国产纳滤膜脱除硝酸盐的试验研究

采用国产纳滤膜脱除水环境中的硝酸根离子,研究进液浓度、浓水流量、压力、温度等对纳滤膜的截留性能和通量的影响。结果表明,压力的升高有利于提高纳滤膜的截留率和产水通量,最佳压力为0.7 MPa,此时截留率和产水通量可达75.0%和153.7 L/(m²·h);适当的提升进水温度可以提高纳滤过程的截留率,最佳进水温度为39.3℃;进料浓度对截留过程有着显著的影响,进料浓度越低,纳滤膜的截留效果越好。     

反渗透膜法处理磷酸铁生产废水的零排放工艺研究

以硫酸亚铁为原料生产电池级磷酸铁过程中产生大量的含硫酸根、磷酸根、钠离子的废水。为减少废水排放并使之得到循环利用,采用反渗透膜技术对中试生产电池级磷酸铁的废水处理进行了零排放设计和实验研究,考察了进水压力、进水浓度、温度、pH等因素对硫酸根和磷酸根的截留率、膜通量和产水率的影响。实验结果表明所采用的反渗透膜对硫酸根、磷酸根的截留率达99.15%以上,进水压力、进水浓度、温度、pH等因素对截留率影响较小,但对膜通量和产水率影响较大。截留率随着进水压力的增加略有增加,随进水浓度增加和温度的升高而略有减小,膜通量和产水率随进水压力和温度的升高而增大,随进水浓度的增大而减小,pH=6.5时截留率、膜通量和产水率最高。同时采用生产废水制备了硫酸钙晶须,实现了废水零排放。     

纳滤法处理含氟废水工艺条件的研究

采用Dow FilmTec公司的NF-90纳滤膜处理模拟含氟废水,主要考察了压力、pH、流量、温度、氟离子初始浓度等对膜渗透通量和氟离子截留率的影响。结果表明:压力升高,膜渗透通量增大,氟离子截留率先增大后减小;pH对膜渗透通量无明显影响,氟离子截留率随pH的升高而增大;流量升高膜渗透通量和氟离子截留率略有增大;温度升高,膜渗透通量增大,氟离子截留率降低;氟离子初始浓度增大,膜渗透通量减小,氟离子截留率降低。在压力1.0 MPa、pH 10.01、流量30 L/h、温度20℃的条件下NF-90膜截留率可达到95%;当处理氟浓度小于100 mg/L,出水氟浓度可达到国家工业一级排放标准。     

腐殖酸共存条件下NF90纳滤膜去除水中邻苯二甲酸二丁酯

水中共存有机物会对纳滤产生影响,以邻苯二甲酸二丁酯(DBP)为对象,研究了NF90膜对纯水、模拟水和河水中DBP的去除效果。DBP的初始质量浓度为100μg/L。结果表明,NF90膜能实现对微量DBP的有效去除,截留率高达90%以上;在模拟水中,腐殖酸共存时,会引起膜通量的下降和截留率的上升,pH为7时,截留率最高,其他无机离子(K+、Ca2+)的加入,会减小膜通量增大截留率,其中,Ca2+的影响尤为明显;河水中的无机物和有机物成分复杂,膜通量会进一步减小,截留率进一步提高;纳滤初期,吸附会影响截留率,6 h后吸附达到饱和,稳定运行96 h后,膜污染会引起膜通量和截留率的下降。     

腐殖酸共存条件下NF90纳滤膜去除水中邻苯二甲酸二丁酯

水中共存有机物会对纳滤产生影响,以邻苯二甲酸二丁酯(DBP)为对象,研究了NF90膜对纯水、模拟水和河水中DBP的去除效果。DBP的初始质量浓度为100μg/L。结果表明,NF90膜能实现对微量DBP的有效去除,截留率高达90%以上;在模拟水中,腐殖酸共存时,会引起膜通量的下降和截留率的上升,pH为7时,截留率最高,     

对纳滤膜分离净化湿法磷酸溶液影响因素的研究

选择NP010和NP030两种纳滤膜对含MgSO_4、Fe_2(SO_4)_3、Al_2(SO_4)_3的磷酸溶液进行分离净化试验,考察了盐含量、操作压力、料液温度等对纳滤膜分离性能的影响。结果表明:随盐含量的增大,纳滤膜的通量减小,其对盐的截留率亦下降;随操作压力的增大,纳滤膜的通量增大,截留率也随之增大,但在压力较高时,截留率增大趋势不明显;料液温度上升,纳滤膜的通量上升,截留率下降;在不同盐含量、操作压力、料液温度的条件下,两种纳滤膜对P_2O_5的截留率均在5%以内。     

低压条件下双甘膦NaCl混合溶液的纳滤分离性能研究

选择纳滤膜NF270对双甘膦和NaCl自配混合溶液进行分离试验研究和理论分析.探讨了pH、操作压力、氯化钠浓度、双甘膦浓度对纳滤膜分离性能的影响.结果表明,由于纳滤膜NF270截留分子量小于双甘膦分子量,孔径筛分效应成为双甘膦截留率的决定性因素,截留率均稳定在97％左右.电荷效应对NaCl截留率与膜通量有着显著的影响,在pH为6.2,压力为0.7 MPa时NaCl截留率达到最低值4.5％,而高浓度氯化钠不利于分离,高浓度双甘膦却有助于二者的分离.结论认为运用NF270在适宜的操作条件下可实现双甘膦和氯化钠的最大分离.     

