陶瓷膜处理储运油泥废水实验研究

采用膜孔径0.05μm、0.2μm和0.5μm陶瓷膜处理储运油泥废水,研究考察了膜孔径、操作温度、跨膜压差、膜面流速对膜通量和油截留率的影响。实验结果表明,膜孔径0.2μm的陶瓷膜适宜于储运油泥废水的处理,在操作温度40℃,跨膜压差0.15 MPa,膜面流速4.66 m/s实验条件下,油截留率在98%以上。     

无机陶瓷膜在脱脂液废水处理中的应用

考察了操作条件对陶瓷膜处理脱脂液废水效果的影响。结果表明：采用孔径为200nm氧化锆膜,在操作压力为0．1MPa,膜面流速5-7m／s,操作温度40℃的操作条件下,陶瓷膜处理此体系废水的分离效果最好。膜的稳定通量为390L／m^2·h,渗透液油含量小于30mg／L,油的截留率大于99．4％,清洗剂中的无机组分完全透过膜,表面活性剂及有机物大约有85％透过膜。     

4nm孔径陶瓷膜去除水中钙离子研究

采用孔径为4 nm的陶瓷膜去除水中的Ca2+,考察了不同Ca2+含量、跨膜压差、溶液pH和温度对陶瓷膜渗透通量和Ca2+截留率随时间的变化情况。结果表明,溶液中的Ca2+含量越低,膜渗透通量越高,Ca2+截留率也越高;跨膜压差升高,膜渗透通量增大,Ca2+截留率降低;降低溶液pH及升高温度能够提高膜渗透通量及对Ca2+的截留率。对Ca2+的质量浓度为10 mg/L的水溶液,在TMP为0.1 MPa、溶液pH为3、温度为50℃时、孔径为4 nm陶瓷膜渗透通量稳定在80 L/(m2.h),Ca2+截留率为85%左右。研究结果可为金属离子微污染水的净化提供方法。     

炭膜处理印染废水的影响因素

用不同孔径的酚醛树脂基管状微滤炭膜,对两种模拟染料废水溶液进行处理,考察了膜孔径、原料液浓度、测试压力和测试时间对截留率和膜通量的影响。实验结果表明,微滤炭膜对模拟染料废水有较好的处理效果,截留率和膜通量受膜孔径及操作条件的影响。     

陶瓷膜处理废聚酯瓶片洗涤废水工艺研究

废聚酯瓶片洗涤废水属于碱性高浓度难降解废水,采用陶瓷膜错流过滤的方式进行试验,孔径50、200、500nm的陶瓷膜对SS和浊度截留率均在99%以上,渗透液存放24 h后保持澄清透明,对COD去除率为40.5%～43.3%,同时发现陶瓷膜对可溶物的透过性较好。陶瓷膜分离工艺参数优化试验表明,在膜孔径为50 nm,操作温度为40～50℃,平均错流速率为2.10 m/s,跨膜压差为0.13～0.15 MPa的条件下,陶瓷膜渗透通量衰减较慢。采用质量分数为0.2%NaClO溶液和0.3%草酸溶液的组合方式进行膜清洗试验,膜通量恢复率达80%以上。     

陶瓷膜微滤集成技术处理电镀废水的研究

研究了孔径分别为0.2、0.5μm的陶瓷膜对电镀废水的微滤行为,考察了温度、错流速度以及跨膜压差等因素对膜通量和镍截留率的影响。研究结果表明,当错流速度维持在3.0 m3/h,跨膜压差为1.2 MPa,温度为35℃时,能获得较好的膜通量和经济效益,此时镍离子的回收率为93.64%。     

陶瓷膜在印钞废水处理中的应用

本文分别采用膜孔径为4nm、50nm、200nm、800nm的陶瓷膜处理印钞废水。通过对膜过滤过程的研究,选择了合适孔径的膜,优化了操作参数。最终确定选用50nm氧化锆膜,在操作压力0．3MPa,膜面流速4．0m／s,操作温度为45℃条件下,可取得较高的稳定渗透通量205L／m^2．h;对COD的截留率为86．6％：对固含量的去除率为43．9％。实验重复性良好。     

