摘要
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。
A kind of activated carbon（GAC）made from grapefruit peel and activated by ZnCl_2 in the laboratory was used to the removal of hexavalent chromium from aqueous solution,with which the experimental studies were conducted to determine the influential factors including p H,adsorbent dose,contact time,Cr（Ⅵ） initial concentration and temperature.When fitting isotherm with the experimental data acquired,it was found the adsorption process was better described by Langmuir and Dubinin–Radushkevich（D-R） isotherms than by Freundlich isotherm. The maximum monolayer adsorption capacity at 25 ℃,35 ℃,and 45 ℃ were 119.54,132.80,and 145.47 mg/g;and the mean free sorption energy was 9.93,17.72 and 20.82 kJ/mol,respectively. Furthermore,the research on adsorptive dynamics presented that the process of Cr（Ⅵ）adsorption on GAC can be described by the pseudo second-order kinetic model,Bangham equation models and intraparticle diffusion model,and the adsorption was mainly attributed to a kind of chemisorption,whereas both of intraparticle diffusion and film diffusion were the rate limiting steps.
出处
《环境科学与技术》
CAS
CSCD
北大核心
2016年第3期74-79,共6页
Environmental Science & Technology
基金
广西矿冶与环境科学实验中心项目资助(KH2012ZD004)
广西高等学校高水平创新团队及卓越学者计划项目资助
关键词
柚皮
活性炭
吸附机理
六价铬
grapefruit peel
activated carbon
adsorption mechanism
hexavalent chromium
