Enhanced coagulation is an important way to remove natural organic matter and reduce disinfection by-products in traditional water treatment processes, in which the micromolecular organic matter that is difficult to be removed during conventional coagulation can be enhanced more conveniently by modulating the dominant Al species in the traditional metal salt coagulants (e.g., polymeric aluminum chloride, PACl). Based on the forcing hydrolysis characteristics of fine bubbles due to the adsorption of hydroxide ions on their surfaces, this study verified the adaptability of the forced PACl hydrolysis by fine bubbles under different operating conditions objectively and comprehensively. The morphological changes of PACl before and after forced hydrolysis by fine bubbles were characterized figuratively, and the evolution of the dominant Al species before and after forced hydrolysis by fine bubbles was reasonably elaborated. The experimental results showed that fine bubbles had the effect of forcing the hydrolysis of PACl with different degrees of alkalinity and modulating the dominant Al species. It was innovatively found that the mass transfer efficiency of the fine bubbles determined their efficiency in forcing PACl hydrolysis (Pearson's r = -0.9423) and the concentration of fine bubbles affected their capacity to force PACl hydrolysis (Pearson's r = 0.8189). At pH = 7 and an air flow rate of 20 mL/min, the DOC concentration of micromolecular organics and the DOC removal efficiency of total organics could be reduced by 0.54 mg/L and enhanced by 12.6%, respectively, after forced PACl hydrolysis by fine bubbles. While deepening the mechanism of forced PACl hydrolysis by fine bubbles, the above results preliminarily verified the relevance and feasibility of modulating the dominant Al species through forced PACl hydrolysis by fine bubbles to improve the coagulation efficiency, which provided theoretical and data support for the construction of a fine bubble-enhanced coagulation process for drinking water treatment plants.

中文翻译：

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细小气泡强迫聚合物氯化铝的水解特性及其影响强迫水解效率和能力的关键因素的研究


增强混凝是传统水处理过程中去除天然有机物和减少消毒副产物的重要途径，其中通过调节传统金属盐混凝剂（例如聚合物氯化铝、 PACl）。本研究基于细气泡表面氢氧根离子吸附的强制水解特性，客观、全面地验证了不同操作条件下细气泡强制 PACl 水解的适应性。对细气泡强制水解前后 PACl 的形态变化进行了形象表征，合理阐述了细气泡强制水解前后优势 Al 物种的演变。实验结果表明，细小气泡具有强制不同碱度的 PACl 水解和调节优势 Al 种类的作用。创新性地发现，细气泡的传质效率决定了它们强制 PACl 水解的效率 （Pearson's r = -0.9423），而细气泡的浓度影响它们强制 PACl 水解的能力 （Pearson's r = 0.8189）。在 pH = 7 且空气流速为 20 mL/min 时，微分子有机物的 DOC 浓度和总有机物的 DOC 去除效率在细小气泡强制 PACl 水解后可分别降低 0.54 mg/L 和提高 12.6%。 在深化细气泡强制 PACl 水解机制的同时，上述结果初步验证了通过细气泡强制 PACl 水解调控优势铝种类以提高混凝效率的相关性和可行性，为构建饮用水处理厂细气泡增强混凝工艺提供了理论和数据支持。