Preprints
https://doi.org/10.5194/egusphere-2023-2632
https://doi.org/10.5194/egusphere-2023-2632
05 Jan 2024
 | 05 Jan 2024
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Measurement Report: Effects of transition metal ions on the optical properties of humic-like substances revealing structural preference 

Juanjuan Qin, Leiming Zhang, Yuanyuan Qin, Shaoxuan Shi, Jingnan Li, Zhao Shu, Yuwei Gao, Ting Qi, Jihua Tan, and Xinming Wang

Abstract. Humic-like substances (HULIS) are complex macromolecules in water-soluble organic compounds containing multiple functional groups, and transition metal ions (TMs) are ubiquitous in atmospheric particles. In this study, potential physical and chemical interactions between HULIS and four TM species including Cu2+, Mn2+, Ni2+, and Zn2+ were analyzed by optical method under acidic, weakly acidic and neutral conditions. The results showed that Cu2+, Mn2+, and Zn2+ only slightly enhanced mass absorption efficiency (MAE365) of HULIS in winter, and had indiscernible effects on absorption Ångström exponent (AAE) of HULIS in both seasons under all acidity conditions. All four TMs had fluorescence quenching effects on winter HULIS, and only Cu2+ had similar effects on summer HULIS, with the highest quenching coefficients found under weakly acidic condition in both seasons. The 1H-nuclear magnetic resonance (1H-NMR) and Fourier-transform infrared (FT-IR) spectra revealed that Cu2+ mainly bound with aromatic species and tightened the molecule structures of HULIS. The parallel factor analysis (PARAFAC) results extracted four components of HULIS, including low-oxidized humic-like substances (C1), N-containing compounds (C2), highly-oxidized humic-like substances (C3), and the mixing residentials (C4), from the fluorescence spectra in both winter and summer. The divergent variations of HULIS spectral components with Cu2+ additions under three acidity conditions indicated that electron-donating groups of HULIS mainly corresponded to C1 and C3, with Cu2+ binding with HULIS by replacing proton, while electron-withdrawing groups of HULIS could correspond to C2, with its connection with Cu2+ through electrostatic adsorption or colliding induced energy transfer.

Juanjuan Qin, Leiming Zhang, Yuanyuan Qin, Shaoxuan Shi, Jingnan Li, Zhao Shu, Yuwei Gao, Ting Qi, Jihua Tan, and Xinming Wang

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2632', Anonymous Referee #1, 15 Feb 2024 reply
    • AC1: 'Reply on RC1', Jihua Tan, 21 Feb 2024 reply
Juanjuan Qin, Leiming Zhang, Yuanyuan Qin, Shaoxuan Shi, Jingnan Li, Zhao Shu, Yuwei Gao, Ting Qi, Jihua Tan, and Xinming Wang

Data sets

Data for manuscript Measurement Report: Effects of transition metal ions on the optical properties of humic-like substances revealing structural preference Juanjuan Qin https://doi.org/10.5281/zenodo.10460562

Juanjuan Qin, Leiming Zhang, Yuanyuan Qin, Shaoxuan Shi, Jingnan Li, Zhao Shu, Yuwei Gao, Ting Qi, Jihua Tan, and Xinming Wang

Viewed

Total article views: 163 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
127 28 8 163 13 3 4
  • HTML: 127
  • PDF: 28
  • XML: 8
  • Total: 163
  • Supplement: 13
  • BibTeX: 3
  • EndNote: 4
Views and downloads (calculated since 05 Jan 2024)
Cumulative views and downloads (calculated since 05 Jan 2024)

Viewed (geographical distribution)

Total article views: 166 (including HTML, PDF, and XML) Thereof 166 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 29 Feb 2024
Download
Short summary
The present research unveiled that acidity dominants, while transition metal ions harmonize, the light absorption properties of HULIS. Cu2+ has obvious quenching effects on HULIS by complexation, hydrogen substitution, or electrostatic adsorption with aromatic structures of HULIS. Such effects are less pronounced from Mn2+, Ni2+, and Zn2+; Cu2+. Oxidized HULIS might contain electron-donating groups, whereas N-containing compounds might contain electron-withdrawing groups.