The influence of dissolved organic matter (DOM) on mineral extraction from salt lake brines depend on DOM quality. This study contributes to our knowledge of DOM’s metal binding behavior in hypersaline environments by characterization of DOM from lakes in the Qaidam Basin, i.e., Qarhan Lake (LQDOM), Da Qaidam (DQDOM) and West Ginair Salt Lake (WGDOM). The DOM was fractionated based on solid phase extraction (SPE) and ultrafiltration (UF), and the spectral and metal binding behavior of these fractions were studied by absorption spectroscopy, Pb(II) titration techniques and fluorescence parallel factor (PARAFAC) analysis. The results showed that bulk DOM generally contained more dissolved organic carbon (DOC), lower specific UV absorbance (SUVA₂₅₄), higher fluorescence and biological indices, comparable humification index, and lower condition stability constants compared to the other nature waters. Compared with UF, SPE-derived DOM exhibited higher DOC recovery and aromaticity and lower carbohydrate yield. It appeared that the SPE procedure used affects the spectral composition of bulk DOM to a larger extent than UF. Source and molecular weight (MW)-dependent differences in abundance and quality of brine DOM was indicated by higher SUVA₂₅₄ in high MW DOM, for LQDOM and DQDOM, and humic-like fluorophores were mainly in high MW-DOM in each lake. Moreover, the high MW humic-like component exhibited higher metal binding potential than the bulk and low MW counterparts for LQDOM and DQDOM, while the inverse was observed for WGDOM. This study revealed the effects of isolation techniques on interpretation of DOM characteristics, and meanwhile highlighted the importance of origin- and MW-dependent DOM in manipulating the behavior, fate, and bioavailability of heavy metals in salt lake brine.

溶解有机物（DOM）对从盐湖盐水中提取矿物的影响取决于DOM质量。这项研究通过对柴达木盆地（Qarhan Lake（LQDOM），Da Qaidam（DQDOM）和West Ginair Salt Lake（WGDOM））湖泊中DOM的表征，有助于我们了解高盐环境中DOM的金属结合行为。基于固相萃取（SPE）和超滤（UF）分离DOM，并通过吸收光谱，Pb（II）滴定技术和荧光平行因子（PARAFAC）分析研究了这些馏分的光谱和金属结合行为。结果表明，散装DOM通常包含更多的溶解有机碳（DOC），较低的比紫外线吸收率（SUVA ₂₅₄），较高的荧光和生物指数，可比的腐殖度指数以及与其他自然水相比较低的条件稳定性常数。与UF相比，SPE衍生的DOM表现出更高的DOC回收率和芳香性以及更低的碳水化合物收率。看来，所用的SPE程序对整体DOM的光谱组成的影响远大于UF。较高的SUVA ₂₅₄表示盐水DOM的丰度和质量的来源和分子量（MW）依赖性差异在高MW DOM中，对于LQDOM和DQDOM，腐殖质样荧光团主要在每个湖泊的高MW-DOM中。此外，对于LQDOM和DQDOM，高分子量腐殖质样组分比大体积和低分子量对应物表现出更高的金属结合潜力，而WGDOM则相反。这项研究揭示了隔离技术对DOM特性的解释的影响，同时强调了起源和MW依赖性DOM在操纵盐湖盐水中重金属的行为，命运和生物利用度方面的重要性。