Department of Civil Engineering, University of Akron, Akron, OH 44325, United States.
Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., Columbia, SC 29208, United States.
Chemosphere. 2018 Jul;202:349-357. doi: 10.1016/j.chemosphere.2018.03.102. Epub 2018 Mar 16.
Iopamidol is a known direct precursor to iodinated and chlorinated DBP formation; however, the influence of iopamidol on both iodo/chloro-DBP formation has yet to be fully investigated. This study investigated the effect of iopamidol on the formation and speciation of halogen-specific total organic halogen (TOX), as well as iodo/chloro-DBPs, in the presence of 3 source waters (SWs) from Northeast Ohio and chlorinated oxidants. Chlorination and chloramination of SWs were carried out at pH 6.5-9.0 and, different iopamidol and dissolved organic carbon (DOC) concentrations. Total organic iodine (TOI) loss was approximately equal (22-35%) regardless of SW. Total organic chlorine (TOCl) increased in all SWs and was substantially higher in the higher SUVA SWs. Iopamidol was a direct precursor to chloroform (CHCl), trichloroacetic acid (TCAA), and dichloroiodomethane (CHClI) formation. While CHCl and TCAA exhibited different formation trends with varying iopamidol concentrations, CHClI increased with increasing iopamidol and DOC concentrations. Low concentrations of iodo-acids were detected without discernible trends. Total trihalomethanes (THMs), total haloacetic acids (HAAs), TOCl, and unknown TOCl (UTOCl) were correlated with fluorescence regional volumes and SUVA. The yields of all these species showed a strong positive correlation with fulvic, humic, and combined humic and fulvic regions, as well as SUVA. Iopamidol was then compared to the 3 SWs with respect to DBP yield. Although the SUVA of iopamidol was relatively high, it did not produce high yields of THMs and HAAs compared to the 3 SWs. However, chlorination of iopamidol did result in high yields of TOCl and UTOCl.
碘海醇是一种已知的直接前体，可形成碘代和氯代 DBP；然而，碘海醇对碘代/氯代 DBP 形成的影响尚未得到充分研究。本研究调查了碘海醇对三种来自俄亥俄州东北部水源（SW）和氯化氧化剂中卤素特异性总有机卤素（TOX）以及碘代/氯代 DBPs 的形成和形态的影响。在 pH 值为 6.5-9.0 时对 SW 进行氯化和氯胺化，并使用不同浓度的碘海醇和溶解有机碳（DOC）。无论 SW 如何，总有机碘（TOI）的损失大致相同（22-35%）。所有 SW 中的总有机氯（TOCl）均增加，且在更高 SUVA 的 SW 中增加幅度更大。碘海醇是三氯甲烷（CHCl）、三氯乙酸（TCAA）和二氯碘甲烷（CHClI）形成的直接前体。虽然 CHCl 和 TCAA 的形成趋势随碘海醇浓度的变化而不同，但 CHClI 随碘海醇和 DOC 浓度的增加而增加。检测到低浓度的碘代酸，但没有明显的趋势。总三卤甲烷（THMs）、总卤乙酸（HAAs）、TOCl 和未知的 TOCl（UTOCl）与荧光区域体积和 SUVA 相关。所有这些物质的产率与富里酸、腐殖酸以及富里酸和腐殖酸的结合区域以及 SUVA 呈强正相关。然后将碘海醇与 3 种 SW 进行比较，以确定其 DBPs 的产率。尽管碘海醇的 SUVA 相对较高，但与 3 种 SW 相比，其并未产生高浓度的 THMs 和 HAAs。然而，碘海醇的氯化会导致 TOCl 和 UTOCl 的高产量。
