Removal of aqueous vanadium(V) by green synthesized iron nanoparticles supported on corn straw biochar

Iron nanoparticles supported on corn straw biochar ([email protected]) were used to remove V(V). This material was prepared by using Yali pear peel extract-supported iron nanoparticles (PE-FeNPs) as the functional body and corn straw biochar (BC) as the support. The synthesis conditions such as Fe/C mass ratio and synthesis temperature were optimized. The material was characterized by SEM-EDS, FTIR, XRD, and XPS. The results showed that particle agglomeration was reduced, and the dispersion was improved after PE-FeNPs were supported on BC. The removal effect was better in the pH range of 2–6, and the removal efficiency was the highest at pH 3.7. At 25 ℃ and pH 3.7, the maximum adsorption capacity qm of V(V) was 362.7 mg/g, and 95.1 % of 90 mg/L V(V) was removed. The coexisting NaCl or NaNO3 had a weaker effect on the removal of V(V). The adsorption reactions followed the pseudo-second-order model and Langmuir model, and chemical adsorption was the dominant process. The main reaction mechanism of [email protected] with V(V) was as follows: adsorbed V5+ was reduced to V4+ by Fe0 and Fe2+ and then removed by co-precipitation in the forms of xFe2O3·yV2O5·zH2O and VO2·H2O. This study promotes the reuse of waste pear peel and can provide an environmentally friendly method for removing V(V) pollution.