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。     

低含氟工业废水分质回用技术研究

研究了纳滤(NF)-反渗透(RO)工艺对低含氟废水的处理效果。结果表明,在pH5、操作压力0.3 MPa、进水F-质量浓度小于80 mg/L的条件下,NF出水均可达到GB 8978-1996规定的一级排放标准,且满足电镀一般用水的水质要求。有机添加剂对NF过程的F-截留率存在不同的影响。NF出水经RO深度处理后,电导率低于10μS/cm,满足特殊电镀用水水质要求,废水回用率可达94%。NF-RO集成工艺可为低含氟废水的分质回用提供良好的解决方案。     

中空纤维纳滤膜的应用性能

研究了中空纤维纳滤膜的长期稳定性,以及操作压力、进料液浓度对膜分离性能的影响。结果表明:中空纤维纳滤膜在长时间运行过程中分离性能稳定;随着操作压力的上升,膜的纯水通量增加,截留率提高;随着进料液浓度的增加,膜的渗透通量基本不变,截留率下降。     

基于化工废水处理中纳滤膜的应用研究

作为一种新型分离技术,纳滤膜不仅能有效净化废水,还能回收其中的有用物质。因此,在化工废水处理中得到多数企业的认可。文章介绍了纳滤膜分离技术的特点与纳滤膜的分离机理。并以陶氏NF270-4040纳滤膜处理盐化工废水为基础,从考察操作压力、温度、进水流量、进水pH入手,依据非平衡热力学模型分析纳滤膜处理化工废水的优势及适宜条件。     

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.     

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。     

操作条件对NF90膜软化水过程的影响

以模拟硬水为水样,针对压力、温度和pH值等操作因子对NF90型纳滤膜软化水过程的影响进行了试验研究。结果表明,在处理暂时硬度为300 mg.L-1(以CaCO3计)的硬水时,NF90膜有较高的通量和Ca2+截留率,适用于水质软化过程。在操作压力为0.5～2.0 MPa、温度为13℃～37℃、水样pH值为6.0～8.0的条件下,膜通量随操作压力、温度的升高而升高,但受pH值的影响不大。在试验条件范围内,Ca2+的截留率均>97%。     

Optimization Study for Treatment of Acid Mine Drainage Using Membrane Technology

The use of membrane technology in the treatment of Acid Mine Drainage (AMD) can result in reduction of chemical usage and sludge production making the treatment process more environmentally friendly. This study deals with the optimization of membrane filtration performance in the treatment of AMD using two nanofiltration (NF) membranes (NF99 and DK) and one reverse osmosis (RO). All membranes were used in various tests treating a model solution at two different concentration levels in order to cover the concentration of actual AMD found in the mining industry. The main parameters which were studied to determine the optimal condition for AMD filtration are pressure, pH, temperature, and flow rate. Pressure and temperature were found to have a considerable influence on flux, while rejection was only slightly influenced by pressure. The feed flow rate had no effect on rejection. The highest flux with moderate rejection was determined for NF99 while RO had the lowest flux but highest rejection. Therefore, NF is preferable for AMD treatment due to lowest energy consumption. The treatment has also been tried on a large scale to check its applicability at a commercial scale. Finally, PHREEQC has been used to determine the scaling risk in the prepared AMD.     

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。     

Intensification and optimization of the characteristics of polyacrylonitrile nanofiltration membranes with improved performance through experimental design and statistical analysis

The present study aims to employ experimental design and statistical analysis in order to investigate in detail the effect of various prominent parameters on the characteristics and performance of polyacrylonitrile nanofiltration membranes for the treatment of electroplating wastewaters targeting Ni, Cr, and Zn ions. Incorporation of TiO₂ into the membrane matrix was effective in improving pure water flux (PWF) by ~16%. Also, PWF and Ni rejection of membranes escalated to 118.55 L m⁻² h⁻¹ and 90.79%, respectively upon addition of 1.5 wt% citric acid to the dope. Variation in coagulation bath temperature from 25°C to 45°C led to the formation of membranes having higher porosity with enhanced PWF by about 25% at the expense of only 5% reduction in Ni rejection. Parameters were optimized by analysis of variance (ANOVA). In contrast to the effect of feed concentration, an increase in feed pressure and pH enhanced permeate flux and total ion rejection. Similarly, permeate flux increased at higher operational temperatures without change in total rejection. A mathematical model was developed by applying ANOVA and the best combination of operating parameters was obtained by optimization.     

纳滤/反渗透膜处理重金属废水的性能

The performance of different nanofiltration （NF） and reverse osmosis （RO） membranes was studied in treating the toxic metal effluent from metallurgical industry. The characteristics and filtration behavior of the processes including the wastewater flux, salt rejection and ion rejection versus operating pressure were evaluated. Then the wastewater flux of RO membrane was compared with theoretical calculation using mass transfer models, and good consistency was observed. It was found that a high rejection rate more than 95% of metal ions and a low Chemical Oxygen Demand （COD） value of 10 mg·L^-1 in permeate could be achieved using the RO composite membrane, while the NF rejection of the salt could be up to 78.9% and the COD value in the permeate was 35 mg·L^-1. The results showed that the product water by both NF and RO desalination satisfied the State Reutilization Qualification, but NF would be more suitable for large-scale industrial practice, which offered significantly higher permeate flux at low operating pressure.