摘要
针对类水滑石因层板存在较强静电作用,难以实现有效剥离这一问题,提出利用类水滑石焙烧产物的“记忆效应”实现乙酸铵对自组装镁铝类水滑石的插层预处理,再通过高温加热使层间有机组分挥发来制备剥离态镁铝类水滑石纳米片;主要考察了过程因素对剥离效果的影响,借助XRD、TEM、AFM等测试分析手段对剥离前后样品进行表征,比较研究了类水滑石剥离前后样品的吸附性能。结果表明,当镁铝类水滑石在450℃下分解为MgO和Al_(2)O_(3)后,将上述混合金属氧化物按3 g/L的投加量投入500 mL、浓度为1 mol/L的乙酸铵溶液中,搅拌剥离12 h后,在200℃下焙烧30 min后可获得剥离态镁铝类水滑石纳米片,该纳米片粒度小、分散性好,在水中可实现重组而具有类水滑石的特征衍射峰。吸附试验结果表明,未剥离类水滑石对Cr(Ⅵ)具有较好的吸附去除效果,而剥离态类水滑石纳米片对Cd(Ⅱ)的吸附性能较剥离前明显提高自我评价。
In view of the problem that Mg-Al hydrotalcite was difficult to be effectively exfoliated because of the strong electrostatic effect between its different laminates,an exfoliating method was put forward in this paper.The“memory effect”of its roasted product was used to realize the intercalation pretreatment of self-assembled Mg-Al hydrotalcite by ammonium acetate and then the organic components evaporated at high temperature to get exfoliated Mg-Al hydrotalcite nanosheets.In this paper,the effect of process factors on the exfoliating effect was investigated,and the samples before and after exfoliation were characterized by XRD,TEM,AFM and other test and analysis methods.The results show that,after Ma-Al hydrotalcite is decomposed into MgO and Al_(2)O_(3) at 450℃for 6 h,the mixed metal oxide is put into 500 mL ammonium acetate solution with a mass concentration of 1 mol/L at 3 g/L,stirred and exfoliated for 12 h,and roasted at 250℃for 30 min to obtain the exfoliated Mg-Al hydrotalcite nanosheets.The nanosheets which have small particle size and good dispersion can be reconstituted in water,and the reconstituted product have the characteristic diffraction peak of Mg-Al hydrotalcite.The results of adsorption test show that Mg-Al hydrotalcite have a good adsorption and removal effect on Cr(Ⅵ)before exfoliation,and its adsorption performance on Cd(Ⅱ)after exfoliation is obviously improved.
作者
莫伟
余畅
何秋芝
包扬阳
何春彦
黄钰华
MO Wei;YU Chang;HE Qiu-zhi;BAO Yang-yang;HE Chun-yan;HUANG Yu-hua(School of Resources,Environment and Materials,Guangxi University,Nanning 530004,China;Department of Medicine,Guangxi University of Science and Technology,Liuzhou 545006,China)
出处
《广西大学学报（自然科学版）》
CAS
北大核心
2022年第3期779-787,共9页
Journal of Guangxi University（Natural Science Edition）
基金
国家自然科学基金项目(51664001)。
关键词
镁铝类水滑石
剥离
吸附
Mg-Al hydrotalcite
exfoliation
adsorption
