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利用ZnCl_2活化法制备的柚皮基活性炭(GAC)处理含Cr(Ⅵ)废水,研究了pH、投加量、吸附时间、初始浓度和温度对Cr(Ⅵ)吸附的影响。吸附等温实验数据拟合显示,与Freundlich相比,吸附等温线更符合Langmuir和Dubinin-Radushkevich(D-R)方程。25、35和45℃时,GAC的单分子层吸附量分别为119.54、132.80、和145.47 mg/g,吸附自由能分别为9.93、17.72和20.82 k J/mol。吸附动力学研究显示:准二级动力学、颗粒内扩散和Bangham模型可以描述GAC吸附Cr(Ⅵ)的反应过程,吸附以化学吸附为主,过程受膜扩散和颗粒内扩散共同控制。
Cr (Ⅵ) wastewater was treated with pomelo peel - based activated carbon (GAC) prepared by ZnCl 2 activation method. The effects of pH, dosage, adsorption time, initial concentration and temperature on Cr (Ⅵ) adsorption were studied. Fitting isotherm data showed that the adsorption isotherm was more in line with the Langmuir and Dubinin-Radushkevich (D-R) equations than Freundlich. At 25, 35 and 45 ℃, the monolayer adsorption capacities of GAC were 119.54, 132.80 and 145.47 mg / g, respectively. The adsorption free energies of GAC were 9.93, 17.72 and 20.82 kJ / mol, respectively. Adsorption kinetics studies show that quasi-second order kinetics, intragranular diffusion and Bangham model can describe the reaction process of GAC adsorbing Cr (Ⅵ). The adsorption is dominated by chemisorption and the process is controlled by membrane diffusion and intragranular diffusion.