Dnyaneshwar Shinde - Academia.edu (original) (raw)
Papers by Dnyaneshwar Shinde
Support File Table-1: Characteristic of Degussa P25 (TiO 2) photocatalyst (As per manufacturers i... more Support File Table-1: Characteristic of Degussa P25 (TiO 2) photocatalyst (As per manufacturers information)
Drinking Water Engineering and Science, Nov 16, 2017
In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, T... more In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO 2 , and SnO 2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO 2 , and SnO 2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO 2 and SnO 2 as well as that of Degussa P-25 (TiO 2). The photocatalytic dye decolourisation rates with ZnO were 1.14-1.35, 1.70-3.1, and 4-8.5 times higher than those of the Degussa P-25, TiO 2 , and SnO 2 , respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.
In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, T... more In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO 2 , and SnO 2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO 2 , and SnO 2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO 2 and SnO 2 as well as that of Degussa P-25 (TiO 2). The photocatalytic dye decolourisation rates with ZnO were 1.14-1.35, 1.70-3.1, and 4-8.5 times higher than those of the Degussa P-25, TiO 2 , and SnO 2 , respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.
Analysis of untreated chrome electroplating effluent procured from electroplating unit showed tha... more Analysis of untreated chrome electroplating effluent procured from electroplating unit showed that it was acidic in nature (pH=1.51) and it contains Cr(VI) at the concentration 70.74±0.31 ppm. This effluent is used for further experiments. Removal of chromium from effluent was achieved in two steps. In first step Cr(VI) was reduced to Cr(III) by reaction with H2O2 and 0.6 ml 30% H2O2 was found sufficient for complete reduction of Cr(VI) from 1 liter of effluent. Then in second step Cr(III) was removed from effluent by precipitating it as Cr(OH)3 in presence of activated charcoal. In absence of activated charcoal pH at which Cr(III) get precipitated, it has been observed that some quantity of Cr(III) oxidizes to Cr(VI) again. Removal of Cr(III) is governed by pH of solution and at pH 6.5 to 7.0 more than 99.00% of Cr(III) has taken place. By this process chromium removal efficiency was observed more than 99.00%. After bench scale experiment process was tried at pilot scale and design...
DESALINATION AND WATER TREATMENT, 2017
Silver metal/Ti-doped ZnO, silver metal/ZnO, Ti(IV)-doped ZnO and ZnO photocatalysts were obtaine... more Silver metal/Ti-doped ZnO, silver metal/ZnO, Ti(IV)-doped ZnO and ZnO photocatalysts were obtained by thermal decomposition of respective oxalate precursors. The synthesized photocatalysts were characterized by chemical and spectroscopic methods. The doping of ZnO with Ti(IV) and the formation of silver metal heterostructures in ZnO nanostructures were confirmed through powder X-ray diffraction and tunneling electron microscopy analysis. The ZnO and Ti-doped ZnO have crystallized in hexagonal wurtzite structure while heterostructured catalysts showed the presence of additional cubic crystalline phase belonging to Ag metal. Surface morphology was observed through scanning electron microscopic imaging while surface area was determined by Brunauer-Emmett-Teller method. The photocatalytic activity of the photocatalysts was studied on the structurally diverse dyes in the sunlight and under optimized conditions of pH of dye solutions and catalyst dose. The degradation of dyes was measured in terms of decolourization as well as chemical oxygen demand. The photocatalytic activities of the catalysts were compared in terms of first-order rate constants of the decolourization of dyes. The photocatalytic activity of the heterostructured Ag metal/Ti-doped ZnO catalysts was found superior to the photocatalytic activity of ZnO, silver metal/ZnO and Ti-doped ZnO catalysts.
