Removal of Cr(VI) from aqueous solution using coir pith biochar – An eco-friendly approach

Coir pith biochar obtained by pyrolysis process is used for Cr(VI) removal from aqueous solution. The biochar has 0.27% moisture and 61.0% carbon contents. Scanning electron micrograph (SEM) of the coir pith biochar shows irregular plates with several developed mesopores over the surface. The coirpith sample optimized with different pH conditions, Cr(VI) concentration and adsorbent dosage. Under optimized condition of pH =7, concentration = 100 mgL^-1 and dosage 0.05g, the coir pith biochar removed 99.6% (100 mg L^-1) of Cr(VI) from aqueous solution. The Langmuir isotherm model and pseudo-second order rate expression show satisfactory fit to the equilibrium adsorption data of coir pith biochar. Fourier transform infrared spectroscopy of the coir pith biochar confirm the ionic interaction between Cr(VI) and surface functional groups. The results of the study indicate that coir pith biochar is a potential adsorbent for the removal of Cr(VI) from aqueous solution.