Highly efficient removal of As(V) with modified electrolytic manganese residues (M-EMRs) as a novel adsorbent

In this research, electrolytic manganese residues (EMRs) modified by NaOH, ultrasonic etching and microwave-assisted heating treatment (called M-EMRs hereafter) were used as a novel adsorbent to remove Arsenic (V) [As(V)] from synthetic wastewater. Results showed that M-EMRs were of nanosheet structure in sizes of about 100–300 nm; the percentage of Fe and Mn on the surface of M-EMRs increased, and Fe and Mn existed in the forms of FeS, FeOOH, Fe₃O₄, and MnO₂. The As(V) concentration in the liquid decreased from 50 to 0.038 mg/L. The maximum adsorption capacity of E-EMRs for As(V) was 23.96 mg/g. The presence of low concentration of salt such as NaCl, Na₂CO₃, Na₂HPO₄, and Na₂SO₄ showed limited inhibition on the adsorption of As(V). Moreover, M-EMRs could be regenerated with 3% NaOH solution and reused for 5 times. Preliminary analysis indicates the application potential of M-EMRs in As-contaminated industrial wastewater.