铁镧双金属MOF去除水体中的磷酸盐和Cr(Ⅵ)  

Removal of phosphates and Cr(Ⅵ) from water by iron lanthanum bimetallic MOF

作　　者：金史怡 郭波[1] 曹群 冯凡 陈彩玉 王瑞麟 JIN Shi-yi;GUO Bo;CAO Qun;FENG Fan;CHEN Cai-yu;WANG Rui-lin(Department of Environmental Science and Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学环境科学与工程学院,山西太原030024

出　　处：《中国环境科学》2024年第9期4918-4928,共11页China Environmental Science

基　　金：山西省专利转化专项计划项目(202202055)。

摘　　要：采用快速高效的电沉积法制备了磁性铁镧双金属MOF(Fe/La-MOF)材料,并用于去除水中的磷酸盐和Cr(VI).结果显示:Fe/La等物质的量比,单独去除磷酸盐或Cr(VI)时,Fe/La-MOF投加量1g/L(除P)或2.5g/L(除Cr(VI)),pH值2~7(除P)或pH值2~11(除Cr(VI)),反应120min,磷酸盐(初始100mg P/L)或Cr(VI)(初始20mg Cr/L)的去除率分别达到94%或95%以上. Langmuir等温线能很好拟合Fe/La-MOF对磷酸盐或Cr(Ⅵ)的吸附,且理论最大吸附量分别是350.4mg P/g和33.4mg Cr/g. Fe/La-MOF吸附磷酸盐或Cr(Ⅵ)的行为更符合拟二级动力学,表明该过程以化学吸附为主;XPS、XRD、FTIR等表征结果进一步揭示:主要的吸附机理是发生在磷酸盐或Cr(Ⅵ)阴离子与Fe/La-OH之间的配体交换.另外,磁性Fe/La-MOF易于分离且在多次循环使用中保持较好的稳定性. Fe/La-MOF可同时用于去除磷酸盐和Cr(VI),pH值近中性, Fe/La-MOF加入量2.5g/L,反应120min,磷酸盐(初始25mg P/L)和Cr(VI)(初始20mg Cr/L)的去除率分别达到100%和92.2%.总之, Fe/La-MOF是一种可以快速制备的、具有良好吸附和稳定性能、宽大的pH值适用范围的高效吸附剂.A magnetic Fe/La bimetallic MOF(Fe/La-MOF) material, which prepared by a rapid and efficient electrodeposition method, was applied for phosphates and Cr(Ⅵ) removal from water. The results indicated that the individual phosphate or Cr(Ⅵ)removal rates could reach over 94% for phosphate(initial concentration of 100mg P/L) or 95% for Cr(Ⅵ)(initial concentration of 20mg Cr/L) after 120 min reaction under the conditions of a equimolar ratio of Fe to La, Fe/La-MOF dosages of 1g/L(for phosphate)or 2.5g/L(for Cr(Ⅵ)) and ranges of pH 2~7(for phosphate) or pH 2~11(for Cr(Ⅵ)), respectively. The Langmuir isotherm model could fit the adsorption of phosphate or Cr(Ⅵ) by Fe/La-MOF well, with theoretical maximum adsorption capacities of 350.4mg P/g and 33.4mg Cr/g, respectively. The adsorption behavior of phosphate or Cr(Ⅵ) by Fe/La-MOF could be better described by pseudo-second-order kinetics model, implying that the process is mainly chemical adsorption. Characterization results of XPS, XRD and FTIR revealed that ligand exchange between phosphate or Cr(Ⅵ) anions and Fe/La-OH could be the main removal mechanism.Furthermore, the magnetic Fe/La-MOF would be easy separated with good stability through 3 cycles of use. The good performances on simultaneous removal of phosphate and Cr(Ⅵ) were also exhibited with the removal rates of 100% for phosphate(initial concentration of 25mg P/L)and 92.2% for Cr(Ⅵ)(initial concentration of 20mg Cr/L) after 120min reaction under a neutral pH and Fe/La-MOF dosage of 2.5g/L. In general, Fe/La-MOF is a highly efficient adsorbent for removing phosphate or Cr(Ⅵ) with greater adsorption capacities and good stability in a wider pH range.

关 键 词：双金属MOF 磁性 电沉积 磷酸盐 Cr(Ⅵ) 

分 类 号：X703.1[环境科学与工程—环境工程]