Asian Journal of Chemistry, 2015
The UV-visible absorption spectra of untreated electroplating effluent indicate that it contain C... more The UV-visible absorption spectra of untreated electroplating effluent indicate that it contain Cr(VI) in the form of dichromate (Cr2O7 2-). Quantitative analysis indicated that effluent was acidic in nature and consists of about 146 ppm Cr2O7 2-. Primary experiment clearly indicated that fresh biomass of plants such as cabbage leaves, cauliflower leaves, Sisuvium, biomass of common agriculture weed, leaves of Colocasia arum, etc. can be used as reducing agent to Cr(VI). pH dependence study showed that acidic and low pH is essential for faster reduction of Cr(VI) to Cr(III). At pH of electroplating effluent and optimized effluent to biomass ratio 60 to 105 minutes were required for nearly 100 % reduction of Cr(VI) to Cr(III). After complete reduction of Cr(VI), it was removed as Cr(OH)3 in presence of hematite ore. Applicability of bench scale experiment for large scale removal of Cr(VI) was tested and results of large scale experiment were found fascinating.
Journal of Heterocyclic Chemistry
International Journal of Engineering Development and Research, 2017
International Journal of Scientific Research in Science and Technology, 2018
The dried biomass of species of cyanobacteria Nostoc entophytum, N. punctiforme and N. ellipsospo... more The dried biomass of species of cyanobacteria Nostoc entophytum, N. punctiforme and N. ellipsosporum was assessed for phycobiliprotein and carotenoid content. The biomass left after extraction of pigments was utilized for the adsorption of heavy metal ions. The phycobiliprotein content of these species ranged from 32.1–51.1 mg g –1 on a dry weight (dw) basis, while the total carotenoids content varied from 9.7 to 14.5 mg g –1 dw. The pH-dependant adsorption of metal ion showed that optimum adsorption of Cu(II) and Cd(II) takes place at pH 4-6, and that of Cr(VI) at pH 1-2. Kinetics of adsorption of metal ions on biomass of these species showed that initial rate of adsorption of metal ions was fast and within 120 min in which 78-88% of Cu(II), 56-62% of Cd(II) and 52-64% of Cr(VI) was adsorbed by the Nostoc species biomass. For more than 90% adsorption, the time required was about 6 h for Cu(II), 36-48 h for Cd(II) and 48-60 h Cr(VI). Column experiments showed that the biomass of the...
ES Food & Agroforestry, 2021
International Nano Letters, 2020
Green synthesis of nanoparticles has attracted significant attention as an alternative to chemica... more Green synthesis of nanoparticles has attracted significant attention as an alternative to chemical synthesis procedure. The bulk availability of plants, microbial biomass and the use of eco-friendly solvents has significantly reduced the cost in addition to the hazards associated with the chemical synthesis of the nanoparticle. In this study, we demonstrated the biosynthesis of titanium nanoparticles (TiO 2 NPs) with the extract of Trichoderma citrinoviridae as a reducing agent. The physicochemical properties of biogenic TiO 2 NPs were studied using FESEM, Zeta sizer, FTIR and XRD. The size (10-400 nm), morphology, crystallinity, zeta potential (29.5 mV), and polydispersity index (0.327) suggested that the biogenic TiO 2 NPs were polymorphic, crystalline and stable. FESEM revealed that the synthesized TiO 2 NPs were majorly irregular, and some interesting TiO 2 NPs structures, i.e., triangular, pentagonal, spherical and rod were also observed. The biogenic TiO 2 NPs showed excellent antibacterial activity (100 µg/mL) against planktonic cells of extremely drug-resistant (XDR) Pseudomonas aeruginosa clinical isolates. The TiO 2 NPs also had better antioxidant potential as compared to standard gallic acid. This study indicates the use of T. citrinoviridae for synthesizing biogenic TiO 2 NPs and their potential use against XDR bacteria.
