Ma H, Allen H E, Yin Y
Department of Civil and Environmental Engineering. University of Delaware, Newark 19716, USA.
Water Res. 2001 Mar;35(4):985-96. doi: 10.1016/s0043-1354(00)00350-x.
Dissolved organic matter (DOM) was concentrated from natural waters and the effluent of a wastewater treatment plant using a portable reverse osmosis (RO) system. The humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The FA fractions predominated in natural waters and accounted for 54-68% of the total amount of dissolved organic carbon (DOC), whereas the HA and HyI fractions constituted, respectively, 13-29 and 9-30% of the total DOC. The effluent of wastewater was almost devoid of HA and the HyI fraction exceeded FA. The elemental compositions of HA and FA were in the ranges typical for natural humic materials, but the HyI fractions did not exhibit humic character. 1H NMR spectra revealed that the HyI fractions were almost devoid of aromatic protons and the aliphatic region featured more sharp signals than HA and FA fractions, indicating that HyI fractions were consisted of more simple compounds and less complex mixtures. The aliphatic functional groups in these fractions of DOM samples followed the order HA < FA <HyI. Proton titrations indicated that HA. FA and HyI fractions of DOM samples from different sources had similar total acidity whose range was 9.0-11.6 meq/g C. This similarity may be due to the sample fractionation method. The copper titration results showed that the number of total Cu binding sites for the three fractions of different DOM samples were quite similar (1.46-1.60 mmol/g C), which was consistent with the similarity in total acidity from proton titrations. The affinity of copper with each isolated fraction followed the order HA approximately = FA > HyI. The rate of Cu complexation with the HyI fraction was faster than the rate with the HA or FA fraction of the Suwannee River DOM, implying that copper reacted with relatively weak ligands faster than with strong ligands.
使用便携式反渗透（RO）系统从天然水和污水处理厂的流出物中浓缩溶解有机物（DOM）。通过XAD - 8树脂结合阳离子交换树脂法分离并纯化腐殖酸（HA）、富里酸（FA）和亲水（HyI）组分。FA组分在天然水中占主导地位，占溶解有机碳（DOC）总量的54 - 68%，而HA和HyI组分分别占总DOC的13 - 29%和9 - 30%。废水流出物中几乎没有HA，HyI组分超过了FA。HA和FA的元素组成在天然腐殖质材料的典型范围内，但HyI组分没有表现出腐殖质特征。1H NMR光谱显示，HyI组分几乎没有芳香质子，脂肪族区域的信号比HA和FA组分更尖锐，表明HyI组分由更简单的化合物和更不复杂的混合物组成。DOM样品这些组分中的脂肪族官能团顺序为HA < FA < HyI。质子滴定表明，来自不同来源的DOM样品的HA、FA和HyI组分具有相似的总酸度，范围为9.0 - 11.6 meq/g C。这种相似性可能归因于样品分级方法。铜滴定结果表明，不同DOM样品的三个组分的总铜结合位点数量非常相似（1.46 - 1.60 mmol/g C），这与质子滴定中总酸度的相似性一致。铜与每个分离组分的亲和力顺序为HA ≈ FA > HyI。铜与HyI组分的络合速率比与苏万尼河DOM的HA或FA组分的络合速率快，这意味着铜与较弱配体的反应比与强配体的反应更快。
