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超滤+反渗透组合的双膜法在海水淡化中已经得到广泛应用,然而反渗透膜的污染问题严重影响了正常生产。淤泥密度指数(SDI)已经成为评价反渗透进水水质的主要指标。通过对超滤出水水质进行检测分析并对反渗透膜主要污染物进行分析,探讨目前胶州湾海水淡化过程中反渗透进水SDI的影响因素及各因素影响程度,结果表明:微生物作为自然水体中广泛存在的生物,其随季节和温度变化造成的总量变化是影响SDI的最主要因素;水体中的硫酸盐以及Si、Al、Fe胶体是造成膜污染的主要无机污染物;此外,浊度与水样的SDI没有相关关系,也不能在反渗透过程中对水质情况进行有效衡量。最后,针对影响SDI的微生物因素的研究以及膜表面无机胶体的清洗提出未来发展方向。 相似文献
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利用浸没式中空纤维膜小试系统,基于膜污染指数(FI)建立超滤膜污染的评价和试验方法。通过试验考察超滤膜污染变化规律,以及运行周期对膜污染指数计算的影响,并确定计算膜污染指数的运行周期;并对膜污染指数评价方法的可重复性进行检验:对化学清洗前后膜污染指数进行比较。试验表明,在过滤初期,滤饼污染和吸附污染并存,所以初期水力不可逆膜污染指数(HIFI)增长较快;中期超滤膜的吸附能力不断减弱,膜污染主要是滤饼污染,所以膜污染较为稳定:后期跨膜压力过大,压缩滤饼层,减小滤饼孔隙率,增加滤饼阻力,所以HIFI有所增加。同时短期的膜污染试验可以用来反映长期的膜污染情况,该超滤膜污染的评价方法重复性好,污染后的超滤膜经过化学清洗后。可以重复利用。 相似文献
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反渗透膜元件胶体污染的预防 总被引:2,自引:0,他引:2
胶体污染是膜元件污堵的主要原因之一。它不仅严重影响膜元件的使用性能:如产水量的急剧下降、系统压差的增加及脱盐率的降低等等,而且还会降低膜元件的使用寿命,以及给用户带来生产上的诸多不便。为此,有效预防膜元件的胶体污染对反渗透系统的正常运行有很大的益处。 相似文献
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超滤膜污染指数模型及其在工程设计中的应用 总被引:11,自引:0,他引:11
本文提出了超过滤的模型,通过对苯二甲酸悬浮液的超滤浓缩数据的线性回归,提出了对该体系的污染方程系数,利用此模型计算了操作参数变化对超滤通量的影响曲线,求出了最佳操作条件。本模型对类似体系的超滤工程设计有参考价值。 相似文献
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反渗透系统的污染及清洗 总被引:6,自引:0,他引:6
反渗透作为水处理领域的一种高新除盐技术应用日益广泛,如何防止膜元件的污染及污染后的清洗是当前反渗透技术应用中的一个难点,本文结合长铝公司400t/h反渗透系统的运行和清洗经验就该问题进行一些探讨。 相似文献
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关于膜净水处理中膜污染物质的研究——关于对污染膜药品洗涤方法的研究 总被引:1,自引:0,他引:1
以北浦湖水作原水,对使用的膜用药品洗涤方法进行了基础研究。药品的洗涤效果,是通过测定由污染膜做成的微型组件,在洗涤前后清水流量变化来评价的。洗涤剂使用了草酸、氢氧化钠、次氯酸钠、过氧化氢、酶、市售洗涤剂等。对于使用在本实验中的污染膜来说,次氯酸钠、过氧化氢、氢氧化钠对膜的透水性的恢复是有效的。在许多的洗涤试验中洗涤水温和洗涤效果是成比例的,但有1%-NaClO 4%NaOH洗涤虽然在低水温(5℃)也显示出良好的洗涤再生性。虽外采用在膜表面涂复洗涤剂达到像间歇浸渍那样的程度的供给洗涤剂的方法,经过足够的时间,可得到良好的洗涤效果。 相似文献
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主要介绍了聚偏氟乙烯(PVDF)树脂在水处理领域的应用情况,比较了市场上常用的PVDF树脂性能,并对由上述树脂制备的水处理膜性能进行对比。 相似文献
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以聚醚砜(PES)为膜材料,N甲基2吡咯烷酮(NMP)为溶剂,分别选用不同分子量的聚乙烯吡咯烷酮(PVP K10、PVP K30、PVP K50、PVP K70)为添加剂,利用相转化法制备了PES平板超滤膜。研究了制备条件对膜结构及性能的影响。当PES含量为18 %(质量分数,下同),PVP K30添加量为6 %时,超滤膜平均水通量和平均截留率最佳,分别为90.7 L/(m2·h)、95.1 %。实验进一步测定了5组膜片对1 g/L牛血清蛋白(BSA)溶液的截留率以及它们对取自生活饮用自来水和泳池水样滤出水的污染密度指数(SDI)值。结果表明,PES超滤膜对生活饮用水滤出水的SDI5 min值随着截留率的升高而降低;针对泳池滤出水,随着超滤膜截留率的升高,其滤出水的SDI5 min值没有明显变化。 相似文献
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Nabil Mameri Farid Halet Madani Drouiche Hocine Grib Hakim Lounici Djamila Belhocine Andr Pauss Dominique Piron 《加拿大化工杂志》2000,78(3):590-595
