric curves. The membrane containing nickel magnetic particles (CHNiF-G) shows high thermal stability compared to the other membranes. The Fourier transform infrared spectroscopy showed successful preparation of chitosan magnetic membrane. Scanning electron microscopy micrographs showed the rough surface of the membrane with increased porosity. The prepared chitosan membranes were applied to cations of copper, nickel and lead in dilute aqueous solution. The chitosan membrane showed the following adsorption order for metallic cations: Cu(2+) > Ni(2+) > Pb(2+), while CHNiF-G showed higher capacity, 3.51 mmol g(-1) for copper, reflecting the improvement in adsorption capacity, since the amount of copper on pristine chitosan gave 1.40 mmol g(-1). The time required for adsorption to reach to the equilibrium was 6 h for the selected cations using different chitosan membranes. The kinetic study showed that adsorption followed pseudo-second order kinetics. The most commonly used isotherm models, Freundlich, Langmuir and Temkin, were applied to experimental data using linear regression technique. However, The Temkin model fits better to experimental data.
Journal of Nuclear Medicine, Apr 30, 1994
There is limited information regarding the incidence of post-I-131 therapeutic side effects in pt... more There is limited information regarding the incidence of post-I-131 therapeutic side effects in pts. undergoing high-dose I-131 therapy for DTC. The purpose of the current study is to characterize side effects experienced by patients following 150 mCi.
Journal of the Pakistan Medical Association, Feb 1, 2011
To assess the in vivo efficacy and adverse effects of Artemether-lumefantrine combination in acut... more To assess the in vivo efficacy and adverse effects of Artemether-lumefantrine combination in acute uncomplicated falciparum malaria. A prospective, observational study was conducted at Department of Medicine and Pathology, Pakistan Medical level II hospital, Tubmanburg and Harper from March 2009 to September 2009. One hundred subjects with positive Plasmodium falciparum rings on malaria slide fulfilled the selection criteria and were included in the study. Mean, minimum and maximum values along with standard deviation of age, malarial parasite index, fever clearance time and parasite clearance time were calculated. A 28 day parasitological cure rate was determined. Frequency of various adverse events observed during this study were also noted. Of 100 subjects, 70 wereAfricans while remaining were Asians. Mean fever clearance time in Africans and Asians were 18.9 +/- 11.5 and 27.9 +/- 14.3 hours respectively. The mean parasite clearance time was almost similar in both races ranging from 28 to 31 hours. A 28 day parasitological cure rate was found to be 100%. About 10% of the subjects developed mild to moderate side effects including headache, vomiting, loss of sleep, vertigo and diarrhoea. There was no mortality during the study. Artemether Lumefantrine combination therapy may be used safely and effectively in the management of acute uncomplicated falciparum malaria.
Food Chemistry, 2016
This work presents an efficient method for the preparation of magnetic nanoparticles modified wit... more This work presents an efficient method for the preparation of magnetic nanoparticles modified with molecularly imprinted polymers (Mag-MIP) through core-shell method for the determination of biotin in milk food samples. The functional monomer acrylic acid was selected from molecular modeling, EGDMA was used as cross-linking monomer and AIBN as radical initiator. The Mag-MIP and Mag-NIP were characterized by FTIR, magnetic hysteresis, XRD, SEM and N2-sorption measurements. The capacity of Mag-MIP for biotin adsorption, its kinetics and selectivity were studied in detail. The adsorption data was well described by Freundlich isotherm model with adsorption equilibrium constant (KF) of 1.46 mL g(-1). The selectivity experiments revealed that prepared Mag-MIP had higher selectivity toward biotin compared to other molecules with different chemical structure. The material was successfully applied for the determination of biotin in diverse milk samples using HPLC for quantification of the analyte, obtaining the mean value of 87.4% recovery.
International Journal of Vegetable Science, 2010
Page 1. International Journal of Vegetable Science, 16:278286, 2010 Copyright © Taylor &... more Page 1. International Journal of Vegetable Science, 16:278286, 2010 Copyright © Taylor & Francis Group, LLC ISSN: 1931-5260 print / 1931-5279 online DOI: 10.1080/19315261003707492 WIJV1931-5260 1931-5279 International Journal of Vegetable Science, Vol. 16, No. ...
Ethnomusicology, 2001
... K. Shridar, sarod, with NV Murthy, tabla ... Reflecting the prodigious rig repertoire of his ... more ... K. Shridar, sarod, with NV Murthy, tabla ... Reflecting the prodigious rig repertoire of his guru, Das Gupta here pre-sents an expansive treatment of the seldom-heard rig ... predominance of this and other as-pects of Vilayat Khan's style-in contrast, for example, to that of Ravi Shan-kar ...
