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首页> 外文期刊>Environmental Science & Technology >Effects of Ozone on the Colloidal Stability and Aggregation of Particles Coated with Natural Organic Matter
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Effects of Ozone on the Colloidal Stability and Aggregation of Particles Coated with Natural Organic Matter

机译：臭氧对天然有机物包覆颗粒胶体稳定性和聚集的影响

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Adsorption of natural organic matter (NOM) onto particles contributes to their colloidal stability and inhibits coagulation in water treatment. Ozone has been shown to assist in the destabilization of particles' during water treatment by several hypothesized mechanisms. The goal of this research was to study the effects of ozone on NOM-coated particles in model (synthetic) waters to determine prevailing mechanisms and to quantify the effects of different variables. The experimental system included particles, aqueous phase NOM in equilibrium with particle phase (sorbed) NOM, and a background solution chemistry reflecting pH, ionic strength, and potentially influential ions (e.g., calcium, bicarbonate). Particle stability was assessed through electrophoretic mobility measurements while particle aggregation was assessed through use of a collision efficiency factor (a) under fluid shear mixing conditions. Changes in molecular weight, acidity, and complexation capacity of NOM (aqueous and mineral-bound) with calcium was studied before and after ozonation. Oxalic acid was. used as a model compound for ozonated NOM. It was found that ozone-induced particle destabilization occurred only in the presence of calcium. Based on the overall results, it is proposed that the ozone-induced particle destabilization observed in our system (with calcium present) is due to the following: (a) an increase in calcium association with ozonated NOM constituents there by inhibiting adsorption of anionic species onto the alumina surface and (b) a production of more ligand sites by ozone on the'surface-sorbed NOM leading to increased NOM complexation with calcium. These effects lead to a reduction in particle stability through surface charge reduction.
机译：天然有机物（NOM）在颗粒上的吸附有助于其胶体稳定性，并抑制水处理过程中的凝结。臭氧已通过多种假设的机制显示出有助于水处理过程中颗粒稳定的作用。这项研究的目的是研究臭氧对模型水（合成水）中NOM涂层颗粒的影响，以确定主要机理并量化不同变量的影响。实验系统包括颗粒，与颗粒相（吸附的）NOM平衡的水相NOM，以及反映pH，离子强度和潜在影响离子（例如钙，碳酸氢根）的背景溶液化学。通过电泳迁移率测量评估颗粒稳定性，同时在流体剪切混合条件下通过使用碰撞效率因子（a）评估颗粒聚集。臭氧化之前和之后，研究了NOM（与矿物质结合的水溶液）的分子量，酸度和络合能力的变化。草酸了。用作臭氧化NOM的模型化合物。发现仅在钙的存在下才发生臭氧引起的颗粒失稳。根据总体结果，建议在我们的系统中观察到的臭氧引起的颗粒失稳（存在钙）是由于以下原因：（a）通过抑制阴离子物质的吸附而增加了与臭氧化NOM成分的钙缔合（b）由臭氧在表面吸附的NOM上产生更多的配体位点，导致NOM与钙的络合增加。这些效果导致通过表面电荷减少而降低了颗粒稳定性。

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