Synthesis of a starch-based sulfonic ion exchange resin and adsorption of dyestuffs to the resin

A starch-based ion exchange resin (SIR) was synthesized by copolymerizing raw starch with sodium medially( sulfonate and styrene. The structural and surface properties of the SIR were characterized by C-13 nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, gel permeation chromatography, scanning electron microscopy. X-ray diffractometry, thermogravimetric analysis, Brunauer-Emmett-Teller surface area analysis, and laser particle size analysis. The SIR was physicochemically and thermally stable and resistant to acids, bases, and enzymes. In static adsorption tests, the SIR had decolorization ratios (DRs) for mixed dyestuffs in wastewater of up to 84.04%, which was higher than the DR for a synthetic ion exchange resin (001 x 7, DR 77.14%). In dynamic adsorption tests, the SIR bed had a DR of 99.85% and a wastewater handling capacity 25 times the column volume. After three adsorption-regeneration cycles, the DR of the resin bed had decreased by <7.5%. The properties of the SIR, particularly the adaptability of the SIR to continuous column adsorption, make the SIR suitable for removing dyestuffs from industrial wastewater and a potential substitute for traditional sorbents such as activated carbon and synthetic resins. (C) 2020 Elsevier B.V. All rights reserved.