Novel hybrid biosorbents of agar: Swelling behaviour, heavy metal ions and dye removal efficacies

Agar based hybrid biosorbents were synthesized by free radical copolymerization of acrylamide, NN'-methylenebisacrylamide (NN'MBAAm) on the agar backbone in presence of free radical initiator (ceric ammonium nitrate (CAN)) via oxidation, grafting and crosslinking reactions. The resultant hybrid materials have been characterized by FTIR spectroscopy, elemental analysis, thermal analysis (TGA/DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) taking agar as a reference. The swelling responses of hybrid materials have been extensively studied with various pH, time, temperature and ionic strength [NaCl] of the solution. These hybrid materials have been utilized for selective removal of heavy metal ions (Fe(III), Cr(III), Ni(II) and Mn(II)) and dye (methylene blue) through adsorption mechanism by formation of complex between the functional groups of biosorbent and metal ions & dye. These hybrid materials showed excellent results with their potential applications for environmental remediation from the textile effluents and heavy metal ions contaminated water bodies. (C) 2018 Elsevier B.V. All rights reserved.