微米级管状氧化镁团簇体的合成及其吸附磷的性能

Synthesis of micron-tubular-magnesium oxide clusters and its adsorption performance for phosphate

利用自组装技术合成了微米级管状团簇体碱式碳酸镁(MTBMg),进一步热解得到管状团簇体氧化镁(MTMgO)。采用X射线衍射(XRD)、扫描电镜(SEM)和BET分析对MTMgO的结构、形貌进行了表征。结果表明,在水解温度为80℃、反应物浓度为0.6 mol/L条件下利用自组装技术构筑了MTBMg,热解后形成的MTMgO保留了前驱体MTBMg的相似结构,且具有丰富的微米尺寸氧化镁,为磷的吸附提供了活性位点。磷模拟废水吸附结果表明,在废水pH为3~11条件下MTMgO表现出优异的吸附磷的性能,其吸附过程满足Langmuir等温吸附模型;当废水pH=10时MTMgO对磷的理论吸附量最大,为2120.12 mg/g。动力学分析结果表明,对于MTMgO吸附磷的过程准一级和准二级动力学方程拟合度均较高,是化学吸附与物理吸附并存的过程,随着MTMgO加入量增加由化学吸附为主导向物理吸附为主导转变。当废水中磷的质量浓度为800 mg/L时,吸附剂对磷的去除率仍达到96.47%。

Micron-tubular-basic magnesium carbonate clusters(MTBMg)was synthesized by self-assembly technology,and micron-tubular-magnesium oxide clusters(MTMgO)was obtained by further pyrolysis.The composition and morphology of MTMgO were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and BET analysis.The results showed that the MTBMg was synthesized at hydrolysis temperature of 80℃and reaction concentration of 0.6 mol/L,the MTMgO retained the similar structure of precursors and had abundant micro-sized MgO particles,which provided active sites for phosphate adsorption.The adsorption results of phosphorus simulated wastewater showed that the MTMgO exhibited excellent phosphate adsorption performance at wastewater p H of 3~11 and the isothermal adsorption was fitted with the Langmuir model.The maximum adsorption capacity of MTMgO was 2120.12 mg/g at pH of 10.The kinetic results showed that the phosphate adsorption by MTMgO fitted both pseudo first order kinetics primary and pseudo second order kinetics models,indicating that the adsorption of phosphate could be described by both chemisorption and physical adsorption mechanism.With the increase dosage of MTMgO,the adsorption process shifted from chemisorption-dominated to physisorptiondominated.When the mass concentration of phosphorus in wastewater was 800 mg/L,the phosphate removal rate by adsorbent was 96.47%.