Polysaccharide separation mechanism in polysulfone-Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> magnetic composite membranes

Polysulfone (PSF)-Fe3O4 composite membranes were prepared by the phase-inversion process and their polysaccharide separation mechanism was explored using chondroitin sulfate (CS) and dextran. The mechanism was analyzed from constraints on the magnetic field and geometric deformation. It was found that variations in dextran rejection from 58% to 46% were mainly influenced by the geometric deformation of the composite membrane, while the magnetic field had a significant influence on variations in CS rejection from 82% to 35%. The results indicate that it is possible to continuously separate different types of polysaccharide with a composite membrane by adjusting the external magnetic field.     

Preparation and characterization of in-site regenerated TiO<Subscript>2</Subscript>-ACFs photocatalyst

In-site regenerated titanium dioxide-activated carbon fibers (TiO₂-ACFs) photocatalyst was prepared by the sol-gel method. Detailed surface and structural characterization of the TiO₂-ACFs photocatalyst was carried out. The photoactivity of TiO₂-ACFs under ultraviolet irradiation was compared with original ACFs and pure TiO₂ by the degradation of methylene blue aqueous solution. The degradation efficiency by the TiO₂ (5wt%)-ACFs sample is much higher than that by TiO₂ and ACFs. The results show that the photocatalysis by TiO₂-ACFs is a six-step process. The adsorption-transfer-photocatalysis rate of TiO₂-ACFs is higher than the adsorption-photocatalysis rate of TiO₂, so the photocatalysis rate of the TiO₂-ACFs system is higher than that of TiO₂ photocatalyst.     

膜分离技术在再生水中的应用及膜污染研究进展

传统的废水处理工艺在一定程度上成功地处理了排放的废水.然而,改善废水处理工艺是必要的,以便使处理后的废水能重复使用.膜技术已成为从不同的废水中回收再利用水的最佳选择.介绍了超滤膜、反渗透膜、微滤膜和纳滤膜的特征,阐述了这些膜在再生水中的研究近况以及膜污染的类型和清洗方法,最后展望了膜工艺在再生水中的应用与发展.     

Photocatalytic degradation of metronidazole in aqueous solution by niobate K<Subscript>6</Subscript>Nb<Subscript>10.8</Subscript>O<Subscript>30</Subscript>

The photocatalytic degradation of antibiotic metroni-dazole in aqueous solution by niobate K6Nb10.8O30 photocatalyst that was prepared using a soft-chemical method was studied by Fourier transform infrared spectroscopy and UV-Vis absorption spectrum. Metronidazole is very stable and is difficult to degrade under UV irradiation. K6Nb10.8O30 photocatalyst cannot degrade metronidazole without UV irradiation and shows very high photo-catalytic activity for the degradation of metronidazole under UV irradiation. The photocatalytic degradation rate of metronidazole increased with increasing the dosage of K6Nb10.8O30 photocatalyst. The photocatalytic degradation reaction of metronidazole by nio-bate K6Nb10.8O30 follows the first-order kinetic equation.     

生物丁醇的渗透蒸发分离膜研究进展

丁醇的分离问题是生物丁醇工业化及应用过程中急需解决的难题之一.从不同发酵-分离耦合技术的分离效果和经济效益出发,分析了渗透蒸发技术在丁醇分离中的优势.综述了渗透蒸发分离丁醇发酵液或模拟发酵液的研究进展,对聚二甲基硅氧烷(PDMS)、聚三甲基硅-1-丙炔(PTMSP)及其改性膜和其他聚合物膜的特点与分离性能进行了总结.另外,还关注了支撑液膜在丁醇分离中的应用及其存在的稳定性问题,分析了丁醇发酵液中存在的溶剂小分子、中间产物及生物大分子等对分离性能的影响.最后,对用于生物丁醇分离的渗透蒸发膜的未来发展进行了展望.     

