活性紫染料纳滤脱盐精制的研究

对某染料厂提供的活性紫粗制染料液进行了纳滤膜筛选和脱盐浓缩精制的间歇恒容渗滤实验研究。膜筛选实验表明:DK膜较之DL膜和NF270膜更适合于活性紫染料脱盐浓缩精制的渗滤过程。间歇恒容渗滤操作参数为:活性紫粗制染料液含染料质量分数 5%,含盐质量分数 0 8%;染料含盐质量分数为 16%,渗滤操作压力 1 0MPa,膜面循环通量 1 4m3 /h,渗滤浓缩 2倍,渗滤时间 80h,结果含盐质量分数降至 0 75%,染料纯度达到 99%以上;最后将料液浓缩 3倍,以降低后续喷雾干燥的能耗。该实验研究为工业化提供了依据。     

水溶性荧光染料溶液脱盐浓缩的纳滤实验研究

选用NTR7450和NF270两种纳滤膜对水溶性工业荧光染料原液进行分离，选择出透过通量大、除盐效果好和染料截留率高的纳滤膜，并对该染料溶液进行了脱盐和浓缩的间歇渗滤过程研究：在温度25℃和压力1.0MPa下，膜对染料截留率达到100％，最终料液中NaCl浓度从0.214mol／L降到0.0025mol／L,料液被浓缩了2．6倍。说明纳滤膜的间歇渗滤操作过程能够实现染料溶液的脱盐浓缩。     

纳滤膜类型对碳酸盐型苦咸水脱盐效能的影响

采用纳滤技术对苦咸水进行脱盐是拓展淡水资源供给的重要途径之一，而膜材料的合理选用与否则会对其脱盐效能产生显著的影响。本研究采用两类商品纳滤膜（NF90和NF270）对典型碳酸盐型苦咸水进行脱盐及污染对比，研究了两类纳滤膜在不同操作压力、原水温度、系统回收率条件及在三类有机物（牛血清白蛋白、腐殖酸和海藻酸钠）污染下的通量变化规律，并通过总溶解固体（TDS）去除率、阳离子截留率和扫描电镜-能谱等分析手段综合探讨了两类纳滤膜的脱盐效能与污染特征差异。结果表明，NF90和NF270在不同操作压力、温度和系统回收率下的出水TDS均能满足《生活饮用水卫生标准》（GB 5749-2022）的限制规定（TDS<1 000 mg/L），而NF270则由于其较为疏松的分离层结构而具有更高的产水通量，且其较低的污染物浓缩效应和亲水光滑的膜面物化特征赋予其更强的抗污染能力，综合而言更为适用于典型碳酸盐型苦咸水的脱盐处理。     

搅拌剪切力强化纳滤脱盐精制活性蓝染料溶液

通过一系列实验,对某染料厂提供的活性蓝染料溶液在搅拌剪切力强化作用下进行了纳滤脱盐精制研究.实验结果表明,搅拌转速为300 r/m in时产生的剪切力能有效控制浓差极化和减缓膜污染.在操作压力1.0 MPa、温度25℃、搅拌转速300 r/m in的操作条件下进行了预浓缩-连续恒容渗滤-后浓缩组合过程操作.先将料液预浓缩1.33倍,经过连续恒容渗滤,染料纯度从71.4%提高至99%以上,最后将染料溶液浓缩2倍,以降低后续喷雾的能耗.在此基础上,进行了模拟计算,为工业化提供依据.     

纳滤膜-间歇渗滤法进行染料脱盐与浓缩的实验研究

根据纳滤膜的截留相对分子质量和对盐具有一定的截留率,针对一种商品代号为对ORD-HPDT的染料所需脱盐和浓缩要求,进行了纳滤膜的筛选和纳滤膜-间歇渗滤操作实验研究.结果表明,选用合适的纳滤膜,采用间歇渗滤法处理该染料溶液,不仅脱盐效果较为理想,而且染料质量分数也从3%浓缩至6%,因而技术上是可行的.     

