Rajesh Shantilal Somani - Academia.edu (original) (raw)
Papers by Rajesh Shantilal Somani
Industrial Engineering Chemistry Research, Jan 11, 2010
ABSTRACT Organoclays or nanoclays have gained increased attention from industry as well as academ... more ABSTRACT Organoclays or nanoclays have gained increased attention from industry as well as academia during the past 11/2 decades. These clays are prepared from natural clays which invariably have other minerals as impurities. It is of prime significance to remove impurities from organoclays which find applications in polymer nanocomposites, paints, cosmetics, and medicinal formulations. The Indian bentonites were treated with sulfuric acid, hydrochloric acid, hydrogen peroxide, oxalic acid, citric acid, and sodium dithionite to remove impurities invariably present in natural clays. Treatment with both minerals and organic acid could remove both interlayer and structural iron and improve the whiteness with breaking up layered structure. However, sodium dithionite treatment is observed to be more suited to remove iron impurities from bentonite and improve whiteness to 11% without any effect on the structure of the clay. Chemically treated bentonites were used for preparing organoclays in a single step to eliminate the filtration and washing steps. The organoclays were prepared under varied reaction parameters such as temperature, the amount and type of organic modifier, and the concentration of the clay. The optimization of these parameters was done to prepare orgnaoclays with controlled particle size and whiteness.
Ind Eng Chem Res, 2006
ABSTRACT The precipitation of calcium carbonate was studied by adding the sodium carbonate soluti... more ABSTRACT The precipitation of calcium carbonate was studied by adding the sodium carbonate solution to a mixed system such as Still effluent (i.e., CaCl2 + NaCl solution) of the soda ash manufacturing (Solvay) process, and the effects of controlling factors on calcium carbonate polymorphs were investigated. The products were characterized with scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and powder X-ray diffraction analysis. The particle size distribution of products was determined as dry powder using laser diffraction technique. It was found that the dilute solutions of the reactants favor the aragonite formation without affecting much the particle size. The formation of calcite is favored with the increase in sodium carbonate concentration. The reaction temperature has no significant effect on polymorphism as well as particle size of calcium carbonate precipitated from solutions having concentration 1.25 M Ca2+ and 1.25 M CO32- and reaction time of 30 min. However, the mode of mixing the reactants has a remarkable effect on the type of polymorph formed and its morphology. When sodium carbonate solution is added to Still effluent maintained at 95 °C, mostly calcite is formed. When the mode of mixing the reactants is reversed, a mixture of calcite and aragonite is formed under identical experimental conditions. In the case of simultaneous addition of both the reactants, aragonite formation is favored. These results indicated that a selective type of polymorph can be produced simply by changing the mode of mixing the reactants. Various morphologies of calcium carbonate crystals such as rhombohedral and needlelike were produced, depending on the preparation conditions.
Current Science, 2007
... Therefore, it is preferred to sus-pend a lower amount of bentonite in deionized water for bet... more ... Therefore, it is preferred to sus-pend a lower amount of bentonite in deionized water for betterbeneficiation. ... Clay Sci., 1997, 11, 329335. 10. Hassan, MS and Abdel-Khalek, NA, Beneficiation and appli-cations of an Egyptian bentonite. Appl. Clay Sci., 1998, 13, 99115. 11. ...
