面向染料清洁生产和染料废水处理的纳滤技术

综述了纳滤膜对含盐染料溶液的分离原理、纳滤膜的选择、纳滤脱盐浓缩工艺过程与应用研究、纳滤处理染料废水与资源化方面的应用研究、纳滤技术的经济性以及应用过程中膜污染的控制。指出利用纳滤技术改进染料生产工艺是可行的,能够实现染料清洁生产,具有明显的经济效益和环境效益;采用纳滤处理染料废水,浓缩液和透过液可以分开处理,易于资源化,并且有利于染料废水的后继处理,是高浓度高含盐染料废水的一种有效处理方法。     

磁化预处理-纳滤联合软化水过程的研究

纳滤目前是软化脱盐领域的一项重要技术并具有广阔应用前景,但膜面结垢会严重降低其操作性能,因此对纳滤的防垢抑垢研究非常重要.本研究在不同操作条件下考察了3种纳滤膜(NF90、NF270和NF-)的软化水过程,并首次将磁化作为纳滤软化过程的预处理措施,使纳滤膜的操作性能得到有效改善.该技术具有简单、安全、能耗小、无二次污染的优点,弥补了当前某些化学法(加抑垢剂、调pH或化学清洗)和物理法(改变流态)抑垢技术的不足.     

纳滤膜技术在甘肃农村安全饮水工程中的应用

采用多介质+精滤+纳滤膜工艺对甘肃陇南农村地区苦咸水进行了中试研究及工程应用,重点考察了工艺对苦咸水中超标物质的去除情况。结果表明:采用纳滤技术应用于农村安全饮水,能保证工艺的稳定运行,工艺对各种超标物质都有很好的去除效果并对工程运行结果和运行成本经济效益进行了分析,认为纳滤处理技术在农村安全饮水处理中是经济和可行的。     

膜分离技术在水处理的应用

介绍了膜分离技术的定义及其特点,综述了微滤、反渗透、超滤、纳滤、电渗析、液膜,膜蒸馏等几种常见膜技术的原理及应用现状,展望了膜分离技术的前景.     

添加阻垢剂和生物抑制剂对纳滤截留效果及膜污染影响试验研究

为探究常规工艺后接纳滤对水中残余铝的去除效果及膜污染情况,选用煤砂双层滤池作为纳滤工艺的前处理单元,通过在纳滤运行过程中投加阻垢剂和生物抑制剂来达到抑制膜污染的目的。试验结果表明,通过阻垢剂和生物抑制剂的添加可以使膜通量下降时间延长1倍,使残余铝在纳滤的截留率降低了15%,有效抑制了无机污染;使ATP、多糖、蛋白质分别下降了16%、64%、58%,对生物污染和有机污染的抑制效果十分显著。     

纳滤膜分离技术处理饮用水的应用研究

简要介绍了纳滤膜的定义及原理，并利用自行设计的小型设备对纳滤NF     

膜法水处理技术研究进展与发展趋势

介绍了膜分离技术的定义及其特点,综述了微滤、反渗透、超滤、纳滤、电渗析、液膜等几种常见膜技术的应用现状及进展情况,展望了膜分离技术的前景。     

低压纳滤膜用于微污染地表水深度处理的中试研究

采用低压纳滤中试装置深度处理微污染地表水源水。探讨了其中纳滤膜的截留性能和膜污染情况。中试结果表明DF30纳滤膜呈现出高天然有机物截留特性,同时保留部分对人体有益的钙镁离子。TOC、硫酸根、电导率和硬度平均去除率分别为94%、87%、27%和43%。纳滤膜对微量有机物平均去除率为65%。膜表征的结果表明膜污染的主要污染物为多糖和蛋白质。污染层ATP含量为20.3ng/cm~2,表明存在中等程度的生物污染。在碱性条件下采用EDTA+SDS的清洗方式能将膜通量恢复至初始通量的90%,有效减缓膜污染。纳滤运行成本约为0.36元/m~3,具有良好的经济性。     

