透析对施氏矿物微观结构及其砷吸附能力的影响

Effects of dialysis on the microstructure of schwertmannite and its arsenic removal ability

探讨透析对施氏矿物微观结构和砷吸附能力的调控,对高效合成施氏矿物,进而将其应用于含砷地下水处理具有重要意义.本研究在利用FeCl3·6H2O与Na2SO4合成施氏矿物的基础上,用截留分子量100000 Da和20000 Da透析袋分别对施氏矿物透析10 d与20 d,探究了透析过程对施氏矿物产生量、比表面积、孔体积、平均孔径等矿物特征的影响,并考察了透析前后施氏矿物对废水中砷的吸附去除效果.研究结果表明,透析过程可显著提高矿物的合成量,增加矿物比表面积及孔体积,增加矿物的平均孔径.施氏矿物在截留分子量100000 Da与20000 Da透析袋中透析20 d,矿物产生量分别增加70.70%与79.84%;比表面积分别增加68.75%与45.85%;其中微孔(<2 nm)比表面积增加439.90%与395.11%,中孔(2~50 nm)比表面积增加30.63%与9.96%;孔体积分别增加332.79%与287.25%,其中微孔体积增加491.61%与419.92%,中孔体积增加了220.36%与211.95%,透析后矿物平均孔径增长了214.77%与244.31%;矿物对污水中砷的吸附去除能力提高65.60%与64.74%.本研究结果可为化学合成施氏矿物改性并将其应用于地下水除砷领域提供必要的参数支撑.

It is of great significance to explore the effect of dialysis on the microstructure of schwertmannite and its arsenic(As) removal efficiency, and in further apply it into the As-containing groundwater treatment. In this study, the schwertmannite was synthesized using FeCl3·6 H2O and Na2SO4 chemical reagent firstly, and then the effect of dialysis on schwertmannite synthetic amount, specific surface area, pore volume, average pore diameter have been investigated based on dialysis schwertmannite by molecular weight cutoff of100000 Da and 20000 Da dialysis tubes. In addition, the effect of As removal efficiency from As-containing wasterwater has also been studied using the original schwertmannite and dialyzed schwertmannite as adsorbent. The results showed that the schwertmannite synthetic amount, specific surface area, pore volume, average pore diameter were significantly increased after dialysis. When schwertmannite were dialyzed in molecular weight cutoff of 100000 Da and 20000 Da dialysis tubes for 20 days, the schwertmannite synthetic amount was increased by 70.70% and 79.84%;the specific surface area of schwertmannite increased by 68.75% and 45.85%, and micropores area increased by 439.90% and 395.11%, mesopores area increased by 30.63% and 9.96%;the volume of pores increased by 332.79% and 287.25%, and micropores volume increased by 491.61% and 419.92%, mesopores volume increased by 220.36% and 211.95%. After dialysis, the average pore diameter increased by 214.77% and 244.31%. what′s more, the As adsorption capacity of schwertmannite could increased by 65.60% and 64.74% when schwertmannite used as the adsorbent material for As removal from As-containing wastewater. The results of this study can provide necessary parameter support for the chemical synthesis of schwertmannite, which will be applied as an adsorbent material for As removal from As-containing groundwater.