Applied Clay Science, Feb 1, 2007
Quaternary phosphonium cations (hexadecyl tributyphosphonium; tetradecyl tributylphosphonium; tet... more Quaternary phosphonium cations (hexadecyl tributyphosphonium; tetradecyl tributylphosphonium; tetraphenylphosphonium; methyl triphenylphosphonium; ethyl triphenylphosphonium and propyl triphenylphosphonium) were intercalated into montmorillonite (MMT) rich bentonite of Indian origin, by ion exchange reaction. The phosphonium MMT were characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction analysis (PXRD), particle size distribution (PSD) and thermogravimetric analysis (TGA). The phosphonium cations significantly influenced the particle
Separation Science and Technology, Feb 1, 2010
The adsorption of CO and N 2 in ZSM-5 with different SiO 2 / Al 2 O 3 ratio has been investigated... more The adsorption of CO and N 2 in ZSM-5 with different SiO 2 / Al 2 O 3 ratio has been investigated both by static volumetric measurements and dynamic adsorption study. The adsorption capacity of CO and its selectivity over N 2 decreases with an increase in the SiO 2 / Al 2 O 3 ratio. ZSM-5 (25) showed highest selectivity for CO over N 2 whereas ZSM-5 (900) showed lowest CO selectivity. The dynamic adsorption study revealed that the breakthrough time of CO decreases while the dynamic adsorption capacity increases with an increase in CO percentage of gas mixture at fixed flow rate. The heat of adsorption for CO and N 2 decreases with an increase in SiO 2 / Al 2 O 3 ratio. The values for the Henry's constant, the Langmuir constant, and the slope are also reported for CO and N 2 adsorption isotherms on ZSM-5 having different SiO 2 /Al 2 O 3 ratio.
Materials Letters, Nov 1, 2009
A simple, rapid and energy efficient approach based on copper mediated chemical reductionsolvothe... more A simple, rapid and energy efficient approach based on copper mediated chemical reductionsolvothermal method was employed to prepare submicron size hollow carbon spheres (SHCS) using carbon tetrachloride as carbon source. The obtained SHCS were characterized by means of various physico-chemical techniques like nitrogen adsorption-desorption measurements at 77 K, XRD, SEM, TEM, EDX and FT-Raman techniques. Thus characterized samples displayed macroporous nature of carbon with carbon and chloride contents of about 73% and 12% on atomic basis respectively. The presence of chloride content may open new avenues for surface modifications of SHCS in the area of catalysis and separation science.
Http Dx Doi Org 10 1080 08927020903487404, Apr 1, 2010
ABSTRACT The present invention provides a process for the preparation of finely divided precipita... more ABSTRACT The present invention provides a process for the preparation of finely divided precipitated silica. Finely divided precipitated silica is prepared by neutralization of alkali silicate solution, under continuous stirring, at 60 to 9O0 °C in presence of alkali metal salt as coagulating agent, in various neutralization steps during which neutralization is interrupted for specific time. Further acidic silica sol, is added until 60 to 80 % of total alkali is neutralized. The reaction mixture is then aged at least for 3 minute under continuous agitation, followed by circulation through centrifugal pump at an appropriate rate.
Journal of Environmental Chemical Engineering, 2015
ABSTRACT Herein, we report the use of mango seed shells as carbon precursor for producing high su... more ABSTRACT Herein, we report the use of mango seed shells as carbon precursor for producing high surface area (2500 m2/g) activated carbon with total pore volume of 2.2 cm3/g by chemical (H3PO4) activation method. The mango seed shell derived activated carbon (MSS-AC) was used as adsorbent for the adsorption of CO2, CH4 and N2. The MSS-AC powder was converted into shaped body (extrudes) using carboxy methyl cellulose sodium salt (viscosity 1% w/v in water at 25 °C, 1100–1900 cPS) and soluble starch (MW: 342.30) as binder (10 wt% of each). The single column breakthrough adsorption of CO2 and CH4 from binary gas mixtures (CO2–N2, CH4–N2, CO2–CH4) and ternary gas mixture (CO2–CH4–N2) were investigated on MSS-AC extrudes. The highest equilibrium adsorption capacity of CO2 on MSS-AC powder obtained was 21.3 wt% and MSS-AC extrudes was 14.3 wt% at 273 K and 1 bar pressure. We have also compared the results of surface area and CO2 adsorption capacity of carbon based materials derived from various sources reported in the literature with MSS-AC.