纳滤在城市污水处理中的应用

介绍了纳滤膜的特性、膜组件、膜材料及膜污染防治方法 ,同时 ,结合一工程实例 ,介绍了纳滤膜在具体污水处理工程实践中的应用     

煤化工浓盐水热膜耦合工业盐资源化利用研究

煤化工废水近零排放技术发展过程中,由反渗透膜系统产生含有高盐高有机物的浓盐水引发的环境问题。由于煤化工浓盐水不完善的处理技术制约煤化工行业发展,因此亟待研发高效可行的煤化工浓盐水处理技术。煤化工浓盐水TMC(Thermal-Membrane Coupling)热膜耦合工业盐分离技术中试以纳滤分离和蒸发结晶为核心,以膜前预处理及共结晶高级催化氧化深度去除有机物保障稳定运行。试验结果表明煤化工浓盐水TMC热膜耦合工业盐分离技术的纳滤能够有效分离多价离子,有机物和单价离子,纳滤产水氯化钠占总溶解性固体的85%以上。由蒸发结晶制备的氯化钠纯度达到工业干盐优级品标准。煤化工浓盐水TMC热膜耦合工业盐分离技术能够解决结晶杂盐难以处置的环境问题,使煤化工浓盐水处理实现近零排放。     

Removal of endocrine disrupting compounds with membrane processes in wastewater treatment and reuse.

Endocrine disrupting compounds can affect the hormone system in organisms and are the subject of environmental and human health concerns. The effluents of wastewater treatment plants contribute to the emission of estrogenically active substances into the environment. Membrane technology, which is an advanced wastewater treatment option, is the subject of this research. The removal techniques under investigation are membrane bioreactors, reverse osmosis, and nanofiltration. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention of NP and BPA ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. Regarding the retention of BPA no dependency on the contact angle was observed. Results of the investigation of a full-scale landfill leachate treatment plant indicate a bisphenol A (BPA) removal of more than 98% with membrane bioreactors and reverse osmosis. The mass balance indicates that biological degradation is the most important removal process in the membrane bioreactor configuration.     

Arsenate removal using a combination treatment of precipitation and nanofiltration

A combination treatment of Ca-precipitation and nanofiltration membrane was studied to remove arsenate from water. The selected nanofiltration membrane was an amphoteric charged membrane, proved by the results of ATR-FTIR spectra and zeta potential. The arsenate and calcium removal efficiencies had the lowest values at the isoelectric point of the nanofiltration membrane, attributed to the loosest steric hindrance and the weakest electrostatic repulsion. Above the isoelectric point, arsenate precipitated with calcium ion to form the low solubility compound calcium arsenate, while steric hindrance was the main mechanism of arsenate removal. In contrast, below the isoelectric point, the nanofiltration membrane with positive charges rejected calcium ion by electrostatic repulsion. The high electrostatic shielding of calcium ion prevented arsenate from coming close to the NF membrane. Either high feed arsenate concentration or high calcium oxide dose improved the removal amount of arsenate during the nanofiltration membrane separation process. In addition, the arsenate removal efficiency approached the highest value at 200 μg/L of feed arsenate concentration. The optimal transmembrane pressure was in a range of 0.5-0.7 MPa to restrict the formation of fouling cake on the nanofiltration membrane surface.     

纳滤膜净化地下水时预处理工艺的选择研究

针对不同地下水水质,分别以活性炭、石英砂、锰砂进行预处理,采用纳滤膜工艺制取优质饮用水。旨在为不同地区、不同水质的地下水净化探索一种更为有效的预处理方法。研究表明,活性炭更适合用作有机污染物含量较高的浅层地下水的预处理;而石英砂、锰砂更适合用作铁、锰含量较高的深层地下水的预处理。也可以将几种预处理工艺联用,以获得更好的效果。     

几种膜组件在管道直饮水处理系统中应用对比

膜处理是管道直饮水处理工艺的核心,介绍了微滤膜(MF)、超滤膜(UF)、纳滤膜(NF)、反渗透膜(RO)四种膜在管道直饮水处理系统中应用的对比,内容包括基本性能、去除杂质能力、工作压力以及出水电阻率等。结果显示,相比于其他三种膜,纳滤膜(NF)在直饮水处理工艺应用更具优势。     

