海水纳滤预处理的优化研究

纳滤已被广泛研究用于反渗透和膜蒸馏海水淡化的预处理,它能有效避免反渗透膜和膜蒸馏装置的结垢污染,但纳滤膜同样存在结垢污染问题。通过配制人工海水及人工脱硬海水等海水体系研究了硬度离子对纳滤膜无机污染的影响,并通过接触角、SEM、EDX等表征方法研究了膜面污染物的主要成分及其对膜性能的影响。结果表明,钙离子是造成纳滤膜无机污染的主要硬度离子,脱硬或脱钙处理能有效避免海水淡化过程中纳滤预处理阶段的无机结垢问题。     

生物活性炭作为纳滤预处理工艺的试验研究

以地表原水为研究对象,进行了生物活性炭(BAC)作为纳滤工艺的预处理单元制备饮用水的中试,考察了BAC对造成纳滤膜污染的有机污染物的去除情况.结果表明,BAC对DOC、COD和UV254的去除率分别为29.0％、19.7％和37.0％.BAC滤柱的出水浊度略高于进水浊度,主要是出水携带破碎炭末及微生物所致,BAC出水中的颗粒物可被保安过滤器截留,BAC后设置足够的砂垫层或单独的滤池、超滤等单元可有效保障纳滤系统的安全.在2个月的连续运行期间,纳滤操作压力变化为0.32～0.37 MPa,膜污染程度很低,BAC作为纳滤预处理工艺是适合的.     

沸石改性吸附重金属离子(Cu2+)技术研究

为处理工业园区因不断扩大规模而产生的大量重金属污染废水，介绍了重金属污染废水的危害和目前的污水处理的方法。进行了三种改性沸石对铜离子的吸附试验研究，结果表明，天然沸石经过Na OH溶液改性吸附性能提升最大，当沸石用量为2 g时，Na OH溶液改性沸石对Cu2+的吸附量达到了89.64 mg/g。     

纳滤去除水中的有害离子

本文综述了纳滤去除饮用水和重金属废水中的有毒有害离子的应用研究,阐述了纳滤膜对无机盐的截留效果主要取决于膜对离子的电荷效应,表现在对多价离子的截留率高于单价离子。利用纳滤膜这种分离性能,可以去除部分饮用水中微量的有害单价离子（如NO2^-、NO3^-、F^-等）和大部分的有毒二价离子（如HAsO4^2-和重金属离子）,获取优质安全的饮用水;也可以用于处理重金属废水,能有效去除废水中的重金属离子。将纳滤和反渗透集成用于重金属废水处理,可以做到对有毒重金属离子的回收利用和出水回用,实现清洁生产,既具经济效益,又具环境效益,在工程实际中极具推广应用价值。     

胶州湾海水纳滤软化的研究

采用超滤-纳滤膜集成膜技术,进行了胶州湾海水纳滤软化现场试验,筛选了纳滤膜,考察了料液流量、操作压力对纳滤膜元件运行效果的影响,评价了纳滤作为海水淡化预处理对海水中主要离子的截留效果,并进行了短期试验。结果表明超滤-纳滤膜集成技术可为淡化系统提供优质的软化水,为胶州湾地区膜法海水淡化奠定了基础。     

纳滤工艺处理微污染原水的中试

南方部分城市由于水质型缺水,水源呈现微污染的水质特点,给常规工艺带来较大的处理难度。为保障饮用水供水安全,该文采用了纳滤工艺进行中试研究。试验结果表明:纳滤能高效去除水中的有机物,出水CODMn、UV254、TOC含量低于0. 3 mg/L、0. 010 cm-1、0. 4 mg/L。纳滤膜可以选择性去除水中的无机离子,保留部分对人体有益的钙镁离子。同时,对多环芳烃、有机氯农药、有机卤化物的截留率在50%、90%和90%左右。     

双膜法深度处理油田采出水的现场试验研究

基于油田注汽锅炉给水的要求,利用商品膜组件,进行了(超滤+纳滤)双膜法深度处理油田采出水的现场试验研究.结果表明,超滤预处理效果良好,出水油的质量浓度小于0.06 mg·L~(-1),SDI_(15)小于4.0,满足了纳滤膜进水要求.氢氧化钠+十二烷基磺酸钠(SDS)复合清洗剂对超滤膜污染表现出较好的清洗效果,纯水通量恢复系数高达92%.在较高的回收率下,纳滤对硬度、总溶解固体(TDS)、SS、和COD仍保持高截留率,且保持了稳定的产水通量,系统出水水质达到油田注汽锅炉进水水质指标.(超滤+纳滤)双膜工艺在长期运行过程中,产水通量及水质表现出较高的稳定性.     

