Bagasse based biochar for the adsorptive removal of chlorpyrifos from contaminated water

Chlorpyrifos (CPS) is an emerging contaminant due to the runoff of CPS from agricultural fields, which find its way to nearby water sources. CPS requires to be removed to ensure the availability of safe drinking water. In this paper we report the experimental investigations carried out for the removal of CPS from waste water streams using bagasse based biochar as an adsorbent. Three different types of biochar were prepared from bagasse through different treatment to the raw bagasse. After identifying the best of the three types of biochar through iodine and methylene blue uptake, experiments were carried out to assess the removal of CPS from the aqueous systems containing 10-50 ppm. The results indicate about 89 % removal from an initial concentration of 10 ppm CPS. The bagasse was also characterized for its morphological and physiochemical characteristics. The optimal conditions for maximum uptake with respect to contact time, pH, initial CPS concentration, initial adsorbate concentration and temperature were studied. The isotherm models were evaluated and the results from error function analysis indicated Freundlich isotherm to be the most suitable model. The maximum adsorption capacity (q(m)) of the biochar for CPS was 3.20 mg g(-1). The kinetics data was best fitted with the pseudo second order model. CPS adsorption onto the biochar occurred in a spontaneous manner, was exothermic and involved physisorption.