铈掺杂镧基钙钛矿制备及对水体磷酸盐和植酸的吸附性能

Preparation of Ce-doped La-based perovskite and its adsorption properties for phosphate and phytic acid in water

为有效防治水体中的磷酸盐和有机磷污染,利用镧基金属氧化物结构灵活易调控和磷亲和力强等优势,本文在柠檬酸溶胶凝胶法制备的镧铁钙钛矿基础上,在镧位点掺杂铈成功制备了铈镧铁钙钛矿(LCFO),研究了LCFO吸附磷酸盐和植酸的热力学和动力学特征;考察了不同氯离子和腐殖酸根离子等因素对吸附过程的影响;采用扫描电子显微镜-能量色散光谱仪、X射线衍射仪、傅里叶变换红外光谱仪、X射线光电子能谱等表征探究吸附机理。结果表明,LCFO对磷酸盐和植酸吸附能力分别比原始钙钛矿提高了11.56倍和1.74倍,LCFO吸附量分别为57.86mg/g和98.71mg/g;两种形态磷吸附特征均符合准二级动力学方程和Langmuir等温吸附方程,腐殖酸根离子对LCFO对磷酸盐和植酸的吸附作用有一定削弱,但吸附量仍保持在80%以上;通过表征分析表明材料吸附磷酸盐和植酸的机理主要为内层络合。本研究为进一步改善镧铁钙钛矿对无机磷的吸附能力及对有机磷的去除提供参考。

In order to effectively prevent phosphate and organophosphorus pollution in water,and fully tap the advantages of flexible structure control and strong affinity for phosphorus of lanthanum-based metal oxides,the Ce-doped La-Fe perovskite(LCFO)was successfully prepared by doping cerium at the lanthanum site on the basis of lanthanum-iron perovskite prepared by the citric acid sol-gel method.The thermodynamic and kinetic characteristics of adsorption of phosphate and phytic acid by LCFO were studied,and the effects of different chloride ions and humic acid ions on the adsorption process were investigated.SEM-EDS,XRD,FTIR,XPS and other characterizations were used to investigate the adsorption mechanism.The results showed that the adsorption capacity of LCFO for phosphate and phytic acid was 11.56 times and 1.74 times higher than that of original perovskite,and the adsorption capacity of LCFO was 57.86mg/g and 98.71mg/g,respectively.The phosphorus adsorption characteristics of both forms conformed to the pseudo-second-order kinetic equation and Langmuir isothermal adsorption equation,and humic acid ions weakened the adsorption of phosphate and phytic acid by LCFO,but the adsorption amount remained above 80%.The mechanism of phosphate and phytic acid adsorption by the material was mainly internal complexation as shown by the characterization analysis.This study provided a reference for further improving the adsorption capacity of lanthanum-iron perovskite on inorganic phosphorus and the removal of organic phosphorus.