Ultrafiltration Based Process for the Recovery of Polysaccharides and Polyphenols from Winery Effluents

Winery effluents have a high pollution potential, especially those effluents that are obtained from the second racking. However, these effluents are rich in phenolic compounds and polysaccharides and can be potential sources for the recovery of these compounds. Therefore, a process was developed in this study to reduce the pollution potential of the winery effluents from the second racking and to recover the polyphenols and polysaccharides from the effluents by utilizing ultrafiltration (UF) and sedimentation operations. The sedimentation was optimized by varying the pH from 3.8 to 8.0, while the UF experiments were optimized by varying the transmembrane pressure from 0.5 to 4.0 bar and the feed circulation velocity from 0.44 to 0.87 ms^?1. This process provided a permeate stream with a reduction in the TOC content by 56.6%, while the polyphenols and the polysaccharides in the concentrate stream were concentrated by 6 times and 5 times, respectively.     

聚酰亚胺纳滤膜分离螺旋霉素萃取液

研究了不同操作条件对聚酰亚胺纳滤膜分离螺旋霉素一乙酸丁酯萃取液性能的影响。考察了操作压力、温度、进料流量和进料中螺旋霉素质量浓度等因素对膜通量和截留率的影响,并观察了长期运行情况下膜分离性能的变化情况。在适宜的操作条件下,膜通量可达20L/（m^2·h）以上,截留率可达99％以上。试验表明,随操作压力增大、温度升高和进料流量增大,膜通量也随之增大,进料中螺旋霉素质量浓度增加使膜通量减小,不同操作条件对截留率的影响很小。在35d的运行期内膜的分离性能变化不大,表明该膜对此物系具有较强的抗污染能力。     

K2CO3生产中NH4Cl废水的回收技术

分析了反渗透的基本原理，详细介绍了采用反渗透膜分离技术回收利用K2CO3生产过程中产生的含NH4Cl废水的工艺过程。处理低浓度含NH4Cl废水100m^3／h和高浓度含NH4Cl废水40m^3／h工业化装置建成投产后，处理前低浓度废水含NH4Cl1000mg／L，高浓度废水含NH4Cl10000mg／L，pH=8～10；处理后，产品淡水含NH4Cl≤10mg／L、pH=7～8，产品浓水含NH4Cl≥60000mg／L、pH=8～lO。该装置的投运，取得了明显的经济效益和社会效益。     

N, O-羧甲基壳聚糖复合纳滤膜的制备及其对酒厂发酵废水的截留效果

N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone （PSF） composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand （CODcr）, total organic carbon （TOC）, and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODcr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h ooeration for the fermentation effluent treatment.     

Modeling of Nanofiltration Process for Solvent Recovery from Aqueous Ethanol Solution of Soybean Isoflavones

Abstract

In this paper, the feasibility of recovering the solvent from the aqueous ethanol solution of soybean isoflavones with nanofiltration (NF) was studied. Five commercially available polymeric NF membranes were employed and STARMEM? 122 showed acceptable flux and high retention. The central composite design (CCD) of the response surface methodology (RSM) was applied to model the effects of temperature, pressure, and feed concentration on the permeate flux and the total soybean isoflavone retention. The results indicate that the developed models were in good agreement with the experimental results and they can be used to predict this NF process.     

Effect of Color and Surfactants on Nanofiltration for the Recovery of Carpet Printing Wastewaters

Abstract

Carpet printing wastewater (CPW) was spiked with metal‐complex dyes at concentrations of 10 and 30 mg/L to investigate the effect of feed color on separation performance of nanofiltration (NF). The rejection was excellent; 98–100% for color and COD under all spiking conditions. Although the flux decline increased with increasing dye concentration, the concentration polarization was the main cause of the flux decline. The effect of surfactants on NF separation performance was also investigated by preparing synthetic wastewaters with dyes and auxiliary chemicals. The presence of a non‐ionic penetrant did not adversely affect the color rejection whereas the COD rejection was reduced from 100% to 91%. Furthermore, fouling became dominant when surfactants were used.     

石煤氯化钠焙烧水浸液纳滤提钒过程

采用石煤氯化钠焙烧浸出液为原料,研究了驱动压力、料液pH值及钒浓度对钒纳滤浓缩效果的影响,并考察了Cl-在纳滤过程中的行为. 结果表明,在驱动压力10.0~12.5 kg/cm2和pH值5.16~6.15的优化条件下,料液中的钒(V2O5)可纳滤浓缩到35 g/L以上. pH值6.15时,钒的截留率最高,达92%. 浓缩液按沉钒化学计量的2.2倍加入NH4Cl,沉淀得到的NH4VO3经500℃煅烧1 h得到的V2O5产品纯度为98.6%.     