Olive oil production requires important quantities of washing water containing low oil concentrations, but classical processes used to recover or to eliminate this oil are ineffective. This study presents a membrane technique to treat olive oil mill washing water using different commercial ultrafiltration membranes: one organic (PCI) and two ceramic (Ceraver) membranes. The influence of the hydrodynamic parameters (transmembrane pressure and flow rate) and the cut‐off membranes on the efficiency of the ultrafiltration process was evaluated, and it was shown the organic PCI membrane could reduce pollution due to organic matter by decreasing the value of the Chemical oxygen demand by about 90%. Moreover, the nature of the ultrafine pore membrane appeared to be an important parameter which may strongly increase or decrease the capacity of the membrane. The membrane cut‐off did not have a strong influence on the performance of the process but if the membrane pores were too large the stability of the dynamically formed membrane decreased at transmembrane pressures greater than 0.2 MPa. 相似文献
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聚酰胺皮层的物化性质是决定反渗透复合膜(TFC-RO膜)物质筛分和水透过效率的关键性因素。近年来,基于超薄皮层(通常<50nm)的高性能复合膜研究取得了重要的进展。本文总结并分析了超薄皮层反渗透复合膜的研究进展,如低单体浓度控制技术、分子层层自组装(mLBL)、静电打印技术、界面优化技术及新型纳米材料技术的成膜机理及特性,对比了各项制备技术的优缺点。总体来说,超薄皮层反渗透复合膜的研究为精细设计聚酰胺皮层的物化结构,进一步设计更高效率的反渗透复合膜提供了重要思路,但超薄皮层与聚酰胺层微纳结构之间的相互联系以及超薄皮层反渗透复合膜长期运行的稳定性仍需进一步探索。 相似文献
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氧化石墨烯(GO)作为理想的膜构筑材料,因其蜂窝状的结构特点及表面分布大量含氧基团的特性,被广泛用于水处理分离膜的构筑。GO膜具有良好的物理特性、优异的化学稳定性和独特的二维层状结构,在污水处理、脱盐和离子筛分等水处理领域备受关注。在水处理中,GO膜对有机物和离子有较好的截留效果,但也存在水通量低、稳定性差等问题。本文分析了近年来GO膜在水处理领域的研究新进展;简单总结了GO膜的制备方法和水处理应用;重点阐述了GO水处理膜分离性能优化的方法和传质机理的研究进展;最后总结并展望了GO膜在结构调控和性能提升方面的发展方向。本文为设计和制备高性能GO水处理膜提供参考。 相似文献
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《分离科学与技术》2012,47(14):2190-2197
This work evaluated the performance of ceramic membranes in removing dispersed oil present in oilfield produced water, seeking to advance knowledge of the process, and identify the conditions for its application. The effect of the operating conditions and effluent characteristics were evaluated across a wide range, enabling establishment of operational limits for the permeation process. It was demonstrated that a flow regime corresponding to a Reynolds number (Re) greater than 6,000 does not imply significant improvements in membrane permeability. It was further found that the permeate flux exhibits a slight linear dependence with the salt concentration (CS). 相似文献
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Kyung Hwa Jung Hee Joong Kim Mun Hyeon Kim Saerom Kong Huiran Seo Jong‐Chan Lee 《大分子材料与工程》2020,305(9)
Ultrafiltration membranes coated with amphiphilic copolymers containing superhydrophilic zwitterionic moieties and hydrophobic POSS moieties (PSM‐coated membranes) are prepared. The free radical polymerization of 2‐(dimethylamino)ethyl methacrylate (DMAEMA) and 3‐(3,5,7,9,11,13,15‐heptaisobutylpentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane‐1‐yl)propyl methacrylate (MAPOSS) monomers is used to prepare a series of copolymers containing different compositions of DMAEMA and MAPOSS units (PDMs). The DMAEMA units in the PDM‐coated membranes are subsequently converted to sulfobetaine methacrylate (SBMA) units