Influence of different pyrolysis methods on the sorption property of rice straw biochar

Rice straw presents a good potential as feedstock to prepare biochar. In this study, two different pyrolysis methods, that is, slow pyrolysis and direct pyrolysis are applied to carbonize the rice straw in muffle furnace. SEM and TEM images indicate that both samples display porous structure, while BET data confirm that biochars from direct pyrolysis process own higher specific surface area and pores volume than that from slow pyrolysis. Two samples are employed to metal ions Pb(II), Cu(II), Mn(II), and Cr(III) sorption from aqueous solution. The influence of reaction time, pH, and metal ions initial concentration on sorption are evaluated.