The conversion of pine needle and coconut shell biomass to activated biochar was done due to their high lignin, low ash content, abundant availability, and lower biodegradability. The production of activated biochar from pine needle and coconut shell impregnated using phosphoric acid was optimized using a full factorial experiment. All combinations of the three factors namely; activation temperature (400, 450, and 500 degrees C); impregnation ratio (1:1.25, 1:1.5, and 1:1.75) and activation time (20, 40, and 60 min) were investigated and optimized based on the responses (yield and adsorption characteristics). Individual second-order response surface models were generated and contour plots were made for the optimization analysis. The pine needle activated biochar (PNAB) and coconut shell activated biochar (CSAB) yields ranged between 47.39-57.81% and 48.79-65.23%, respectively. For PNAB and CSAB, the maximum iodine number was obtained as 1024.56 and 1234.13 mg/g, respectively. The responses were in good agreement with the prediction models for the validation of optimum variable parameters at generally acceptable values of the residual percentages. The optimum process parameters were evaluated as 450 degrees C, 60 min, 1:1.25 and 500 degrees C, 60 min, 1:1.25 for production of PNAB and CSAB, respectively. The high adsorption capacity of PNAB and CSAB paved their way for industrial applications.
