铈/粉煤灰复合吸附剂的制备及其对Cd(Ⅱ)的吸附

Preparation of cerium/fly ash composite adsorbent and its adsorption on Cd(Ⅱ) from aqueous solution

以固体废物粉煤灰(FA)为原料,通过掺杂稀土铈元素结合碱熔融法改性制备了铈/FA复合吸附剂(Ce/MFA),并用XRD,SEM及EDS进行了表征.以吸附水溶液中Cd2+为反应模型,研究了各种制备条件对复合材料吸附性能的影响.结果表明:1)当所取FA、无水Na2CO3和Ce(SO4)2·4H2O的质量比为1∶2∶0.045,焙烧温度为800℃,焙烧时间为2h时,制得的Ce/MFA吸附剂对于水体中的Cd2+具有最佳去除效果;2)当Ce/MFA的投加量为10g/L,吸附时间和吸附温度分别为2.5h和25℃时,对起始质量浓度为800mg/L模拟废水中Cd2+的去除率可达99.67%,比FA增大了37倍,实现了对废水中高含量Cd2+的有效去除;3)通过表征发现FA掺杂铈元素-碱熔融后会使其结构发生明显变化,活性增大,吸附性能显著增强.作为一种性价比高的吸附剂,Ce/MFA用于废水中Cd2+的去除极具开发应用价值.

A novel cerium/modified fly ash （Ce/MFA） composite adsorbent was prepared by mixing raw FA with hydrated cerium sulfate and anhydrous sodium carbonate using calcination method and characterized with XRD, SEM and EDS. Based on the adsorption of Cd （Ⅱ） from aqueous solution as a reaction model, the effects of preparing conditions on the adsorption properties of Ce/MFA were investigated. The results show that： 1） The prepared Ce/MFA composite adsorbent exhibits excellent adsorption performance for Cd（Ⅱ） removal from aque- ous solution when the mass ratio of FA, Na2CO3 and Ce（804）2 · 4H2O is 1 ： 2 ： 0. 045 and calcination time is 2 h at 800℃. 2） The removal rate of Cd（Ⅱ） with the initial concentration of 800 mg/L on Ce/MFA can reach 99.67% under the optimum conditions of Ce/MFA dosage of 10 g/L and adsorption time of 2.5 h at 25 ℃, 37 times greater than that on FA, indicating that Ce/MFA is a high-performance adsorbent for the removal of high-concentration Cd^2＋ in the wastewater. 3） It is found by the characterization that the structure of FA changes obviously after doping with rare earth cerium. The increase of activity results in the significant enhance- ment of Ce/MFA adsorption performance. As an effective and cheap adsorbent, Ce/MFA is valuable in development and application prospect for the removal of Cd（Ⅱ） in wastewater.