KOH活化法制备气化稻壳活性炭及其吸附性能

以气化稻壳炭(GRHC)为原料,KOH为活化剂制备活性炭,研究了不同活化温度和碱炭比对活性炭得率、比表面积、孔径分布以及碘值的影响.利用全自动气体吸附分析仪、X射线衍射仪、傅里叶变换红外光谱仪、扫描电镜等仪器对活性炭的理化性质进行表征,并通过吸附等温线、吸附动力学探讨其对甲基橙的吸附机制.结果表明:活化时间为1h时,随...

Preparation of Activated Carbon from Gasified Rice Husk Char Activated by KOH and Its Adsorption Properties

Potassium hydroxide (KOH) was used as activating agent to prepare activated carbon with gasified rice husk char (GRHC) as raw material. The effects of activation temperature and mass ratio of KOH to char on the specific surface area, pore diameter distribution and iodine value of activated carbon were investigated. The physicochemical properties of activated carbon were characterized by automatic gas adsorption analyzer, X-ray diffraction, Fourier transform infrared spectrometer, and scanning electron microscope, et al. The adsorption mechanism of methyl orange was studied by adsorption isotherm and adsorption kinetics. The results showed that when the activation time was 1 h, the yield of activated carbon decreased gradually with the increase of activation temperature and alkali-carbon ratio, and the specific surface area and iodine adsorption value increased first and then decreased. The optimal conditions for preparation of activated carbon were mass ratio of KOH to char 2:1 and activation temperature of 800℃. Under these conditions, the specific surface area, total pore volume, iodine value and saturated adsorption value of methyl orange reached their maximum values of 1 829.09 m²/g, 1.007 cm³/g, 1 984.85 mg/g and 217.87 mg/g, respectively and the yield of activated carbon was 41.73%. The adsorption process of methyl orange by activated carbon was highly correlated with Langmuir and Freundlich models (R²>0.99), and the adsorption kinetics was more consistent with the pseudo-second-order kinetic model.