Remediation performance of As-contaminated water and soil using a novel Fe–Mn bimetallic (oxyhydr)oxide coated on natural magnetite

Abstract

It is challenging to separate the materials for treating arsenic contamination of soil and water from systems. The natural magnetite covered with Fe–Mn bimetallic (oxyhydr)oxide (Fe–Mn MSM) was effectively created in this study, and its potential use in removing As from water and soil was investigated. Batch adsorption studies showed that the As(V) adsorption on Fe–Mn MSM could achieve equilibrium after 120 min when the initial As(V) concentration was 39.85 mg/L. The calculated maximum adsorption of Fe–Mn MSM for As(V) was 17.94 mg/g at 20 °C. The mechanism of As(V) adsorption was confirmed to be a combination of ligand exchange and electrostatic attraction by the outcomes of FTIR analysis, SEM, and batch adsorption tests. Fe–Mn MSM can also be a successful amendment for cleaning up As-polluted soil. The 5% Fe–Mn MSM treatment group had the lowest exchangeable fraction of As (EX-As) concentration, 0.039 mg/kg (8.3% of initial EX-As), after 40 days. Magnetic separation could be used to quickly and completely recover the used Fe–Mn MSM from the soil. EX-As was present in higher concentrations on Fe–Mn MSM than that of the original soil. As a result, this work offers a strategy that may be put into practice to cheaply remove As from soil and water while also encouraging the reuse of natural magnetite. Graphical abstract: [Figure not available: see fulltext.].