纳滤膜在生活垃圾填埋场渗滤液处理中的应用发展

纳滤是介于反渗透和超滤之间的一种膜分离技术,现已成为是国内外研究的热点。本文简单介绍了垃圾渗滤液的特点及目前处理工艺,分析了纳滤膜的分离机理及特点：利用纳滤膜技术处理MBR二级处理后出水,研究纳滤膜在垃圾渗滤液应用中进出水COD变化情况。通过自身所做的纳滤膜设计工艺,进一步反馈了纳滤膜在渗滤液处理中的良好效果。     

MOFs改性纳滤膜去除饮用水中微量有机物进展

纳滤是一种可用于去除微量小分子有机污染物的技术，但目前纳滤膜难以同时实现高通量及高有机物去除率，限制了其大规模应用。在纳滤膜中添加金属有机框架复合物（MOFs），通过其大量的纳米孔道及其筛分、吸附和催化降解等作用可以使纳滤膜实现高通量和对有机物的高效去除。分析阐述了近年来国内外基于MOFs改性纳滤膜去除微量小分子有机污染物的研究进展，并分析了MOFs改性纳滤膜存在的问题，以期为改性纳滤膜去除饮用水中微量小分子有机物提供参考。     

市政纳滤饮用水深度处理——张家港第四水厂纳滤膜系统工程实践与经验总结

随着社会发展和生活水平的日益提高,居民对饮用供水安全及自来水水质要求也越来越高,市政给水也逐渐从供合格水的思路转向供优质水,纳滤膜处理技术也因其显著的工艺优势及投资运营成本的不断降低,开始在给水深度处理领域中大放异彩。金科环境一直致力于纳滤膜技术在市政饮用水深度处理领域的工程应用与研究,所承建的纳滤膜系统累计日处理规模已超过55万m³/d。金科环境于2019年承建的国内首个10万m³/d规模的张家港第四水厂一期纳滤膜系统正式投运,为新工艺、新技术、新装备在我国饮用水安全建设方面起到了良好的示范作用,并为近几年纳滤膜技术在国内微污染地表水处理中的大规模应用奠定了基础。     

纳滤膜污染形成与控制研究进展

纳滤技术以其操作压力低、对二价离子截留率高且能保留水中有益微量元素等特点广泛应用于水处理领域的各个方面,但是膜污染一直是影响纳滤膜应用和发展的瓶颈问题。本文总结了纳滤膜污染的类型、形成机理及污染特性,讨论了膜污染形成的影响因素及预防控制方法措施,提出了今后膜污染机制及控制的研究方向,以促进纳滤技术在饮用水处理行业的推广应用。     

纳滤膜元件的运行特性分析

通过对影响纳滤膜元件性能的给水温度、膜通量及含盐量3项重要因素进行的正交设计试验,分析了不同脱盐率纳滤膜元件的工作压力和透盐率的给水温度、给水含盐量及膜元件通量的特性,并明确了不同脱盐率纳滤膜元件工作压力及透盐率的回收率特性,从而为建立特定系列纳滤膜元件的连续运行特性图谱提供了一个典型模式。     

膜分离技术在矿井水净化中的应用

文章通过实践,介绍了纳滤膜的特点以及纳滤膜在矿井水中的应用.     

纳滤膜系统在地下水处理中的应用

考察了DS水厂纳滤膜处理系统对地下水的净化效果.结果表明,在纳滤膜前增加碟片过滤及超滤预处理工艺可以提高系统的净化效果,且可有效保护纳滤膜,减少化学清洗频率,以及延长纳滤膜的使用寿命；该系统运行情况良好,出水水质较好,硬度、碱度及硝酸盐去除率分别可以达到94％,92％和58％.     