ES Energy & Environment, 2021
Asian Journal of Chemistry, 2020
In present study, ZnO photocatalysts were successfully synthesized by thermal decomposition of di... more In present study, ZnO photocatalysts were successfully synthesized by thermal decomposition of different precursors. Thermal decomposition temperatures of precursors were obtained by thermogravimetric analysis. The synthesized ZnO photocatalysts were characterized for their crystalline phase, surface morphology and band gap, respectively by powder X-ray diffraction, scanning electron microscopy and diffuse reflectance spectroscopic methods. Chemical analysis of synthesized ZnO photocatalysts was performed for Zn(II) content. Photocatalytic activity of ZnO photocatalysts was evaluated under the solar irradiation on crystal violet dye in aqueous solution. The results of experiments showed that ZnO synthesized from zinc carbonate consists of higher photocatalytic activity than ZnO synthesized from other precursors, which is even higher than bench mark Degussa P-25 TiO2 photocatalyst. ZnO synthesized from zinc carbonate is further used for mineralization of dyes from three different eff...
Engineered Science, 2020
In the present study, dye-sensitized solar cells (DSSCs) were fabricated using novel [(2-hydroxy-... more In the present study, dye-sensitized solar cells (DSSCs) were fabricated using novel [(2-hydroxy-1-naphthyl) diazenyl] benzoic acid (2-HNDBA) dye. The effect of dye absorption time on the performance of DSSCs was studied. The doctor blade method was employed to prepare the ZnO seed layer. The structural, morphological and optical properties of the ZnO photoanode were studied systematically. The syntesized ZnO was found to be of hexagonal wurtzite structure. The 2-HNDBA sensitized zinc oxide based DSSCs have been studied for its photoresponse at the dye absorption time from 60-240 min. The fabricated DSSC prepread at 60 min dye absorbtion time was found to exibit a fill factor and a photo conversion efficiency of 0.44 and 1.09 %, respectively. As the preparing time increases to 120 min, the respective parameters increase to 0.53 and 2.08 % at 120 min. However, on further increasing the dye absorbtion time, the fill factor and photo conversion efficiency are reduced to 0.51, and 1.69%. Thus, 120 min dye absorbtion time has been found to be the optimized dye absorption time for novel 2-HNDBA dye-sensitized ZnO photoanode based DSSCs.
![Research paper thumbnail of A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine promoted synthesis of 3-aroylimidazo[1,2-a]pyridines](https://attachments.academia-assets.com/98729417/thumbnails/1.jpg)
](Tetrahedron Letters, 2020
A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine pr... more A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine promoted synthesis of 3-aroylimidazo[1,2-a]pyridines
Materials Science-Poland, 2018
A dye-sensitized solar cell (DSSC) was assembled using a dye 4-(3-chloro-1, 4-dioxo-1, 4-dihydron... more A dye-sensitized solar cell (DSSC) was assembled using a dye 4-(3-chloro-1, 4-dioxo-1, 4-dihydronaphthalen-2-ylamino) benzoic acid with ZnO as a photoanode. It was synthesized using 2, 3-dichloro 1, 4-naphthoquinone and p-amino benzoic acid. The spectral features of the dye were analyzed in ethanol using experimental and computational methods. The theoretical investigations revealed that the synthesized dye may act as a sensitizer in DSSCs. The photoelectrochemical performance was tested under direct sunlight using a sandwich type DSSC. The photovoltaic data of the dye adsorbed on ZnO films indicated thepower conversion efficiency of 1.07 % under sunlight with a light intensity of 39 mW·cm-2.
Oriental Journal of Chemistry, 2018
A powdered activated charcoal (PAC) based process was evaluated at a bench and pilot scale to det... more A powdered activated charcoal (PAC) based process was evaluated at a bench and pilot scale to determine its effectiveness towards the removal of Cr(VI) from the electroplating effluent. In the first step, reduction of Cr(VI) to Cr(III) was achieved while in a second step Cr(III) was removed by adsorption. In both steps PAC is utilized. Different experimental parameters affecting the reduction of Cr(VI) by PAC were investigated. The rate of reduction reaction was found to be dependent on the pH of effluent and the dose of PAC. Removal of Cr(III) from initially treated effluent was achieved under optimum condition of pH and dose of PAC. After a bench scale experiments, the reduction and removal of chromium from the effluent was achieved at a pilot scale successfully. The experimental result suggests that PAC is a suitable material for the reduction and removal of chromium from the electroplating effluent.
