钙铝层状双氢氧化物(CaAl-LDH)对铅镉砷污染废水的吸附性能及机制研究
Adsorption performance and mechanistic study of Pb,Cd and As by CaAl-LDH in wastewater
侯金凤 1孙倩 2郝秀珍3
作者信息
- 1. State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China
- 2. College of Agricultural Sciences and Engineering,Hohai University,Nanjing 210098,China
- 3. State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China
- 折叠
摘要
重金属污染普遍存在且日趋严重,解决阳离子和阴离子重金属共存的复合污染问题依然是一个严峻的挑战.本研究采用简便的原位共沉淀法制备了钙铝层状双氢氧化物(CaAl-LDH),用于去除水中的重金属离子.通过XRD、SEM、FTIR和XPS等表征方法研究CaAl-LDH的制备及其对重金属离子的吸附机理.采用批吸附实验研究CaAl-LDH对Pb(Ⅱ)、Cd(Ⅱ)和As(Ⅴ)三种金属离子的吸附能力.结果表明,准一级动力学模型可以很好地拟合CaAl-LDH对三种重金属的吸附.吸附等温线结果表明,与Freundlich模型(R2<0.67)相比,Cd的吸附过程更符合Langmuir模型(R2>0.92).Langmuir和Freundlich模型都能有效拟合Pb和As的吸附(R2>0.90).CaAl-LDH对Pb(Ⅱ)、Cd(Ⅱ)和As(Ⅴ)的最大吸附量分别为786.6、437.2和72.9 mg/g,并且在10 min内能够达到吸附平衡,反应快速高效.CaAl-LDH对铅、镉、砷的吸附机理各异.铅的吸附可能通过表面沉淀实现,而镉的吸附机理为同晶置换.至于As的吸附,可能涉及LDH层间的离子交换.该实验提供了一种对阴、阳离子重金属都具有高效吸附性能的LDH材料,并在重金属复合污染废水治理中显示出一定的应用潜力.
Abstract
Heavy metal composite pollution is becoming increasingly serious.In this study,CaAl-layered double hydroxide(CaAl-LDH)was prepared using the facile co-precipitating method,and was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),fourier transform infrared(FTIR)spectroscopy and X-ray photoelectron spectroscopy(XPS).Lead(II),Cd(II),and As(V)were selected as the representative heavy metals to evaluate the adsorption capability of the synthesized CaAl-LDH by the batch experiments.The maximal adsorption capability of CaAl-LDH for Pb(II),Cd(II),and As(V)was 786.6,437.2 and 72.9 mg/g,respectively.The adsorption mechanism of Pb,Cd and As may be surface precipitation,isomorphic substitution and ion exchange within the interlayer spaces of LDH,respectively.In conclusion,this experiment provides a LDH material with fast and efficient adsorption performance for both anionic and cationic metals,indicating its potential for practical application in the remediation of heavy metal composite pollution.
关键词
钙铝层状双氢氧化物(CaAl-LDH)/吸附/重金属/复合污染/废水治理Key words
CaAl-LDH/adsorption/heavy metal/combined contamination/wastewater treatment引用本文复制引用
基金项目
国家重点研发计划(2019YFC1803602)
出版年
2024
NETL
NSTL
万方数据