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Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied. © 2013 Elsevier Ltd. All rights reserved.

Bhattacharyya R.,University of Calcutta | Ray S.K.,University of Calcutta | Mandal B.,Bijoy Krishna Girls College
Journal of Industrial and Engineering Chemistry | Year: 2013

A systematic method was employed to synthesize several hydrogels by crosslink copolymerization of acrylamide (AM), hydroxyl ethylmethacrylate (HEMA) and N,N'-methylenebisacrylamide (NMBA) at varied operating conditions. Composite hydrogels were also prepared by in situ incorporation of varied amounts of sodium aluminosilicate filler to the monomer mixtures at optimum operating conditions. These hydrogels were used for removal of rhodamine B and methyl violet dye from water at low (0.5-3. mg/L) and high concentration (50-500. mg/L) ranges. The composite hydrogels showed much higher dye adsorption than the unfilled hydrogels. Kinetic, adsorption and thermodynamic parameters for dye adsorption were also evaluated. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Mandal B.,Bijoy Krishna Girls College | Ray S.K.,University of Calcutta | Bhattacharyya R.,University of Calcutta
Journal of Applied Polymer Science | Year: 2012

Semi and full interpenetrating network (IPN) hydrogels were synthesized by allowing free radical copolymerization of acrylic acid (AA) and hydroxyethyl methacrylate (HEMA) in the matrix of polyvinyl alcohol (PVOH). Accordingly, four different semi IPN hydrogels were prepared with PVOH: copolymer mass ratio of 1: 1, 1: 0.75, 1: 0.5, and 1: 0.25. These hydrogels were designated as SEMIIPN1, SEMIIPN2, SEMIIPN3, and SEMIIPN4, respectively. In all of these SEMIIPN, after polymerization PVOH was crosslinked with 2 mass % glutaraldehyde to form the semi IPN structure. In a similar way, sequential full IPN were prepared from PVOH and copolymer of AA and HEMA (designated as PAAHEMA) with same composition except in this case apart from crosslinking of PVOH by 2 mass % glutaraldehyde the PAAHEMA copolymer was further crosslinked with N,N′- methylenebisacrylamide (NMBA) to produce four full IPN hydrogels designated as FULLIPN1, FULLIPN2, FULLIPN3, and FULLIPN4. All of these semi and full IPN type hydrogels were characterized by carboxylic %, FTIR, UV, DTA-TGA, XRD, SEM, and mechanical properties. The network parameters, swelling and diffusion characteristics of these hydrogels were also studied. The performance of these semi and full IPNs were compared in terms of their relative abilities for removing varied concentration of rhodamine B (RB) and methyl Violet (MV) dyes from water. © 2011 Wiley Periodicals, Inc.

Mandal B.,Bijoy Krishna Girls College | Ray S.K.,University of Calcutta
Materials Science and Engineering C | Year: 2014

Interpenetrating network (IPN) type hydrogels of a biopolymer and a synthetic polymer were prepared from chitosan and crosslink copolymer of acrylic acid, sodium acrylate and hydroxyethyl methacrylate. Acrylic acid, sodium acrylate, hydroxyethyl methacrylate and N′N′-methylenebisacrylamide (MBA) monomers were free radically copolymerized and crosslinked in aqueous solution of chitosan. Several IPN hydrogels were prepared by varying concentrations of initiator, crosslinker (MBA) and weight% of chitosan. These hydrogels were characterized by free acid content, pH at point of zero charge (PZC), FTIR, DTA-TGA, SEM and XRD. The swelling and diffusion characteristics, network parameters and adsorption of cationic methyl violet (MV) and anionic congo red (CR) dyes by these hydrogels were studied. The hydrogels showed high adsorption (9.5-119 mg/g for CR and 9.2-98 mg/g for MV) and removal% (98-73% for CR and 94-66% for MV) over the feed concentration of 10-140 mg/l dye in water. The isotherms and kinetics of dye adsorption by the hydrogels were also studied. © 2014 Elsevier B.V.

Mandal B.,Bijoy Krishna Girls College | Ray S.K.,University of Calcutta
International Journal of Biological Macromolecules | Year: 2015

Several hydrogels were prepared by a free radical polymerization of acrylic acid (AA), sodium acrylate (SA) and AA/hydroxy ethyl methacrylate (HEMA) in the presence of starch in water. These starch incorporated acrylic gels were prepared by varying the concentration of the initiator, monomer, crosslinker and the starch. The resulting gels were characterized by FTIR, SEM, XRD, DTA-TGA, pH at point zero charge (PZC), swelling and the diffusion in water. The gels showed high adsorption and removal% of Safranine T (ST) and Brilliant Cresyl Blue (BCB) dyes from water. The swelling and the adsorption data were fitted to different kinetic models and isotherms. Amongst the three kinds of gels, the starch incorporated sodium polyacrylate gel showed the highest adsorption of 9.7-85.3. mg/L (97-61% removal) of BCB dye and 9.1-83. mg/L (91-60% removal) of ST dye for a feed dye concentration of 10-140. mg/L. © 2015 Elsevier B.V.

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