Adsorption Study on Hexavalent Chromium Removal Using Magnetic Biochar from Ziziphus jujube Seed

Abstract The study explores removal of hexavalent chromium (Cr(VI)) from wastewater using magnetic biochar (MB) from Ziziphus jujube seeds (ZJS). Modified biochar was characterized for functional groups, crystalline structure, morphological characteristics, surface area, elemental content, and magnetic properties. Batch experiments were conducted considering pH, initial chromium, adsorbent dosage, and contact time as controlling factors. The study demonstrates MB, with its high carbonization and magnetic saturation, effectively removes 98 % of hexavalent chromium from aqueous solutions. Langmuir and pseudo‐second‐order models were best fit models for adsorption, and 0.3 M HCl recovered more than 95 % of Cr(VI) than other concentrations.