VOC removal from contaminated groundwater through membrane pervaporation. (Ⅱ): 1,1,1-trichloroethane-SDS surfactant solution system

IntroductionTheconventionalmethodforsubsurfaceremediationofgroundwatercontaminationwithVOCsistheso called“pump and treat”technology .Thelimitationofthisapproachistheprohibitivelylongtreatmenttimeforremediatingthegroundwatercontaminatedwithcommonchlorinatedsolventsthathavedensitiesgreaterthanthatofwater(classifiedasDNAPLs densenon aqueousphaseliquids) .Thisislargelyduetotheverylowwatersolubilityandlowbiodegradabilityofthisclassofsolventsandthetendencyofthesolventssettlinginthebottomofanaqu…     

有机蒙脱石填充PDMS膜分离水相有机物的渗透汽化研究

以乙醇、乙酸的水溶液为渗透汽化分离对象，将CTAB柱撑蒙脱石作为填充剂，制备了填充型PDMS(聚二甲基硅氧烷)膜，研究填充膜对乙醇／水及乙酸／水体系的渗透汽化分离，结果表明，蒙脱石的吸附特性及其层间柱撑通道可以明显改善PDMS膜的选择性和通量，填充膜分离乙醇或乙酸的分离效果明显不同，对可能存在的渗透汽化分离机理进行了探讨。     

渗透汽化复合膜分离废水中的低浓度甲醇

采用两种商品化渗透汽化复合膜--GKSS-GS膜和PDMS-P膜分离模拟低浓度甲醇废水,考察了操作温度、甲醇质量分数、废水流量对膜渗透汽化性能的影响.实验结果表明:随温度升高、废水中甲醇质量分数的增大,两种膜的渗透通量都呈增加趋势;GKSS-GS膜的分离系数变化较明显,而PDMS-P膜的分离系数变化较小;废水流量对渗透通量和分离系数的影响均较小.在最佳条件下,GKSS-GS膜的渗透通量为914.6 g/(m~2·h),分离系数为5.6;PDMS-P膜的渗透通量为1 887.2 g/(m~2·h),分离系数为4.8.     

VOC removal from contaminated groundwater through membrane pervaporation. (Ⅰ): Water- 1,1,1- trichloroethane system

1,1,1-trichloroethane(TCA), a common chlorinated organic solvent and volatile organic compound(VOC), was removed from contaminated groundwater by using a bench-scale membrane pervaporation unit. The effects of TCA concentration, temperature, and flow rate on permeation flux and selectivity(a value) of the process were evaluated. In general, higher temperature leads to higher VOC flux but lower selectivity; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation, however, the selectivity was virtually unchanged.     

VOC removal from contaminated groundwater through membrane pervaporation. (Ⅱ): 1,1,1-trichloroethane- SDS surfactant solution system

The conventional “ pump-and-treat“ technology for subsurface remediation of groundwater contaminated with volatile organic compounds(VOCs) such as 1,1, l-trichloroethane(TCA), a common chlorinated organic solvent, has hmitation of prohibitively long treatment time due to extremely low water solubility of the VOCs. Surfactant-based soil remediation has emerged as the effective technology that substantially reduces the treatment time. In order to make the whole process economical, the surfactant used in soil washing has to be recovered and reused. This study examined the recovery of anionic surfactant, sodium dodecyl sulfate( SDS), from soil remediation fluids containing TCA, using a bench-scale membrane pervaporation unit. The effects of high TCA concentration, surfactant dosage, and flow rate on permeationflux and selectivity( a value) of the process were evaluated. In general, higher surfactant concentration yielded lower TCA flux and constantwater flux, resulting in declining a values; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation across the membrane, however, the seletlvity was virtually unchanged unless the total TCA concentratinn exceeded 2000 ppm.     

水中微量有机物氯化物脱除复合膜的研制

采用溶液聚合法合成了丙烯酸及丙烯酸酯共聚物，并利用该共聚物可与环氧树脂交联的作用制备出交联聚丙烯酸及基酯的共聚物，并在聚砚底膜上涂膜形成可优先透过氯化有机物（THMs)的复合膜，以1，1，2－三氯乙烷，三氯乙烯等稀水溶液对丙烯酸酯系列复合膜进行了系统测试和研究，分别考察了不同制膜液、交联剂、操作压力、操作温度、进料液浓度、不同分离体系等条件对膜性能的影响，并优选出交联AB－AA－MAA／PS复合膜，表明效果良好，有很好的研究和发展前景。     

VOC removal from contaminated groundwater through membrane pervaporation. (Ⅰ): Water-1,1,1-trichloroethane system

IntroductionRapidindustrializationofthelastcenturybroughtwithhugeenvironmentalcosts:vastquantitiesoforganicsolventsweredisposedofintheoceans ,rivers lakes,andmorelikelyinthesoil(Hunter,2 0 0 0 ) .Amongallorganicsolventsthatcontaminatesoilandconsequently,thegroundwater,isagroupofchlorinatedorganicsolventsthatareparticularlyproblematic(Love ,1 982 ) .Thesesolventshaveverylowwatersolubility,lowbiodegradability,andhigherdensitythanthatofwater.Asaresult,thesesolventssettlethroughthewatertableuntil…     

渗透汽化膜分离技术在环保中的应用

渗透汽化膜分离技术 (PV)和传统的分离技术相比 ,它具有技术可靠、工艺简单、操作方便及费用经济等优点。主要应用于有机溶剂脱水、有机混合物的分离等 ,并部分实现了工业化。随着高分子科学以及膜合成技术的发展 ,PV逐渐应用到一些新的领域。主要介绍了渗透汽化膜分离的基本原理 ,以及它在环保领域的新应用。     

水中VOCs的渗透蒸发分离技术研究进展

介绍了水中VOCs的各种分离方法,重点分析了渗透蒸发分离技术的技术优势;提出了渗透蒸发膜的选择标准;归纳了渗透蒸发过程的传质机理与模型;探讨了原料液浓度、温度、流量,渗透侧压力、添加剂、膜组件型式等因素对渗透蒸发效率的影响;简要预测了渗透蒸发过程的发展趋势与动态。     

发酵-渗透汽化膜技术制无水乙醇研究进展

渗透汽化膜技术作为一种新型的膜分离技术和清洁生产技术,与发酵法相耦合生产燃料乙醇,具有高效、节能和环保的优势。综述了发酵-渗透汽化膜技术的研究进展,介绍了该工艺动力学模型的研究成果,与传统的发酵法进行了经济性对比,阐述了渗透汽化膜技术应用于无水乙醇工业化生产的现状和存在的问题,展望了发酵-渗透汽化膜技术的研究方向。