Study on the hydrolysis characteristics of polymeric aluminum chloride forced by fine bubbles and its key factors affecting the efficiency and capacity of forcing hydrolysis

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL Water Research Pub Date : 2024-11-05 DOI:10.1016/j.watres.2024.122757

Xiaojiang Huang , Kunyu Chen , Zhiqiang Zhang , Chunbo Li , Ping Li , Xuan Wang , Jinsuo Lu

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Abstract

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.

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细气泡强制水解聚合氯化铝的特性及其影响强制水解效率和能力的关键因素研究

强化混凝是传统水处理工艺中去除天然有机物、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（如聚合氯化铝，PACl）中的优势铝物种，可以更方便地强化传统混凝中难以去除的微分子有机物。本研究基于细小气泡表面吸附氢氧根离子而产生的强制水解特性，客观、全面地验证了细小气泡强制水解 PACl 在不同操作条件下的适应性。研究形象地描述了细小气泡强制水解前后 PACl 的形态变化，并合理地阐述了细小气泡强制水解前后主要 Al 物种的演变过程。实验结果表明，细小气泡对不同碱度的 PACl 有强制水解的作用，并能调节主要的 Al 种类。实验创新性地发现，细小气泡的传质效率决定了其强制 PACl 水解的效率（Pearson's r = -0.9423），而细小气泡的浓度影响了其强制 PACl 水解的能力（Pearson's r = 0.8189）。在 pH = 7、空气流量为 20 mL/min 的条件下，细气泡强制 PACl 水解后，微分子有机物的 DOC 浓度和总有机物的 DOC 去除率分别降低了 0.54 mg/L 和提高了 12.6%。上述结果在深化细泡强制PACl水解机理的同时，初步验证了通过细泡强制PACl水解调节Al优势物种以提高混凝效率的相关性和可行性，为饮用水处理厂构建细泡强化混凝工艺提供了理论和数据支持。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.