应用化学 ›› 2016, Vol. 33 ›› Issue (4): 473-480.DOI: 10.11944/j.issn.1000-0518.2016.04.150265

• 研究论文 • 上一篇    下一篇

纯相钙铝层状双氢氧化物对磷的吸附特性

谢发之(),汪雪春,杨佩佩,李海斌,圣丹丹,胡婷婷,谢志勇   

  1. 安徽建筑大学材料与化学工程学院 合肥 230601
  • 收稿日期:2015-07-24 接受日期:2015-11-18 出版日期:2016-04-01 发布日期:2016-04-01
  • 通讯作者: 谢发之
  • 基金资助:
    国家自然科学基金项目(21107001);安徽省自然科学基金(1608085MB43);安徽省高校自然科学研究重点项目;2014年安徽省高校优秀青年人才支持计划项目资助

Pure Ca-Al- Layered Double Hydroxides as an Efficient Sorbent for Phosphate

XIE Fazhi(),WANG Xuechun,YANG Peipei,LI Haibin,SHENG Dandan,HU Tingting,XIE Zhiyong   

  1. School of Materials Science and Chemical Engineering,Anhui Jianzhu University,Hefei 230601,China
  • Received:2015-07-24 Accepted:2015-11-18 Published:2016-04-01 Online:2016-04-01
  • Contact: XIE Fazhi
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.21107001), the Natural Science Foundation of Anhui Province(No.1608085MB43), Key Program of the Education Department of Anhui Province, Excellent Young Talents Supporting Plan for University of Anhui Province(2014)

摘要:

采用乙醇辅助液相共沉淀法制备了纯相Ca-Al-LDH层状双金属氢氧化物,考察了Ca-Al-LDH的投加量、吸附时间、pH值、无机电解质(Na2CO3 ,KCl ,Na2SO4,KNO3)和温度等因素对磷吸附的影响,结果表明,纯相Ca-Al-LDH对磷酸根离子具有很好的吸附性能,最大饱和吸附量可达160.78 mg/g,当pH值为5.1、温度为45 ℃、吸附时间为600 min、LDH投加量为0.6 g/L、磷初始浓度为80 mg/L时,磷的去除率高达95.88%;无机阴离子会抑制磷在吸附剂上的吸附,当Cl-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量从69.96 mg/g降至53.18 mg/g,降低了23.99%;当SO42-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量降低了24.79%,其它无机阴离子对磷在吸附剂上的吸附也有一定的影响。 Ca-Al-LDH对水中磷的吸附符合二级动力学方程和Langmuir等温模型。 采用扫描电子显微镜、傅里叶变换红外光谱仪和X射线衍射仪等技术手段对制备的纯相Ca-Al-LDH及其吸附磷酸根后的产物进行表征,揭示了Ca-Al-LDH对磷酸根的吸附可能是静电吸引、化学吸附和阴离子插层等过程协同作用的吸附机理。

关键词: 乙醇辅助液相共沉淀, 层状双金属氢氧化物, 磷吸附, 动力学方程

Abstract:

High purity Ca-Al-layered double hydroxides(LDH) was prepared in an ethanol/water solution at a volume ratio of 4:1. Effect of sorbent dosage, adsorption time, pH value, inorganic electrolyte(Na2CO3, KCl, Na2SO4, KNO3), temperature for phosphate adsorption were investigated. As prepared Ca-Al-LDH is an effective sorbent for phosphate adsorption. The maximum adsorption capacity of phospahte is 160.78 mg/g and the phosphate removal efficiency reaches to 95.88% at pH 5.1, temperature 318 K, time 600 min, solid/liquor ratio of 0.15 g/250 mL and initial phosphate concentration of 80 mg/L. Inorganic anions can restrain the adsorption of phosphorus on Ca-Al-LDH absorbent. Sorption capacity of phosphate is decreased 23.99% from 69.96 mg/g to 53.18 mg/g with increasing the concentration of Cl- from 2.5 g/L to 25 g/L. The sorption capacity is reduced about 24.79% with SO42- at the same conditions. Other inorganic anion also has a certain influence on phosphate sorption in pure Ca-Al-LDH. The second order kinetic equation is suitable for describing the adsorption process, and the Langmuir isotherm model fits the data well. The sorption mechanism is electrostatic attraction, chemosorption and anion intercalation.

Key words: liquid phase coprecipitation, layered double hydroxides, phosphate adsorption, thermodynamics and kinetics equation