Application of High-pressure Flat Membranes in Coal Chemical Wastewater Treatment

In the process of using high-pressure flat membranes to treat coal chemical wastewater,the effects of high-pressure flat membranes on the concentration of salt ions and the removal of pollutants were studied under the conditions of different concentrations of influent TDS,COD and silicon dioxide.The results showed that when the concentration of influent TDS was 35 000-55 000 mg/L,the economic benefit of high-pressure flat membrane operation was the best,and the concentration ratio of high-pressure flat membranes was stable,varying from 3.3 to 3.6.As the concentration of influent organic matter ranged from 100 to 1 800 mg/L,the removal rate of organic matter ranged from 60% to 79%.In addition,the retention rate of high-pressure flat membranes to silicon dioxide was more than 90%.

Preparation of hydrophobic flat sheet membranes from PVDF-HFP copolymer for enhancing the oxygen permeance in nitrogen/oxygen gas mixture

In this study, poly(vinilydene fluoride-co-hexafluoropropylene)(PVDF-HFP) was used for preparation of hydrophobic membranes using non-solvent induced phase inversion(NIPS) technique. PVDF-HFP copolymer with concentrations of 10 wt% and 12 wt% was prepared to investigate the effect of polymer concentration on pore structure,morphology, hydrophobicity and performance of prepared membranes. Besides, the use of two coagulation baths with the effects of parameters such as coagulant time, polymer type and concentration, and the amount of nonsolvent were studied. The performance of prepared membranes was evaluated based on the permeability and selectivity of oxygen and nitrogen from a gas mixture of nitrogen/oxygen under operating conditions of feed flow rate(1–5 L·min-1), inlet pressure to membrane module(0.1–0.5 MPa) and temperatures between 25 and 45 °C. The results showed that the use of two coagulation baths with different compositions of distillated water and isopropanol,coagulant time, polymer type and concentration, and the amount of non-solvent additive have the most effect on pore structure, morphology, thickness, roughness and crystallinity of fabricated membranes. Porosity ranges for the three fabricated membranes were determined, where the maximum porosity was 73.889% and the minimum value was 56.837%. Also, the maximum and minimum average thicknesses of membrane were 320.85 μm and115 μm. Besides, the values of 4.7504 × 10-7 mol· m-2· s-1· Pa-1, 0.525 and 902.126 nm were achieved for maximum oxygen permeance, O2/N2 selectivity and roughness, respectively.

Water as the Pore Former in the Synthesis of Hydrophobic PVDF Flat Sheet Membranes for Use in Membrane Distillation

Although PVDF flat sheet membranes have been widely tested in MD,their synthesis and modifications currently require increased use of green and inexpensive materials.In this study,flat sheet PVDF membranes were synthesized using phase inversion and water as the pore former.Remarkably,the water added in the casting solution improved the membrane pore sizes;where the maximum pore size was 0.58μm.Also,the incorporation of f-SiO2NPs in the membrane matrix considerably enhanced the membrane hydrophobicity.Specifically,the membrane contact angles increased from 96°to 153°.Additionally,other parameters investigated were mechanical strength and liquid entry pressure(LEP).The maximum recorded values were 2.26 MPa and 239 kPa,respectively.The modified membranes(i.e.,using water as the pore former and f-SiO2NPs)were the most efficient,showing maximum salt rejection of 99.9%and water flux of 11.6 LMH;thus,indicating their capability to be used as efficient materials for the recovery of high purity water in MD.

Transport Behaviour of La^（3＋） with Flat－Sheet－Sandwich Supported Liquid Membrane Extraction System

This paper suggested a modified model of SLM which could improve its stability.In the model, an organic solution was sandwiched between two layers of supported film,which we called sandwich supported liquid membrane(SSLM).The transport experiments of La3+ were performed with SSLM containing HEH(EHP)as a carrier. The permeability coefficient (p) of La3+ were measured and some factors affecting the p were investigated. The results showed that if the pH of the feed was below 4.0,the p was increased with increasing in pH. The p was also increased when the strip acidity increases.Inspite of not enough satisfactory reproducibility on test result, the stability of the model was improved.

Simultaneous nitrogen and phosphor removal in an aerobic submerged membrane bioreactor

Simultaneous nitrification and denitrification （SND） effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids （MLSS） 19--20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor （MBR） and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2-- 0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate （PFS） addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances （EPS） of mixed liquor.

