摘要
以合成的活性氧化铝微粉为吸附剂,研究了碱性含氟废水中pH值、初始氟浓度、吸附时间、氧化铝添加量等对除氟率和吸附容量的影响,讨论了其吸附机理。以铝酸钠溶液为原料,经氢氧化铝、丝钠铝石、碳酸铝铵和氧化铝等物相转化,制备了比表面积为409.03 m^2·g^-1的介孔氧化铝微粉。当pH值为7.0~9.4时,氧化铝微粉的除氟率较高。延长吸附时间、降低氟浓度或提高微粉加入量有利于提高除氟率。Zeta电位随溶液pH值的增大而减小,等电点为9.77。当pH值为8.1时,高比表面积、静电吸引、多层吸附是碱性条件下氧化铝微粉吸附容量大(9.28 mg·g^-1)、除氟率高(94.20%)的主要原因。同时,吸附也符合拟二级动力学模型,对氟的吸附受化学吸附控制。
Effect of pH,initial fluoride concentration,duration,alumina dosage on removal rate and adsorption capacity were studied by adding the fine activated alumina,and removal mechanism was then discussed.A fine activated alumina with specific surface area of 409.03 m^2·g^-1 was prepared by phase evolution from gibbsite,dawsonite,ammonia aluminate carbonate hydrate to mesoporousγ-Al 2O 3 after gibbsite precipitated from sodium aluminate solution.Results indicate that fluoride is efficiently removed within pH range from 7 to 9.4.Prolonging adsorption time,reducing fluoride concentration,and increasing alumina dosage improve removal rate.Meanwhile,increase in pH reduces zeta potential,and IEP is equal to 9.77.High specific surface area,electrostatic attraction,and multilayer adsorption contribute to adsorption capacity of 9.28 mg·g^-1 and removal rate of 94.20%in solution of pH 8.1.In addition,chemisorption is rate controlling step according to pseudo-second rate equation in removal of fluoride in alkaline solution.
作者
张婷
刘桂华
陈斌斌
齐天贵
周秋生
彭志宏
李小斌
ZHANG Ting;LIU Guihua;CHEN Binbin;QI Tiangui;ZHOU Qiusheng;PENG Zhihong;LI Xiaobin(School of Metallurgy and Environment,Central South University,Changsha 410083,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第4期20-24,55,共6页
Materials Reports
基金
国家自然科学基金(51874366)~~
关键词
活性氧化铝
比表面积
氟
碱性溶液
脱除
activated alumina
specific surface area
fluoride
alkaline solution
removal
