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本研究采用大蒜素为原料,将其包埋在海藻酸钠中,制成大蒜素包埋球(allicin entrapping beads, AEBs)并投加至膜生物反应器(membrane bioreactor, MBR)中,以探讨大蒜素的群体淬灭(quorum quenching, QQ)效应对MBR污泥混合液可滤性的影响。实验结果表明:QQ作用对污泥混合液性质影响显著,对MBR污染物去除影响较小;混合液中胞外聚合物(extracellular polymeric substances, EPS)和溶解性微生物代谢产物(soluble microbial products, SMP)含量降低;通过对修正污染指数(modified fouling index, MFI)检测表明,QQ可提高污泥混合液可滤性,该指标与胞外多糖浓度紧密相关。 相似文献
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膜生物反应器(membrane bioreactor, MBR)作为一种高效的污水处理及回用工艺,比传统的活性污泥法具有更多优势。然而,膜污染问题是限制其广泛应用的关键性问题。众多研究者已证实Fe3+能有效的改善MBR中混合液的可滤性及减缓膜污染。本文简述了MBR污泥混合液中主要污染物—胞外聚合物(extracellular polymeric substances, EPSs),并总结Fe3 在去除混合液中污染物、减缓膜污染方面的效能及其对污泥混合液的影响。最后,对Fe3 在减缓MBR膜污染的未来研究方向进行展望。 相似文献
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膜生物反应器(Membrane bioreactor,MBR)作为一种新型的污水处理技术,近些年来备受关注。然而,膜污染问题成为了该工艺广泛应用的最大障碍。现已证明,向MBR中投加铁系混凝剂能够减缓膜污染。本文首先综述了不同价态铁离子对MBR污染物去除的影响,然后对铁离子在污泥混合液中分布及迁移转化进行了分析,接着阐明了铁离子对膜污染的影响,最后对该领域的研究进行了展望。 相似文献
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采用重力出流式膜生物反应器(MBR)对生活污水进行处理, 选择两种孔径的微滤膜考察其对污水中T4和f 2两种模型病毒的去除情况. 清水试验结果表明, 两种膜孔径组件对T4和 f 2病毒的实际截留率远大于理论截留率; 两种膜组件对T4病毒的截留均高于f 2病毒. 在MBR稳定运行状况下, 两种不同孔径的膜组件对同一病毒的截留效果无显著差别: 孔径为0.1 mm的聚丙烯(PP)和孔径为0.22 mm的聚偏氟乙烯(PVDF)对T4去除率均大于5.5 lg; 对f 2的去除率大于3.0 lg. 其原因是膜表面的滤饼层、凝胶层在病毒的截留中起了重要的作用. 膜生物反应器对病毒的去除由膜的截留、污泥絮体的吸附和生物灭活等作用共同完成. 进一步的研究发现: 活性污泥系统对病毒去除率稳定在97%以上, 主要依靠生物灭活作用完成对病毒的去除. 相似文献
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膜污染问题严重制约了膜生物反应器(MBR)的广泛应用,因此膜污染机制的研究对于有效控制膜污染十分重要。XDLVO理论合理地解析了范德华力、极性作用力、双电层作用力在膜污染过程中的贡献,有效地揭示了膜污染机理。本文首先阐述了XDLVO理论;然后运用XDLVO理论,解析界面微距离范围内膜表面凝胶层及泥饼层形成过程;最后总结了XDLVO理论在MBR膜污染方面的应用,并对该领域未来的研究方向进行了展望。 相似文献
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膜生物反应器技术作为一种新型、高效的水处理技术,已成功应用于废水处理系统。在膜分离工程领域,聚偏氟乙烯(PVDF)作为一种优异的膜材料,成为人们热衷的研究对象。本文综述了目前应用于MBR的PVDF膜制备方法,重点介绍了Fe(OH)3、TiO2t、ween-20+戊二醛、PEBAX、PVDF-g-POEM、PVDF-g-PEGMA、TPU、Al2O3、SiO2微粒等对PVDF膜的改性研究,并对PVDF制备MBR膜的发展前景进行了展望。经过改性后的膜在一定程度上能够有效增强亲水性和抗污染能力,延长膜的寿命,降低运行成本,而且出水水质更好,若增强其机械强度,将会有更广泛的用途。 相似文献
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荷电膜的膜电位研究进展 总被引:1,自引:0,他引:1
膜电位的测定是表征荷电膜的传递现象的重要参数之一。本文简要介绍了膜电位理论基础,包括T. M. S.理论和不可逆热力学理论。分别阐述了关于离子交换膜、双极膜、两性膜以及复合膜的膜电位的最新进展,并提出今后的发展方向。 相似文献
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A model of the composite membrane consisting of the catalytic layer (CL) and the nanofiltration layer (NFL) is presented. It has been found that applying NFL on the permeate side of CL it is possible to enhance substantially the conversion of substrate into the product. The best performance is obtained for high retention of substrate and low of product. At higher values of volume flow and/or longer catalytic path the retention degree of product becomes negligible. The presence of NFL enhances the influence of distribution of the reaction rate constant, k, on the conversion ratio. Comparing to k = constant the positive effect is obtained if k increases along the catalytic pore, whereas negative—if k decreases. 相似文献
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Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50 200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2 0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of γ-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes have zeolitic top-layers with a thickness of 10-25 μm, and zeolite crystals can be intruded into pores of the supports as deeply as 100μm. The experimental results indicate that the precoating of zeolitic seeds on supports is beneficial to crystallization by shortening the synthesis time and improving the membrane strength. The resulting zeolite X membrane shows permselectivity to tri-n-butylamine((C4H9)3N) over perfluro-tributyl-amine ((C4Fg)3N), and a permeance ratio of 57 for ((C4Hg)3N to (C4F9)3N could be reached at 350℃. Permeances of BZ, EB and TIPB through the zeolite membrane were also measured and were found to slightly increase with temperature. 相似文献
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Zhongqiang Xu Qingling Chen Guanzhong LuShanghai Research Institute of Petrochemical Technology Shanghai ChinaInstitute of Industrial Catalysis East China University of Science Technology Shanghai China 《天然气化学杂志》2002,(Z2)
Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50-200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2-0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of r-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes hav 相似文献
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