臭氧/陶瓷膜/除臭处理核酸药物废水应用

针对核酸类药物生产废水中高浓水废水生物毒性强的特点,首先采用臭氧氧化大幅度消减毒性后和低浓度废水混合,采用水解+A/O+浸没式MBR组合处理工艺进行处理。水解过程中加入零价铁来提高水解效率;浸没式MBR采用多巴胺修饰的纳米平板陶瓷膜,具有亲水性强,膜通量大,化学清洗频率低等优点。整个污水站除臭系统采用碱喷淋+生物除臭+活性炭吸附的组合工艺。长期工程调试运行效果表明,出水水质优于《废水综合排放标准》(DB 12/356-2018)(天津市地方标准)表2中的间接排放标准,即COD≤500 mg/L,BOD5≤300 mg/L,氨氮≤45 mg/L,总氮≤70 mg/L,SS≤400 mg/L。经过核算,水处理运行费用为9.8元/m^(3)。

铁路站段含油废水处理模式的碳排放研究

为提高铁路站段含油废水的去除效果,同时达到节能降耗减排的目的,以某铁路局车辆段含油废水为研究对象,对比研究传统方案“加压溶气气浮法”与新方案“平板陶瓷膜法”的去除效果和碳排放效果。此外,将传统方案中含油污泥的直接外运处理更改为掺入燃煤中焚烧,探讨其产生的环境效益。结果表明,平板陶瓷膜的整体碳排放强度仅占加压溶气气浮法的35.47%,年碳减排量可达70.2 tCO_(2)。平板陶瓷膜法电耗和药耗的碳排放量相较传统方案而言大幅降低,是因为处理过程所需能耗较小且反应无需添加药剂,仅需使用次氯酸钠对反应装置定期进行反冲洗,物耗使用量也大大降低。将含油污泥直接外运更改为掺入燃煤中焚烧法处理,能够在有效回收资源、实现污泥资源化利用的同时节约成本。整体而言,使用平板陶瓷膜法对铁路站段含油废水进行处理在碳减排方面具有明显优势,同时能够带来更好的处理效益和经济效益,是一项可行的方案,可以进行大范围推广使用。

箱体型正压式平板负离子抗菌陶瓷膜MBR在城市新鲜垃圾渗滤液处理应用实例

山东某垃圾焚烧厂中产生的新鲜垃圾渗滤液有机物和氨氮浓度高,同时含有多种重金属,属于难处理的废水。本工程采用气浮预处理+两级UASB+A/O+平板式MBR膜过滤+后续深度处理(纳滤+反渗透)工艺。厌氧处理阶段采用投加零价铁来提高处理效果。MBR工艺采用箱体型正压式优化结构,比传统的浸没式结构能提高膜通量和优化操作。MBR膜采用能抑菌杀菌的负离子抗菌平板陶瓷膜,具有膜通量大,缓解膜污染能力强的特点。工程运行表明,出水水质低于≤生活垃圾卫生填埋场污染控制标准≥(GB 16889-2008)表3中的标准要求,即COD≤60 mg/L,BOD_(5)≤20 mg/L,ρ(氨氮)≤8 mg/L,ρ(总氮)≤20 mg/L,ρ(SS)≤2.0 mg/L等。工程投资总成本500万左右。吨水成本将核算后为14.9元。

AOPAN/PU复合膜的制备及其金属离子吸附性能研究

采用聚乙烯吡咯烷酮(PVP)和聚乙二醇(PEG)对聚丙烯腈/聚氨酯(PAN/PU)涂层微孔进行调控。通过扫描电镜分析和水通量截留率测试发现,PVP含量为6%、PEG含量为4%时,平板膜涂层性能最佳。以无纺布作为基底,采用浸轧涂覆的方法将最优参数的铸膜液涂覆在无纺布上,通过化学改性制备胺肟化聚丙烯腈/聚氨酯(AOPAN/PU)复合膜,探究复合膜通量变化和金属离子截留性能。研究表明,改性后制备的AOPAN/PU熔喷复合膜水通量由349L/(m^(2)·h)增长到435L/(m^(2)·h),在对100mg/L的Cu^(2+)、Fe^(3+)、Zn^(2+)混合金属溶液3次吸附循环测试后发现,最终滤液中金属离子截留率均在90%以上。

聚氯乙烯平板膜的制备及性能研究

主要介绍了在制备平板膜的实验教学中,采用聚氯乙烯作为膜材料进行制备,这不仅降低了实验教学的成本,同时还提高了平板膜的性能。对表面活性剂含量、聚合物浓度对平板膜的膜通量和截留率等基本性能的影响进行了研究,取得了比较满意的结果。