Clinical Nuclear Medicine, 1992
British Journal of Dermatology, 2010
Desalination and Water Treatment, Jan 12, 2015
ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution u... more ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution using brick kiln chimney waste as adsorbent, Desalination and Water Treatment, makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Heavy metals are toxic to aquatic flora and fauna even in relatively low concentrations. Chromium is a commonly occurring toxic metal in ecosystems. This study aims the adsorption of Cr(VI) on a novel low-cost carbonaceous material under different experimental conditions such as contact time, initial concentration of metal ions, pH, and temperature. The adsorbent was characterized by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The equilibrium data were fitted well with Langmuir and Freundlich isotherms. Adsorption kinetics of Cr(VI) ions onto chimney waste adsorbent were analyzed by pseudo-first-order and pseudo-second-order models. The adsorption process is favored by acidic pH and followed the second-order kinetics. Various thermodynamic parameters like activation energy (E a), Gibbs free energy change (DG o), enthalpy change (DH o), and entropy change (DS o) were calculated. The results showed that the carbonaceous material obtains from bricks kiln chimneys can be efficiently used for Cr(VI) removal from wastewater.
Desalination and Water Treatment, 2015
ABSTRACT The adsorption of Acid Blue 129 (AB129) from aqueous solution onto hydrochloric acid-act... more ABSTRACT The adsorption of Acid Blue 129 (AB129) from aqueous solution onto hydrochloric acid-activated montmorillonite clay (HCl-bentonite) was investigated. The activated clay was characterized by scanning electron microscopy, energy dispersive spectroscopy, and Brunauer-Emmett-Teller surface area. Batch adsorption experiments were performed to investigate the effects of pH, contact time, initial dye concentration, and temperature (10, 20, 30, and 40°C). Acidic conditions was suitable for higher adsorption of AB129, and kinetic studies demonstrate that the process followed a pseudo-second-order model. An activation energy of 23.858 kJ mol−1 was obtained for adsorption process. Adsorption data were fitted to Freundlich and Langmuir isotherms and various adsorption parameters have been calculated. Standard enthalpy (ΔH°) and standard entropy (ΔS°) were −44.90 kJ mol−1 and −68.44 kJ mol−1 K−1, respectively, showing that overall adsorption process was exothermic and is spontaneous in nature with a decrease in the disorder of the system at the dye/adsorbate interface. However, the mechanism of the dye-Bentonite interaction is likely to be very complicated, involving a wide range of sites having different energy considerations. The activated clay was effective toward adsorption of AB129. The results show that activated bentonite clay could be employed as low-cost materials for the removal of acid dyes from colored effluents.
Biosensors and Bioelectronics, 2006
... concentration that yields a signal-to-noise (S/N) ratio of 3, the LOD of the sensor with opti... more ... concentration that yields a signal-to-noise (S/N) ratio of 3, the LOD of the sensor with optimal immobilization is 0.234 ppb, which is lower than the LOD of 0.3 and 0.4 ppb by an amperometric biosensor (Jeanty and Marty, 1998) and an optical fiber biosensor (Xavier et al., 2000 ...
Arabian Journal of Geosciences, 2014
ABSTRACT The purpose of the present study was to investigate the effects of brick kiln exhaust on... more ABSTRACT The purpose of the present study was to investigate the effects of brick kiln exhaust on the quantity of polycyclic aromatic hydrocarbons in surrounding soils and plants. In Pakistan, a big problem is the rapid conglomeration of the brick kilns in out skirt of nearly all urban centers to cope with the rapid construction work in big cities. A huge amount of low-grade coal, rubber, tires is used in non-scientific manner. The study was conducted in the City of Peshawar the capital of Kyber Pakhtunkhwa where many brick kilns are located in the periurban areas. Soil and medicinal plants samples were collected from different locations around the bricks kiln and were analyzed for selected polycyclic aromatic hydrocarbons (PAHs), i.e., benzo(a)pyrene, anthracene, chrysene, flourene, flouranthene, phenanthrene, naphthalene, and acenapthylene. Quantitative and qualitative analysis was carried out by UV spectrophotometer and high-performance liquid chromatography. Benzo[a]pyren and Chrysene were found to be the most abundant compounds. The total load of PAHs in the central location was found to be 0.4014 mg/kg. General trend of PAHs distribution was such that the concentration of individual PAHs was found to increase with depth clearly indicating their absorption in the soil. PAHs concentration increased with the distance up to 300 m and then gradual decreased which showed their movement with the water and air. The PAHs load was found high in the leaves as compared to stem and roots. This high load in the aerial parts indicated their excretion route as well as air deposition.
Desalination and Water Treatment, 2013
ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution u... more ABSTRACT Din , Desalination and Water Treatment (2013): Removal of Cr(VI) from aqueous solution using brick kiln chimney waste as adsorbent, Desalination and Water Treatment, makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at Heavy metals are toxic to aquatic flora and fauna even in relatively low concentrations. Chromium is a commonly occurring toxic metal in ecosystems. This study aims the adsorption of Cr(VI) on a novel low-cost carbonaceous material under different experimental conditions such as contact time, initial concentration of metal ions, pH, and temperature. The adsorbent was characterized by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The equilibrium data were fitted well with Langmuir and Freundlich isotherms. Adsorption kinetics of Cr(VI) ions onto chimney waste adsorbent were analyzed by pseudo-first-order and pseudo-second-order models. The adsorption process is favored by acidic pH and followed the second-order kinetics. Various thermodynamic parameters like activation energy (E a), Gibbs free energy change (DG o), enthalpy change (DH o), and entropy change (DS o) were calculated. The results showed that the carbonaceous material obtains from bricks kiln chimneys can be efficiently used for Cr(VI) removal from wastewater.
