不同方法改性柚皮制备的活性炭吸附亚甲基蓝试验

Experimental study of absorption of methylene blue with activated carbon prepared by modification pomelo peel in different methods

采用不同方法对柚子皮改性后制备活性炭,考察溶液pH值、活性炭投加量、亚甲基蓝初始质量浓度、吸附时间等因素对吸附效果的影响,并对吸附动力学和吸附机理进行了探讨。结果表明,在最佳条件下未改性和采用氯化铝、硫化钠、氢氧化钾改性柚子皮制备的4种活性炭对亚甲基蓝的脱色率分别为84.5%、87.3%、91.1%和95.5%。分析不同活性炭平衡吸附量的值可以得出结论:经过氯化铝和氢氧化钾改性的柚子皮制备的活性炭吸附亚甲基蓝的能力明显提高;4种活性炭对亚甲基蓝的吸附过程均符合准二级动力学模型;氯化铝和氢氧化钾改性柚子皮制备的活性炭表面包含更多的有机官能团,这与活性炭对应较高的亚甲基蓝废水初始质量浓度和高的平衡吸附量是一致的。

In this study,activated carbons were prepred by the modified grapefruit peel with different methods.The effects of the pH value,the dosage of activated carbon,the initial concentration of methylene blue and the adsorption time on the adsorption effect were investigated.The adsorption kinetics and adsorption mechanism were also discussed.The results showed that under the optimal conditions,the removal rates of methylene blue by four activated carbons were 84.5%(unmodified),87.3%(modified by aluminum chloride impregnation method),91.1%(modified by sodium sulfide activation),and 95.5%(modified by potassium hydroxide activation),respectively.Comparing the value of the equilibrium adsorption capacity of different activated carbons,the activated carbons prepared from modified pomelo peel with aluminum chloride and potassium hydroxide had a significantly improved adsorption ability.The analysis of adsorption kinetics showed that the adsorption process of methylene blue on four kinds of activated carbons all accorded with the quasi-second-order kinetic model.The surface of activated carbons prepared from modified pomelo peel with aluminum chloride and potassium hydroxide contained many organic functional groups,which was consistent with the higher initial concentration of methylene blue wastewater and high equilibrium adsorption of activated carbons.