Synthesis and characterization of carboxymethyl cellulose based hydrogel and its applications on water treatment

Abstract

ABSTRACT The synthesis of carboxymethyl cellulose/potato starch/amylum starch-based hydrogel was done by using aluminum sulfate octahydrate as a cross-linking agent. The novel hydrogel was then investigated and characterized by studying different parameters like swelling behavior, swelling kinetics, scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), powdered X-ray diffractrometry, and thermogravimetric analysis (TGA). This novel hydrogel was applied to tap water for the removal of heavy metal ions which are health hazardous for human life. Among all these mentioned above, the FT-IR analysis was done primarily to evaluate the structure of hydrogels. The resulting structures were in accordance with the expected structures of hydrogels. These hydrogels were then analyzed by the TGA in order to evaluate the thermal stability of hydrogel which should be more than its ingredients. After the thermal gravimetric analysis, these hydrogels were then examined morphologically by SEM. The swelling ability of the prepared hydrogel was examined in the basic medium as well as in the acidic medium. Resultantly it was found to be more in proportion in the basic medium than in acidic medium. Moreover, the hydrogel shows its swelling and de-swelling behaviors in different solvents like water, ethanol, acidic, and basic buffers and also in salt solutions when inferred by the swelling experiments. By the application of the prepared hydrogel on the aqueous solutions, Cd 2+ , Pb 2+ , and Fe 2+ ions were separated. Th order of selectivity of the hydrogel toward different metal ions was found to be Cd 2+ > Pb 2+ > Fe 2+ . It can be inferred that the capacity of the hydrogel to bind with heavy metal ions depends upon the interaction of different metal ions with the hydrogel monomers.

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