Abstract:Characteristics phosphate adsorption onto biochars derived from dairy manure was investigated by batch adsorption experiments, and the influences of pH, coexisting anions, temperature, dosage of biochar, and pyrolysis temperature on the phosphate adsorption were studied. The results indicate that the optimal initial pH value for phosphate adsorption was 7.0, and low temperature favored the adsorption of phosphate. The coexisting anions had little effect on the adsorption and the optimal dosage of biochar for removing phosphate was 0.1g. The adsorption kinetic was well described by Pseudo-second kinetic model, whereas adsorption isotherm results elucidated that Langmuir-Freundlich (R2=0.9705) and Temkin (R2=0.9556)model provided the best fit for the equilibrium data. Furthermore, with regard to thermodynamic parameters, it was found that Gibbs free energy change or adsorption energy (ΔG0), -17.43at 25℃, -15.98at 35℃, and -15.89kJ/mol at 45℃ is negative indicating the spontaneous nature of the adsorption process.