Nanofiltration for separation and purification of saccharides from biomass

Saccharide production is critical to the development of biotechnology in the field of food and biofuel. The extraction of saccharide from biomass-based hydrolysate mixtures has become a trend due to low cost and abundant biomass reserves. Compared to conventional methods of fractionation and recovery of saccharides, nanofiltration (NF) has received considerable attention in recent decades because of its high selectivity and low energy consumption and environmental impact. In this review the advantages and challenges of NF based technology in the separation of saccharides are critically evaluated. Hybrid membrane processes, i.e., combining NF with ultrafiltration, can complement each other to provide an efficient approach for removal of unwanted solutes to obtain higher purity saccharides. However, use of NF membrane separation technology is limited due to irreversible membrane fouling that results in high capital and operating costs. Future development of NF membrane technology should therefore focus on improving material stability, antifouling ability and saccharide targeting selectivity, as well as on engineering aspects such as process optimisation and membrane module design.     

低分子量聚谷氨酸的制备及其在眼科靶向药物中的应用研究

人体角膜难以吸收分子量较大的药物分子,为了减少高毒药物治疗眼表疾病时经角膜吸收导致的眼内副作用,设计了丝裂霉素C的L-聚谷氨酸衍生物高分子前药。为了减少市售链状大分子聚谷氨酸修饰后,丝裂霉素C被其包缠导致的药效降低,将市售的L-聚谷氨酸先进行定量水解,获得了一系列较低分子量的L-聚谷氨酸(1~5 k),通过电泳法确证其分子量,并将其应用制备了系列低分子量L-聚谷氨酸衍生物高分子丝裂霉素C前药。     

Modification of Low Molecular Weight Polysaccharides from Tremella Fuciformis and Their Antioxidant Activity in Vitro

In this study, sulfated low molecular-weight Tremella fuciformis polysaccharides (SLTP) with different sulfate contents were synthesized and their antioxidant activities, including superoxide anion radical, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical and hydroxyl radical scavenging activities were investigated. The results indicated that, compared to natural Tremella fuciformis polysaccharide (TP) and low molecular weight Tremella fuciformis polysaccharide (LTP), sulfated LTP (SLTP) exhibited stronger scavenging activity towards superoxide anion, DPPH and hydroxyl radicals. In all the cases the effect was found to be dose dependent. The scavenging activity of SLTP was found to be in parallel with the degree of sulfation of SLTP.     

A Two-Step Nanofiltration Process for the Production of Phenolic-Rich Fractions from Artichoke Aqueous Extracts

Commercial nanofiltration (NF) membranes in spiral-wound configuration (NP030 from Microdyn Nadir and Desal DK from GE Water & Process Technologies) were used in a sequential design in order to produce a separated fraction of phenolic and sugar compounds from an aqueous artichoke extract. For both membranes, the effect of transmembrane pressure (TMP) on the permeation flux was evaluated. In optimized conditions of TMP, the NP030 membrane exhibited high rejections of apigenin, cynarin and chlorogenic acid (higher than 85%); on the other hand, very low rejections of fructose, glucose and sucrose (lower than 4%) were measured. Starting from an extract with a total antioxidant activity (TAA) of 5.28 mM trolox a retentate fraction with a TAA of 47.75 mM trolox was obtained. The NF permeate from the NP030 membrane was processed with the Desal DK membrane in optimized conditions of TMP producing a permeate stream free of phenolic and sugar compounds. Accordingly, as most part of phenolic compounds was removed in the first NF step, the concentration of sugar compounds in the NF retentate had much higher results than that of phenolic compounds.     

活性黑染料纳滤脱盐浓缩的研究

选用纳滤膜DK对宜兴某染料厂生产的活性黑粗制染料液进行了脱盐浓缩的间歇恒容渗滤实验。经过间歇渗滤操作,染料纯度从76％上升到97％,染料浓度从5％上升到15％,染料质量得到显著提高,同时降低了厂家后续干燥操作的能耗。实验结果表明：膜法生产新工艺完全可以用于改造该厂染料的传统生产工艺。     

Separation and Recovery of Low Molecular Weight Organic Acids by Emulsion Liquid Membranes

Abstract

Emulsion liquid membrane (ELM) extraction of low molecular weight organic acids resulting from whey fermentations was investigated. Rates of removal of lactic, acetic, propionic, and acrylic acids decreased as pH and concentration were increased. An ELM process for selective removal of acrylic acid from acrylic acid-propionic acid mixtures was developed through incorporation of a co-solvent (cyclohexanone) in the membrane phase of the emulsion. Degree of removal for each acid and, hence, selectivity among the acids appears to be determined by the water-membrane phase partition coefficient.     

