Microwave-assisted functionalized biosorbent preparation using seed gum of Tamarindus indica: characterization and evaluation of Cr(VI) removal potency from tannery effluents.

An appropriate exploitation of biosorbents for the adsorptive removal of toxic heavy metal ions has gained huge interest among the researchers due to concerns on adverse impact by chemical methods and its generation of harmful sludge as byproduct. In the present study, the efficacy of a grafted biosorbent prepared using Tamarindus indica seed gum was ascertained for removing Cr(VI) from both synthetic solution and real tannery effluent. The adsorptive performance of Cr(VI) was optimized for microwave power, exposure time, methylmethacrylate concentration, and adsorbent dosage. Further, a sample of the adsorbent was subjected to characterization using TGA, FTIR, SEM, and XRD investigations. The acquired grafter polymeric material having the highest grafting ratio and grafting efficiency was employed to optimize Cr(VI) adsorption. The results showed that the highest adsorptive removal of Cr(VI) occurred at an initial pH of the solution, 1.0, which showed the pH dependent of the process. The findings explicated that the Cr(VI) sorption by grafted copolymer biosorbent followed both the Freundlich and Langmuir isotherms, suggesting that the absorbing active sites on the biosorbent's surface were heterogeneous and that several mechanisms at work were adopted. Kinetic analysis indicated that the second-order mechanism was found to be the best fit. In addition, actual industrial effluent from tanneries was investigated for the removal of Cr(VI) using the acquired adsorbent. Furthermore, the adsorbed chromium was removed by desorption using NaOH and the reusability of the binding capacity was assessed with different cycles. [ABSTRACT FROM AUTHOR]