Environmental Progress & Sustainable Energy, 2015
ABSTRACT The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based... more ABSTRACT The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based metal organic framework, MIL-101(Cr) and its application for hydrogen storage. MIL-101(Cr) has been synthesized hydrothermally using HF, acetic acid, perfluorobenzoic acid, and without acid. The characterization of the synthesized materials were carried out using powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and surface area (BET) by nitrogen adsorption isotherm at 77 K. The results demonstrated that acetic acid mediated synthesized MIL-101(Cr) exhibited higher surface area and pore volume than those synthesized with other organic acids. This may be due to the enhanced dissolution of terephthalic acid in the presence of acetic acid which facilitates the formation of MIL-101(Cr) nuclei during the synthesis. A comparison of conventional and HF free-synthesized MIL-101(Cr) for hydrogen adsorption capacity determined at 77 K up to 4500 kPa revealed that MIL-101(Cr) synthesized using acetic acid exhibited higher hydrogen adsorption capacity (5.6 wt %) than the MIL-101(Cr) synthesized with perfluorobenzoic acid (3.7 wt %) and without acid (4.8%). However, it is slightly less than the H2 adsorption capacity of MIL-101(Cr) synthesized using HF (6.1 wt %). The higher H2 adsorption capacity of MIL-101(Cr) synthesized using acetic acid can be attributed to the better terephthalate–chromium interaction which facilitates the formation of more crystalline product thereby creating more unsaturated metal centers in MIL-101(Cr). The present study suggested that acetic acid may be a suitable alternative for highly corrosive and hazardous HF which led to easier preparation of MIL-101(Cr) for the large-scale production and applications. © 2015 American Institute of Chemical Engineers Environ Prog, 2015
The present invention provides a process for the preparation of finely divided precipitated silic... more The present invention provides a process for the preparation of finely divided precipitated silica. Finely divided precipitated silica is prepared by neutralization of alkali silicate solution, under continuous stirring, at 60 to 9O0 °C in presence of alkali metal salt as coagulating agent, in various neutralization steps during which neutralization is interrupted for specific time. Further acidic silica sol, is added until 60 to 80 % of total alkali is neutralized. The reaction mixture is then aged at least for 3 minute under continuous agitation, followed by circulation through centrifugal pump at an appropriate rate.
RSC Adv., 2015
Herein we report the eco-friendly and catalyst-free single step synthesis of solid carbon spheres... more Herein we report the eco-friendly and catalyst-free single step synthesis of solid carbon spheres, 1-10 mm in diameter, using vegetable oils derived from different bio-resources as the carbon source. The surface functionality of the synthesized carbon spheres was examined by Fourier transform infrared and charge polarized magic angle spinning nuclear magnetic resonance spectroscopy. The resulting carbon spheres were 100% pure, i.e. free of metal impurities, carbon soot and other structures; and do not require post treatments, such as extraction and purification. A detailed study showed that the synthesis of the carbon spheres proceeds through the formation and self-condensation of aromatic hydrocarbons generated from the oil precursor under autogenic pressure. The carbon spheres were used further as a template for the synthesis of nano crystalline ZnO and MgO hollow spheres.
RSC Adv., 2015
ABSTRACT A low temperature, single-pot, bottom-up approach for the synthesis of few layered graph... more ABSTRACT A low temperature, single-pot, bottom-up approach for the synthesis of few layered graphene sheets using the modified Ullmann reaction is reported. The synthesis protocol involved a solvothermal technique under an autogenic pressure of chloroform, which was used as the carbon source. Scanning and transmission electron microscopy revealed the formation of randomly aggregated, thin, crumpled graphene sheets with a thickness of ~2 nm. Solid state 13C nuclear magnetic resonance and Fourier transform infrared spectroscopy showed that the prepared graphene sheets have copious surface functionality. The possible growth mechanism for the formation of graphene sheets is proposed based on an analysis of the intermediate products by gas chromatography coupled with mass spectroscopy. The growth of few layered graphene sheets proceeded through the addition and cyclisation reactions of different chloroalkene intermediate products formed by the addition reaction of chloroform molecules, and not by the chain polymerization of chloroform molecules.
