Arsenic removal by layered double hydroxides (LDH): A mini review

Abstract

The World Health Organization (WHO) has classified arsenic as the most toxic chemical with carcinogenic effects and WHO has established a value of 10 μg/L arsenic as the maximum contaminant level for arsenic in potable water. High selectivity and high removal capacity are one of the most important factors when choosing an adsorbent. Hydrotalcite and hydrotalcite-like compounds have received much attention for the remediation of As-contaminated waters. The most interesting properties of layered double hydroxides (LDHs) include a large surface area and high anion exchange capacity. In this study, the importance of double-layered hydroxides, which has gained importance with the increasing environmental pollution recently, in removing oxyanion pollutants from water has been emphasized. This review article focuses on LDH synthesis and characterization techniques and arsenic removal potential using LDHs, as well as the safe consumability of water obtained after removal. In this review, various factors such as pH, dosage, and temperature that affect oxyanion adsorption on LDHs are discussed. The reusability of LDHs has been discussed. In addition, it has been investigated whether double-layer hydroxides (FeHT) could be used successfully in the removal of arsenic from polluted waters. It was also discussed whether the adsorbent used was safe for health.