Upcycling tea waste particles into magnetic adsorbent materials for removal of Cr(VI) from aqueous solutions

In this work, locally available tea wastes were used as precursors for the development of cost-effective bio-sorbent materials for heavy metal removal from wastewater. Chemical and thermal treatments to prepare magnetic/non-magnetic tea waste-based adsorbents were discussed and correlated their properties with corresponding Cr(VI) adsorption capacity. These bio-sorbents were thoroughly charac-terized by FT-IR, PXRD, N2 adsorption-desorption surface area techniques and Cr adsorption performance was investigated in batch reactor under different conditions such as adsorbent dosage, initial Cr con-centration, solution pH and contact time. Careful bleaching steps, incorporation of magnetic iron nanoparticles and judicious temperature treatments of tea wastes resulted in high performing bio-sorbents with a complete removal of Cr at a dosage of 0.25 g/mL of the solution. Cr adsorption on these tea waste-based bio-sorbents were found to be fitting to a pseudo 2nd order kinetics.(c) 2022 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study developed cost-effective bio-sorbent materials for heavy metal removal from wastewater using locally available tea wastes as precursors. The preparation methods of magnetic/non-magnetic tea waste-based adsorbents were discussed, and their properties were correlated with Cr(VI) adsorption capacity. The bio-sorbents were characterized by various techniques, and the Cr adsorption performance was investigated under different conditions. The tea waste-based bio-sorbents showed high efficiency in removing Cr.