一体式平板膜生物反应器处理商场污水的运行效能及膜污染研究

本研究首先利用实验室小试A^(2)O-MBR一体化装置考察了其在HRT为24 h时处理BOD_(5)、NH_(4)^(+)-N浓度分别为~300、~100 mg/L的模拟商场污水的效果,稳定后出水BOD_(5)、NH_(4)^(+)-N平均浓度分别为5.07、4.26 mg/L,平均去除率分别达到了98.27%、95.56%。通过比较发现在相同运行条件下聚偏氟乙烯平板膜(FS-PVDF)的使用寿命最长。滤饼层阻力和浓差极化作用引起的过滤阻力分别是影响平板膜和中空纤维膜过滤能力的主要阻力类型。选择FS-PVDF进一步搭建中试规模A^(2)O-MBR一体化装置,在HRT为48 h时处理BOD_(5)、NH_(4)^(+)-N分别为200~400、60~100 mg/L的上海某商场污水,稳定后出水BOD_(5)、NH_(4)^(+)-N平均浓度分别为7.14、0.25 mg/L,平均去除率分别达到了97.66%、99.51%。在监测时间内,膜压始终保持在0.001 MPa左右。微生物群落分析发现,Dependentiae和包括Chloroflexi在内的丝状菌在膜表面积累可能是造成小试/中试中膜污染的主要原因。

拉伸法制备聚四氟乙烯平板膜的研究进展

聚四氟乙烯(PTFE)因其自身的优异性能,吸引了国内外众多专家学者的注意力。PTFE拉伸平板膜具有独特的“原纤-节点”结构,在航天、汽车、化工、医疗等领域有着广阔的应用前景。文中主要综述了在采用机械拉伸法制备PTFE平板膜过程中,通过控制原料种类与组成、设备、工艺参数等方式来调控糊料挤出物和薄膜的结构性能。最后,对PTFE独特的成纤和拉伸成孔机理与工艺参数之间的研究进行了展望,指明了PTFE平板膜应用领域的研究方向。

基于动态阵元合成孔径聚焦超声成像的平板陶瓷膜内部缺陷三维重建

针对平板陶瓷膜内部缺陷可视效果差和超声三维重建运算数据量大等问题,提出了一种基于动态阵元合成孔径聚焦超声成像的平板陶瓷膜内部缺陷三维重建方法。动态阵元合成孔径聚焦超声成像方法是通过在缺陷区域使用多阵元合成孔径,在非缺陷区域使用单阵元合成孔径。采用动态阵元合成孔径聚焦超声成像方法获取多个位置序列的平板陶瓷膜的缺陷B扫描图像,并采用体绘制的方法,实现了平板陶瓷膜缺陷的三维可视化。实验结果表明,采用动态阵元合成孔径聚焦超声成像方法时划痕的重建相对误差在1.27%~2.70%之间,对孔洞的重建相对误差在2.38%~3.03%之间,重建速度平均提高了26.57%。通过对缺陷的三维重建,使得缺陷的呈现更加直观,为后续的缺陷分析的客观性提供了保障。提出的方法具有良好的适应性、经济性,在无损检测领域有重要的意义。

Study on a novel flat renewal supported liquid membrane with D2EHPA and hydrogen nitrate for neodymium extraction

The Nd（III） extraction in flat renewal supported liquid membrane（FRSLM）,with polyvinylidene fluoride membrane and renewal solution including HNO3 solution as the stripping solution and di（2-ethylhexyl） phosphoric acid（D2EHPA） dissolved in kerosene as the membrane solution,was investigated.The effects of pH in the feed phase,volume ratio of membrane solution to stripping solution,concentra-tion of HNO3 solution and concentration of carrier in the renewal phase on extraction of Nd（III） were also studied,respectively.As a result,the optimum extraction conditions of Nd（III） were obtained when concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.100 mol/L,and volume ratio of membrane solution to stripping solution was 1.00 in the renewal phase,and pH was 4.60 in the feed phase.When initial concentration of Nd（III） was 2.00×10-4 mol/L,the extraction percentage of Nd（III） was up to 92.9% in 75 min.

MBR工艺在农村生活污水处理中的应用

近年来,MBR工艺在农村生活污水处理中逐步得到应用,其采用较多的膜组件类型为平板膜和中空纤维膜。以国内采用平板膜和中空纤维膜处理农村生活污水的项目为基础,对比分析了平板膜和中空纤维膜的处理效果、预处理要求、膜通量及产水效率、清洗方式、工艺成本等相关参数,并分析了平板膜和中空纤维膜用于农村生活污水处理的优缺点,分析结果对MBR工艺在农村生活污水处理中的应用具有一定的参考价值。

Preparation and characterization of PVDF-PFSA flat sheet ultrafiltration membranes