无机陶瓷膜处理印染废水的研究

研究了无机陶瓷膜处理印染废水过程,考察了膜孔径,操作条件对处理效果的影响及清洗剂和清洗时间对清洗效果的影响。结果表明:选用200nm的Al2O3膜管处理染料废水效果较好,合适的操作条件为:膜面流速4.2m/s,操作压力0.2MPa,温度30℃,此时渗透通量为129.64L/m2·h,CODCr的截留率达65%以上,色度去除率达90%以上。选择0.5mol/L硝酸溶液为清洗剂,清洗20min后,通量恢复为原来的81%以上。     

无机膜处理乳化废水中试研究

为除去废水中的乳化油,采用无机陶瓷微滤膜对乳化废水进行了中试实验研究.实验结果表明:乳化液废水经孔径为200 nm的无机陶瓷膜处理后,透过液可达国家排放标准;在最佳操作压力0.16 MPa下,系统可连续、稳定运行20 h以上,平均膜通量为272 L/(m2·h);化学清洗30 min后,可使膜通量恢复至初始通量的95%;平均料液运行成本为4.49元/m3.用无机陶瓷膜处理乳化液废水是一种经济、技术可行的方法.     

络合-陶瓷膜耦合技术处理低浓度含铜废水

采用孔径为200nm的陶瓷膜,以聚丙烯酸(PAA)为络合剂,含Cu2+废水为模拟废水,研究了络合-陶瓷膜耦合技术处理低浓度含铜废水过程。重点考察了运行时间、络合剂浓度、络合剂/金属离子质量浓度比(P/M)、溶液pH、离子强度、操作压力等对膜通量及Cu2+截留率的影响。结果表明,当P/M≥5、pH为5~6时,Cu2+的截留率接近100%,膜通量较高且趋于稳定;外加盐(NaCl和Na2SO4)导致Cu2+截留率下降,可以通过增加P/M值多级处理达到对Cu2+的理想去除。     

Electrospun nanofibrous polyvinylidene fluoride-co-hexafluoropropylene membranes for oil–water separation

Effective separation of oil from water is of significant importance globally for various applications such as wastewater treatment, oil spill cleanup, and oil purification. Among the numerous approaches for oil removal, membrane separation is considered one of the most promising approaches due to its selectivity and ease of operation. Electrospinning is a promising technique for producing polymeric membranes with tunable structures with interconnected pores, large surface area, and high porosity. In this study, hydrophobic poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibrous membranes were electrospun and used for this purpose. The effects of various parameters (e.g., polymer concentration, applied voltage, tip to collector distance, and feed rate) were investigated to find the optimum electrospinning conditions. Further, the electrospun membranes were characterized according to average fiber diameter, morphology, average pore size, and wettability to identify the combinations most likely to succeed in oil–water filtration. The physical–chemical properties of the membranes (i.e., thickness, areal density, porosity, average pore size, water/oil contact angle, hydrostatic pressure head, and oil filtration flux) were studied based on standard test methods. The separation efficiency of eight electrospun membranes with various pore sizes and average fiber diameters were tested for diesel/water mixtures. A linear relation was found between the initial oil flux and the average pore size of the membranes. The maximum oil filtration flux of about 224 L/m²/h, achieving over 75% oil recovery in 10 min, was obtained for the electrospun membrane with the average pore size of 4.5 μm. The membranes were successfully used for eight consecutive oil–water separation cycles without noticeable loss of flux.     

碳化硅陶瓷膜处理采油污水的中试试验

用0.02μm的多通道非对称性碳化硅陶瓷膜对采油污水进行了现场中试。在各种运行条件下,陶瓷膜出水SS<1.0 mg/L,油<10 mg/L,粒径中值<1.0μm。还考察了不同运行条件下陶瓷膜膜通量和跨膜压差的变化,以及强化混凝过滤对膜通量的影响。根据试验结果对陶瓷膜在采油污水处理中的进一步研究提出了建议,并对其工程应用前景进行了展望。     

Membrane degumming of crude rice bran oil: Pilot plant study

The procedure for the classical chemical refining of vegetable oils consists of degumming, alkali neutralization, bleaching, and deodorization. Conventional refining of rice bran oil using alkali gives oil of acceptable quality, but the refining losses are very high. A critical work has been carried out to study the application of membrane technology in the pretreatment of crude rice bran oil. Oils intended for physical refining should have a low phosphorus content, and this is not readily achievable by the conventional acid/water degumming process. The application of membrane technology for the pretreatment of rice bran oil has been investigated. The process has already been successfully applied to other vegetable oils. Ceramic membranes, which are important from the commercial point of view, were examined for this purpose. The results showed that the membrane‐filtered oils met the requirements of physical refining, with a substantial reduction in color. It was observed that most of the waxy material was also rejected. Experiments were carried out to establish the relationship between permeate flux and rejection with membrane pore size, trans‐membrane pressure and micellar solute concentration.     