Molecular Weight Distribution of Low Molecular Weight Polyols Derived from Fatty Acid Methyl Esters

A series of commercial polyether polyols with well-defined molecular weights (MW) was used along with propylene glycol and dipropylene glycol as gel permeation chromatography (GPC) calibration standards to determine the MW and oligomeric composition of the synthesized low MW fatty acid methyl ester (FAME) polyols, having an MW of lower than 600 Da. This GPC analysis was compared to the one calibrated against the commercially-available polystyrene (PS) standards and to the number-average molecular weight (M _n) obtained via vapor pressure osmometry (VPO) technique. The MW of FAME polyols obtained with GPC calibrated against polyether polyols were closer to the M _n values obtained via VPO than the MW obtained via GPC calibrated against PS standards. Using the reliable GPC calibration, the MW distribution and the hydroxyl functionality of FAME polyols were determined with greater confidence.     

肝素钠生产副产物中低分子肝素钠的分离纯化

用制备普通肝素钠过程中含低分子肝素钠的副产物为原料制备低分子肝素钠。先用2%NaCl溶解除去不溶物,用HCl-焦磷酸钠初步除去核苷酸和寡聚DNA,用乙醇沉淀法初步除去小肽和氨基酸,通过D-254离子交换层析法进一步纯化低分子肝素钠。100g副产物可以获得效价为145IU/mg、相对分子质量为的4000～8000D的低分子肝素钠4.67g,纯化了8.5倍,得率为40%,该研究取得了初步成果。     

Concentration and Drying of Tea Polyphenols Extracted from Green Tea Using Molecular Distillation and Spray Drying

The purpose of this study was to develop a method of combining molecular distillation and spray drying to concentrate and dry tea polyphenols extracts. Molecular distillation and spray drying of tea phenols extracts were performed using an orthogonal array design. The order of importance that influenced molecular distillation was distillation temperature > flux > rotational speed. The optimal conditions for concentration by molecular distillation were 70°C distillation temperature, 10 mL/min flux, and 1,200 n/min rotational speed. Inlet temperature was found to be the most important determinant of spray drying. The order of importance that influenced the spray drying was inlet temperature > feed flux > wind capacity > feed concentration. The optimal conditions for drying of tea polyphenols extracts by spray drying were determined as follows: 170°C distillation temperature, 3 mL/min feed flux, 30% feed concentration, and 30 m³/h wind capacity. Results of this study indicated that the combination of molecular distillation and spray drying was very suitable for the concentration and drying of tea polyphenols extracts. Using this approach to process tea polyphenol extracts can not only maintain the quality of tea polyphenols but also save time and energy.     

水溶性多糖酶解过程分子量变化与动力学建模

以魔芋葡甘聚糖-β-甘露聚糖酶水解体系为例,研究了水溶性多糖酶解过程中产物的分子量变化与动力学行为.利用凝胶排阻色谱法和特性粘度法,分别测定了酶解物的分子量分布和重均分子量(-Mw),结果表明:随着反应的进行,酶解物分子量分布先变宽再逐渐变窄,这是由酶在底物反应体系中的镶嵌式分布,不均一的底物分子序列结构与酶分子的选择性剪切,酶剪切的多种途径以及酶与底物的结合模式等四种因素共同作用的结果;初始阶段酶解物(-Mw)先快速下降再逐渐趋于平缓,其速率与底物浓度有关;基于酶解产物重均分子量变化规律而建立的(1/-Mw)随反应时间t变化的动力学模型,确定了常见的水溶性多糖浓度下酶解过程为零级降解,并与实验结果相当一致.     

超滤-纳滤联合膜技术在土霉素提取中的应用研究

将超滤纳滤联合膜技术应用到土霉素的提取过程中,旨在探索一种既能提高土霉素产品质量,又能提高土霉素收率,并有助于解决废水污染的切实可行的土霉素提取新工艺。实验结果表明,采用PES20进行超滤,去除部分大分子杂质,再采用NF270进行纳滤浓缩,浓缩至2.5倍进行结晶,可以使提取过程和结晶过程的土霉素总收率比原工艺提高近4.6%,产品纯度可提高近2.6%,废水中CODcr总排放量可减少近2.3倍。     

高活性低相对分子质量聚异丁烯

概念了低相对分子质量取异丁烯（LPIB）的聚合机理、制备、国内LPIB合成技术发展和其应用,并对我国LPIB的发展方向提出一些建议。     

玉米须中植物多酚的提取及其抗氧化性研究

研究了玉米须中植物多酚的提取工艺及抗氧化性。以玉米须为原料,采用有机溶剂法提取玉米须中植物多酚,单因素试验优化植物多酚提取工艺条件。结果表明:有机溶剂提取法的最佳条件为:在50℃下,60%甲醇溶液作为提取剂,料液比为1∶60,提取时间4 h;玉米须中植物多酚的浓度达到60 mg/m L对羟基自由基清除率为62.16%,超氧自由基清除率为65.67%。