Removal of crystal violet, an emerging pollutant from aqueous solution using biochar prepared from coconut shell

Abstract

Crystal violet is an emerging pollutant which may be transferred into water bodies and does not have any established guidelines for detection. Biochar, a material derived from the partial pyrolysis of biomass, exhibits remarkable potential in removing organic contaminants like crystal violet due to its porous structure. In this study coconut shell powder was subjected to pyrolysis at four distinct temperatures to obtain biochar samples. Proximate analysis was performed for all the biochar samples obtained. The sample were characterised using FTIR, SEM and XRD. Kinetics and isotherm studies were performed on the biochar to determine the mechanism of adsorption and maximum removal capacity. As the pyrolysis temperature increased the pH and ash content increased, the yield of biochar decreased. The biochar prepared at 700 °C showed the best adsorption capacity among all the prepared biochar samples. Response surface methodology suggested the optimum dosage of biochar required is 210 mg at a concentration of 12 ppm. The adsorption process adhered to second-order kinetics, and the maximum adsorption capacity, according to the Langmuir adsorption isotherm, was determined to be 124.5 mg.g-1