超滤膜分离工艺处理大豆乳清蛋白废水的效能

为考察膜分离技术处理大豆乳清蛋白废水的效能及其运行特征,采用再生纤维膜（RC）和聚醚砜膜（PES）进行试验,每种膜的截留分子量（MWCO）分别选定为5000、10000和30000。试验考察了各种膜的渗透通量、膜衰减系数、蛋白截留率、总糖透过率随时间的变化情况,结果表明：截留分子量为10000的RC超滤膜,在渗透通量、蛋白截留率、总糖透过率、膜衰减系数等方面皆优于其他超滤膜。超滤的最佳工艺条件为压力30kPa、pH值9、浓缩比3∶1、温度20℃,膜渗透通量31.2 L·m^-2·h^-1,蛋白截留率78.46%,蛋白含量51.37%。在曲线拟合和BP神经网络的基础上,建立了不同条件下膜渗透通量随时间变化的数学模型,模型模拟结果与试验结果基本一致,这说明基于曲线拟合和BP神经网络建立模型是可行的。     

超滤-反渗透集成工艺处理玉米酒糟废水

研究了玉米酒精生产过程中产生的玉米酒糟废水的膜分离过程,开发了处理玉米酒糟废水的超滤-反渗透集成工艺。超滤选用截留相对分子质量为6 000的GR81PP膜平板分离器,入口压力控制为0.6 MPa,操作温度为50℃;反渗透选用标准脱盐率为90%的ESNAI-4040卷式膜分离器,入口压力控制为2.2 MPa,操作温度为40℃。反渗透透过液中蛋白质的平均截留率为94.70%,甘油的平均截留率为65.15%,COD值降到1 000 mg/L左右,可作为工艺回用水,而且反渗透浓缩液中可回收甘油等有用物质,超滤浓缩液可浓缩成饲料,节能效果显著。     

纳滤膜在染料生产废水处理中的应用

采用超滤、纳滤集成技术,对高盐度、高色度、高COD的染料生产废水进行中试处理试验,分别考察了恒容脱盐、恒压浓缩、连续化处理等不同工艺的效果.结果表明,纳滤膜对COD的去除率大于90%,对色度去除率基本为100%,对染料截留率大于97%,能有效截留废水中的染料和有机物,同时一价盐(NaCl)大部分能透过膜.因此,对染料废水进行脱盐,浓缩、回用及连续化处理是可行的.     

栲胶溶液超滤过程

本文研究了栲胶超滤过程中截留率和透过率变化规律,ｐＨ值对它们的影响。超滤初始阶段,溶液中非单宁优先过膜,使得膜的截留率较低而透过率较高。但溶液中非单宁的减少,加速溶液中单宁缔合,导致透过率的降低,截留率提高,栲胶溶液在其等电点条件下进行超滤时截留较高,而透过率较低。     

栲胶溶液超滤过程

本文研究栲胶超滤过程中截留率和透过率变化规律,ｐＨ值对它们的影响,超滤初始阶段,溶液中非单宁优先过膜,使得膜的截留率较低而透过率较高,但溶液中非单宁的减少,加速溶液中单宁缔合,导致透过率的降低,截留率提高,栲胶溶液在其等电点条件下进行超滤时截留较高,而透过率较低。     

络合超滤过程处理重金属工业废水

以废水回用为目的,研究了络合 超滤耦合过程处理重金属工业废水。利用聚丙烯酸(PAA)为络合剂和含Zn2+和Cu2+的重金属废水,讨论了各种因素,如操作压力、膜面流速、重金属与络合添加剂的质量比、pH、体积浓缩因子对超滤过程的影响。在NaCl或Na2SO4存在的条件下,对Zn2+和Cu2+仍可达到100%的去除。在较高的离子强度下,如0.203mol/L时,对Zn2+和Cu2+的截留率仍可达到95%以上。经过浓缩的重金属废水,可回收重金属,而透过液可达到回用水的标准。     

纳滤膜在染料生产废水处理中的应用

采用超滤、纳滤集成技术,对高盐度、高色度、高COD的染料生产废水进行中试处理试验,分别考察了恒容脱盐、恒压浓缩、连续化处理等不同工艺的效果。结果表明,纳滤膜对COD的去除率大于90％,对色度去除率基本为100％,对染料截留率大于97％,能有效截留废水中的染料和有机物。同时一价盐（NaCl）大部分能透过膜。     

膜分离技术在麻黄碱生产中的应用研究

采用膜分离技术对麻黄碱提取液进行除杂、浓缩,以降低苛化工段NaOH和二甲苯用量,并减少废水产生量.确定一级膜最佳型号为微滤膜Ⅰ,麻黄碱透过率高迭98.56%、杂质截留率达27.95%;二级膜最佳型号为纳滤膜Ⅱ,麻黄碱截留率高达100%、滤液可直接回用提取工序;经两级膜处理后提取液体积减少到原来的9.2%,废水量减少85%.     