ACS Omega, 2019
A novel heterogeneous catalytic method was developed for the synthesis of coumarin and its deriva... more A novel heterogeneous catalytic method was developed for the synthesis of coumarin and its derivatives using the Ti(IV)doped ZnO matrix forming catalyst Zn 0.925 Ti 0.075 O having a high surface area and good Lewis acidity. The catalyst shows high activity toward a broad spectrum of the substituted phenols with β-ketoesters such as ethyl acetoacetate, ethyl butyryl acetate, ethyl benzoyl acetate, and so forth in good yields over short reaction times during the synthesis of coumarins. The methodology was further extended for the synthesis of ayapin molecules. The catalyst also shows recycle activity up to seven cycles with very good stability. ■ INTRODUCTION Coumarins are a class of oxygen heterocycles, contributing in the field of natural products which are medicinally important. 1 Coumarin derivatives are utilized as intermediate chemicals in the synthesis of pharmaceuticals, agrochemicals, insecticides, food additives, fragrances, and cosmetics. 2 Additionally, they are applicable as optical whitening agents, laser colors, dyes, and fluorescent probes for the identification of biologically important chemical species as medicinal stains. 3 In the synthetic organic chemistry, the class of coumarin compounds is useful for the synthesis of chromones, coumarones, fluorocoumarins, and 2-acyl resorcinol. 4 However, many important drug molecules have coumarin moieties such as warfarin, calanolide A, 667 coumate, novobiocin, ensaculin alexa 350, hymecromone, and umbelliferone (Figure 1). In the past reports, novel and well-organized methodologies have been developed to prepare coumarin compounds. Currently, the number of methods are available for the coumarin synthesis such as Pechmann reaction, 5 Knoevenagel condensation, 6 Claisen rearrangement, 7 Perkin, 8 Wittig, 9 Reformatsky, 10 catalytic cyclization, 11 flash vacuum pyrolysis, 12 and so forth. Amongst all, Pechmann reaction is widely useful for the synthesis of coumarin because of the simple starting materials, mild reaction conditions, and excellent yields of the products in short reaction times.
RSC Advances, 2019
In the present study, we demonstrated the use of fragmented lignin in the synthesis of a hierarch... more In the present study, we demonstrated the use of fragmented lignin in the synthesis of a hierarchical-type structure of ZnO nanorods. Lignin was isolated from bagasse by the microwave assisted method and its fragmentation was achieved in alkaline conditions along with hydrogen peroxide. Lignin and fragmented lignin were purified by crystallisation followed by column chromatography and characterized by UVvisible spectroscopy, Frontier infra-red spectroscopy (FTIR), 1 H-NMR and high resolution mass spectroscopy (HRMS). Fragmented lignin was utilized as a template for the synthesis of ZnO nanorods, which were characterized by powder XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-DRS for the determination of crystal structure, particle morphology and band gap. XRD of the ZnO samples revealed a hexagonal wurtzite structure. The morphology of ZnO without fragmented lignin showed agglomerated nanoparticles and with fragmented lignin, a self-assembled hierarchical nanostructure due to nanorods of 30 nm diameter and 200-500 nm length was observed. The fragmented lignin showed a pronounced effect on the particle size and morphology of ZnO nanoparticles. We measured the response of the hierarchical ZnO nanostructure (50 ppm) for sensing NH 3 in terms of change in voltage across known resistance. We observed the response and recovery upon introduction of the analyte ammonia gas at 175 C.
Support File Table-1: Characteristic of Degussa P25 (TiO 2) photocatalyst (As per manufacturers i... more Support File Table-1: Characteristic of Degussa P25 (TiO 2) photocatalyst (As per manufacturers information)
Drinking Water Engineering and Science, Nov 16, 2017
In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, T... more In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO 2 , and SnO 2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO 2 , and SnO 2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO 2 and SnO 2 as well as that of Degussa P-25 (TiO 2). The photocatalytic dye decolourisation rates with ZnO were 1.14-1.35, 1.70-3.1, and 4-8.5 times higher than those of the Degussa P-25, TiO 2 , and SnO 2 , respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.