纳滤技术在海水淡化中的应用实验研究(Ⅱ)

采用NF90-4040膜组件对海水脱盐进行了实验研究,考察进水压力、温度、流量和进水含盐量对纳滤系统水收率、膜通量的影响。结果表明,随着进水压力的增大、温度的升高,膜通量均增大;而随着进水含盐量增大、进水流量的增大,水回收率降低。     

亚氨基二乙酸母液的电渗析脱盐实验

在对亚氨基二乙酸母液(IDA)进行调等电点的基础上,采用电渗析技术对该母液进行了脱盐的实验研究,考察了电渗析运行电压、料液循环流量等工艺参数对电渗析脱盐工艺过程的影响. 结果表明:均相离子交换膜电渗析技术能有效脱除亚氨基二乙酸母液中的盐,而且具有较高的亚氨基二乙酸回收率,在料液流量为300 L/h、运行电压为30 V时,IDA回收率为92.4%.     

基于脱硫废水零排放的膜法深度处理工艺研究

以脱硫废水为处理对象,提出了软化预处理后的纳滤-电渗析深度处理组合工艺。考察了纳滤分盐特性及电渗析浓缩工艺特性。实验结果表明：纳滤膜 NF270 相比于 NF90 膜接触角较小,膜通量更大。同时 NF270 对 SO₄^2-的截留率为 90% 以上,对 Cl^-的截留率仅为 4%,可以实现良好的分盐效果。两段式纳滤膜处理进一步降低了杂质离子的干扰,提高了 Cl^-的纯度。电压对电渗析浓缩 Cl^-的相对浓缩率影响较大,而温度影响相对较小。经 7次浓缩,Cl^-浓度从77.6 mmol/L提升至1 201.2 mmol/L,可以满足制次氯酸钠的生产标准（GB 19106-2013）。     

扩散渗析-电渗析回收赖氨酸离子交换废液中的盐

为缓解电渗析膜污染,提高电渗析性能,采用阴膜扩散渗析对待脱盐的赖氨酸离子交换废液进行净化处理,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩。结果表明,当扩散渗析流量为5.6 L/h时,扩散渗析的扩散系数达2.24?10?7 cm2/s,离子交换废液中(NH4)2SO4透过率约为30%,可截留90.1% Mg2+和94.5%有机氮、80.3%蛋白、86.0%总糖、79.3%化学需氧量(COD);与直接电渗析赖氨酸离子交换废液相比,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩,SO42?膜通量、电流效率分别提高了55.7%和18.3%,操作时间、单位膜通量能耗分别降低了26.1%和42.3%。用扩散渗析净化赖氨酸离子交换废液可有效缓解后续电渗析的膜污染,提高电渗析性能。     

聚酰胺非对称纳滤膜在印染废水深度处理中的应用

利用自制的聚酰胺非对称纳滤膜处理水溶性阴离子染料废水,并与NF270商品膜性能进行了比较研究。在0.7 MPa和25℃的条件下,所制纳滤膜对3种阴离子染料的截留率均大于95%。24 h染料连续脱盐运行条件下,膜的水通量保持在50 L.m-2·h-1,染料截留率96%以上,脱盐率稳定在5%以下,具有较好的选择分离性和耐污染性。2种纳滤膜的性能对比研究表明,所制PMIA非对称纳滤膜的染料截留能力和耐高温性优于NF270商品膜,但膜通量稍低。     

Stainless steel membrane UF coupled with NF process for the recovery of sodium hydroxide from alkaline wastewater in chitin processing

The recovery of sodium hydroxide from alkali wastewater in chitin processing was investigated using stainless steel ultrafiltration membrane (SSM) and HDS-04 nanofiltration (NF) membranes with membrane area of 0.35 m² and 1.4 m², respectively. Flux behaviors were observed with respect to filtration time, volumetric concentration ratio (VCR), operating pressure, temperature, and cleaning. As the VCR increased, the permeate flux declined while almost the same concentration of NaOH was permeable. The SSM and NF operations end with a concentrated protein solution that needed a small amount of waste acid for neutralization and easy spray drying and the permeate of the NaOH solution can be reused. Concentrations of NaOH that govern reusability of permeate were measured to be independent on VCR. The most suitable VCRs for SSM and NF in terms of maintaining relatively good membrane productivity and high rejection of protein and chemical oxygen demand (COD) were approximately 50. At a VCR of 50, the total rejections of protein, COD and suspended solid (SS) were 82.5%, 94% and 100%, respectively, while total NaOH recovery was 96% with SSM average flux 270 LMH and NF average flux 25 LMH. SSM filtration was essential for the pretreatment of the alkali wastewater before it was fed into the NF system.     