JMS-逆流气浮-纳滤集成工艺去除水中腐殖酸的研究

本试验研究了JMS-逆流气浮-纳滤集成工艺去除水中腐殖酸的工艺特征和效果.试验结果表明：JMS-逆流气浮工艺去除水中腐殖酸时,在最佳投药点（PFC）,出水水质符合纳滤系统预处理单元的要求.该预处理系统与纳滤系统组合的集成工艺可以使水中的腐殖酸有机物浓度大大降低,且设有TQ56-36FC型纳滤膜的流程比设有M-N1812A型纳滤膜的流程效果好.前者出水的TOC值可达0.17～0.25mg/L,CODMn值为0.32～0.44mg/L,UV254nm值为0,且有95%以上的脱盐率;后者出水的TOC值在0.47～0.94mg/L,CODMn值为0.62～0.96mg/L,UV254nm值为0～0.0064cm^-1,脱盐率很低.另外,尽管保安过滤-活性炭预处理有利于纳滤膜（尤其是M-N1812A型纳滤膜）出水水质的提高,但活性炭柱与纳滤膜能去除的有机物种类是有些重合.     

陶瓷超滤膜用于盐湖卤水提锂合格液的中试研究

为解决纳滤膜用于盐湖卤水镁锂分离中长时间运行后出现通量下降、膜污染和分离效率下降的问题,开展了将陶瓷超滤膜作为纳滤预处理措施用于盐湖卤水提锂合格液的中试研究。中试设在吸附提锂车间,进水为提锂工序中的合格液。结果表明,在冬天低温环境合格液浊度<50 NTU的条件下,以及在合格液浊度上升至50~170 NTU的极端进水水质条件下,陶瓷超滤膜均可在300 L/（m ²·h）的测试通量下稳定运行,过滤时间为30~50 min/周期。产水浊度稳定<0.1 NTU,优于后续纳滤系统进水要求。     

天然沸石吸附电镀废水中重金属离子的实验研究

针对含重金属离子电镀废水,国内外普遍采用化学沉淀法来处理,而化学沉淀法存在运行费用高、二次污染等问题。由于铜离子、锌离子是最常出现在电镀工业中,本文选择铜离子和锌离子为研究对象,本文采用天然沸石处理模拟电镀废水中的铜离子和锌离子,考察了溶液pH值、天然沸石用量、反应时间、共存阳离子等多种物理化学参数的影响。实验结果表明,天然沸石吸附铜离子的最佳参数：当初始浓度为200 mg/L,溶液pH值为7,天然沸石用量为30 g/L,反应时间为20 min时,处理后的水质满足《污水综合排放标准》(GB8978-1996)要求。铜离子分别与锌、镍、铅和六价铬离子共存时,锌和镍离子在低浓度时对铜离子的吸附影响不大;铅和六价铬离子明显抑制铜离子的吸附。天然沸石吸附新离子的最佳参数：初始浓度在200 mg/L,溶液pH值为7,天然沸石用量为30 g/L,反应时间在20 min时,处理后的水质满足《污水综合排放标准》(GB8978-1996)要求。锌离子分别与铜、镍、铅和六价铬离子共存时,铜离子几乎对锌离子无影响;镍离子的影响很小;铅和六价铬离子明显抑制锌离子的吸附,为实际电镀废水的高效处理提供理论依据。     

Potential use of nanofiltration like-forward osmosis membranes for copper ion removal