In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, T... more In this study, we evaluated the photocatalytic activities of analytical reagent (AR) grade ZnO, TiO 2 , and SnO 2 to identify a low-cost photocatalyst for dye degradation. The obtained samples of ZnO, TiO 2 , and SnO 2 were characterised by X-ray diffractogram (XRD), scanning electron microscope imaging, and UV-VIS diffuse reflectance spectroscopy. The decolourisation of three structurally diverse dyes, namely crystal violet, basic blue, and methyl red under solar irradiation, was used to evaluate the photocatalytic activities of three metal oxides. The photocatalytic activities of the received three metal oxides were tested with the photocatalytic degradation of dyes and compared with Degussa P-25. Dye solutions with each metal oxide at initial pH 9 were subjected to irradiation under sunlight and monitored for up to the stage of complete decolourisation. The results indicate that ZnO exhibited the highest photocatalytic activity as compared to TiO 2 and SnO 2 as well as that of Degussa P-25 (TiO 2). The photocatalytic dye decolourisation rates with ZnO were 1.14-1.35, 1.70-3.1, and 4-8.5 times higher than those of the Degussa P-25, TiO 2 , and SnO 2 , respectively. The percentage COD removal was studied for ZnO and partial removal was observed at the decolourisation stage. To enhance photocatalytic activity of AR grade ZnO, it was loaded with Ag metal and about 20 % enhancement in the activity was observed.
Analysis of untreated chrome electroplating effluent procured from electroplating unit showed tha... more Analysis of untreated chrome electroplating effluent procured from electroplating unit showed that it was acidic in nature (pH=1.51) and it contains Cr(VI) at the concentration 70.74±0.31 ppm. This effluent is used for further experiments. Removal of chromium from effluent was achieved in two steps. In first step Cr(VI) was reduced to Cr(III) by reaction with H2O2 and 0.6 ml 30% H2O2 was found sufficient for complete reduction of Cr(VI) from 1 liter of effluent. Then in second step Cr(III) was removed from effluent by precipitating it as Cr(OH)3 in presence of activated charcoal. In absence of activated charcoal pH at which Cr(III) get precipitated, it has been observed that some quantity of Cr(III) oxidizes to Cr(VI) again. Removal of Cr(III) is governed by pH of solution and at pH 6.5 to 7.0 more than 99.00% of Cr(III) has taken place. By this process chromium removal efficiency was observed more than 99.00%. After bench scale experiment process was tried at pilot scale and design...
DESALINATION AND WATER TREATMENT, 2017
Silver metal/Ti-doped ZnO, silver metal/ZnO, Ti(IV)-doped ZnO and ZnO photocatalysts were obtaine... more Silver metal/Ti-doped ZnO, silver metal/ZnO, Ti(IV)-doped ZnO and ZnO photocatalysts were obtained by thermal decomposition of respective oxalate precursors. The synthesized photocatalysts were characterized by chemical and spectroscopic methods. The doping of ZnO with Ti(IV) and the formation of silver metal heterostructures in ZnO nanostructures were confirmed through powder X-ray diffraction and tunneling electron microscopy analysis. The ZnO and Ti-doped ZnO have crystallized in hexagonal wurtzite structure while heterostructured catalysts showed the presence of additional cubic crystalline phase belonging to Ag metal. Surface morphology was observed through scanning electron microscopic imaging while surface area was determined by Brunauer-Emmett-Teller method. The photocatalytic activity of the photocatalysts was studied on the structurally diverse dyes in the sunlight and under optimized conditions of pH of dye solutions and catalyst dose. The degradation of dyes was measured in terms of decolourization as well as chemical oxygen demand. The photocatalytic activities of the catalysts were compared in terms of first-order rate constants of the decolourization of dyes. The photocatalytic activity of the heterostructured Ag metal/Ti-doped ZnO catalysts was found superior to the photocatalytic activity of ZnO, silver metal/ZnO and Ti-doped ZnO catalysts.
