Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity f...Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity for Pb2+ were examined to optimize these parameters. The optimal conditions for the preparation of AC were determined to be activation temperature of 500 °C, activation time of 1 h, impregnation ratio of 1:1(solid-to-liquid volume) with the 30% ZnCl2 solution(mass fraction), giving the BET surface area of 393.85 m2/g and yield of 30.14% with 33.45% ash. Also, the pyrolysis temperature was found to be the most important parameter in chemical activation. FTIR spectra provided the evidence of some surface structures such as C=C and C—O—C. In the adsorption studies, a rise in solution pH led to a significant increase in adsorption capacity when the pH value varied from 3.0 to 7.0, and the optimal pH for removal of Pb2+ was 7.0. It was observed that the pseudo-second-order equation provided better correlation for the adsorption rate than the pseudo-first-order and the Langmuir model fitted better than the Freundlich model for adsorption isotherm. The adsorption capacity of AC to Pb2+ was 11.75 mg/L at solution pH 7.0, the equilibrium time 480 min and 25 °C. Moreover, the adsorption process is endothermic according to the value of enthalpy change.展开更多
基金Project supported by the Open Fund of State Key Laboratory of Photocatalysis,China
文摘Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity for Pb2+ were examined to optimize these parameters. The optimal conditions for the preparation of AC were determined to be activation temperature of 500 °C, activation time of 1 h, impregnation ratio of 1:1(solid-to-liquid volume) with the 30% ZnCl2 solution(mass fraction), giving the BET surface area of 393.85 m2/g and yield of 30.14% with 33.45% ash. Also, the pyrolysis temperature was found to be the most important parameter in chemical activation. FTIR spectra provided the evidence of some surface structures such as C=C and C—O—C. In the adsorption studies, a rise in solution pH led to a significant increase in adsorption capacity when the pH value varied from 3.0 to 7.0, and the optimal pH for removal of Pb2+ was 7.0. It was observed that the pseudo-second-order equation provided better correlation for the adsorption rate than the pseudo-first-order and the Langmuir model fitted better than the Freundlich model for adsorption isotherm. The adsorption capacity of AC to Pb2+ was 11.75 mg/L at solution pH 7.0, the equilibrium time 480 min and 25 °C. Moreover, the adsorption process is endothermic according to the value of enthalpy change.
文摘以椰壳炭化料为原料,采用K2CO3活化法在不同操作条件下制备椰壳活性炭,探讨了K2CO3活化实验中K2CO3与炭化料质量比、活化时间和活化温度对活性炭得率、活性炭亚甲蓝吸附值和苯酚吸附值的影响.实验结果表明,K2CO3与炭化料质量比和活化温度是K2CO3活化法制备椰壳活性炭最重要的影响因素.综合考虑活性炭的得率和活性炭吸附性能受活化操作参数的影响规律,探讨了K2CO3活化法制备椰壳活性炭的最优操作参数,得到了实验范围内的最佳工艺条件为:K2CO3与炭化料的质量比为2∶1,活化温度为800℃左右,活化时间为120m in.
