School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China.
School of Metallurgy and Environment, Central South University, Changsha, 410083, PR China.
Chemosphere. 2020 Sep;255:127055. doi: 10.1016/j.chemosphere.2020.127055. Epub 2020 May 11.
Nanofiltration concentrated landfill leachate (NCLL) is produced during the integration process of biodegradation and nanofiltration, containing a large amount of recalcitrant dissolved organic matter (DOM). In this work, electrocatalytic oxidation technology was employed to degrade DOM in NCLL and spectroscopic technology was applied to explore the structural changes. The results showed that under the optimal experimental condition (pH = 2.0, NaCl concentration = 0.7%, Fe(SO) concentration = 0.8%, the retention time = 6 h), the removal rates of COD, TOC, and UV were 99.0%, 57.4%, 99.3% respectively. Ultraviolet-Visible (UV-Vis) spectral analysis showed that aromatic CC can be effectively degraded by electrocatalytic oxidation, resulting in decreases of aromaticity and molecular weight in NCLL. Two fluorescent components (terrestrial humic-like substances and fulvic-like substances) were identified in NCLL by parallel factor analysis, which can be effectively removed by electrocatalytic oxidation with removal rates of 99.9% and 90.5%, respectively. In addition, through two-dimensional correlation spectroscopic analysis, the sequence of structural changes of the DOM in NCLL was confirmed: unsaturated double bonds → fulvic-like components/aromatic structures → terrestrial humic-like components. These spectral characterization techniques can provide a deep understanding of the degradation pathways of DOM and provide new insights for the treatment of NCLL.
纳滤浓缩垃圾渗滤液（NCLL）是在生物降解和纳滤集成过程中产生的，其中含有大量难生物降解的溶解有机物（DOM）。本工作采用电催化氧化技术降解 NCLL 中的 DOM，并运用光谱技术探究其结构变化。结果表明，在最优实验条件（pH=2.0、NaCl 浓度=0.7%、Fe(SO)浓度=0.8%、保留时间=6 h）下，COD、TOC 和 UV 的去除率分别为 99.0%、57.4%和 99.3%。紫外-可见（UV-Vis）光谱分析表明，电催化氧化可有效降解芳香族 CC，导致 NCLL 中芳香度和分子量降低。通过平行因子分析，在 NCLL 中鉴定出两种荧光成分（类腐殖质物质和类富里酸物质），电催化氧化可有效去除这两种荧光成分，去除率分别为 99.9%和 90.5%。此外，通过二维相关光谱分析，确定了 NCLL 中 DOM 结构变化的顺序：不饱和双键→类富里酸成分/芳香结构→类腐殖质物质。这些光谱特征技术可以深入了解 DOM 的降解途径，并为 NCLL 的处理提供新的思路。