Asian Journal of Chemistry, 2015
The UV-visible absorption spectra of untreated electroplating effluent indicate that it contain C... more The UV-visible absorption spectra of untreated electroplating effluent indicate that it contain Cr(VI) in the form of dichromate (Cr2O7 2-). Quantitative analysis indicated that effluent was acidic in nature and consists of about 146 ppm Cr2O7 2-. Primary experiment clearly indicated that fresh biomass of plants such as cabbage leaves, cauliflower leaves, Sisuvium, biomass of common agriculture weed, leaves of Colocasia arum, etc. can be used as reducing agent to Cr(VI). pH dependence study showed that acidic and low pH is essential for faster reduction of Cr(VI) to Cr(III). At pH of electroplating effluent and optimized effluent to biomass ratio 60 to 105 minutes were required for nearly 100 % reduction of Cr(VI) to Cr(III). After complete reduction of Cr(VI), it was removed as Cr(OH)3 in presence of hematite ore. Applicability of bench scale experiment for large scale removal of Cr(VI) was tested and results of large scale experiment were found fascinating.
Journal of Heterocyclic Chemistry
International Journal of Engineering Development and Research, 2017
International Journal of Scientific Research in Science and Technology, 2018
The dried biomass of species of cyanobacteria Nostoc entophytum, N. punctiforme and N. ellipsospo... more The dried biomass of species of cyanobacteria Nostoc entophytum, N. punctiforme and N. ellipsosporum was assessed for phycobiliprotein and carotenoid content. The biomass left after extraction of pigments was utilized for the adsorption of heavy metal ions. The phycobiliprotein content of these species ranged from 32.1–51.1 mg g –1 on a dry weight (dw) basis, while the total carotenoids content varied from 9.7 to 14.5 mg g –1 dw. The pH-dependant adsorption of metal ion showed that optimum adsorption of Cu(II) and Cd(II) takes place at pH 4-6, and that of Cr(VI) at pH 1-2. Kinetics of adsorption of metal ions on biomass of these species showed that initial rate of adsorption of metal ions was fast and within 120 min in which 78-88% of Cu(II), 56-62% of Cd(II) and 52-64% of Cr(VI) was adsorbed by the Nostoc species biomass. For more than 90% adsorption, the time required was about 6 h for Cu(II), 36-48 h for Cd(II) and 48-60 h Cr(VI). Column experiments showed that the biomass of the...
ES Food & Agroforestry, 2021
International Nano Letters, 2020
Green synthesis of nanoparticles has attracted significant attention as an alternative to chemica... more Green synthesis of nanoparticles has attracted significant attention as an alternative to chemical synthesis procedure. The bulk availability of plants, microbial biomass and the use of eco-friendly solvents has significantly reduced the cost in addition to the hazards associated with the chemical synthesis of the nanoparticle. In this study, we demonstrated the biosynthesis of titanium nanoparticles (TiO 2 NPs) with the extract of Trichoderma citrinoviridae as a reducing agent. The physicochemical properties of biogenic TiO 2 NPs were studied using FESEM, Zeta sizer, FTIR and XRD. The size (10-400 nm), morphology, crystallinity, zeta potential (29.5 mV), and polydispersity index (0.327) suggested that the biogenic TiO 2 NPs were polymorphic, crystalline and stable. FESEM revealed that the synthesized TiO 2 NPs were majorly irregular, and some interesting TiO 2 NPs structures, i.e., triangular, pentagonal, spherical and rod were also observed. The biogenic TiO 2 NPs showed excellent antibacterial activity (100 µg/mL) against planktonic cells of extremely drug-resistant (XDR) Pseudomonas aeruginosa clinical isolates. The TiO 2 NPs also had better antioxidant potential as compared to standard gallic acid. This study indicates the use of T. citrinoviridae for synthesizing biogenic TiO 2 NPs and their potential use against XDR bacteria.
