市政污水深度回用系统中反渗透膜表面微生物污染特性研究进展

污水深度回用是世界各国解决水资源危机的战略性选择,反渗透是污水深度回用不可替代的核心技术.中水水质有其自身的污染特点,微生物污染是最复杂的污染形式,是市政污水深度回用反渗透运行过程关注的焦点,目前对生物膜形成和其对反渗透运行性能的影响还知之甚少.结合国内外反渗透膜微生物污染研究及分析的文献成果,总结了微生物污染造成渗透通量和脱盐率变化的规律;为了阐明由于微生物细胞沉积和生物膜生长造成膜性能下降的机理,对微生物污染的性质、影响因素及相关理论、污染评价方法进行了总结,重点分析了微生物和胞外聚合物(EPS)对生物膜形成的影响,并提出今后研究的方向,以期为实际工程污染的评价、预测和减轻污染提供系统指导.     

Adaptive Coatings with Anticorrosion and Antibiofouling Properties

Biofouling on surfaces immersed in aquatic environment induces catastrophic corrosion of metallic materials in petrochemical infrastructures, maritime facilities, and power plants. To combat the synergistic effect of biofouling and corrosion on the deterioration of metallic materials, smart coatings possessing a dual function of antibiofouling and anticorrosion properties are needed. Herein, redox-responsive copolymer conjugates are synthesized and employed as coatings with the dual function of biofouling and corrosion mitigation. The dual function of copolymers is attributed to fluorinated units and the corrosion inhibitor 2-mercaptobenzothiazole (MBT) conjugated via disulfide linkages. Indeed, the disulfide linkages can be cleaved in a reducing environment, yielding controlled release of the corrosion inhibitor MBT during corrosion process. The antibiofouling action against protein adsorption and algal attachment is enabled by cooperation of the repellent characteristic of fluorinated moieties and the biocidal effect of conjugated MBT.     

污水深度回用反渗透膜面微生物污染机理试验研究

微生物污染是最复杂的膜污染形式,是污水深度回用反渗透设备运行过程关注的焦点.通过实验室静态试验和错流过滤动态试验研究了污水回用反渗透膜的微生物污染的机理和特性,结果表明:造成污染的微生物主要为杆菌和丝状菌;在没有微生物源及没有微生物生长和繁殖的必需营养物质的情况下,膜面基本不发生微生物污染;杀菌处理对于防止微生物污染很重要,已经污染的膜面更易于发生微生物污染,做好反渗透设备的停备用保护工作是防止微生物污染的必要手段.     

仿生防污材料的研究进展

船舶表面的生物污损会带来极大的危害,如何防除生物污损已成为一个世界难题。尽管氧化亚铜等有毒防污剂可以有效防止海生物的附着污损,但这类防污剂对非目标生物也具有负面作用,可能带来严重的生态问题。随着国际社会对有毒防污剂和海洋环境的日益关注,发展环境友好型防污材料已势在必行。人们经常观察到自然界许多生物并没有被其它生物种类寄生聚居,这是因为在自然界中生物自身存在着各不相同但极为有效的防污机制,包括化学性质、物理性质、机械清理、生活习性,以及各种防污机制的组合等,这为研制环境友好型仿生防污材料提供了依据。综述海洋环境中仿生防污材料的研究进展,重点介绍了基于生物防污剂、表面微结构、水凝胶、抗蛋白吸附等特性进行防污的仿生材料研究,并阐述了我国在该领域已经取得的重要技术突破和主要技术成果,展望了仿生防污技术的发展趋势。     

An Incidence of Massive Biofouling of Sand Filters: A Biochemical Detective Story

A serious biofouling incident at an overseas water treatment plant is described, together with the background information and recorded operational data which provided the subtle, but unheeded, physicochemical clues to the developing biological problem. At the time, however, it was not realised just what was causing the serious filtration problems and even upon discovery of the filter-clogging algae it was not immediately obvious what had caused their appearance, growth and subsequent rapid death within a sealed groundwater system. However, piecing together the story with hindsight from all the available clues has proved to be a fascinating and illuminating piece of biochemical detective work with unexpected conclusions which have wider ramifications within the water industry.     