Natural Organic Matter and Disinfection By-products Formation Potential in Water Treatment

The performance of a conventional sequence (pre-ozonation, coagulation/ flocculation/ sedimentation, filtration, disinfection) and two non-conventional sequences (pre-ozonation, nanofiltration; and pre-ozonation, coagulation/ flocculation/ sedimentation, nanofiltration) on the removal of natural organic matter (NOM) and disinfection by-products (DBPs) formation potential was evaluated. Raw and treated waters were characterized in terms of molecular weight, which includes the amount of NOM removed and the qualitative changes in the NOM characteristics (molecular weight and hydrophobicity) since they could be directly related with the DBPs formation. The results demonstrate that, for the type of raw water analysed (hydrophilic with low dissolved organic carbon content, 0.99 L/(mg.m) and 1.31 mg DOC/L), both treatment sequences remove larger molecular weight compounds (>1,900 g/mol). Treated waters have the dominant fractions in the smaller molecular size fractions (<750 g/mol). However, the sequences with nanofiltration have a higher percentage of low molecular weight compounds removed (between 430 and 250 g/mol), when compared with conventional sequence, thus the water from nanofiltration sequences will have lower DBPs formation potential. The removal of the smallest molecular size fractions can be enhanced by optimising the water treatment process and the quality of water will improve relating with DBPs formation.     

Comparing the effluent organic matter removal of direct NF and powdered activated carbon/NF as high quality pretreatment options for artificial groundwater recharge.

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization.     

Preparation of three-bore hollow fiber charged nanofiltration membrane for separation of organics and salts

Three-bore hollow fiber charged nanofiltration (NF) membrane was prepared by interfacial polymerization (IP). The results showed that the flux and rejection of NF membrane prepared in this study increased with the increasing in the operating pressure. The water flux decreased and rejection for obvious dyes increased as the solute concentration increased. The separation factor for mixture of Xylenol orange/NaCl decreased when NaCl concentration in solution increased and could reach to as high as 18. In addition, three-bore hollow fiber charged nanofiltration membrane prepared in this study has excellent stability for strong acid (pH = 3), strong alkali (pH = 11) and high temperature solution (80 °C).     

Ultrafiltration and nanofiltration in the pulp and paper industry using cross-rotational (CR) filters.

Ultra- and nanofiltration with high shear CR-filters have been utilized for cleaning of clear filtrates and effluents from the pulp and paper industry. The aim was to find out how different nanofiltration membranes operate at high shear conditions. The filtration efficiency of the membranes was evaluated by measuring flux, retention and fouling at various recovery and pH conditions. High fluxes (approximately 100 L/(m2h)) for nanofiltration membranes were measured when circulation waters from the paper machine were filtered at neutral conditions. In the filtration of discharge of external activated sludge treatment plants we measured fluxes around 150 L/(m2h) even at a concentration factor of 12. The best NF membranes removed over 80% of the organic carbon and of the conductivity and almost completely eliminated the color. With acidic waters fluxes and retentions were significantly lower. The NF270 membrane from Dow and the Desal-5 membranes from Osmonics had the highest flux and retention properties. However, the Desal-5 membrane lost its retention properties slowly, which restricts its use in the high shear CR-filter. CR-nanofiltration can be used in the pulp and paper industry without feed pre-treatment by ultrafiltration. This increases the attractiveness of high shear CR-nanofiltration.     

Advanced membrane technology for application to water treatment

Following the successful implementation of the ‘MAC21’ Project, the ‘New MAC21’ Project is being implemented for further development of membrane technology in Japan. The project includes various pilotscale and laboratory experiments on 1) nanofiltration system, and 2) MF/UF system combined with advanced treatment processes such as activated, carbon treatment, ozonation and biological treatment. As the result. it has been shown that both systems are applicable to drinking water treatment. Although a NF system was very effective for the removal of organic contaminants such as precursors of disinfection by-products, it is considered that the development of a proper treatment method for the concentrate will be very important in the future.