title: Removal of chromium (VI) using poly(methylacrylate) functionalized guar gum.
abstract: Using persulfate/ascorbic acid redox pair, poly(methylacrylate) was grafted on to guar gum and the conditions for the grafting were optimized. The copolymer sample having maximum %G was evaluated for the removal of Cr(VI) and the sorption conditions were optimized. The sorption was found pH dependent, pH 1.0 being the optimum value. Sorption data at pH 1.0 were modeled using both the Langmuir and Freundlich isotherms where the data fitted better to Freundlich isotherm. The equilibrium sorption capacity of 29.67mg/g was determined from the Langmuir isotherm. The sorption followed a pseudo-second-order kinetics with a rate constant 2.5x10(-4)gmg(-1) min(-1). The grafted product was also evaluated for Cr(VI) removal from local electroplating industrial waste water. The regeneration experiments revealed that the guar-graft-poly(methylacrylate) could be successfully reused for five cycles. In the present study conductivity measurements were used instead of conventional photometric method for determining Cr(VI) concentration in the equilibrium solutions and the results obtained have been compared with photometric method. Optimum Cr(VI) binding under highly acidic conditions indicated significant contribution of non electrostatic forces in the adsorption process.
authors.affiliation: Department of Chemistry, University of Allahabad, Allahabad 211002, Uttar Pradesh, India. singhvandanasingh@rediffmail.com
authors.forename: Vandana
authors.initials: V
authors.lastname: Singh
authors.forename: Premlata
authors.initials: P
authors.lastname: Kumari
authors.forename: Sadanand
authors.initials: S
authors.lastname: Pandey
authors.forename: Tripti
authors.initials: T
authors.lastname: Narayan
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000302:isolation & purification*; D005685:Galactans / Q000737:chemistry*; D007700:Kinetics; D008351:Mannans / Q000737:chemistry*; D053149:Plant Gums / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D011109:Polymethacrylic Acids; D002857:Chromium; C030613:polymethacrylic acid; C007894:guar gum