Interaction of arsenic with biochar in water and soil: Principles, applications, and prospects

Arsenic (As) is known as an extremely toxic metalloid available in the environment due to both anthropogenic and geogenic activities. Even though adsorption has shown promising results in remediating As, the speciation of As poses a challenge. Bioavailability and mobility of As can be potentially improved with the addition of biochar to contaminated soil systems. Further, biochar modification can also aid in better As removal. Biochar, prepared via pyrolysis of organic materials is characterized with unique properties namely large surface area, elevated sorption capacity, ion exchange capacity, micro porosity, significant mineral, and carbon contents which are highly beneficial in water and soil remediation. The conditions of pyrolysis and the type of feedstock are two key factors that directly affect the characteristics of biochar. The abundant availability of feedstock, cost effectiveness and favorable physiochemical parameters of biochar aid in remediating metalloids like As in the environment. This chapter focuses on the principles, interactions, application of biochar in As remediation in soil and water and future perspectives.