标题: Phototransformation of Lignin-related Compounds in Chromophoric Dissolved Organic Matter Solutions

作者: Zhou, RY (Zhou, Ruiya); Liu, J (Liu, Juan); Zhou, C (Zhou, Chi); Zhang, X (Zhang, Xu)

来源出版物: WATER RESEARCH  卷: 245  文献号: 120586  DOI: 10.1016/j.watres.2023.120586  出版年: OCT 15 2023  

摘要: Lignin is a major terrestrial source of chromophoric dissolved organic matter (CDOM), and studying the phototransformation of lignin monomers and their related compounds can enhance our understanding of CDOM intramolecular interactions. Coniferyl aldehyde (Coni) and sinapaldehyde (Sina) form ground-state complexes with CDOM, with equilibrium constants of 7,800 (+/- 1,800) and 20,000 (+/- 2,000) M-1, respectively. In comparison, vanillin (Van) exhibits minimal affinity for CDOM complexation. The bimolecular reaction rate constants between singlet oxygen (O-1(2)) and these phenolic carbonyl compounds ranged from 0.46 (+/- 0.02) to 1.8 (+/- 0.1) x 10(7) M(-1)s(-1) which is approximately one order of magnitude lower than their reaction rate constants (0.51 (+/- 0.02)-1.25 (+/- 0.02) x 10(8) M(-1)s(-1)) with the triplet excited state of CDOM ((CDOM)-C-3*). In acidic CDOM solutions (pH 5.0), O-1(2), H2O2, and organic peroxyl radicals had negligible impact on the transformation. Comparing the initial transformation rate in the presence and in the absence of NaN3 or furfuryl alcohol led to an overestimation of the contribution of O-1(2) to the transformation of Van, Coni, or Sina. (CDOM)-C-3* scavengers could not fully inhibit the transformation of Coni or Sina. The remaining transformation is considered to arise from either the unquenched intra-CDOM phase (CDOM)-C-3* or a fraction of Coni.CDOM or Sina.CDOM complex, which underwent intramolecular photoinduced chemical reactions.

作者关键词: CDOM complex; Lignin-related compounds; Singlet excited state; Sinapaldehyde

地址: [Zhou, Ruiya; Liu, Juan; Zhang, Xu] Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Peoples R China.

[Zhou, Chi] Hubei Water Resources Res Inst, Wuhan 430070, Peoples R China.

通讯作者地址: Zhang, X (通讯作者)，Wuhan Univ, Sch Resources & Environm Sci, Wuhan 430079, Peoples R China.

Zhou, C (通讯作者)，Hubei Water Resources Res Inst, Wuhan 430070, Peoples R China.

电子邮件地址: zhouc0222@126.com; xuzhangwhu@gmail.com

影响因子：12.8