Novel co-doped iron oxide and graphitic carbon nanosheets on biochar for arsenite removal from contaminated water: Synthesis, applicability and mechanism

Arsenite (AsIII) is the most toxic form of arsenic in drinking water, but AsIII removal is still a challenge. In this study, alpha-Fe2O3-doped graphitic carbon nanosheets were coated on the surfaces of coconut biochar backbone to remove AsIII from contaminated water. The properties of the composites and the efficiency of AsIII treatment were measured by modern techniques and methods, such as XPS, SEM-EDS, ICP-MS, BET analyses. The novel composites enhance AsIII removal capacity by up to 99.85%, and exhibited high effectiveness for AsIII removal over a large pH range from 3 to 9. In addition, XPS analysis revealed that the FeCl3-derived composites have the ability to oxidize AsIII into AsV species on the composite surfaces due to its catalytic properties. The novel composites can be considered adsorbents that can treat a large AsIII concentration range to obtain safe aqueous As levels according to the WHO guidelines for drinking water.