机械力预处理磷酸法与传统磷酸法制备活性炭

摘要

The activated carbon was prepared from kenaf rod core by mechanical force pretreatment process and conventional process with phosphoric acid as activator.The effects of activation time on the yield, adsorption performance of the kenaf rod based-activated carbon were discussed.The pore structure characteristics were characterized by specific surface area and pore size analyzer and the surface functional groups were characterized by Fourier transform infrared spectroscopy.The results showed that compared with the conventional process, the mechanical force pretreatment process made phosphoric acid permeate into the inner layer of raw material to strengthen the activation efficiency, which improved the yield, adsorption performance, BET specific surface area and pore volume of kenaf rod based-activated carbon.Under the activation time 90 min, the yield, iodine adsorption value, methylene blue adsorption value, BET specific surface area and total pore volume of the activated carbon prepared by mechanical force pretreatment process were 50.24％, 1024 mg/g, 275 mg/g, 1625.42 m2/g and 0.762 cm3/g, respectively. According to pore size analysis, activated carbons prepared by the two methods were mainly microporous and contained a certain number of mesopores.It was known from infrared spectrum analysis that the mechanical force pretreatment process didn't destroy the basic structure of activated carbon.The surface of kenaf rod based-activated carbon prepared by the two methods contained oxygen-containing functional groups, such as -OH,C-O and C O groups.%以速生材红麻秆芯为原料,磷酸为活化剂,采用传统磷酸活化法和机械力预处理磷酸活化法制备红麻秆基活性炭.考察了不同活化时间下2种制备方法对红麻秆基活性炭得率和吸附性能的影响,并借助比表面积分析仪、红外光谱仪表征了活性炭的孔结构及表面官能团特征.结果表明:相比于传统磷酸活化法,机械力作用能使磷酸渗入到原料里层,提高活化效率,使活性炭具有更高的得率、吸附性能、BET比表面积和孔容.在活化时间90 min下,机械力预处理磷酸活化法制得的活性炭得率为50.24％,碘吸附值为1024 mg/g,亚甲基蓝吸附值为275 mg/g,BET比表面积为1625.42 m2/g,总孔容为0.762 cm3/g.由孔径分析可知,2种方法制备的活性炭均以微孔为主,并含有一定数量的中孔.由红外光谱分析可知,机械力预处理不会破坏炭化物的基本结构,2种方法制备的活性炭表面均含有-OH、C-O和C O等含氧官能团.