Industrial Engineering Chemistry Research, Jan 11, 2010
ABSTRACT Organoclays or nanoclays have gained increased attention from industry as well as academ... more ABSTRACT Organoclays or nanoclays have gained increased attention from industry as well as academia during the past 11/2 decades. These clays are prepared from natural clays which invariably have other minerals as impurities. It is of prime significance to remove impurities from organoclays which find applications in polymer nanocomposites, paints, cosmetics, and medicinal formulations. The Indian bentonites were treated with sulfuric acid, hydrochloric acid, hydrogen peroxide, oxalic acid, citric acid, and sodium dithionite to remove impurities invariably present in natural clays. Treatment with both minerals and organic acid could remove both interlayer and structural iron and improve the whiteness with breaking up layered structure. However, sodium dithionite treatment is observed to be more suited to remove iron impurities from bentonite and improve whiteness to 11% without any effect on the structure of the clay. Chemically treated bentonites were used for preparing organoclays in a single step to eliminate the filtration and washing steps. The organoclays were prepared under varied reaction parameters such as temperature, the amount and type of organic modifier, and the concentration of the clay. The optimization of these parameters was done to prepare orgnaoclays with controlled particle size and whiteness.
Ind Eng Chem Res, 2006
ABSTRACT The precipitation of calcium carbonate was studied by adding the sodium carbonate soluti... more ABSTRACT The precipitation of calcium carbonate was studied by adding the sodium carbonate solution to a mixed system such as Still effluent (i.e., CaCl2 + NaCl solution) of the soda ash manufacturing (Solvay) process, and the effects of controlling factors on calcium carbonate polymorphs were investigated. The products were characterized with scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and powder X-ray diffraction analysis. The particle size distribution of products was determined as dry powder using laser diffraction technique. It was found that the dilute solutions of the reactants favor the aragonite formation without affecting much the particle size. The formation of calcite is favored with the increase in sodium carbonate concentration. The reaction temperature has no significant effect on polymorphism as well as particle size of calcium carbonate precipitated from solutions having concentration 1.25 M Ca2+ and 1.25 M CO32- and reaction time of 30 min. However, the mode of mixing the reactants has a remarkable effect on the type of polymorph formed and its morphology. When sodium carbonate solution is added to Still effluent maintained at 95 °C, mostly calcite is formed. When the mode of mixing the reactants is reversed, a mixture of calcite and aragonite is formed under identical experimental conditions. In the case of simultaneous addition of both the reactants, aragonite formation is favored. These results indicated that a selective type of polymorph can be produced simply by changing the mode of mixing the reactants. Various morphologies of calcium carbonate crystals such as rhombohedral and needlelike were produced, depending on the preparation conditions.
Current Science, 2007
... Therefore, it is preferred to sus-pend a lower amount of bentonite in deionized water for bet... more ... Therefore, it is preferred to sus-pend a lower amount of bentonite in deionized water for betterbeneficiation. ... Clay Sci., 1997, 11, 329335. 10. Hassan, MS and Abdel-Khalek, NA, Beneficiation and appli-cations of an Egyptian bentonite. Appl. Clay Sci., 1998, 13, 99115. 11. ...
