Department of Environmental Engineering, Chang'An University, Xi'an710064, Shaanxi, China.
Technology Institute of Beijing Waterworks Group Co. Ltd., Beijing100012, China.
Water Res. 2021 Feb 15;190:116682. doi: 10.1016/j.watres.2020.116682. Epub 2020 Nov 25.
Residual dissolved aluminum (Al) in drinking water is becoming a serious concern due to its high potential risks to human health. However, the mechanism by which residual dissolved Al forms is yet to be elucidated in detail. In this study, the effects of pre-oxidation by ozonation and chlorination on the properties of dissolved organic matter (DOM) and residual Al concentrations remaining in solution after coagulation were explored in a pilot-scale test. Changes in the DOM properties caused by the water treatment process were characterized by ultraviolet-visible absorbance spectroscopy. Theprotonation-active sites, carboxylic- and phenolic-type groupsof DOM were quantified by spectral parameter DlnA400 (differential log-transformed spectra at wavelength 400 nm) in combination with the revised non-ideal competitive adsorption model. The results show that ozonation and chlorination significantly affect the properties of DOM and the amount of residual dissolved Al in coagulated drinking water. This effect was associated with the changes in the carboxylic- and phenolic-type groups in DOM. Results of the study show that residual dissolved Al in coagulated water can be controlled by affecting theAl binding sites in DOM by pre-oxidation before coagulation. The nature of pre-oxidation agent and its dosage should be selected depending on the quality of the raw water to be treated. Ozonation was concluded to be preferable pre-oxidation agent for the water in examined this study.
饮用水中残留溶解态的铝（Al）因其对人体健康的高潜在风险而成为一个严重的问题。然而，残留溶解态 Al 形成的机制尚未得到详细阐明。在这项研究中，通过臭氧氧化和氯化预氧化来探索混凝后溶液中残留溶解态 Al 浓度的特性。采用紫外-可见吸收光谱法对水处理过程中 DOM 特性的变化进行了表征。通过光谱参数 DlnA400（在 400nm 波长下的差分对数变换光谱）与修正后的非理想竞争吸附模型相结合，定量了 DOM 中的质子化活性位点、羧酸型和酚型基团。结果表明，臭氧氧化和氯化显著影响 DOM 的特性以及混凝后饮用水中残留溶解态 Al 的含量。这种影响与 DOM 中羧酸型和酚型基团的变化有关。研究结果表明，通过在混凝前进行预氧化来影响 DOM 中的 Al 结合位点，可以控制混凝水中的残留溶解态 Al。预氧化剂的性质及其用量应根据待处理原水的质量进行选择。研究结果表明，臭氧氧化是该研究中所用水的首选预氧化剂。