ES Energy & Environment, 2021
Asian Journal of Chemistry, 2020
In present study, ZnO photocatalysts were successfully synthesized by thermal decomposition of di... more In present study, ZnO photocatalysts were successfully synthesized by thermal decomposition of different precursors. Thermal decomposition temperatures of precursors were obtained by thermogravimetric analysis. The synthesized ZnO photocatalysts were characterized for their crystalline phase, surface morphology and band gap, respectively by powder X-ray diffraction, scanning electron microscopy and diffuse reflectance spectroscopic methods. Chemical analysis of synthesized ZnO photocatalysts was performed for Zn(II) content. Photocatalytic activity of ZnO photocatalysts was evaluated under the solar irradiation on crystal violet dye in aqueous solution. The results of experiments showed that ZnO synthesized from zinc carbonate consists of higher photocatalytic activity than ZnO synthesized from other precursors, which is even higher than bench mark Degussa P-25 TiO2 photocatalyst. ZnO synthesized from zinc carbonate is further used for mineralization of dyes from three different eff...
Engineered Science, 2020
In the present study, dye-sensitized solar cells (DSSCs) were fabricated using novel [(2-hydroxy-... more In the present study, dye-sensitized solar cells (DSSCs) were fabricated using novel [(2-hydroxy-1-naphthyl) diazenyl] benzoic acid (2-HNDBA) dye. The effect of dye absorption time on the performance of DSSCs was studied. The doctor blade method was employed to prepare the ZnO seed layer. The structural, morphological and optical properties of the ZnO photoanode were studied systematically. The syntesized ZnO was found to be of hexagonal wurtzite structure. The 2-HNDBA sensitized zinc oxide based DSSCs have been studied for its photoresponse at the dye absorption time from 60-240 min. The fabricated DSSC prepread at 60 min dye absorbtion time was found to exibit a fill factor and a photo conversion efficiency of 0.44 and 1.09 %, respectively. As the preparing time increases to 120 min, the respective parameters increase to 0.53 and 2.08 % at 120 min. However, on further increasing the dye absorbtion time, the fill factor and photo conversion efficiency are reduced to 0.51, and 1.69%. Thus, 120 min dye absorbtion time has been found to be the optimized dye absorption time for novel 2-HNDBA dye-sensitized ZnO photoanode based DSSCs.
Tetrahedron Letters, 2020
A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine pr... more A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine promoted synthesis of 3-aroylimidazo[1,2-a]pyridines
Materials Science-Poland, 2018
A dye-sensitized solar cell (DSSC) was assembled using a dye 4-(3-chloro-1, 4-dioxo-1, 4-dihydron... more A dye-sensitized solar cell (DSSC) was assembled using a dye 4-(3-chloro-1, 4-dioxo-1, 4-dihydronaphthalen-2-ylamino) benzoic acid with ZnO as a photoanode. It was synthesized using 2, 3-dichloro 1, 4-naphthoquinone and p-amino benzoic acid. The spectral features of the dye were analyzed in ethanol using experimental and computational methods. The theoretical investigations revealed that the synthesized dye may act as a sensitizer in DSSCs. The photoelectrochemical performance was tested under direct sunlight using a sandwich type DSSC. The photovoltaic data of the dye adsorbed on ZnO films indicated thepower conversion efficiency of 1.07 % under sunlight with a light intensity of 39 mW·cm-2.
