Removal of Arsenic by Wheat Straw Biochar from Soil.

Biochar prepared from wheat straw (Triticum aestivum) at different pyrolysis temperatures was screened, followed by its application to soil for arsenic removal in the present study. Characterization of biochar by Field emission scanning electron microscope studies and Fourier thermal Infrared imaging showed smooth and porous biochar surface and abundance of surface functional groups. A low value of H/C was obtained by CHNS analyzer, indicating high stability of biochar. The surface area was 15.86 m2/g on an average. Batch sorption experiments were carried out to optimize conditions for arsenic sorption. Maximum arsenic removal of 83.7% was obtained when applied at a 7.5% dose for a contact time of 60 min at 25 °C. Isotherm, kinetic and thermodynamic studies revealed the feasibility of sorption and removal of arsenic through physisorption, chemisorption, ion exchange, and diffusion.