Synthesis, characterization and application of activated pineapple crown leaf-based adsorbent in vanadium and cadmium ions removal from water

The utilization of agricultural waste for water purification offers a sustainable approach to environmental remediation. Therefore, pineapple crown leaves were transformed into mesoporous activated carbon using a chemical activation process to remove cadmium and vanadium ions from water. The transformation of biomass to an efficient adsorbent was confirmed by X-ray diffraction (XRD), The SEM, FTIR, TGA, and BET analyses also revealed that the pristine powdered pineapple crown leaves (PPCL) contained cellulose and hemicellulose. However, post-pyrolysis-activated pineapple crown leaves (APCL) contained more carbonaceous material than PPCL. Therefore, APCL surface area increased from 0.87 to 1.32 m2/g upon activation treatment. Adsorption of Cd and V using PPCL and APCL was assessed under different conditions, including variations in solution pH, adsorbent dosage, initial concentration of metal ions and temperature. The adsorption equilibrium data were analyzed using the Langmuir and the Freundlich isotherm models. The Langmuir isotherm model showed the best fit with high correlation factors (R2) of 0.999, indicating monolayer adsorption on a homogeneous surface in both cases. The maximum adsorption capacities (qm) for V⁵⁺ and Cd²⁺ ions were 67.7 mg/g and 61.3 mg/g, respectively. Nonetheless, the application of APCL in actual effluent treatment will validate its resilience in water treatment.