膜分离技术及其在发酵液后处理中的应用

介绍了膜分离技术的原理以及发酵液后处理过程中常用的提取精制方法 ,如吸附、沉淀、结晶、萃取、离子交换等。介绍了膜技术在抗生素、维生素、氨基酸、酶制剂及其他发酵液后处理过程中的应用现状。实现膜技术在生产过程中的应用需要在膜与物料的适应性、适宜的操作条件和清洗、再生等方面进行研究 ,使后处理过程在低成本、高收率下进行     

耐酸性分子筛膜的研究进展

分子筛膜是一种可以实现分子筛分的新型无机膜,是膜分离技术的重要组成部分.分子筛膜在分离过程中具有浓缩、纯化、分离和反应促进等作用,且能耗较低,是理想的膜分离和膜催化材料.随着工业的发展,物质的提纯、化学反应过程中产物的分离等分离条件愈加苛刻,对分子筛膜的耐酸性、抗腐蚀性等要求越来越高.因此,耐酸性和抗腐蚀性分子筛膜的制备技术和表征技术有待改进和完善,进而促进膜分离技术在工业生产中发挥更大的作用.主要介绍了耐酸性分子筛膜的制备以及应用现状,并展望了耐酸性分子筛膜在工业方面的发展前景.     

炭膜的制备及应用

炭膜是一种新型的无机功能分离膜,与传统的高分子分离膜相比,炭膜具有耐高温、耐氧化性、耐腐蚀能力强的优点.选择廉价易得的炭膜制备原料,研究和制备高性能的气体和液体分离用炭膜,提高膜的通量和膜分离过程的选择性,一直是国内外研究人员不断探索的目标.研究炭膜催化反应器、炭膜生化反应器、集成膜反应器以及无机-有机复合膜是今后的发展方向.     

渗透汽化分离膜及膜反应器 Ⅰ．聚离子复合腹性能的研究

通过两层复合制得壳聚糖－聚丙烯酸钠和壳聚糖－褐藻酸钠聚离子复合膜，研究了其对乙醇－水混合体系的分离性能，并比较了壳聚糖膜、聚丙烯酸钠、褐藻酸钠及聚离子复合膜对乙醇－水二元体系和乙酸－丁醇－乙酸丁酯－水多元体系的渗透汽化分离性能．结果表明，聚离子复合膜适于作膜反应器的膜材料．     

膜型生物反应器酒精发酵与分离耦合过程的动力学模型

提出了利用无机硅沸石膜组成的膜型生物反应器进行发酵和分离过程中乙醇连续发酵与渗透气化分离的耦合模式,并根据发酵和膜分离过程初步提出反应动力学模型。     

Applications of membrane distillation technology in energy transformation process-basis and prospect

Membrane distillation technology is a new type of efficient separation technology that combines traditional distillation technology and membrane separation technology. In the study, applications of membrane distillation technology in thermal engineering and refrigerating engineering with typical energy transformation process were presented. Desorption and regeneration process of saline solution by vacuum membrane distillation was proposed on the basis of the concentration and separation properties of membrane distillation. Membrane distillation technology could be used in lithium bromide absorption refrigeration system, energy storage system, and the regeneration process of liquid desiccant solution in temperature-humidity independent control air-conditioning system. The aim of the applications was to use the low-grade energy such as waste heat, solar energy and geothermal energy adequately and to improve the available temperature difference of heat source. According to latent heat transfer and thermal conduction across the membrane in direct contact membrane distillation process, a novel membrane heat exchanger with both heat transfer and mass transfer processes was proposed. The heat exchanger could be used as the solution heat exchanger of lithium bromide absorption refrigeration system and as the special heat exchanger that recovered heat and pure water simultaneously. Some feasible process flows about the applications of membrane distillation technology to energy transformation process were listed and analyzed. Finally, future research emphases were indicated.     

甘氨酸的pH聚焦膜分离工艺

在氯乙酸催化氨解甘氨酸的生产工艺中，利用甘氨酸与副产物氯化铵的物化性质差异，采用相分离结合pH聚焦膜分离工艺取代传统的醇析工艺，得到甘氨酸和氯化铵2种产品。甘氨酸的相分离收率为90％，膜分离效率可以达到97％。     

膜分离技术在环境保护中的应用

扼要阐述了膜分离技术在环境保护应用中的基本原理、特点,介绍了该技术在国外应用于环保领域的水处理、废气处理的具体实例,对加快和拓宽我国膜分离技术的研究与开发具有借鉴作用。     

