摘要
随着现代工业的飞速发展,工业废水中的重金属离子对人类生存和健康已造成严重的威胁,因此,如何有效去除重金属是当前环境治理领域中需要解决的重要问题。层状双金属氢氧化物(LDHs)作为一种二维层状化合物,具备来源广泛、化学性质稳定、合成成本低、无毒性等优势,被广泛应用于吸附材料、催化剂和药物学等领域。大量实验证明,层状金属氢氧化物能作为吸附剂去除水中的重金属离子,且吸附效果显著。但单一LDHs因官能团较少、耐酸碱性较差、重复使用率低、易聚集等缺点难以在环境修复领域的实际应用中进一步推广,因此,如何改善其吸附性能,即如何以层状双金属氢氧化物为基体材料来构筑功能性的层状金属氢氧化物材料,成为近期环境修复领域研究的热点之一。目前,研究人员试图以煅烧、插层、表面修饰和复合材料等方法对LDHs进行表面改性,以达到提高LDHs材料的层间距离、比表面积和表面官能团等目的,继而增加其与重金属离子之间的作用位点,提升吸附性能。大量研究表明,采用煅烧法能获得大比表面积和丰富含氧功能团的LDHs;如将苯二甲酸(TAL)和均苯四羧酸(PAL)等应用到插层改性能获得层间距离更大的LDHs,或者将甘油小分子应用于表面修饰改性LDHs,可以增加LDHs材料表面官能团的数量。以上改性方法均能提高LDHs的吸附性能,但改性后的LDHs材料仍存在回收效果差、重复利用率低等问题。因此,研究者制备了以Fe 3O 4为主的磁性LDHs复合材料,该制备方法既满足了高吸附性能的要求,也极大地提高了其重复利用效率;不仅突破了回收利用率低的瓶颈,还为LDHs材料在实际应用中的推广奠定了基础。基于水环境修复角度,本文首先论述了层状双金属氢氧化物的制备,及以层状双金属氢氧化物为基体材料的常用改性方法和可能的作用机理,并进一步论
With the rapid development of modern industry,heavy metal ions in industrial wastewater have caused serious threats to human survival and health.Therefore,how to effectively remove heavy metals is a top priority in the current environmental governance field.As a two-dimensional layered compound,layered double hydroxides(LDHs)have many advantages such as wide source,stable chemical properties,low synthesis cost and no toxicity.They are widely used in adsorption materials,catalysts and pharmacology.A large number of experiments have proved that the layered metal hydroxide can be used as an adsorbent to remove heavy metal ions in water,and the adsorption effect is remarkable.However,single LDHs is difficult to be further promoted in practical applications in the field of environmental remediation due to fewer functional groups,poor acid and alkali resistance,low reusability,and easy aggregation.Therefore,how to improve their adsorption performance,that is,how to use metal hydroxide as a matrix material to construct a functional layered metal hydroxide material,which has become one of the hotpots in the field of environmental restoration in the future.At present,researchers have attempted to modify the surface of LDHs by calcination,intercalation,surface modification and composite materials,so as to increase the interlayer distance,specific surface area and surface functional groups of LDHs materials,and then increase the interaction sites between them and heavy metal ions and the adsorption performance is improved.A large number of studies have shown that calcination can obtain large specific surface area and rich LDHs with oxygen-containing functional groups.For example,the application of phthalic acid(TAL)and pyromellitic acid(PAL)to intercalation modification can obtain larger interlayer distance.Large LDHs,or the application of small glycerol molecules to surface-modified LDHs,can increase the number of surface functional groups in LDHs.The above modification methods can improve the adsorption performance of LDH
作者
肖江
周书葵
刘星
储陆平
张建
李智东
田林玉
李嘉丽
XIAO Jiang;ZHOU Shukui;LIU Xing;CHU Luping;ZHANG Jian;LI Zhidong;TIAN Linyu;LI Jiali(School of Civil Engineering,University of South China,Hengyang 421000,China;School of Civil Engineering and Architecture,Chang an University,Xi an 710000,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第5期23-31,共9页
Materials Reports
基金
国家自然科学基金(51174117)
湖南省教育厅科研平台项目(15K106)
湖南省创新平台开放基金(17K078)~~
关键词
层状双金属氢氧化物
功能化
重金属
吸附机理
影响因素
layered double hydroxides
functionalization
heavy metals
adsorption mechanism
influencing factors