Biofouling control in industrial water systems: What we know and what we need to know

Biofouling contributes substantially to economic losses in industry. Although much progress has been made in understanding biofouling and its implications in industrial water systems, many questions remain unanswered. The cost of biofouling has not been enumerated. A prerequisite for this is research to elucidate the contribution that microbiologically influenced corrosion makes, to the overall corrosion process. Surface characteristics play a major role in the initial stages of microbial attachment. Ways of preventing preferential attachment to certain areas, i.e. grain boundaries and welds need further investigation. Biocides are routinely used to control biofouling. Due to the problem of resistance and potential environmental impact, alternative strategies for biofouling control need to be investigated and put to practice. These should focus on an integrated approach with the minimum impact on the environment. A number of biofouling monitoring devices have been developed. The advantages of biofouling monitoring needs to be demonstrated and monitors should become commercially available.     

水系统中微生物和碳酸钙混合垢的形成过程

实验通过固定循环系统中荧光假单孢菌的数量,研究了不同材料表面上,随着水中碳酸钙浓度的改变,混合垢生长曲线的特征。结果发现随着碳酸钙浓度的增大,平均污垢量及标准偏差随之降低;碳酸钙的浓度不是影响非金属材料诱导期的主要因素,但对于金属材料却存在较大影响。同时,实验还确定了垢层的结构及性质,分析了污垢形成的机理:首先是碳酸钙颗粒和有机大分子吸附到材料表面上,然后是微生物的粘附生长。碳酸钙的存在影响微生物与表面的结合,反之亦然。     

Antifouling properties of hydrogels

Abstract

Marine sessile organisms easily adhere to submerged solids such as rocks, metals and plastics, but not to seaweeds and fishes, which are covered with soft and wet ‘hydrogel’. Inspired by this fact, we have studied long-term antifouling properties of hydrogels against marine sessile organisms. Hydrogels, especially those containing hydroxy group and sulfonic group, show excellent antifouling activity against barnacles both in laboratory assays and in the marine environment. The extreme low settlement on hydrogels in vitro and in vivo is mainly caused by antifouling properties against the barnacle cypris.     

海洋船舶无毒、低毒防污涂料的研究进展

介绍了现代海洋船舶防污涂料的研究和应用情况,分别阐述了电化学防污涂料、化学活性物质释放型防污涂料和非化学活性物质释放型防污涂料的原理及其应用进展,并着重介绍了无毒低毒防污剂及防污涂料,指出长效、无毒的防污涂料将是未来涂料的发展方向。     

Bacterial adhesion to solid substrata coated with conditioning films derived from chemical fractions of natural waters

Dissolved organic carbon from seawater and freshwater was separated into hydrophilic-base, hydrophilic-neutral, hydrophilic-acid as well as hydrophobic-base, hydrophobic-neutral, and hydrophobic-acid fractions which were used to form conditioning films on hydrophilic stainless steel and aluminium as well as on hydrophobic polypropylene and perspex. Water contact angles indicated that every conditioning film modified the wettability of clean substrata; the wettability of hydrophobic surfaces was generally increased and that of hydrophilic surfaces decreased. Adhesion results with carbon- and nitrogen-limited phenotypes of the Gram-negative bacterium SW8 suggested that adhesive or abhesive components of conditioning films were not associated with particular chemical fractions. The proportion of conditioning films derived from water fractions which modified the attachment of carbon-limited SW8 on hydrophobic and hydrophilic substrata was 29 and 71 %, respectively. These films generally reduced the number of organisms on hydrophobic substrata but increased it on hydrophilic materials. No fraction produced films which either altered the adhesion of carbon-limited organisms on all substrata or which did not affect adhesion of the phenotype. The adhesion of these cells to stainless steel and perspex depended on the concentration of film-forming material in solution. Mixing of a fraction which produced adhesive films with material from another fraction whose films were less adhesive produced hybrid films which retained carbon-limited SW8 in amounts which were proportional to the relative content of organic matter from the adhesive fraction. Attachment of the carbon- and nitrogen-limited phenotypes differed on 69% of surfaces coated with films from natural water fractions. Carbon-limited cells attached in higher numbers than nitrogen-limited SW8 on 82% of these surfaces. Nitrogen-limited SW8 generally adhered less to conditioning films from seawater than carbon-limited cells. The contact angle values did not correlate with the numbers of SW8 attached to conditioned substrata.