Applied Clay Science, Feb 1, 2007
Quaternary phosphonium cations (hexadecyl tributyphosphonium; tetradecyl tributylphosphonium; tet... more Quaternary phosphonium cations (hexadecyl tributyphosphonium; tetradecyl tributylphosphonium; tetraphenylphosphonium; methyl triphenylphosphonium; ethyl triphenylphosphonium and propyl triphenylphosphonium) were intercalated into montmorillonite (MMT) rich bentonite of Indian origin, by ion exchange reaction. The phosphonium MMT were characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction analysis (PXRD), particle size distribution (PSD) and thermogravimetric analysis (TGA). The phosphonium cations significantly influenced the particle
Separation Science and Technology, Feb 1, 2010
The adsorption of CO and N 2 in ZSM-5 with different SiO 2 / Al 2 O 3 ratio has been investigated... more The adsorption of CO and N 2 in ZSM-5 with different SiO 2 / Al 2 O 3 ratio has been investigated both by static volumetric measurements and dynamic adsorption study. The adsorption capacity of CO and its selectivity over N 2 decreases with an increase in the SiO 2 / Al 2 O 3 ratio. ZSM-5 (25) showed highest selectivity for CO over N 2 whereas ZSM-5 (900) showed lowest CO selectivity. The dynamic adsorption study revealed that the breakthrough time of CO decreases while the dynamic adsorption capacity increases with an increase in CO percentage of gas mixture at fixed flow rate. The heat of adsorption for CO and N 2 decreases with an increase in SiO 2 / Al 2 O 3 ratio. The values for the Henry's constant, the Langmuir constant, and the slope are also reported for CO and N 2 adsorption isotherms on ZSM-5 having different SiO 2 /Al 2 O 3 ratio.
Materials Letters, Nov 1, 2009
A simple, rapid and energy efficient approach based on copper mediated chemical reductionsolvothe... more A simple, rapid and energy efficient approach based on copper mediated chemical reductionsolvothermal method was employed to prepare submicron size hollow carbon spheres (SHCS) using carbon tetrachloride as carbon source. The obtained SHCS were characterized by means of various physico-chemical techniques like nitrogen adsorption-desorption measurements at 77 K, XRD, SEM, TEM, EDX and FT-Raman techniques. Thus characterized samples displayed macroporous nature of carbon with carbon and chloride contents of about 73% and 12% on atomic basis respectively. The presence of chloride content may open new avenues for surface modifications of SHCS in the area of catalysis and separation science.
Http Dx Doi Org 10 1080 08927020903487404, Apr 1, 2010
ABSTRACT The present invention provides a process for the preparation of finely divided precipita... more ABSTRACT The present invention provides a process for the preparation of finely divided precipitated silica. Finely divided precipitated silica is prepared by neutralization of alkali silicate solution, under continuous stirring, at 60 to 9O0 °C in presence of alkali metal salt as coagulating agent, in various neutralization steps during which neutralization is interrupted for specific time. Further acidic silica sol, is added until 60 to 80 % of total alkali is neutralized. The reaction mixture is then aged at least for 3 minute under continuous agitation, followed by circulation through centrifugal pump at an appropriate rate.
Journal of Environmental Chemical Engineering, 2015
ABSTRACT Herein, we report the use of mango seed shells as carbon precursor for producing high su... more ABSTRACT Herein, we report the use of mango seed shells as carbon precursor for producing high surface area (2500 m2/g) activated carbon with total pore volume of 2.2 cm3/g by chemical (H3PO4) activation method. The mango seed shell derived activated carbon (MSS-AC) was used as adsorbent for the adsorption of CO2, CH4 and N2. The MSS-AC powder was converted into shaped body (extrudes) using carboxy methyl cellulose sodium salt (viscosity 1% w/v in water at 25 °C, 1100–1900 cPS) and soluble starch (MW: 342.30) as binder (10 wt% of each). The single column breakthrough adsorption of CO2 and CH4 from binary gas mixtures (CO2–N2, CH4–N2, CO2–CH4) and ternary gas mixture (CO2–CH4–N2) were investigated on MSS-AC extrudes. The highest equilibrium adsorption capacity of CO2 on MSS-AC powder obtained was 21.3 wt% and MSS-AC extrudes was 14.3 wt% at 273 K and 1 bar pressure. We have also compared the results of surface area and CO2 adsorption capacity of carbon based materials derived from various sources reported in the literature with MSS-AC.
