Comparative Study of Synthetic and Bio‐Based Adsorbents for Vanadium Recovery: α‐Aminophosphonate versus Magnetic Cysteine‐Functionalized Chitosan

ABSTRACT A considerable increase in the global importance of vanadium and its extensive use in alloy manufacturing has stimulated growing interest in its extraction and recovery. In this study, a magnetic chitosan functionalized with cysteine moieties (MCC) and a synthetic α‐aminophosphonate (o‐phenylenediamine‐based adsorbent, OPDA) were prepared and evaluated as adsorbents for vanadium ions from sulfate media. The prepared bio‐ and synthetic adsorbents were characterized using FT‐IR, TGA, BET surface area, pH PZC , XRD, elemental analysis, and SEM–EDX techniques. Optimization of sorption parameters indicated that the highest vanadium uptake was achieved at pH 4.0 for MCC and 2.0 for OPDA, with contact times of 120 and 90 min, an adsorbent dosage of 0.01 g, and an initial vanadium concentration of 150 mg L −1 , respectively. The adsorption process followed the Langmuir isotherm model, with maximum experimental adsorption capacities of 90 mg g −1 for MCC and 70 mg g −1 for OPDA, in good agreement with calculated values. Thermodynamic parameters confirmed the spontaneous and exothermic nature of the adsorption process. Application of MCC and OPDA to a real residue liquor obtained from ferruginous gibbsite‐bearing shale (Um Bogma Formation, Abu Thor locality, Southwestern Sinai, Egypt) resulted in vanadium removal uptakes of 70 and 50 mg g −1 , respectively, demonstrating the practical applicability of the prepared adsorbents for technological and industrial purposes.