using 1,3‐propane sultone (post‐zwitterionization) to give the PSM‐coated membranes. The PSM‐coated membranes show improved fouling resistance/release properties, compared with a neat polysulfone (PSf) membrane. The improved fouling resistance properties of the PSM‐coated membranes are attributed to the superhydrophilic zwitterionic moieties, which form a hydration layer on the membrane surface via electrostatic interactions between the zwitterions and water molecules. Moreover, the total surface energy (γS) value of the PSM‐coated membrane is smaller than that of the PSf membrane due to the hydrophobic POSS moieties. This results in the superior fouling release properties of the PSM‐coated membranes. 相似文献
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Lebea N Nthunya Leonardo Gutierrez Sebastiaan Derese Edward N Nxumalo Arne R Verliefde Bhekie B Mamba Sabelo D Mhlanga 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2019,94(9):2757-2771
Membrane distillation (MD) is a thermally driven process that uses low-grade energy to operate and has been extensively explored as an alternative cost-effective and efficient water treatment process compared to conventional membrane processes. MD membranes are synthesized from hydrophobic polymers, e.g. polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) or polypropylene (PP), using various methods including phase inversion and electrospinning techniques. Recent literature on MD membranes clearly shows their important role in surface water/wastewater treatment and seawater desalination. Modification of MD membranes with nanoscale materials significantly improves their performance, preventing wetting and fouling. This review presents a critical assessment of the progress on the use of nanomaterials for the modification of MD membranes. The techniques commonly used to synthesize MD membranes, the modifications that have been adopted for the incorporation of nanomaterials onto membranes, and the unique properties these nanomaterials impart on the membranes are discussed. The use of modified membranes in different MD configurations and their application in groundwater, surface water, wastewater, brackish water and seawater treatment is reviewed. Finally, cost implications, commercial viability, environmental sustainability, and future prospects of MD are also discussed to elucidate promising approaches for a future and successful implementation of MD at an industrial scale. © 2019 Society of Chemical Industry 相似文献
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基于压力驱动的超滤膜面临渗透性和选择性的制衡及膜污染问题。多孔纳米材料是高性能超滤膜改性制备中一类重要的添加剂,是新型水处理功能膜的研究热点之一。多孔纳米材料的添加为膜提供了额外水通道,其可调的孔尺寸又为在膜内构建出具有高度选择性的纳米通道提供了潜在有利条件,进而突破膜渗透性和选择性的Trade-off效应。同时,亲水性多孔纳米材料的添加有利于提升膜的抗污染性能。本文综述了近年来多孔纳米材料对超滤膜的改性方法,总结了微孔沸石分子筛、介孔炭、介孔二氧化硅、金属有机骨架材料和共价有机骨架材料对超滤膜的改性研究进展,着重评价了不同改性材料对超滤膜在亲水性、渗透性、污染物截留和抗污染能力等方面的影响。最后对未来多孔纳米材料改性超滤膜的研究及应用的发展趋势进行了展望。 相似文献