Cleaning of fouled ultrafiltration (UF) membrane by algae during reservoir water treatment

Ultrafiltration (UF) membrane fouling is often encountered in water treatment. Algae could be removed by UF membrane for its nominal pore size, and the algae cells deposited on the surface of UF membrane. The cells attach to the membrane, they start to release secretion and produce extracellular polymetric substances (EPS), which accumulate on the surface and cause the flux decline. This study examined the effects of hydraulic and chemical cleaning on fouled membrane by algae-rich reservoir water. Four kinds of hydraulic cleaning method were investigated, including forward flushing, backwashing, forward flushing followed by backwashing and backwashing followed by forward flushing. Backwashing followed by forward flushing was more effective for flux recovery, and 20 min duration were enough for the cleaning. To maximize flux recovery for the algae-fouled membrane, chemical cleaning was applied as enhanced cleaning strategies. NaOH, NaOCl, and citric acid were used for cleaning agents. The cleaning with the combination of NaOH (0.02 N) and NaOCl (100 mg/L) was effective than separate uses. And the cleaning duration was determined as 4 h.     

超滤膜法提取精制油茶皂甙的研究

油茶皂甙是一种性能优良的表面活性剂 ,可做洗涤剂和农药的原料。在小试基础上 ,采用膜技术对生产工艺和生产设备进行了生产性研究 ,确定了合理的工艺路线和设备。最终工艺路线为 :油茶饼粕→粉碎→浸提→浆渣分离→絮凝→离心分离 (或板框过滤 )→预滤→精滤→超滤→喷雾干燥→成品。用上述工艺生产的产品纯度可达 80 %左右。     

大豆分离蛋白生产新工艺的研究

全面而系统地分析了目前大豆分离蛋白生产中存在的主要问题如蛋白得率低、灰分高、色泽深、溶解性差等及其他影响因素，并在此基础上提出了切实有效的措施和大豆分离蛋白的生产新工艺，提高了产品质量，降低了损耗。     

组合膜技术在分离中药有效成分中的应用

对膜技术的特性、分类及原理等作了简要分析,重点介绍了几种组合膜技术在中药有效成分分离中的应用,并对该技术的发展前景及存在的问题进行了分析。     

环保型脲醛树脂胶粘剂的合成

以聚乙烯醇(PVA)、三聚氰胺为改性剂,采用单因素试验法优选出制备低n(甲醛):n(尿素)比例的环保型脲醛树脂(UF)胶粘剂的最佳工艺条件。结果表明:当n(甲醛):n(尿素)=1.14:1、w(三聚氰胺)=19%、w(PVA)=1.7%(相对于尿素质量而言)、反应温度为88～90℃和反应时间为3 h左右时,制成的UF胶粘剂具有良好的综合性能;由该胶粘剂生产的人造板,其甲醛释放量达到E1级标准要求。     

粉末活性炭/污泥回流工艺强化膜前预处理的研究

采用粉末活性炭(PAC)吸附/混凝沉淀/浸没式超滤膜组合工艺处理苏州市某河水,考察了PAC/污泥回流工艺对膜前预处理的强化效果及对膜污染的影响,并与常规混凝沉淀、污泥回流强化混凝沉淀、PAC吸附/混凝沉淀等3种预处理工艺进行了对比。结果表明,PAC/污泥回流强化预处理工艺对浊度、DOC、UV254和THMFP的去除率分别为80.2%、47.5%、42.3%和52.3%,均比其他预处理工艺的高,对MW30 ku和MW1 ku有机物的去除效果明显。PAC/污泥回流强化预处理和超滤膜组合工艺对浊度、DOC、UV254和THMFP的去除率分别可达到99.2%、54.1%、47.2%和60.2%;经过15 d的运行,超滤膜的跨膜压差基本保持稳定,而其他预处理工艺虽能在一定程度上减轻膜污染,但无法避免不可逆膜污染的发生。     

Short-term adhesion and long-term biofouling testing of polydopamine and poly(ethylene glycol) surface modifications of membranes and feed spacers for biofouling control

Ultrafiltration, nanofiltration membranes and feed spacers were hydrophilized with polydopamine and polydopamine-g-poly(ethylene glycol) surface coatings. The fouling propensity of modified and unmodified membranes was evaluated by short-term batch protein and bacterial adhesion tests. The fouling propensity of modified and unmodified membranes and spacers was evaluated by continuous biofouling experiments in a membrane fouling simulator. The goals of the study were: 1) to determine the effectiveness of polydopamine and polydopamine-g-poly(ethylene glycol) membrane coatings for biofouling control and 2) to compare techniques commonly used in assessment of membrane biofouling propensity with biofouling experiments under practical conditions. Short-term adhesion tests were carried out under static, no-flow conditions for 1 h using bovine serum albumin, a common model globular protein, and Pseudomonas aeruginosa, a common model Gram-negative bacterium. Biofouling tests were performed in a membrane fouling simulator (MFS) for several days under flow conditions similar to those encountered in industrial modules with the autochthonous drinking water population and acetate dosage as organic substrate. Polydopamine- and polydopamine-g-poly(ethylene glycol)-modified membranes showed significantly reduced adhesion of bovine serum albumin and P. aeruginosa in the short-term adhesion tests, but no reduction of biofouling was observed during longer biofouling experiments with modified membranes and spacers. These results demonstrate that short-term batch adhesion experiments using model proteins or bacteria under static conditions are not indicative of biofouling, while continuous biofouling experiments showed that membrane surface modification by polydopamine and polydopamine-g-poly(ethylene glycol) is not effective for biofouling control.     

超滤在黄酮类化合物分离中的研究进展

概述了超滤的原理、特点、应用领域以及影响因素,并对黄酮类化合物的常用分离方法以及超滤技术在黄酮类化合物分离中的应用进行了介绍,最后对超滤技术未来的发展做了展望。     

超滤/反渗透组合工艺用于矿井水深度处理回用

超滤(UF)/反渗透(RO)作为高矿化度矿井水处理的主体工艺,可以有效提高出水水质。银洞沟煤矿矿井水采用UF/RO组合工艺,其处理水量为2 000 m3/d,出水水质达到生活饮用水水质标准,满足了矿区生产和居民生活用水需要。介绍了该工程工艺流程、各处理构筑物设计参数及技术特点,为类似矿区废水回用设计提供可借鉴的经验,同时为水资源匮乏地区开辟第二水源提供一种较好的方案。