School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
J Environ Sci (China). 2011;23(7):1079-85. doi: 10.1016/s1001-0742(10)60520-7.
Due to the formation of disinfection by-products and high concentrations of Al residue in drinking water purification, humic substances are a major component of organic matter in natural waters and have therefore received a great deal of attention in recent years. We investigated the effects of advanced oxidation pretreatment methods usually applied for removing dissolved organic matters on residual Al control. Results showed that the presence of humic acid increased residual Al concentration notably. With 15 mg/L of humic acid in raw water, the concentrations of soluble aluminum and total aluminum in the treated water were close to the quantity of Al addition. After increasing coagulant dosage from 12 to 120 mg/L, the total-Al in the treated water was controlled to below 0.2 mg/L. Purification systems with ozonation, chlorination, or potassium permanganate oxidation pretreatment units had little effects on residual Al control; while UV radiation decreased Al concentration notably. Combined with ozonation, the effects of UV radiation were enhanced. Optimal dosages were 0.5 mg O3/mg C and 3 hr for raw water with 15 mg/L of humic acid. Under UV light radiation, the combined forces or bonds that existed among humic acid molecules were destroyed; adsorption sites increased positively with radiation time, which promoted adsorption of humic acid onto polymeric aluminum and Al(OH)3(s). This work provides a new solution for humic acid coagulation and residual Al control for raw water with humic acid purification.
由于饮用水净化过程中消毒副产物的形成和高浓度的铝残留，腐殖质是天然水中有机物的主要成分，因此近年来受到了广泛关注。我们研究了常用于去除溶解有机物的高级氧化预处理方法对残余铝控制的影响。结果表明，腐殖酸的存在显著增加了残余铝的浓度。在原水中含有 15mg/L 的腐殖酸的情况下，处理水中的可溶性铝和总铝浓度接近铝添加量。将混凝剂用量从 12mg/L 增加到 120mg/L 后，处理水中的总铝被控制在 0.2mg/L 以下。经过臭氧、氯化或高锰酸钾氧化预处理单元的净化系统对残余铝控制的影响很小；而紫外线辐射显著降低了铝浓度。紫外线辐射与臭氧结合后，其效果得到增强。对于含有 15mg/L 腐殖酸的原水，最佳剂量为 0.5mgO3/mgC 和 3 小时。在紫外线辐射下，腐殖酸分子之间存在的结合力或键被破坏；随着辐射时间的增加，吸附位点呈正增加，这促进了腐殖酸对聚合铝和 Al(OH)3(s)的吸附。这项工作为腐殖酸混凝和含腐殖酸原水的残余铝控制提供了一种新的解决方案。
