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Natural organic matter and particle fouling of spiral-wound nanofiltration membrane elements.

机译：螺旋缠绕纳滤膜元件的天然有机物和颗粒结垢。

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摘要

The fouling behavior of natural organic matter (NOM) and particles was assessed for spiral-wound nanofiltration membrane elements using a membrane pilot-plant. Experiments involved circulating experimental waters spiked with varying concentrations of collected NOM and different particle size ranges through elements for a period of 28 days. Twelve experiments were conducted, each using a new membrane element. At the end of each experiment, elements were dissected and examined visually and microscopically for deposited matter.; Data showed NOM adsorption following a Freundlich Isotherm. Adsorption was non-linear, adsorbing quickly in the first 48 hours, slowly decreasing over a period of two weeks to a steady-state (i.e., up to 13 percent of the total available mass of NOM). Adsorbing NOM was characterized primarily by lower and higher molecular weight molecules 5k da and >30k da, respectively. Particles were shown to interfere with NOM adsorption resulting in reduced levels.; Particles deposited continuously and at a constant rate. NOM increased the rate of deposition for 0.5–1.0 μm size particles while decreasing the rates for >1.0 μm size particles.; Although high concentrations of both NOM and particles were used in some experiments, neither was sufficient to cause membrane fouling. Hydraulic conductivities remained constant throughout the 28 day duration of each experiment.; Inspections of dissected elements showed both NOM and particle deposits on membrane surfaces. Patterns were influenced by the hydraulic flow conditions through the element and the feed water spacer. Deposits were heaviest in regions where velocities were relatively low or near stagnant such as those occurring at the periphery of the element and in front of feed water spacer fibers.; The feed water spacer was central to the deposition of both NOM and particles. A modified spacer design that provides a uniform flow across the surface of the membrane at an adequate cross-flow velocity to improve scouring, may reduce surface deposits, which in turn, should reduce membrane fouling.
机译：使用膜中试装置对螺旋缠绕式纳滤膜元件评估了天然有机物（NOM）和颗粒的结垢行为。实验涉及循环实验水，这些水以不同浓度的收集到的NOM和不同粒径范围的元素贯穿整个元素28天。进行了十二个实验，每个实验都使用了新的膜元件。在每个实验结束时，将元素解剖并在视觉和显微镜下检查沉积物。数据显示在弗氏等温线之后NOM吸附。吸附是非线性的，在开始的48小时内迅速吸附，在两周的时间内缓慢下降至稳态（即，最多占NOM总可用质量的13％）。吸附NOM的主要特征是分子量分别<5k da和> 30k da的较低和较高分子。已显示颗粒会干扰NOM吸附，从而降低含量。颗粒以恒定速率连续沉积。 NOM增加了0.5-1.0μm尺寸颗粒的沉积速率，同时降低了> 1.0μm尺寸颗粒的沉积速率。尽管在某些实验中使用了高浓度的NOM和颗粒，但两者均不足以引起膜污染。在每个实验的28天中，水力传导率保持恒定。解剖元素的检查显示膜表面有NOM和颗粒沉积物。模式受通过滤芯和给水垫片的液压流动条件的影响。沉积物在速度相对较低或接近停滞的区域中最重，例如那些发生在滤芯外围和给水隔离纤维前面的区域。进水隔板对NOM和颗粒的沉积至关重要。改进的隔离物设计可在足够的错流速度下提供均匀的流过整个膜表面的流量，以改善洗涤效果，可减少表面沉积物，从而减少膜污染。

著录项

  • 作者

    Champlin, Tory Lee.;

  • 作者单位

    Colorado State University.;

  • 授予单位 Colorado State University.;
  • 学科 Engineering Environmental.; Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 747 p.
  • 总页数 747
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;化学;
  • 关键词

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