Preparation of activated carbon by phosphoric acid through low temperature pretreatment

Activated carbons were prepared by phosphoric acid activation from Chinese fir powder which was impregnated by phosphoric acid and pretreated at low temperature.The effect of pretreatment temperature,activation temperature,impregnation ratio,holding time and phosphoric acid concentration on the properties of the activated carbons were studied.The results showed that pretreatment at low temperature promoted the penetration of phosphoric acid into lignocellulose,enhanced the activation of phosphoric acid,and increased the adsorption capability of activated carbon.As the increasing of activation temperature,holding time and phosphoric acid concentration,the adsorption capability,specific surface area and pore volume of activated carbon were increased;with the increasing of impregnation ratio,the adsorption properties of activated carbon increased at a maximum value and then decreased.N2 adsorption isotherms showed that the increasing of activation temperature was benefited for surface area and pore volume.Under optimized experimental condition,the surface area,total pore volume and microporous volume of the samples were 1628.7 m2·g-1,0.894 cm3·g-1 and 0.699 cm3·g-1,respectively.