Vandana Singh; Stuti Tiwari; Sadanand Pandey; Rashmi Sanghi
Abstract
This study puts forward the synthesis of an excellent cadmium adsorbent having unprecedented high capacity (Qmax = 5000 mg g -1 ) to capture cadmium ions from synthetic cadmium solution. To synthesize the adsorbent (A700), base catalyzed polymerization of tetra ethylorthosilicate (TEOS) was conducted ...
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This study puts forward the synthesis of an excellent cadmium adsorbent having unprecedented high capacity (Qmax = 5000 mg g -1 ) to capture cadmium ions from synthetic cadmium solution. To synthesize the adsorbent (A700), base catalyzed polymerization of tetra ethylorthosilicate (TEOS) was conducted under the sacrificial templation effect of poly(acrylamide) grafted Cassia grandis seed gum (CG) while using H2O, TEOS and EtOH in 8:1:1: ratio (v/v). The CG inspired adsorbent was characterized by FTIR, XRD and SEM, both before and after cadmium adsorption. The adsorption parameters for the synthesized adsorbent were optimized by performing the batch adsorption studies under different pH, initial cadmium concentration, adsorbent dose, and contact time. The adsorption showed pseudo second order kinetics with a rate constant of 1.55 x 10 -4 g mg -1 min -1 at 450 mg mL -1 Cd(II) concentration. The thermodynamic study showed that the adsorption is endothermic and spontaneous. The adsorbent could be successfully reused for three cycles. The present adsorbent is not only very efficient in cadmium uptake; it is greener than the contemporary porous silica adsorbents derived through templation of pure synthetic polymers or surfactants. Moreover the source polysaccharide used for its synthesis is abundant and cheap. This hybrid can utilized as versatile and sustainable adsorbent for cadmium recovery from industrial wastes.
Amar Singh Singha;Raj K. Rana
Abstract
Owing to hydrophilic behavior lignocellulosic fibers, e.g. Agave is unacceptable in various fields of applications. In the present communication attempts have been made to enhance hyrdrophobicity of these fibers through surface modification using methyl methacrylate as vinyl monomer. The grafting reaction ...
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Owing to hydrophilic behavior lignocellulosic fibers, e.g. Agave is unacceptable in various fields of applications. In the present communication attempts have been made to enhance hyrdrophobicity of these fibers through surface modification using methyl methacrylate as vinyl monomer. The grafting reaction initiated by ceric ion was carried out in vacuum. The various reaction parameters such as reaction time, temperature, monomer concentration, initiator concentration and vacuum were optimized to obtain the maximum percent graft yield. The grafted samples were evaluated for the hydrophobic character and other physico- chemical properties such as swelling behavior in different polar and nonpolar solvents alongwith chemical resistance behavior. The grafted products were further characterized by different techniques such as FT-IR, SEM, X-RD and thermogravimetric studies.
Ajit Kumar Sharma;Ajay Kumar Mishra
Abstract
In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar ...
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In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar condition of concentration of styrene and chitosan, 148% grafting was observed with potassium persulphate (K2S2O8)/ascorbic acid as redox initiator and atmospheric oxygen as co-catalyst in 1 h using conventional method at 35 o C. Microwave synthesized Ch-g-sty copolymer was characterized by Fourier transform-Infrared (FTIR) spectroscopy, thermo gravimetric analysis (TGA), X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM). Maximum grafting was optimized by varying the microwave power, exposure time and styrene/chitosan concentration. Ch-g-sty copolymer was found to be more efficient for Cr(VI) removal as compare to conventionally and parent chitosan in aqueous solution. Sorption of Cr(VI) was depending upon pH and concentration, with pH=3 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 526.3 mg/g, 312.5 mg/g and 166.7 mg/g for Ch-g-sty copolymer, conventional (thermostatic water bath) method and parent chitosan respectively.
Ajit Kumar Sharma;Ajay Kumar Mishra
Abstract
In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar ...
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In this study, we have synthesized chitosan-grafted-styrene (Ch-g-sty) without any radical initiator or catalyst using microwave (MW) irradiation. Ch-g-sty was synthesized with 187% grafting using 80 % MW power in 40 second at (styrene) 0.13 M, (Chitosan) 0.1 g/25 mL. On the other hand, under similar condition of concentration of styrene and chitosan, 148% grafting was observed with potassium persulphate (K2S2O8)/ascorbic acid as redox initiator and atmospheric oxygen as co-catalyst in 1 h using conventional method at 35 o C. Microwave synthesized Ch-g-sty copolymer was characterized by Fourier transform-Infrared (FTIR) spectroscopy, thermo gravimetric analysis (TGA), X-ray diffraction (XRD) measurement and scanning electron microscopy (SEM). Maximum grafting was optimized by varying the microwave power, exposure time and styrene/chitosan concentration. Ch-g-sty copolymer was found to be more efficient for Cr(VI) removal as compare to conventionally and parent chitosan in aqueous solution. Sorption of Cr(VI) was depending upon pH and concentration, with pH=3 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 526.3 mg/g, 312.5 mg/g and 166.7 mg/g for Ch-g-sty copolymer, conventional (thermostatic water bath) method and parent chitosan respectively.