二级超滤系统处理大豆乳清

通过实验研究了由气冲强化动态超滤(MWCO 50kDa)和切向流超滤(MWCO 10kDa)组成的二级超滤系统处理大豆乳清的可行性。结果表明,该系统处理大豆乳清的单周期运行时间可达23 h以上,可将蛋白质含量从0.50%滤除到0.04%左右,而对糖和盐类的截留率均在10%以下。系统污染后的化学清洗只需2 h,膜通量恢复90%以上。长期运行不会改变膜对目标物质的截留效果。所得乳清蛋白产品中蛋白质≥70%、灰分约10%。     

络合-超滤-电解集成过程处理重金属工业废水 Ⅰ络合-超滤耦合过程

以废水回用为目的 ,研究了络合 -超滤耦合过程处理重金属工业废水。利用聚丙烯酸( PAA)为络合剂和含 Zn2 + 和 Cu2 + 的重金属废水 ,讨论了各种因素 (如操作压力 (Δp)、膜面流速( VL)、重金属浓度与络合剂添加浓度比 ( L)、p H、体积浓缩因子 ( VCF) )对超滤过程的影响。在 Na Cl或 Na SO4存在的条件下 ,对 Zn2 + 和 Cu2 + 仍可达到 1 0 0 %的去除。在较高的离子强度下 ,如离子强度为 0 .2 0 3mol/L时 ,对 Zn2 +和 Cu2 +的截留率仍可达到 95 %以上。经过浓缩的重金属废水 ,可回收重金属 ,而透过液可以达到回用水的标准     

反渗透、纳滤过程的物理化学研究(Ⅰ)多孔膜的溶质脱除率方程和膜渗透通量方程

引言 溶解扩散模型、摩擦模型、Sourirajan方程和表面力孔流模型均假设稳态条件下溶质通量和溶液体积通量恒定[13].     

Possibilities for the use of membrane processes for the pre-treatment of wastewater from the production of dried potato purée

Our research focused on the membrane separation of wastewater resulting from the production of dried potato purée. Our aim was to investigate possibilities for recycling obtained retentate back to the actual production process, and, consequently, for reducing wastewater pollution. This paper describes trials of MF and RO membrane filtration of starch wastewater. The treated water contained starch, in either granulated or gelatinized form, and solids (fine pieces of potato skins). The trials were conducted in either one or two stages. We used a pilot plant equipped with a ceramic membrane with a filtration area of 0.35 m² and pore sizes of 500 and 100 nm. We also tested an organic RO membrane (7410) in the laboratory.High permeate flux above 100 l/(m² h) was measured for the 100 nm membrane, but with considerable fouling. Filtration through this membrane resulted in high COD and BOD₅ rejection (approximately 60%), an effect which was increased by the subsequent RO filtration. The content of soluble carbohydrate, 0.011% in permeate (with 0.44% dry substance), was analyzed using high-performance anion-exchange chromatography coupled with pulsed amperometric detection.     

Treatment of oily wastewater using membrane with 2-hydroxyethyl methacrylate-modified surface

To enhance the hydrophilicity, the surface of polysulfone membrane was modified by UV-irradiation induced coating of HEMA in the presence of AIBN as free radical source. The permeation characteristics of oily water through the surface-modified membrane were investigated. The fluxes of wastewater with oil concentrations of 100 ppm, 200 ppm and 400 ppm through an un-coated membrane were 0.123, 0.081, and 0.076 g/cm²·min, respectively. However, the fluxes through the surface-modified membrane were 0.253, 0.242, and 0.173 g/cm²·min, respectively. The fluxes through the surface-modified membrane were much higher than those through an un-coated membrane: 2.1, 3.0 and 2.3 times higher fluxes. The rejection of oil emulsions by the membrane was higher than 99%. The membrane with HEMA-modified surface, which has a higher flux and less fouling than an original polysulfone membrane, may be a promising candidate for wastewater treatments as well as oily wastewater treatments.     

