Synthesis of amine-functionalized CeFe2O4-biochar for V(Ⅳ) and V(V) adsorption: characterization, mechanism, and regeneration capacity

Abstract

A novel amine-functionalized cerium ferrite biochar (NCFBC) was firstly synthesized by microwave-assisted anaerobic carbonation and subsequently applied for the adsorption of V(Ⅳ) and V(V) in water in the work. In comparison with other biochars that have been synthesized (e.g., BC, CFBC, and NCFBC), NCFBC demonstrated superior vanadium (V) adsorption properties. The V adsorption by NCFBC was a monolayer, homogeneous process of chemical and physical co-action through adsorption kinetics and isotherm modeling. The maximum V(Ⅳ) and V(V) adsorption by NCFBC, as predicted by the Langmuir model, was 345.72 mg/g and 178.97 mg/g, respectively. The surface structural characterization revealed that the amine-functionalized NCFBC exhibited an increased particle size, specific surface area, pore size, and pore volume. The XPS and FTIR characterization results demonstrated that CO/C=O functional groups on the NCFBC surface exhibited a preference for binding to V(V) during the adsorption process. However, the -NH₂ functional group demonstrated a preference for binding to V(Ⅳ). The adsorption mechanism of NCFBC for V included functional group complexation, surface precipitation, pore adsorption, and electrostatic attraction. The findings from the renewable cycle test, anion interference assessment, various metal removal trials, and real-world environmental applications highlight the remarkable stability of NCFBC during the metal removal process. Its efficiency in eliminating diverse metals in practical settings underscores its vast potential for widespread utilization.