非织造纤维膜的离子分离特性研究

通过对离子水pH值及膜的性能测试，分析各种不同工艺、原料的非织造纤维膜在水的电离过程中所表现出的各自特性，及其对水中酸、碱离子的分离效果的影响，实验证明，非织造复合纤维膜具有良好的酸、碱离子分离性能。     

膜分离技术在H_2回收中的应用

结合成都科特瑞兴科技有限公司利用PRISM膜从合成氨驰放气、炼厂气以及甲醇驰放气和焦炉煤气中的H2回收技术,阐述了膜分离技术在H2回收领域中的重要应用,同时系统的介绍了膜的类型与选择依据,膜回收H2相关工艺流程,H2回收过程中应密切关注的问题等,并提出了相关的应对措施。     

Cryogenic induced phase separation of chitosan solution

The chitosan porous membrane was prepared by extending the principle of thermally induced phase separation (TIPS) for the polymer-diluent system to the polymer solution at arnbient temperature to carry out the cryogenic induced phase separation (CIPS). The porous membrane obtained was characterized by scanning electron microscopy (SEM) and gas permeability. It was found that a specific lacy pore structure morphology corresponding to the TIPS’ solicd-liquid phase separation was formed in the demixing process and the porosity could be more than 70%. The research of demixing mechanism and membrane-formation process showed that the membrane was stacked through porous lamella. The porosity of membrane increases and the pore diameter decreases with increasing solidtfying temperature. Both the porosity and pore diameter decrease with the chitosan concentration increase.     

Cryogenic induced phase separation of chitosan solution——A novel method for preparation of membrane with high porosity

The chitosan porous membrane was prepared by extending the principle of thermally induced phase separation (TIPS) for the polymer-diluent system to the polymer solution at ambient temperature to carry out the cryogenic induced phase separation (CIPS). The porous membrane obtained was characterized by scanning electron microscopy (SEM) and gas permeability. It was found that a specific lacy pore structure morphology corresponding to the TIPS' solid-liquid phase separation was formed in the demixing process and the porosity could be more than 70%. The research of demixing mechanism and membrane-formation process showed that the membrane was stacked through porous lamella. The porosity of membrane increases and the pore diameter decreases with increasing solidifying temperature. Both the porosity and pore diameter decrease with the chitosan concentration increase.     

稀溶液中微量组分的分离与分离方法选择

稀溶液中微量组分的分离是近年来分离过程这一领域的热门课题 ,讨论了超临界萃取 ,膜分离以及泡沫分离技术在这方面的应用及分离方法的选择。     

双极性膜电渗析法用于糖酸分离的研究

提出了双极性膜电渗析用于生物质水解液糖酸分离的方法，通过实验验证了该方法的可行性。实验考察了操作电压、电流强度、操作时间、处理溶液组分以及平均电流效率等因素对糖酸分离效果的影响。研究结果表明：生物质水解液中的糖酸可以得到分离，盐酸(w=0．01)和醋酸(w=0．01)可以完全回收，还需进一步解决的问题是提高电流效率和操作的经济性。     

Preparation and photocatalytic properties of ilmenite NiTiO<Subscript>3</Subscript> powders for degradation of humic acid in water

The powders of ilmenite structure NiTiO₃ were prepared by a modified Pechini process using tetrabutyl titanate and nickel acetate as raw materials, and using citric acid and ethanol as a chelating agent and a solvent respectively. The powder samples were characterized by thermogravimetric and differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). The photocatalytic activity of NiTiO₃ under the irradiation of ultraviolet rays (UV) light was evaluated by degrading humic acid (HA) in water as a probe reaction. The possible photodegradation mechanism was studied by the examination of active species ·OH, ·O₂⁻, and holes (h⁺) through adding scavengers. The TG-DTA and XRD results indicated that the good crystal structure of ilmenite phase NiTiO₃ could be obtained when the Ni-Ti citrate complex was calcined at 600°C. The photocatalytic activity experiments indicated that NiTiO₃ had favourable photocatalytic activity under the irradiation of UV light, and the photocatalytic degradation rate of HA reached 95.3% after a 2.5 h reaction with the photocatalyst calcined at 600°C and a photocatalyst dosage of 0.4 g/L. The possible photocatalytic mechanism was deduced that holes (h⁺) and ·OH radicals are the major reactive active species in the photocatalytic reaction, and dissolved oxygen plays a weak role in the degradation of HA.