纳滤技术在直饮水处理系统中的应用

介绍了纳滤技术的主要特点，并论述了其在直饮水深度处理系统中应用的可行性。同时，对以市政自来水为原水．纳滤膜为主体的直饮水生产工艺进行了探讨。     

纳滤膜去除饮用水中无机离子的中试研究

采用纳滤作为主体工艺生产直饮水,考察了两组标准脱盐率不同的纳滤膜对各种无机离子的去除效果.结果表明,纳滤膜可以确保直饮水中总溶解性固体(TDS)、SO24-、F-的含量达到《饮用净水水质标准》的要求,同时纳滤膜对自来水中的NH4+、NO2-、Cl-等离子的去除效果良好;标准脱盐率高的纳滤膜对无机离子的去除率较高,反之则较低.综合考虑各种因素,建议直饮水工程中选用标准脱盐率为80%-85%的纳滤膜.     

二级出水中内分泌干扰物的检测与去除试验

研究使用C18固相萃取柱,用气质联用仪GC-MS对邯郸市东污水厂二级出水中内分泌干扰物进行检测,考察了纳滤膜对内分泌干扰物的去除效果,同时验证了固相萃取—气质联用技术的可行性,以推广该技术的应用。     

rGO/ZIF-8改性聚酰胺纳滤膜的制备及分盐性能

为了改善纳滤膜的性能,用水热合成法制备了rGO/ZIF-8复合纳米材料,通过界面聚合法引入到纳滤膜的功能层中,制成新型改性聚酰胺复合纳滤膜,并研究了改性膜的表面形貌、结构及分盐性能。结果表明:改性膜的表面出现沟壑状聚酰胺簇突起,粗糙度有较大提升,负电性增强,接触角降至42.7°,亲水性能有所提高。改性膜对Na₂SO₄的截留率由原状膜的95.8%下降至85.6%,但纯水通量提升近一倍,达到39.2 L/(m²·h),且在连续48 h运行过程中性能稳定。由此可见,新型rGO/ZIF-8材料的引入虽然会导致截留率略有下降,但可以大幅提高改性纳滤膜的水通量。     

双膜法处理污水厂尾水效能分析与膜再生研究

为提高污水厂出水水质,寻求适合处理污水厂尾水滤膜的再生方法,采用超滤—纳滤双膜工艺,针对辽宁省本溪市某城市污水厂二级尾水开展深度处理研究。考察了进水流速、累积过滤水量(超滤进水流速为25 L/min,纳滤进水流速为4 L/min)对膜分离效果的影响,同时开展了超滤和纳滤膜再生方式及效果研究。结果表明:在考察范围内,超滤装置的分离性能受进水流速影响较小,主要与进水污染程度有关,对COD、TP、氨氮的平均去除率分别为48%、55%、27%。当纳滤单元进水流速为4 L/min时,双膜法对COD、TP、氨氮的平均去除率分别为87%、96%、68%。双膜法对COD、TP的去除率随着进水污染程度的减轻而降低,氨氮去除率受累积过滤水量的影响较小,这与原水污染程度有关。随着累积过滤水量的增加,膜分离性能呈减弱趋势。超滤膜轻微污染时采用物理清洗效果良好,严重污染时需采用化学清洗的方法。超滤有效延缓了纳滤膜污染,纳滤膜轻微污染时采用酸碱浸泡法再生效果良好。     

Selective removal of dissolved uranium in drinking water by nanofiltration

A procedure for the selective removal of uranium traces dissolved in drinking water has been studied. Plate module membrane filtration equipment was operated to evaluate the performance and selectivity of three different nanofiltration flat-sheet membranes. Experiments were carried out using various commercial mineral waters with distinct physicochemical compositions. The membranes were first discriminating by their ability to reject uranium in the presence of the main cations found in mineral waters, using a 2 mg L(-1) (2000 ppb) concentration of uranium. The rejection of U(VI) was dependent on the uranyl speciation and the ionic strength. Second, removal of uranium traces (0.02 mg L(-1), 20 ppb) was performed using the nanofiltration membrane showing the highest selectivity for uranium toward alkaline and alkaline-earth ions. The results showed a high performance of the nanofiltration membrane, Osmonics DL, for selective uranium rejection at low pressure (1 bar), illustrating the advantage of nanofiltration for the selective removal of uranium from drinking water.     

