纯相钙铝层状双氢氧化物对磷的吸附特性  

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

作　　者：谢发之[1] 汪雪春 杨佩佩[1] 李海斌[1] 圣丹丹 胡婷婷[1] 谢志勇[1] 

机构地区：[1]安徽建筑大学材料与化学工程学院

出　　处：《应用化学》2016年第4期473-480,共8页Chinese Journal of Applied Chemistry

基　　金：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~~

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、p H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p H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SO2-4浓度从2.5 g/L升高到25 g/L时,Ca-AlLDH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。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,p H 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 p H 5. 1,temperature 318 K,time 600 min,solid /liquor ratio of 0. 15 g /250 m L 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 SO4^2-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.

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 

分 类 号：O647.3[理学—物理化学]