Changes in water quality along the process of coal chemical reverse osmosis wastewater advanced treatment: Spectral analysis and molecular level exploration

[Display omitted] •The advanced technology achieved a removal rate of 96.75% for COD in RO wastewater.•The changes in DOM were analyzed using spectroscopic methods and FTICRMS.•Humic acid like substance are the main fluorescent substances in RO wastewater.•DOM were mainly distributed in the lignin-l...

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Published inSeparation and purification technology Vol. 360; p. 131267
Main Authors Yuan, Run, Qin, Yihe, Wang, Hao, He, Xuwen
Format Journal Article
LanguageEnglish
Published Elsevier B.V 08.07.2025
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ISSN1383-5866
DOI10.1016/j.seppur.2024.131267

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Summary:[Display omitted] •The advanced technology achieved a removal rate of 96.75% for COD in RO wastewater.•The changes in DOM were analyzed using spectroscopic methods and FTICRMS.•Humic acid like substance are the main fluorescent substances in RO wastewater.•DOM were mainly distributed in the lignin-like and condensed aromatic regions.•Hydrophobic DOM in coal chemical RO wastewater has a higher proportion. Investigating changes in the organic pollutant composition of coal chemical wastewater during the advanced treatment process is crucial for enhancing the efficiency of wastewater treatment systems. In this study, the molecular composition and changes in dissolved organic matter (DOM) were analyzed in a typical coal gasification reverse osmosis concentrate during various advanced treatment processes, including flocculation, ultrafiltration, adsorption, and catalytic ozonation, were investigated using conventional water quality analysis, ultraviolet spectroscopy, fluorescence spectroscopy, molecular weight fractionation analysis, organic component fractionation methods, and Fourier-transform ion cyclotron resonance mass spectrometry. After the advanced treatment process, the concentrations of organic pollutants in the effluent decreased significantly, and the final treated effluent COD was reduced to 90 mg/L. Analysis of the molecular weight fractions showed that after treatment, the proportion of low-molecular-weight organic pollutants (<3k Da) in the coal chemical reverse osmosis concentrate exceeded 50 %. The mass-to-charge ratio of organics in wastewater ranged between 100 and 800, most DOM molecules were unsaturated reduced-state recalcitrant organic molecules, and the DOM molecules in wastewater were mainly distributed among lignin-like, condensed aromatic, and protein-like organics. Compared to the other advanced treatment processes, catalytic ozonation efficiently removed refractory lignin-like organics from wastewater. We revealed the characteristics of organic pollutants in coal chemical reverse osmosis concentrates during the advanced treatment process using various characterization methods, which can assist in further exploring the degradation mechanisms of organics in actual wastewater to enhance the efficiency of wastewater treatment units.
ISSN:1383-5866
DOI:10.1016/j.seppur.2024.131267