硫铝酸盐水泥及其改性材料对典型重金属的去除性能

Performance on typical heavy metals removal by sulphoaluminate cement and its modified material

应用经济高效的材料和简易的方法去除水中重金属已成为当前的研究热点。选择硫铝酸盐水泥(L)及其改性材料(LA)为清除剂,以Cu^(2+)、Pb^(2+)、Zn^(2+)、Cd^(2+)4种典型的重金属离子为研究对象,通过考察L和LA去除重金属过程中单因素的影响,对去除条件进行了优化,此外,通过竞争吸附实验及吸附动力学模型探究了对金属离子的去除机理。结果表明,L和LA可以有效地去除废水中的重金属离子,在pH为3.0~10.0条件下能够以较少的投加量(0.05~3 g·L^(−1))使目标离子达到94%以上的去除率,30 min内表观吸附速率可降到零。相比之下,LA对金属离子的去除率略高于L。在最佳应用条件下,金属离子的去除率基本在90%以上。在竞争吸附实验中Cu^(2+)的竞争性最强,且其能够促进其他离子被吸附。吸附动力学分析表明,L和LA对重金属的吸附是以化学吸附为主,去除机理以水解沉淀为主。以上研究结果可为该类材料对重金属的处理提供参考。

The application of cost-effective materials and simple methods to remove heavy metals from water has become a research hotspot.In this study,a type of sulphoaluminate cement(L)and its modified material(LA)were used to remove four typical heavy metal ions of Cu^(2+),Pb^(2+),Zn^(2+)and Cd^(2+)from the simulated wastewater.The removal conditions were optimized by investigating the effects of single factors on heavy metals removal by L and LA.In addition,the removal mechanism was analyzed by the competitive adsorption test and adsorption kinetic model.The results indicate that L and LA had a good performance on heavy metal ions removal from wastewater,under the conditions of pHs 3.0~10.0 and low dosages(0.05 g·L^(−1)~3 g·L^(−1)),the removal rate could reach higher than 94%,and the apparent adsorption rate decreased to zero within 30 minutes.The removal rate by LA was slightly higher than L.Under the best application conditions,the removal rates for these heavy metals were basically higher than 90%.In the competitive adsorption,Cu^(2+)showed the strongest competition and could promote the adsorption of other ions.The adsorption kinetics analysis shows that the heavy metals adsorption by L and LA was mainly dominated by chemical adsorption,and the mechanism of heavy metals removal was mainly dominated by hydrolytic precipitation.These results can provide a reference for heavy metals treatment in wastewater by this type of material.