The discharge of industrial effluent containing heavy metal ions would cause water pollution if such effluent is not properly treated. In this work, the performance of emerging nanofiltration(NF) like-forward osmosis(FO)membrane was evaluated for its efficiency to remove copper ion from water. Conventionally, copper ion is removed from aqueous solution via adsorption and/or ion-exchange method. The engineered osmosis method as proposed in this work considered four commercial NF membranes(i.e., NF90, DK, NDX and PFO) where their separation performances were accessed using synthetic water sample containing 100 mg·L~(-1) copper ion under FO and pressure retarded osmosis(PRO) orientation. The findings indicated that all membranes could achieve almost complete removal of copper regardless of membrane orientation without applying external driving force.The high removal rates were in good agreement with the outcomes of the membranes tested under pressuredriven mode at 1 MPa. The use of appropriate salts as draw solutes enabled the NF membranes to be employed in engineered osmosis process, achieving a relatively low reverse solute flux. The findings showed that the best performing membrane is PFO membrane in which it achieved N 99.4% copper rejection with very minimum reverse solute flux of 1 g·m~(-2)·h~(-1).     

超滤集成工艺对西北村镇窖水处理的应用研究

研究了以超滤为核心,流程为颗粒活性炭-纳米金属簇-超滤-紫外线的集成净水工艺对原水中浊度、CODMn、氨氮的去除,进行了不同原水浊度下超滤的膜污染成因分析和化学清洗试验。结果表明,集成工艺出水浊度稳定在1 NTU以下,对CODMn和氨氮的平均去除率为29.86%和50.95%。出水水质达到了现行GB 5749-2006的要求。在短时间内较高浊度的进水对超滤膜不会造成不可逆的膜污染,但在持续较高浊度进水条件下膜阻力会快速提高并最终造成膜污染。对原水中的有机物和浊度进行更有效的预处理能减缓膜污染的进程,膜污染发生后进行有针对性的化学清洗能有效的恢复膜通量。     

高盐度对突发重金属污染水源水应急处理的影响研究

针对沿海城市饮用水受咸潮影响的实际情况,探讨突发重金属污染的应急处理技术的可行性及高盐度对该技术的影响,试验结果表明,调节pH值-强化混凝可以有效控制突发的铅、镉、镍污染;亚铁还原(六价铬为三价铬)-铁盐混凝法可以有效控制突发的铬污染;NaClO氧化(三价砷为五价砷)-铁盐混凝法可以有效控制突发的砷污染;高盐度对突发重...     

Adsorption equilibrium of heavy metals on natural zeolites

Prior to equilibrium experiments, a clinoptilolite-type Korean natural zeolite was pretreated with HCl, NaOH, and NaCl to improve the ion-exchange capacity for heavy metals. Singleand multi-species equilibrium data of heavy metals such as copper, cadmium, cesium, and lead on treated and untreated natural zeolites were measured experimentally. For single-species equilibrium data, one of the conventional adsorption isotherms, the Sips equation, was used to fit them and then multi-species equilibrium data were predicted by using the loading ratio correlation (LRC), the ideal adsorbed solution (IAS) theory, and the real adsorbed solution (RAS) theory based on the Sips equation. In applying the RAS theory, we used the Wilson equation for fitting activity coefficients of metal ions in the ion-exchanger phase. It was proven that basic adsorption models except the LRC model could describe multi-species ion-exchange equilibrium for heavy metals/natural zeolite systems well.     

Removal of heavy metals from wastewater by membrane processes: a comparative study

Wastewater containing copper and cadmium can be produced by several industries. The application of both reverse osmosis (RO) and nanofiltration (NF) technologies for the treatment of wastewater containing copper and cadmium ions to reduce fresh water consumption and environmental degradation was investigated. Synthetic wastewater samples containing Cu²⁺ and Cd²⁺ ions at various concentrations were prepared and subjected to treatment by RO and NF in the laboratory. The results showed that high removal efficiency of the heavy metals could be achieved by RO process (98% and 99% for copper and cadmium, respectively). NF, however, was capable of removing more than 90% of the copper ions existing in the feed water. The effectiveness of RO and NF membranes in treating wastewater containing more than one heavy metal was also investigated. The results showed that the RO membrane was capable of treating wastewater with an initial concentration of 500 ppm and reducing the ion concentration to about 3 ppm (99.4% removal), while the average removal efficiency of NF was 97%. The low level of the heavy metals concentration in the permeate implies that water with good quality could be reclaimed for further reuse.     

