Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China.
J Environ Sci (China). 2010;22(2):211-7. doi: 10.1016/s1001-0742(09)60095-4.
This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L (calculated as TOC). Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.
本文重点研究了腐殖酸和富里酸对饮用水中铝形态的影响。关注的因素包括余氯浓度和 pH 值。实验中研究的铝物种包括无机单核、有机单核、单核、聚合物、可溶性和悬浮形式。结果表明，腐殖酸和富里酸对铝形态的影响主要取决于它们的分子量。分子量小于 5000 道尔顿的腐殖酸对铝形态的影响较小；而分子量大于 5000 道尔顿的腐殖酸和富里酸即使在低于 0.5mg/L（以 TOC 计）的浓度下也会显著增加可溶性铝的浓度。在存在分子量大于 5000 道尔顿的腐殖酸和富里酸的情况下，铝物种比在存在分子量小于 5000 道尔顿的富里酸的情况下更稳定，并且随反应时间变化很小。在 pH 值为 6.5-7.5 范围内，水中的有机物显著增加了可溶性铝的含量。随着余氯浓度的增加，腐殖酸和富里酸的作用变得较弱。腐殖酸、富里酸与大分子量铝之间的反应被认为是一种多齿配位过程。考虑到铝的生物利用度，在饮用水处理过程中建议降低腐殖酸和富里酸的浓度，并将 pH 值保持在 6.5-7.5 之间。
