Development of gum acacia based magnetic nanocomposite adsorbent for wastewater treatment

Abstract

Adsorbents fabricated on polysaccharides have captivated growing attention in water treatment owing to their low-cost and biodegradability. Modification of polysaccharides by incorporation of functional groups with potential binding ability towards pollutants is a good strategy to develop adsorbent materials. Imparting magnetic property to the materials facilitates easy separation of the adsorbent after use. The present work reports development of a magnetic hydrogel adsorbent material based on the polysaccharide, gum acacia. The graft copolymer nanocomposite hydrogel of gum acacia and poly(3-chloro-2-hydroxypropylmethacrylate) containing magnetite nanoparticles has been prepared using microwave assisted technique and evaluated as adsorbent for sequestration of cationic dyes and metal ions from aqueous solutions. The FTIR, XRD, SEM, TGA, VSM and BET studies have been performed to characterize the sample. The nanocomposite displayed super-paramagnetic nature owing to the existence of magnetite nanoparticles. The presence of magnetite nanoparticles is observed to influence the adsorption characteristics favourably as evident from the comparative studies performed with the non-magnetic parent gel. It exhibited larger surface area of 2.524 m2g− 1 compared to the parent hydrogel with surface area of 0.481 m2g− 1. The adsorption capability of the parent hydrogel towards methylene blue, rhodamine 6G, Cu(II) and Hg(II) are 224.4, 283.5, 282.4 and 275.3 mgg− 1 respectively are enhanced to 265.2, 344.4, 307.5 and 292.8 mgg− 1 respectively in the case of nanocomposite. The adsorption isotherm and kinetic data fitted well with Freundlich and pseudo second order model respectively. Desorption studies indicated excellent reusability characteristics of the novel adsorbent developed, indicating its potential use in wastewater treatment.