以天然硅铝质黏土矿物为原料制备沸石分子筛及其应用

沸石分子筛是一种具有规则孔道结构的硅铝酸盐晶体,在气体吸附分离、工业催化、重金属离子污染治理等领域被广泛应用.传统沸石分子筛的水热合成常以含硅、铝的化工产品以及有机模板剂为原料,不仅价格昂贵,且污染环境.因此,开展以天然黏土为原料绿色合成沸石分子筛的相关研究,将廉价的天然黏土资源转化成高附加值的化工产品,具有重要的研究...     

Combined Humic Substance and Heavy Metals Agglomeration,and Membrane Filtration under Saline Conditions

Abstract

Humic substances‐heavy metals complexation combined with membrane filtration is reported. The effects of salinity, humic substances (HS) concentration, heavy metals concentration, and trans‐membrane pressure (TMP) on HS and heavy metals retention using two membranes are studied. Membrane fouling is also studied at the aforementioned conditions. NF270 experienced higher fouling. Moreover, salinity tests showed increasing fouling rate and reduction in membrane retention with increasing salinity level. While increasing HS concentration reduced HS retention and increased heavy metals retention and membrane fouling. Heavy metals concentration reduced the NF270 HS retention, but did not affect the P005F HS retention. In addition, TMP did not affect HS and heavy metals retention nor NF270 fouling, but increased P005F fouling.     

A comprehensive review of nanofiltration membranes:Treatment, pretreatment, modelling, and atomic force microscopy

Nanofiltration membranes (NF) have applications in several areas. One of the main applications has been in watertreatment for drinking water production as well as wastewater treatment. NF can either be used to treat all kinds of water including ground, surface, and wastewater or used as a pretreatment for desalination. The introduction of NF as a pretreatment is considered a breakthrough for the desalination process. NF membranes have been shown to be able to remove turbidity, microorganisms and hardness, as well as a fraction of the dissolved salts. This results in a significantly lower operating pressure and thus provides a much more energy-efficient process. Similar to other membrane processes, a major problem in NF membrane applications is fouling. Several studies have investigated the mechanisms of fouling in NF membranes and suggested methods to minimize and control the fouling of NF membranes. For NF membrane characterizations and process prediction, modeling of NF processes and the use of atomic force microscopy (AFM) are very important. The ability to predict the performance of NF processes will lead to a lower number of experiments, saving of time and money, and help to understand the separation mechanisms during NF. A comprehensive review of NF in water treatments is presented including a review of the applications of NF in treating water as well as in the pretreatment process for desalination; the mechanism as well as minimization of NF membrane fouling problems; and theories for modelling and transport of salt, charged and noncharged organic compounds in NF membranes. The review will also address the application of AFM in studying the morphology of membrane surfaces as part of the NF membrane characterization.     

应用超滤技术分析海藻酸钠对废水中Pb~(2+)的吸附规律

含铅离子废水污染事件近年来尤为严重,使得含铅废水的治理成为关系到社会稳定的重大环境安全问题之一。海藻酸钠为天然高分子有机物,来源广泛,成本低廉且无生物毒性,可吸附重金属离子形成凝胶。文章以超滤过程为研究对象,对海藻酸钠吸附Pb2+的的规律进行了研究,结论如下:(1)海藻酸钠对铅离子的吸附容量Q0随pH值的升高和铅离子的浓度升高而升高,吸附时间对海藻酸钠吸附铅离子的影响较小,在1分钟内就达到吸附平衡;(2)pH值对于铅离子的截留效果影响很大,pH值越高,铅离子的截留效果越好。     

不同预处理方式对超滤膜深度处理印染废水效能影响的研究

以印染废水处理站的二级出水为原水,考察了不同预处理方式(砂滤、微絮凝、微絮凝直接过滤)对超滤膜性能及其去除印染废水中污染物的影响。结果表明,砂滤随着运行时间的延长造成膜的不可逆污染,微絮凝可缓解膜污染,微絮凝直接过滤对膜污染在微絮凝基础上有所改善;不同预处理方式均能保证出水浊度小于0.1NTU;微絮凝直接过滤预处理工艺对CODCr去除率接近70%,微絮凝直接过滤处理方法能有效缓解膜污染,对浊度和有机物的去除效果较好,是较有优势的预处理工艺。