Advanced Polymer Laboratory, Department of Polymer Science and Technology, Government College of Engineering and Leather Technology (Post-Graduate), Maulana Abul Kalam Azad University of Technology, Salt Lake, Kolkata 700106, West Bengal, India. Electronic address: [Email]
Response surface methodology (i.e., RSM)-optimized starch-g-[2-acrylamido-2-methylpropane sulfonic acid (AMPS)-co-[2-(N-(3-(hydroxymethyl)amino)-3-oxopropyl)acrylamido)-2-methylpropane sulfonic acid] (NHMAOAMPS)-co-[2-(3-(N-(hydroxymethyl)acrylamido)propanamido)-2-methylpropane sulfonic acid (NHMAPMPS)]-co-N-(hydroxymethyl)acrylamide (NHMA)] (i.e., starch-g-tetrapolymer) was synthesized via grafting of starch and in situ strategic protrusion of NHMAOAMPS and NHMAPMPS, using optimum ingredients and temperature. This interpenetrating tetrapolymer-hydrogel bearing extraordinary physicochemical properties and recyclability was applied for unary and/or binary removal(s) of Bi(III)-Hg(II) and brilliant green-crystal violet. The N-H-activated in situ allocation of monomers, grafting of starch, thermal stabilities, surface properties, swellability, sustainability, adsorption capacities, and superadsorption were apprehended via microstructural analyses of unadsorbed and/or adsorbed starch-g-tetrapolymer(s) through FTIR-1H-/13C-NMR-UV-vis, TGA-DSC, XRD, SEM-EDX, DLS, and %gel-content-pHPZC-%graft-ratio. The chemisorption data for metal ions best fitted with Langmuir and combined Langmuir-Freundlich isotherm models for unary and binary adsorption, respectively. The unary/binary adsorption capacities were 1005.41/959.25 and 1087.79/758.56 mg g-1 for Bi(III) and Hg(II), respectively, at 293 K, 0.02 g, and within 500-1000 ppm.