UF,NF处理酵母废水可行性研究

采用ＵＦ或ＮＦ技术可以处理酵母生产中不同阶段高浓度有机物的废水，废水经ＵＦ膜处理可１００％回收酵母蛋白等成份，对色度浊度具有〉９０％的去除率，从浓缩液中回收的酵母蛋白等成份，经进一步浓缩干燥可作动物饲料添加剂，干燥物蛋白质含量〉３０％，膜透过液含有发酵过程所需的营养成分，可重新用于发酵生产用水。废水用ＮＦ膜处理对ＣＯＤ去除率〉９０％并接近或达到排放标准，对于直接从发酵液中经高速离心分离的酵母废水（     

反渗透过程溶质脱除率方程

<正>溶解扩散理论、摩擦模型和表面力-孔流模型假设稳态时膜中溶质通量恒定“-”。本文分 析了该假设存在的理论依据,并基于膜的吸附-扩散模型’‘’建立了反渗透过程溶质脱除率方 程。     

Controlled deposit formation to influence the retention of solutes in reverse osmosis and ultrafiltration

Deposited layers of milk protein reduce the rate of permeation of both lactose and salt ions by compression of the region of the deposited layer adjacent to the membrane into a secondary membrane with solution diffusion properties. The formation of a deposited layer with solution diffusion properties from a macromolecular solution prior to concentrating products such as fruit juices, wine, coffee and tea could be applied for a higher rejection of dissolved and volatile compounds. The stability and the rejection characteristics of deposited layers were studied with a reverse osmosis membrane and a ceramic ultrafiltration membrane with applied pressures up to 6 MPa. The ultrafiltration membrane was used because most of the dissolved low molecular weight compounds pass through. An increase in retention of these compounds depends therefore only on the deposit layer on the membrane.     

纳滤膜技术处理印染废水试验研究

本文用复合纳滤膜对印染厂提供印染废水进行了色度和COD的去除试验研究。试验结果表明，纳滤膜技术可有效去除印染废水中的色度和COD，即使对废水的处理率高达90%（过程回收率高达90%）时，膜对印染废水中的COD的去除率仍高达98%以上、对色度的去除率则仍几乎为100%。膜的水通量随着进料流量、操作压力的增大而增大，随着过程回收率的提高而下降。     

Sugar Purification from Enzymatic Rice Straw Hydrolysis Products using Cross-Flow Diafiltration

The sugars produced by enzymatic hydrolysis of rice straw are separated using cross-flow diafiltration in this study. The effects of membrane type, membrane pore size, cross-flow velocity and transmembrane pressure on the filtration flux, sugar rejection, and sugar mass flux transported to the filtrate are discussed. The filtration flux increases with increasing cross-flow velocity or transmembrane pressure. When the membrane made of mixed cellulose ester (MCE) is used, over 70% filtration resistances are caused by the membrane fouling; while the resistance due to virgin membrane is dominant when regenerated cellulose (RC) membranes are used. A force balance model is applied to relate the filtration flux and filtration resistance to operating conditions. The calculated data of filtration flux based on this model agree fairly well with experimental data. In addition, a theoretical model is used to explain the sugar transmission through the cake and membrane pores. The sugar rejection coefficient decreases with increasing cross-flow velocity because of the effect of cake reduction. This effect is more significant when the MCE membrane is used. Comparing the sugar mass flux transported into the filtrate, it is more effective for sugar purification by using 10 kD RC membrane and under higher transmembrane pressures.     

Sub-20 nm Bilayer Hydrophilic Poly(Vinyl Pyrrolidone) Coatings for Antifouling Nanofiltration Membranes

Fouling is a major concern in membrane technology. Neutral hydrophilic coatings alleviate fouling on membrane surfaces by passively resisting the adsorption of foulants without altering the properties of membranes. Coatings, however, often result in a trade-off of reduced water flux. Ultrathin hydrophilic coatings could minimize the influence on water flux, but its fabrication is challenging via traditional methods. Here, fabrication of sub-20 nm bilayer hydrophilic coating is reported that is grafted onto nanofiltration (NF) membranes via a one-step initiated chemical vapor deposition (iCVD) method. The iCVD coating is conducted by conformally depositing a crosslinked poly(vinyl pyrrolidone-co-ethylene glycol dimethacrylate) bottom layer on pretreated NF membrane, followed by in situ grafting of poly(vinyl pyrrolidone) homopolymer to further improve surface hydrophilicity. Both thickness and crosslinking degree of the bottom coating are systematically tailored to reduce its side effects on permeation rate and salt rejection. The modified NF membranes exhibit 99% lower microbial adhesion compared to the pristine membrane, with minor impact on permeation and salt rejection performance. The coating is also stable against continuous ultrasonication. The reported method is thus expected to shed light on facile novel ways of reducing membrane fouling in desalination and industrial wastewater treatment.