Removal of chromium(VI) from water utilizing a column loaded with H3PO4-activated Areca catechu waste

The current study evaluates the efficiency of a biosorbent produced from Areca catechu waste (ACW) for removing chromium(VI) from both synthetic and industrial water in a packed column system. ACW was initially activated with phosphoric acid (H3PO4) and thereafter carbonized to make phosphoric acid activated Areca catechu waste (PACW), where active sites were generated for the biosorption of chromium(VI) ions from the aqueous phase. Biosorption performance of PACW was measured under various operational conditions, where an equilibrium column capacity of 12.03 ± 0.08 mg/g was achieved at a continuous fluid flow rate of 2.33 mL/min. Furthermore, the experimental data were analyzed utilizing the linear and nonlinear forms of the Thomas, the Adams-Bohart, and the Yoon-Nelson models to evaluate the various column parameters. The column capacities from linear and nonlinear Thomas models were determined to be 11.74 ± 0.16 and 12.31 ± 0.16 mg/g, respectively. A study on industrial wastewater obtained from the carpet dyeing industry located in Jorpati, Kathmandu, Nepal, which contained 2.30 mg/L of chromium(VI), indicated that PACW could successfully reduce the chromium(VI) to 0.10 mg/L, meeting the water regulatory standard as specified by the World Health Organization. Therefore, the PACW investigated in this study demonstrates significant potential for the removal of trace amounts of chromium from contaminated water in a packed column setting.