Biochar Derived from Rice by-Products for Arsenic and Chromium Removal by Adsorption: A Review

Environmental pollution by arsenic (As) and hexavalent chromium (Cr(VI)) has been one of the most serious environmental problems in recent years around world. Their presence water is a result both natural anthropogenic activities, poses risks to human health due their high toxicity. Adsorption leading method used remove chromium, with biochar, carbonaceous pyrolytic product made from various types biomass, under low oxygen conditions, being common adsorbents its surface area. Although biochar’s ability immobilize As Cr(VI) high, order increase adsorption capacity nutrient release potential rice husk it essential select an appropriate pyrolysis biochar modification technique. Physical or biological activation, steam/gas UV irradiation, magnetization, alkali/acid treatment, nano-modification are main methods that will be discussed this review. These modifications have led multi-fold enhancement adsorption/reduction Cr(VI), compared plain biochar. This review provides literature overview different methods, as well factors influence successfully along regeneration potentials.