Cross-Flow Microfiltration of Industrial Oily Wastewater: Experimental and Theoretical Consideration

Microfiltration of industrial oily wastewater was performed using polyamide membrane. A rectangular cross flow membrane cell was used for the experiments. Effects of different operating parameters such as transmembrane pressure drop and Reynolds numbers on the steady state permeate flux and oil rejection was investigated in detail. Initial oil concentration in the industrial oil-water emulsion was found to be 192 mg/L with average oil droplet range size 0.01 to 47 µm. The treated industrial oily water was characterized in terms of electrical conductivity, total dissolved solids (TDS), and chemical oxygen demand (COD). It was observed that the steady state permeate flux increased with transmembrane pressure drop and Reynolds numbers. The oil concentration in permeate was found to be around 4.5 mg/L, after treatment, which was lower than the permissible discharge limit. The results showed that microfiltration was an efficient and ecologically suited technology for the treatment of industrial oily wastewater. The cross flow velocity was considered in both laminar and turbulent regimes. A model was proposed by combining of Brownian diffusion and shear-induced diffusion to predict the steady state permeate flux data at different Reynolds numbers and different transmembrane pressure drops.     

Separation of nickel catalyst by microfiltration

Ceramic membranes with pore size of 0.1 and 0.2 µm are used for the separation of nickel catalyst. Effect of trans‐membrane pressure (TMP), linear velocity, temperature and nickel content (solute) on flux and rejection has been investigated. The flux increased with increase in pore size of the membrane. The rejection characteristics were similar for 0.1 and 0.2 µm membranes. The nickel content and iodine value of the membrane‐filtered oil was comparable with that of conventional processes. Permeate flux increased with increase in temperature. Flux increased with increase in linear velocity and a marginal rise was observed above 2.09 m/s. The rejection characteristics were only slightly affected by higher linear velocity. The flux improved after back flushing. The average flux was higher with back flushing as compared to continuous (with out back flushing) filtration process. The results indicated that the secondary layer effect was more pronounced in microfiltration. The flux decreased with increase in solute concentration. The rejection characteristics were not affected by solute concentration. The rejection characteristic of the membranes remained unaltered after membranes were repeatedly cleaned with sodium hydroxide and HCl solutions, however, the flux was decreased marginally.     

Study on Preparation and Performance of Modified Polyvinyl Chloride-co-vinyl Acetate Microfiltration Membranes

In this paper, flat-sheet microfiltration membranes were prepared from modified polyvinyl chloride-vinyl acetate (VC-co-VAc) material with hydroxyl group, VC-co-VAc-OH, by phase inversion technique. The influences of casting solution composition (polymer concentration, additive types, and content) and preparation conditions (coagulation temperature, evaporation time of solvent, and the relative humidity in the environment) on pure water flux, retention, and pore size distribution were discussed. The results showed that casting solution composition and the membrane preparation conditions all have significant impacts on the performances of the membrane: on the one hand, in order to prepare membranes with high flux, either decrease the polymer concentration, or increase the PEG molecular weight or the coagulation temperature or the relative humidity can achieve it; on the other hand, with the increase of additive content, the pure water flux increased quickly, then decreased dramatically, while the effect of evaporation time were the opposite. And these results were confirmed by the SEM images. Furthermore, the microfiltration membranes, which were prepared under optimized conditions, were used to treat synthetic oilfield polymer-flooding wastewater, and good experimental results were obtained.     

