摘要:以活性炭为原料,用溶胶—凝胶法和浸涂法制备了改性活性炭,采用了静态吸附法研究了改性活性炭对亚甲蓝染料的吸附性能。考察了温度、吸附时间、不同负载量、亚甲蓝初始浓度和pH 值等因素对亚甲蓝染料吸附效果的影响,并研究了染料在活性炭上的吸附平衡。实验结果表明,在pH=2时改性活性炭的吸附性能最好,并且随着温度的升高,吸附量增加。对于吸附饱和的改性活性炭进行了光催化再生,结果表明光催化再生恢复了吸附饱和活性炭的部分吸附能力。
关键词:TiO2改性活性炭, 吸附, 亚甲蓝
Abstract: The activated carbon loaded by TiO2 is prepared by the sol-gel method using active carbon as raw material. The effect on the adsorption of methylene blue was studied of temperature, adsorption time, different load of TiO2, initial dye concentration, and initial pH values, and the methylene blue adsorption equilibriums on carbon was also studied. The results of adsorption indicate that the largest adsorption capacity of activated carbon modified by TiO2 is achieved at pH = 2. The adsorption is an endothermic process with increasing temperature, and higher temperature will benefit the adsorption. The activated carbon saturated with methylene blue is regenerated by photocatalytic regeneration method,and the results indicated that part of adsorption capacity is restored。
keywads: actived carbon loaded by TiO2,adsorption,methylene blue
通过改性后活性炭吸附亚甲蓝表明:负载了TiO2的活性炭对高浓度的亚甲蓝染料具有良好的吸附效果,其结论如下:
(1) 当改性活性炭0.5g加入到50ml亚甲蓝溶液中时,初始浓度为1800 mg/L 时就可以使改性活性炭达到吸附饱和状态;30摄氏度时吸附时间为24h的情况下就可以达到饱和吸附平衡。考查了同一初始浓度下不同pH条件对于饱和吸附量的影响,得出pH的影响不是很大,但是当pH为2时,饱和吸附量最大。
(2) 在其他条件相同的情况下考查了环境温度对于吸附效果的影响,结果表明随着环境温度的升高,改性活性炭对亚甲蓝的吸附能力相应的增加
(3) 负载了TiO2的活性炭经过光催化再生处理后恢复了部分吸附能力,但是随着光催化再生次数的增加,活性炭吸附能力的再生率逐渐下降,这可能是由于在再生过程中生成了与活性炭结合更强的中间物种在活性炭孔内驻留,或堵塞了部分吸附通道。