Simultaneous removal of chloride and hardness from groundwater by cassava peel biosorption: Optimization and sorption studies

Abstract In this study, activated carbon produced from cassava peel (CP) via carbonization at 400°C was utilized as a biosorbent for the removal of chloride (Cl − ) and total hardness (TH) from groundwater. A response surface methodology (RSM) employing a Box–Behnken design (BBD) was implemented to optimize process parameters, including pH (3–10), biosorbent dosage (1–10 g), contact time (10–60 min), initial Cl − concentration (50–2000 mg/L), and initial TH concentration (40–900 mg/L). The biosorbent was applied in a batch reactor setup to evaluate its performance in removing Cl − and TH from groundwater under the optimized conditions. The experimental data showed good agreement with the model predictions, exhibiting R 2 of 0.991 and 0.905 for Cl − and TH removal, respectively. The CP biosorbent removed Cl − (245 mg/L) and TH (321 mg/L) by 84% and 90%, respectively, under optimal conditions of 6.9 g CP dose, 19.6 min, and initial pH of 8.1. The sorption kinetics followed a pseudo‐second‐order, and the equilibrium data fit the Freundlich and Langmuir models to Cl − and TH, respectively. The removal of Cl − and TH exhibited maximum adsorption capacities ( q m ) of 31.25 and 6.57 mg/g for Cl − and TH, respectively. Overall, CP shows potential as an adsorbent for remediating groundwater containing Cl − and TH.