Impact of montmorillonate on the process of purification of waters containing uranium by ultra- and nanofiltration

The article has investigated the impact of montmorillonite (natural and modified) for purification of waters containing uranium by ultraand nanofiltration. It has been shown that maximally possible uranium retention coefficient by a nanofiltration membrane was obtained when a modifier with the molecular weight 2 kDa was used. Whereas for an ultrafiltration membrane a high index of purification is achieved when using a modifier with the molecular weight 10 kDa.     

Removal of THMP by nanofiltration: Effects of interference parameters

An experimental investigation is conducted to evaluate the effects of interference parameters on the performance of nanofiltration for removal of trihalomethane precursors (THMPs). The influence of operating pressure, feed THMPs concentration, pH, presence of other ions (Ca²⁺ and Mg²⁺), and suspended solids on nanofiltration performance are determined. The effect of membrane precompaction is studied as well. Membrane performance for reversible and irreversible compaction is compared. Pretreated surface water from a pond is used as the feed water in the study to simulate the practical conditions in water treatment industries. Experimental results show that precompacted membrane has a higher rejection capacity. Higher pressure, feed THMP concentration, and suspended solids increase rejection. However, overall flux variation due to these parameters is found to be negligible. On the other hand presence of divalent ions reduce the rejection capacity. Generally rejection is found to be greater than 90% for a precompacted membrane, which turned out to be well suited for industrial scale application of nanofiltration for removal of THMPs.     

Removal of boron compounds in pressure-driven desalination of the Black Sea water

The article has investigated the process of removing boron from the water of the Black Sea during its pressure-driven desalination using an OPMN-P nanofiltration membrane (ZAO NTTs Vladipor) and an ESPA-1 reverse-osmosis membrane (Hydronautics). It has been shown that the boron removal degree in a two-stage treatment (nanofiltration and reverse osmosis) is much lower than in a single-stage one (reverse osmosis). For the first time it was shown that there is a substantial impact of salts of calcium and magnesium on the boron retention coefficient with reverse-osmosis membranes. We have studied the conditioning process in terms of the content of boron (using an Amberlite IRA-743 boron-containing sorbent and the method of reverse osmosis in the alkaline medium) permeate obtained in the two-stage desalination of the Black Sea water.     

MIBR-纳滤系统中的膜污染及清洗

综述了膜污染的机理和清洗方法,在MIBR,纳滤组合工艺处理生活污水为再生水的现场中试中,采用1％NaOH,1％H2SO4及2％5％NaClO对MIBR和MBR中空纤维膜进行了清洗,对比了MBR和MIBR膜清洗的效果,证明MIBR膜的清洗效果更好,同时,采用酸（pH=2）、碱（pH=12）液对纳滤膜进行了清洗,结果表明酸清洗后的效果更好。     

Stabilized landfill leachate treatment by combined physicochemical-nanofiltration processes

Landfill leachate is a complex wastewater which the composition and concentration of contaminants are influenced by the type of waste deposited and the age of landfill. In the last years, several processes or process combinations were developed and tested to reach requirements for the discharge of leachate. Among the new processes, membrane processes are considered as promising: reverse osmosis is one of the most widely used treatment in the Northwestern European countries and nanofiltration is gained in popularity during the last 5 years. Successful application of membrane technology for the treatment of landfill leachates, requires efficient control of membrane fouling. Two organic membranes of nanofiltration were used for pilot-scale testing. Leachates were subject to several pretreatments (pH modification, prefiltration and coagulation with FeCl3) to remove potential foulants including dissolved organic and inorganic substances, colloidal and suspended particles. These pretreatments do not enhance the performances (retention and permeation flux) of membranes because the pH range and the presence of Fe3+ ions contribute greatly to change the characteristics of organic matter and the surface charges of membranes. However, the results show that nanofiltration is sufficient to eliminate refractory COD, the permeates have a COD lower than the requirements for discharge.     

Nanofiltration in drinking water supply

The paper has presented an analytical review of the state of the art in scientific developments and technological solutions of nanofiltration in drinking water treatment. The article has shown the possibilities of nanofiltration and analyzed reasons restricting its wide-scale use in drinking water supply. It has covered new approaches to the solution of problems related to membrane fouling.