Oriental Journal of Chemistry, 2018
A powdered activated charcoal (PAC) based process was evaluated at a bench and pilot scale to det... more A powdered activated charcoal (PAC) based process was evaluated at a bench and pilot scale to determine its effectiveness towards the removal of Cr(VI) from the electroplating effluent. In the first step, reduction of Cr(VI) to Cr(III) was achieved while in a second step Cr(III) was removed by adsorption. In both steps PAC is utilized. Different experimental parameters affecting the reduction of Cr(VI) by PAC were investigated. The rate of reduction reaction was found to be dependent on the pH of effluent and the dose of PAC. Removal of Cr(III) from initially treated effluent was achieved under optimum condition of pH and dose of PAC. After a bench scale experiments, the reduction and removal of chromium from the effluent was achieved at a pilot scale successfully. The experimental result suggests that PAC is a suitable material for the reduction and removal of chromium from the electroplating effluent.
ACS Omega, 2019
A novel heterogeneous catalytic method was developed for the synthesis of coumarin and its deriva... more A novel heterogeneous catalytic method was developed for the synthesis of coumarin and its derivatives using the Ti(IV)doped ZnO matrix forming catalyst Zn 0.925 Ti 0.075 O having a high surface area and good Lewis acidity. The catalyst shows high activity toward a broad spectrum of the substituted phenols with β-ketoesters such as ethyl acetoacetate, ethyl butyryl acetate, ethyl benzoyl acetate, and so forth in good yields over short reaction times during the synthesis of coumarins. The methodology was further extended for the synthesis of ayapin molecules. The catalyst also shows recycle activity up to seven cycles with very good stability. ■ INTRODUCTION Coumarins are a class of oxygen heterocycles, contributing in the field of natural products which are medicinally important. 1 Coumarin derivatives are utilized as intermediate chemicals in the synthesis of pharmaceuticals, agrochemicals, insecticides, food additives, fragrances, and cosmetics. 2 Additionally, they are applicable as optical whitening agents, laser colors, dyes, and fluorescent probes for the identification of biologically important chemical species as medicinal stains. 3 In the synthetic organic chemistry, the class of coumarin compounds is useful for the synthesis of chromones, coumarones, fluorocoumarins, and 2-acyl resorcinol. 4 However, many important drug molecules have coumarin moieties such as warfarin, calanolide A, 667 coumate, novobiocin, ensaculin alexa 350, hymecromone, and umbelliferone (Figure 1). In the past reports, novel and well-organized methodologies have been developed to prepare coumarin compounds. Currently, the number of methods are available for the coumarin synthesis such as Pechmann reaction, 5 Knoevenagel condensation, 6 Claisen rearrangement, 7 Perkin, 8 Wittig, 9 Reformatsky, 10 catalytic cyclization, 11 flash vacuum pyrolysis, 12 and so forth. Amongst all, Pechmann reaction is widely useful for the synthesis of coumarin because of the simple starting materials, mild reaction conditions, and excellent yields of the products in short reaction times.
RSC Advances, 2019
In the present study, we demonstrated the use of fragmented lignin in the synthesis of a hierarch... more In the present study, we demonstrated the use of fragmented lignin in the synthesis of a hierarchical-type structure of ZnO nanorods. Lignin was isolated from bagasse by the microwave assisted method and its fragmentation was achieved in alkaline conditions along with hydrogen peroxide. Lignin and fragmented lignin were purified by crystallisation followed by column chromatography and characterized by UVvisible spectroscopy, Frontier infra-red spectroscopy (FTIR), 1 H-NMR and high resolution mass spectroscopy (HRMS). Fragmented lignin was utilized as a template for the synthesis of ZnO nanorods, which were characterized by powder XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-DRS for the determination of crystal structure, particle morphology and band gap. XRD of the ZnO samples revealed a hexagonal wurtzite structure. The morphology of ZnO without fragmented lignin showed agglomerated nanoparticles and with fragmented lignin, a self-assembled hierarchical nanostructure due to nanorods of 30 nm diameter and 200-500 nm length was observed. The fragmented lignin showed a pronounced effect on the particle size and morphology of ZnO nanoparticles. We measured the response of the hierarchical ZnO nanostructure (50 ppm) for sensing NH 3 in terms of change in voltage across known resistance. We observed the response and recovery upon introduction of the analyte ammonia gas at 175 C.