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题名	新型环境污染物全氟辛烷磺酸（PFOS）的纳滤去除研究
作者	张健
学位类别	硕士
答辩日期	2013-05
授予单位	中国科学院研究生院
授予地点	北京
导师	赵长伟
关键词	PFOS 纳滤膜 截留率 膜通量 钙离子 PFOS nanofiltration membrane retention flux calcium ions
其他题名	Removal of PFOS from water with nanofiltration membrane
学位专业	环境工程
中文摘要	本文采用纳滤膜分离技术开展饮用水中新型持久性有机污染物全氟辛烷磺酸（PFOS）的去除实验研究，系统深入地研究了不同进水水质、纳滤不同操作条件等因素对PFOS去除效果和膜污染的影响。取得创新性研究成果如下： 1．筛选出适宜于饮用水中PFOS去除的纳滤膜材料。实验中分别选取了陶氏公司NF270、海德能公司HYDRA-core 10、GE公司DK纳滤膜及自制PMIA纳滤膜等几种不同性能的纳滤膜，分别考察了不同操作条件下纳滤膜对PFOS的截留效果及通量变化。结果表明NF270对PFOS具有较高的截留率（0.8 MPa压力下94.41%），通量适宜（0.8 MPa压力下137 L/m2h），因此选取NF270作为去除PFOS的较优的纳滤膜。 2．研究考察了压力、pH值、PFOS初始浓度、腐殖酸共存等不同操作条件下纳滤膜对单一PFOS的截留率及膜通量的变化，分析了影响截留效率的因素并探讨了截留机理。结果表明随着压力的升高，膜通量增大，截留率有所提高；PFOS的截留率随着pH、PFOS初始浓度、腐殖酸浓度的升高而升高，在pH=7、压力为1 MPa下，当腐殖酸浓度为20 mg/L时，PFOS的截留率最高可达到98.37%。纳滤膜对PFOS的吸附实验说明，NF270纳滤膜对PFOS的吸附量很小。纳滤膜对PFOS的去除主要是筛分作用和电荷作用。 3．考察了Na+、Ca2+等不同电解质存在条件下，NF270纳滤膜对PFOS的截留效果，发现二价盐对截留率提高的贡献率要大于一价盐。系统考察与钙离子共存条件下纳滤膜截留PFOS的效果，并根据PFOS截留率及实验后膜片的SEM、AFM等表征数据对截留机理进行了分析。结果表明，PFOS的截留率随着钙离子浓度的升高而升高，膜通量在钙离子浓度小于2 mmol/L时，随着钙浓度的增加而升高，但当钙离子浓度为3 mmol/L时，通量反而降低。钙离子对PFOS截留率的影响主要因为PFOS会与钙离子发生络合而使体积增大，提高了筛分作用；当溶液中加入腐殖酸后，截留率有一定提高，但膜污染加重，膜通量急剧降低，PFOS的截留率最高可达到99.25%。 4．考察了Pb2+、Cd2+、Cr6+、As5+等重金属离子对PFOS截留效果的影响， 结果表明Pb2+和Cd2+对PFOS去除效果的影响存在明显的区别，Pb2+存在时纳滤膜对PFOS的截留率降低，并且随着投加量增大截留率降低；Cd2+存在时纳滤膜对PFOS的截留率提高，可能是因为络合作用的发生，并且随着投加量的增加PFOS的截留率提高的越多；铬和砷以Cr2O72-和AsO42-的形式存在，由于电荷作用而使纳滤膜对PFOS的排斥作用增强，因此PFOS截留率提高并且随着Cr2O72-和AsO42-浓度的提高而上升。
英文摘要	Perfluorooctane sulfonate (PFOS) as one class of emerging pollutants detected from waters has drew great attention in recent years. How to remove PFOS from surface water and ensuring the security of drinking water for human beings is very important. In this study, nanofiltration membrane was used to remove the PFOS from water, the effects of different water quality conditions, nanofiltration operation condition on the PFOS removal efficiency and membrane fouling were systematically investigated.. The main conclusions are as follows: 1. The suitable kind of nanofiltration membrane to remove PFOS from water was selected. NF270、DK membrane、HYDRA-core membrane and homemade PIMA membrane were chosen as the membrane for nanofiltration separation. The PFOS rejection and membrane flux were investigated under different operating conditions. The result showed that NF270 membrane was appropriate for the removal of PFOS, because it did not only have high rejection of PFOS but also considerable water flux. Under the pressure of 0.8 MPa, PFOS retention reached 94.41% and water flux reached 137 L/m2h. 2. The effects of operating pressure, pH, the initial concentration of PFOS and the concentration of HA on PFOS retention and membrane flux were investigated. The rejection mechanism was also analyzed. The results showed that with increasing pressure, the membrane flux and PFOS rejection rate increased. PFOS rejection rate increased as pH, PFOS initial concentration of humic acid concentration increased. The adsorption experiment showed that only a little PFOS was adsorbed on NF270 membrane. The removal mechanism of PFOS from water was mainly sieving effect and charge effects. 3. The impact of electrolyte on the rejection of PFOS was investigated, The contribution of divalent salt in enhancing the retention rate is greater than the monovalent salt. The effect of calcium ions on the nanofiltration performance was studied in detail, and the retention mechanism was analyzed. The rejection of PFOS and membrane flux were elevated with the calcium concentration increased, but the flux reduced when the concentration increases to a certain extent of 3mmol/L. The effects of calcium mainly have two reasons, one is the screening effect improves as PFOS may complexed with calcium and the volume of PFOS increases, the other is Donnan effect. When humic acid was added to the solution, the rejection had a certain improvement but the membrane flux is drastically reduced, the highest rejection rate could reach 99%. 4. The effects of heavy metal ions on nanofiltration were also studied. Pb2 + and Cd2+ had obviously different influence on PFOS removal. The Pb2 + could restrain the rejection of PFOS as the Cd2+ promote. Chromium and arsenic were exist as Cr2O72- and AsO42- in the water, they could increase the rejection of PFOS due to the charge repulsion between the nanofiltration membrane and the PFOS enhancement.
公开日期	2014-10-20
内容类型	学位论文
源URL	[http://ir.rcees.ac.cn/handle/311016/7699]
专题	生态环境研究中心_环境水质学国家重点实验室
推荐引用方式 GB/T 7714	张健. 新型环境污染物全氟辛烷磺酸（PFOS）的纳滤去除研究[D]. 北京. 中国科学院研究生院. 2013.

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