High performance polyvinylidene fluoride （PVDF） flat sheet ultrafiltration （UF） membranes have been prepared by an immersion precipitation phase inversion method using perfluorosulfonic acid （PFSA） as a pore former and as a hydrophilic component of the membranes and polyethylene glycol （Mw = 400） （PEG400） as a pore forming agent. The effects of the presence of PEG and the concentration of the PFSA on the phase separation of the casting solutions and on the morphologies and performance of UF membranes including their porosity, water flux, rejection of bovine serum albumin （BSA） protein, and anti-fouling property were investigated. Phase diagrams, viscosities and the phase separations upon exposure to water vapor showed that both PEG400 and PFSA promoted demixing of the casting solution. Scanning electron microscopy measurements showed that the PVDF-PFSA blend membranes had more macropores and finger-like structures than the native PVDF membranes. The PVDF-PFSA membrane （5 wt-% PEG400 ＋ 5 wt-% PFSA） had a pure water flux of 141.7L/m2.h, a BSA rejection of 90.1% and a relative pure water flux reduction （RFR） of 15.28%. These properties were greatly superior to those of the native PVDF membrane （pure water flux of 5.6 L/m2. h, BSA rejection of 96.3% and RFR of 42.86%）.

防水卷材搭接缝剥离强度及不透水性影响因素研究

通过对比试验研究了不同类型防水卷材搭接缝施工方式、卷材外观、胶层厚度以及搭接施工后热处理、浸水处理等因素对卷材搭接缝剥离强度和不透水性的影响。结果表明,不同类型防水卷材搭接缝剥离强度在热处理和浸水处理后有一定增长;改性沥青防水卷材热熔搭接只要严格按工艺要求施工,搭接缝不透水性均有保障;自粘聚合物改性沥青防水卷材搭接的平整度控制对于搭接缝不透水性至关重要;高分子自粘胶膜防水卷材的搭接缝不透水性受胶层厚度和搭接平整度的影响较大,背胶必不可少。

不同烧结助剂对中空平板陶瓷膜性能的影响

为了在较低烧结温度下获得性能良好的中空平板陶瓷膜,烧结助剂的优化选择至关重要。本文系统探究了锆钛微粉、钾长石微粉、硅溶胶和铝溶胶四种烧结助剂对氧化铝陶瓷膜晶相组成、微观结构、抗折强度、孔隙率、纯水通量、平均孔径、化学稳定性和收缩率的影响。结果表明,不同烧结助剂具有不同的作用机理并形成不同的微观形貌结构。微粉类添加剂对抗折强度的提升效果明显优于溶胶类,其中锆钛微粉在低含量(1~3 wt%),而钾长石微粉在高含量(≥15 wt%)时作用效果显著,但孔隙率随添加量的提高而下降。添加锆钛微粉时膜孔径和纯水通量下降,而添加钾长石微粉时膜孔径增加,纯水通量呈现先升高后下降的趋势。微粉类添加剂陶瓷膜的化学稳定性明显优于溶胶类,但收缩率也较高,且过度添加对生产过程不利,实际应用中应控制在合理范围。

电化学氧化降解水中三唑酮效能与反应路径

三唑酮(TDF)等有机农药在生产和使用中存在环境风险,其难以被常规水处理工艺有效去除。电化学氧化技术应用于水中有机农药去除极具潜力,有机农药降解效率与电化学阳极材料性能有关。以Ti/RuO_(2)-IrO_(2)、Pt、Ti_(4)O_(7)电极为电化学阳极,开展电化学氧化技术降解和矿化水中TDF研究,比较和评估了不同类型阳极电化学降解TDF和溶液中TOC的效率;考察了电流密度、TDF初始浓度、溶液初始pH等反应参数对TDF电化学降解效率的影响;探究了TDF电化学降解路径及其降解产物毒性对溶液毒性的影响。结果表明:与Ti/RuO_(2)-IrO_(2)和Pt平板阳极相比,Ti/Ti4O_(7)平板阳极对水中TDF和溶液总有机碳(TOC)去除效果较好;Ti_(4)O_(7)平板和膜阳极均对水中TDF的降解和矿化具有较高活性,TDF电化学降解效率和溶液TOC去除率可达94.5%-95.7%和72.5%-75.5%,达到相同TOC去除率时Ti_(4)O_(7)膜阳极较其平板阳极反应能耗低低50%左右;水中TDF电化学降解效率与电流密度、TDF初始浓度、溶液初始pH值等反应参数有关,TDF电化学降解效率随电流密度增大而增大、随TDF初始浓度和溶液初始pH的增大而减少;水中TDF(m/z=294.5)电化学降解生成A(m/z=224.5)和B(m/z=103),A(m/z=224.5)继续氧化生成了C(m/z=173.5)和D(m/z=86),这些中间产物可进一步氧化为二氧化碳、水等无机物;TDF、A、B、C和D对水生生物分别呈有毒性、无害性、无害性、有害性和无害性,有毒性的TDF逐渐降解为无毒性的降解副产物,可能是造成TDF溶液毒性随着反应时间逐渐下降的原因。该研究表明TDF可被Ti_(4)O_(7)阳极电化学氧化技术高效降解和矿化,为电化学氧化技术去除水中TDF等有机农药的研究与实践提供思路借鉴。