气升式陶瓷膜过滤装置处理油田含聚采出水

采用新型的气升式陶瓷膜过滤系统处理油田含聚采出水,通过气液两相流替代单一的液相流动,降低了陶瓷膜处理油田含聚采出水过程的能耗,系统考察了曝气孔大小、曝气量和跨膜压差对膜渗透通量的影响。结果表明,采用孔径为微米级的曝气头曝气使高压气体在多通道膜管内的分布更为均匀,进而有效抑制膜污染和浓差极化,延缓通量衰减。当曝气孔径为1 μm时,渗透通量达到最大,且曝气量从300 L·h^-1增加到600 L·h^-1时,通量显著增加。此外,跨膜压差对膜的渗透通量影响显著,当跨膜压差为0.4 MPa时,渗透通量最佳。陶瓷膜处理油田采出水的出水水质各方面指标数据较为稳定,达到5.1.1回注水标准。最后,计算讨论了气升式陶瓷膜过滤装置的吨水能耗。     

渗透模式影响纳米涂层修饰陶瓷微滤膜分离性能的研究

研究了膜分离技术处理含油废水存在因油滴变形引起的膜堵塞问题。为减少膜污染,使用在市场上销售氧化铝微滤膜孔道表面制备纳米ZrO2涂层,利用纳米涂层改变微滤膜的表面亲水憎油性,具有良好的效果。考虑其工业应用条件,重点研究了循环模式（模拟大量废水处理）和浓缩模式（模拟少量废水处理）对膜渗透通量的影响。结果表明：循环模式下料液的油浓度为恒定的,纳米涂层能有效提高微滤膜的渗透通量。膜面流速的增加在一定程度上能提高膜渗透通量,但超过一定程度后,增加不明显。当膜面流速为7m／s时,修饰陶瓷膜的最大渗透通量为280L／（m^2·h）,油截留率为96．4％。在浓缩模式下,料液的油浓度随渗透液的排出呈指数性增加,随着油浓度的增加,渗透通量持续衰减,油截留率持续上升。当油浓度达到一定程度后,修饰陶瓷微滤膜不能有效地实现稳定含油废水的油水分离。     

Fenton试剂协同预涂动态膜处理乳化油废水

为减低预涂动态膜处理乳化油废水过程中的在线膜污染阻力,对Fenton试剂协同高岭土预涂动态膜处理乳化油废水特性进行了研究,考察了Fe2+/H2O2配比、溶液pH值及操作温度对减缓膜污染程度的影响。研究结果表明：投加Fenton试剂可明显地降低在线膜污染阻力,有效去除溶液及动态膜表面的污染物,CH2O2/CFeSO4最佳配比为1,其稳态膜通量是未投加Fenton试剂的3倍以上;Fenton试剂在酸性条件下减缓膜污染的效果较好,其中pH值为3时的稳态膜通量最高;最佳工艺操作温度为312 K,温度过高时尽管初始膜通量非常高,但稳态膜通量较低;原料液中油浓度越高,Fenton试剂对在线膜污染阻力的削减程度越小,投加和未投加Fenton试剂时达到稳态时的截留率相差在1%以内。     

Investigations on the use of different ceramic membranes for efficient oil-field produced water treatment

Efficient performance of the combination of treatment processes for oilfield produced water generated from oil tank dewatering was investigated in the study presented below. By-produced wastewater is generated in significant quantity during exploitation of crude oil and gas from onshore and offshore production operations. This wastewater, commonly referred to as “produced water”, has distinctive characteristics, due to their organic and inorganic compounds. However, these characteristics change from well to well. The treatment process investigated here consists of a pre-treatment step utilizing microfiltration (0.1 and 0.2 µm pore size filters) and/or a simulated batch dissolved air flotation (DAF), and a multistage post-treatment step utilizing cross-flow ultra- (0.05 µm pore size and 20 kDa molecular weight cut-off filters), and nanofiltration (1 and 0.75 kDa MWCO filters). Filters used were ceramic membranes. To determine the separation capability of the processes described, various parameters, such as trans-membrane pressure varying from 0.5 to 2 bar, cross-flow velocity in the range of 0.6 to 1.3 m/s, influent oil concentration ranging from 32 to 5420 parts per million (ppm) and different membrane cleaning methods used were investigated. The average permeate flux varied from 3.4 to 3300 l/h m² bar, total oil removal was up to 99.5% and total organic carbon removal reached 49%.