天然有机物对国产纳滤膜的污染及清洗效果研究

为考察水体中天然有机物(NOM)对纳滤膜性能产生的影响,以腐殖酸(HA)、牛血清蛋白(BSA)和海藻酸钠(SA)分别模拟水中常见NOM,腐殖质、蛋白质和多糖,对国产NF-1812纳滤膜进行单组分及其混合物定性定量有机污染及清洗实验。结果表明,有机污染造成膜通量下降,膜污染程度为SA>HA>BSA;NOM截留率可稳定在99.2%~99.6%;膜污染阻力主要为浓差极化阻力,其次是凝胶层阻力和内部污染阻力,有机污染液综合黏度和综合含量越大,浓差极化阻力的比例越高;对多组分有机污染膜进行错流速度9 cm/s的物理水力清洗和pH=10.0的质量分数分别为0.1%的NaOH+0.025%Na-SDS化学药剂清洗,膜通量、NOM截留率、苦咸水截留率、SEM成像均恢复至原膜状态,纳滤膜清洗效果良好,适用于中国西北苦咸水地区。     

磁场强化膜分离土霉素发酵液工艺研究

引入磁场强化膜分离技术对板框过滤后的土霉素发酵液进行提纯和浓缩,研究结果表明,经0.4T磁段磁场强化后,PES20超滤膜及NF270纳滤分离性能均表现出较佳的正效应,土霉素产品质量较无磁场作用及原工艺有所提高。     

Performance of Nanofiltration Membranes in the Treatment of Synthetic and Real Seawater

Abstract

Nanofiltration membranes (NF) are being employed in pretreatment unit operations in both thermal and membrane seawater desalination processes and as partial demineralization to seawater. In order to predict NF membrane performance, a systematic study on the filtration performance of selected commercial NF membranes against seawater is presented in this paper. Two commercial nanofiltration membranes (NF90 and NF270) have been investigated in details to study their performance in filtering the salt mixture, synthetic and real seawater in a cross‐flow NF membrane process at a pressure range from 4 to 9 bars. The Spiegler‐Kedem model was used to fit the experimental data of rejection with the permeate flux in order to determine the fitting parameters of the reflection coefficient (σ) and the solute permeability (P_s). The results showed that the rejection increases with pressure for NF90 and slightly increases with pressure for NF270. Also, the NF90 membrane has shown to be able to reject both monovalent and divalent of all investigated mixtures and seawater with very reasonable values but at a relatively low flux. Moreover, it reduced the salinity of investigated seawater from 38 to 25.5 g/L using one stage of the NF membrane at 9 bars. This makes NF90 more suitable for the application in the pretreatment of desalination processes. On the other hand, NF270 can reject monovalent ions at relatively low values and divalent ions at reasonable values. It has also reduced the seawater salinity to 33.6 g/L, but at a very high permeate flux. The SKM model fitted the experimental data of divalent ions in salt mixture and seawater.     

