多价态金属离子与藻菌共生体胞外聚合物作用对膜污染的影响

Effects of multivalent metal ions interacting with extracellular polymers of microalgae-bacteria symbionts on membrane fouling

采用藻菌共生体-膜组合工艺处理养殖废水,针对不同价态金属离子与藻菌共生体分泌的胞外聚合物(extracellular polymeric substance,EPS)相互作用对超滤过程中膜污染的影响展开研究。通过分别向EPS溶液中添加不同浓度(20、30 mg·L^(-1))Ca^(2+)、Mg^(2+)、Fe^(3+)、Al^(3+)离子,与未添加金属离子的对照组比较,探究不同浓度金属离子添加对膜通量衰减的影响和作用机制。实验结果表明,在超滤过程中加入Mg^(2+)会使膜通量减小,加剧了膜污染状况;Ca^(2+)对超滤过程影响较小,但也在一定程度上加剧了膜污染;而Fe^(3+)和Al^(3+)的加入则对膜污染有一定缓解作用,使得添加组膜通量较对照组反而有所提高。采用Hermia模型对实验数据进行拟合分析发现加入多价态金属离子的EPS溶液均呈现出与标准堵塞模型拟合程度最高的特征。

The microalgae-bacteria symbitic membrane coupling technology was used to treat swine wastewater.Effects of the interaction between different valence metal ions and EPS secreted by microalgae-bacteria symbionts on membrane fouling of ultrafiltration were studied.By adding different concentrations(20、30 mg·L^(-1))of Ca^(2+),Mg^(2+),Fe^(3+)and Al^(3+)ions to the EPS solution any by comparing with the control group without metal ions,the effect and mechanism of different concentrations of metal ions on membrane flux decline were investigated.The experimental results showed that the addition of Mg^(2+)during ultrafiltration would reduce the membrane flux and aggravate the membrane fouling.Ca^(2+)showed limited influence on the ultrafiltration performance,while also increased the membrane fouling conditions to some extent.The addition of Fe^(3+)or Al^(3+)showed some effort on the alleviation of membrane fouling,leading to relatively higher filtration flux than that of the control.The Hermia model was used to fit and analyze the experimental data and it was found that the EPS solution added with Ca^(2+),Mg^(2+),Fe^(3+)and Al^(3+)ions showed high fitting degree with the standard plugging model.