Magnetic molecularly imprinted polymer (mag-MIP) were developed for the analysis of ametryn (4-N-... more Magnetic molecularly imprinted polymer (mag-MIP) were developed for the analysis of ametryn (4-N-ethyl-6-methylsulfanyl-2-N-propan-2-yl-1,3,5-triazine-2,4-diamine), a popular triazine herbicide. Iron oxide (Fe3O4) nanoparticles were synthetized, and then modified with tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPS). Then MIPs' polymerimerization occurred in the nanoparticles' surface, using ethylene-glycol-dimethacrylate (EGDMA) as the building monomer, 2,2′-azobis(2-methylpropionitrile) (AIBN) as the radical initiator, and 2-vinylpyridine as the functional monomer. The functional monomer was previously chosen by computational simulation. The mag-MIPs' adsorption behavior well-fitted a Langmuir model (qm of 8.6 mg g− 1, KL of 5.2 L mg− 1) and pseudo first order kinetics (k1 of 2.5 × 10− 4 s− 1). The developed analytical methodology, using high-performance liquid chromatography with UV detection (HPLC-UV), showed suitable selectivity and had a limit of detection (LOD) and quantification (LOQ) of 25 and 82 nmol L− 1, respectively.
This article reveals the qualitative analysis of different metabolites, seven heavy metals concen... more This article reveals the qualitative analysis of different metabolites, seven heavy metals concentration and antioxidant activity of the fruit of Solanum nigrum (L). Qualitative analysis is very essential for identifying the various classes of compounds present in the medicinal plants. Solanum nigrum (L) is an important herbaceous medicinal plant belongs to Solanacae family. Phytochemical screening of the crude extracts revealed the presence of secondary compounds such as alkaloids, flavonoids, steroids and tainns. Also the concentration of seven heavy metals Zinc (Zn), Cobalt (Co), Lead (Pb), Nickle (Ni), Cadmium (Cd), Iron (Fe) and Copper (Cu) were determined. On comparison the concentration of all metals were high in Solanum nigram. The iron was in high amount 46.46 mg/L, while cobalt was in less amount 0.082 mg/L in Solanum nigram. The fruit extract show a good antioxidant activity at low concentration at 20 and 40 ppm.
Application of ultrasonically modified cloud point extraction method for simultaneous enrichment ... more Application of ultrasonically modified cloud point extraction method for simultaneous enrichment of cadmium and lead in sera of different types of gallstone patients, Ultrasonics Sonochemistry (2017), doi: http://dx.
O metóxido de sódio é usado como reagente ou como catalisador em muitos processos industriais com... more O metóxido de sódio é usado como reagente ou como catalisador em muitos processos industriais como, por exemplo, na síntese de fármacos e de biodiesel. O presente trabalho apresenta um novo e seletivo método analítico quantitativo termométrico para a determinação de metóxido de sódio em soluções de metanol na presença de íons hidróxido. Para fins de comparação com o método Karl-Fischer, os dois procedimentos foram aplicados a quatro diferentes soluções de metóxido de sódio em metanol, inclusive em presença de hidróxido de sódio, e os resultados foram comparados estatisticamente mostrando total concordância. Sodium methoxide is used as a reagent or a catalyst in many industrial processes such as, for example, pharmaceuticals and biodiesel syntheses. This work presents a new and selective quantitative analytical thermometric method for sodium methoxide determination in methanol solutions in the presence of hydroxide ions. For comparative purposes with the Karl-Fischer procedure, these two methods were applied to four different solutions of sodium methoxide in methanol, including in presence of sodium hydroxide, and the results were compared statistically showing total agreement.
A simple, low-cost, sensitive and selective method for the determination of trace quantities of n... more A simple, low-cost, sensitive and selective method for the determination of trace quantities of nitrite in foods such as cheese and cured meat using diffuse ultraviolet-visible reflectance was developed. It is based on the reaction of nitrite with sulphadiazine and -naphthol, which produces a coloured product in basic medium. The reaction is carried out directly in the measuring cell. For cheese the limit of detection (LOD), expressed as NaNO 2 , was estimated to be about 2.0 Â 10 À2 mg l À1 (2.9 Â 10 À7 mol l À1 ) in the final measuring solution and 0.17 mg kg À1 in cheese (2.5 Â 10 À6 mol kg À1 ). The relative standard deviation (RSD) varied from 5% to 8% depending on the sample. For meat the LOD was estimated to be about 2.0 Â 10 À2 mg l À1 (2.9 Â 10 À7 mol l À1 ) in the final measuring solution and 0.13 mg kg À1 in meat (1.9 Â 10 À6 mol kg À1 ). The RSD varied from 3% to 6% depending on the sample. The results of the proposed method were also compared with those obtained with the official method using the statistical Student's t-test and F-test procedures.