Rejection of salt mixtures from high saline by nanofiltration membranes

Nanofiltration (NF) membranes have recently been employed as pretreatment unit operations in seawater desalination processes and as partial demineralization to seawater. The present paper investigates the performance of selected commercial NF membranes to reject salts of high concentrations at salinity levels representative of brackish and sea water. Two commercial nanofiltration membranes (NF90 and NF270) have been investigated in detail to study their performance in filtering aqueous solutions containing different salt mixtures in a cross-flow NF membrane process within the pressure range from 4 to 9 bar. Spiegler-Kedem model (SKM) was used to fit the experimental data of rejection with the permeate flux. The results showed that NF90 membrane was shown to have a distinct ability to reject both monovalent and divalent ions of all investigated mixtures with very reasonable values but with relatively low flux. This will make NF90 more suitable for the application in the pretreatment of desalination processes. On the other hand, NF270 can reject monovalent ions at relatively low values and divalent ions at reasonable values, but at very high permeate flux. The SKM model only fitted well the experimental data of divalent ions in salt mixture. Based on the evaluation of the overall performance of NF90 and NF270 membranes, their distinct ability to reject salts at high salinity from seawater is considered an advantage in the field of pretreatment of seawater feed to desalination units.     

进水水质对纳滤膜苦咸水软化的分离性能

针对黄淮地区苦咸水,构建了小试级别的纳滤膜法软化系统,并开展了包括pH、总溶解固体含盐量（TDS）和总有机碳（TOC）等进水水质对DL、DK型纳滤膜的软化分离实验。结果表明,pH为3~10、TDS为1317~5926 mg·L^-1和TOC为2.72~12.24 mg·L^-1的进水条件下,DL和DK纳滤膜比通量随pH的增加分别呈先上升后下降和缓慢下降的趋势,随进水TDS和TOC的增加呈整体下降趋势,而纳滤膜对硬度离子（Mg²⁺和Ca²⁺）的截留率均呈明显的上升趋势。DL膜运行至267 h时,膜比通量下降幅度超过10%,进行化学清洗,酸洗后膜比通量恢复率达到85.05%,酸洗加碱洗后该值高达97.2%,结合扫描电子显微镜和原子力显微镜表征结果,可知化学清洗对膜面污染有较好的去除效果。     

Performance evaluation of polyamide nanofiltration membranes for phosphorus removal process and their stability against strong acid/alkali solution

In this study,a quantitative performance of three commercial polyamide nanofiltration(NF) membranes(i.e.,NF,NF90,and NF270) for phosphorus removal under different feed conditions was investigated.The experiments were conducted at different feed phosphorus concentrations(2.5,5,10,and 15 mg·L~(-1)) and elevated pHs(pH 1.5,5,10,and 13.5) at a constant feed pressure of 1 MPa using a dead-end filtration cell.Membrane rejection against total phosphorus generally increased with increasing phosphorus concentration regardless of membrane type.In contrast,the permeate flux for all the membranes only decreased slightly with increasing phosphorus concentration.The results also showed that the phosphorus rejections improved while water flux remained almost unchanged with increasing feed solution pH.When the three membranes were exposed to strong pHs(pH 1.5 and 13.5) for a longer duration(up to 6 weeks)it was found that the rejection capability and water flux of the membranes remained very similar throughout the duration,except for NF membrane with marginal decrement in phosphorus rejection.Adsorption study also revealed that more phosphorus was adsorbed onto the membrane structure at alkaline conditions(pH 10 and 13.5) compared to the same membranes tested at lower pHs(pH 1.5 and 5).In eonelusion,NF270 membrane outperformed Nf and NF90 membranes owing to its desirable performance of water flux and phosphorus rejection particularly under strong alkali solution.The NF270 membrane achieved 14.0 L·m~(-2)·h~(-1) and 96.5% rejection against 10 mg·L~(-1) phosphorus solution with a pH value of 13.5 at the applied pressure of 1 MPa.     

纳滤膜分离皂素水解原液的试验研究

将纳滤膜用于皂素行业水解原液的处理中,原水经纳滤膜分离后,渗透液作为生产用酸回用,其浓缩液经脱盐精制后作为工业碳源使用.选用一种耐酸型纳滤膜,并通过试验确定了最佳浓缩比、脱盐方式,同时考察了纳滤膜的分离效果.结果表明,耐酸型纳滤膜能够有效地从原水中分离出盐酸,最佳浓缩比为2.25,脱酸后的浓缩液通过加RO产水稀释两次可以较好地脱除氯离子.还原糖回收率为64%,盐酸回收率为40%,浓缩液中氯离子的脱除率为38%,通过清洗可使膜通量恢复.