Environmental Progress & Sustainable Energy, 2015
ABSTRACT The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based... more ABSTRACT The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based metal organic framework, MIL-101(Cr) and its application for hydrogen storage. MIL-101(Cr) has been synthesized hydrothermally using HF, acetic acid, perfluorobenzoic acid, and without acid. The characterization of the synthesized materials were carried out using powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and surface area (BET) by nitrogen adsorption isotherm at 77 K. The results demonstrated that acetic acid mediated synthesized MIL-101(Cr) exhibited higher surface area and pore volume than those synthesized with other organic acids. This may be due to the enhanced dissolution of terephthalic acid in the presence of acetic acid which facilitates the formation of MIL-101(Cr) nuclei during the synthesis. A comparison of conventional and HF free-synthesized MIL-101(Cr) for hydrogen adsorption capacity determined at 77 K up to 4500 kPa revealed that MIL-101(Cr) synthesized using acetic acid exhibited higher hydrogen adsorption capacity (5.6 wt %) than the MIL-101(Cr) synthesized with perfluorobenzoic acid (3.7 wt %) and without acid (4.8%). However, it is slightly less than the H2 adsorption capacity of MIL-101(Cr) synthesized using HF (6.1 wt %). The higher H2 adsorption capacity of MIL-101(Cr) synthesized using acetic acid can be attributed to the better terephthalate–chromium interaction which facilitates the formation of more crystalline product thereby creating more unsaturated metal centers in MIL-101(Cr). The present study suggested that acetic acid may be a suitable alternative for highly corrosive and hazardous HF which led to easier preparation of MIL-101(Cr) for the large-scale production and applications. © 2015 American Institute of Chemical Engineers Environ Prog, 2015
The present invention provides a process for the preparation of finely divided precipitated silic... more The present invention provides a process for the preparation of finely divided precipitated silica. Finely divided precipitated silica is prepared by neutralization of alkali silicate solution, under continuous stirring, at 60 to 9O0 °C in presence of alkali metal salt as coagulating agent, in various neutralization steps during which neutralization is interrupted for specific time. Further acidic silica sol, is added until 60 to 80 % of total alkali is neutralized. The reaction mixture is then aged at least for 3 minute under continuous agitation, followed by circulation through centrifugal pump at an appropriate rate.
RSC Adv., 2015
Herein we report the eco-friendly and catalyst-free single step synthesis of solid carbon spheres... more Herein we report the eco-friendly and catalyst-free single step synthesis of solid carbon spheres, 1-10 mm in diameter, using vegetable oils derived from different bio-resources as the carbon source. The surface functionality of the synthesized carbon spheres was examined by Fourier transform infrared and charge polarized magic angle spinning nuclear magnetic resonance spectroscopy. The resulting carbon spheres were 100% pure, i.e. free of metal impurities, carbon soot and other structures; and do not require post treatments, such as extraction and purification. A detailed study showed that the synthesis of the carbon spheres proceeds through the formation and self-condensation of aromatic hydrocarbons generated from the oil precursor under autogenic pressure. The carbon spheres were used further as a template for the synthesis of nano crystalline ZnO and MgO hollow spheres.
RSC Adv., 2015
ABSTRACT A low temperature, single-pot, bottom-up approach for the synthesis of few layered graph... more ABSTRACT A low temperature, single-pot, bottom-up approach for the synthesis of few layered graphene sheets using the modified Ullmann reaction is reported. The synthesis protocol involved a solvothermal technique under an autogenic pressure of chloroform, which was used as the carbon source. Scanning and transmission electron microscopy revealed the formation of randomly aggregated, thin, crumpled graphene sheets with a thickness of ~2 nm. Solid state 13C nuclear magnetic resonance and Fourier transform infrared spectroscopy showed that the prepared graphene sheets have copious surface functionality. The possible growth mechanism for the formation of graphene sheets is proposed based on an analysis of the intermediate products by gas chromatography coupled with mass spectroscopy. The growth of few layered graphene sheets proceeded through the addition and cyclisation reactions of different chloroalkene intermediate products formed by the addition reaction of chloroform molecules, and not by the chain polymerization of chloroform molecules.