2026-10-13T04:36:53Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34028743 2026-09-30T03:04:01Z category_1 category_4 category_14 category_21 category_272 category_873 category_39 category_502 category_734 category_61 category_133 portal_63 item_type_6 month_year_09_2026

Molecular Fingerprint-Dependent Retention and Fractionation of Combustion-Derived Dissolved Organic Matter on Kaolinite and Montmorillonite Weifeng Chen (14035) Yixin Xu (255926) Yan Wang (15435) Youtao Si (4789467) Huiying Zhang (200681) Hualong Hong (13915161) Abdallah Abdelfattahe (25139956) Hui Jia (638620) Biophysics Biochemistry Molecular Biology Biotechnology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology Astronomical and Space Sciences not elsewhere classified Biological Sciences not elsewhere classified Developmental Biology Plant Biology two distinct mechanisms small polar molecules pyrogenic carbon sequestration large aromatic molecules hydration steric hindrance decreasing binding energies increasing binding energies 8 ev ). mixed – cooh 3 ∼ 1 2 ∼ 1 synergistic ligand exchange cdom showed mineral 3 </ sub rich environmental matrices dependent fractionation shifted cdom (− nh ligand exchange – nh environmental fate dependent retention 7 ev cdom (− selective retention negligible adsorption molecular fingerprint maize straw interfacial behavior increasing concentration highest adsorption contaminant mobility cation bridging applied ft additional contributions The environmental fate of combustion-derived dissolved organic matter (CDOM) at clay mineral interfaces remains poorly understood. We applied FT-ICR-MS, XPS, and other techniques to investigate the interfacial behavior of CDOM from coal, charcoal, pinewood, and maize straw on kaolinite and montmorillonite. Two distinct mechanisms were identified: ligand exchange on kaolinite (increasing binding energies by 1.2 ∼ 1.7 eV) and Ca²⁺/Mg²⁺-mediated cation bridging on montmorillonite (decreasing binding energies by 0.3 ∼ 1.8 eV). Maize straw-CDOM and charcoal-CDOM exhibited the highest adsorption on both clays, while pinewood-CDOM showed mineral-selective retention (montmorillonite only) and coal-CDOM showed negligible adsorption. Coal-CDOM (−SO₃H-rich) with negligible adsorption was due to electrostatic repulsion and hydration steric hindrance. Pinewood-CDOM (phenolic) was retained only on montmorillonite via cation bridging, as its phenolic groups cannot undergo ligand exchange with kaolinite. Charcoal-CDOM (−NH₂-rich) was retained on both clays primarily through electrostatic attraction of –NH₃⁺, with additional contributions from Ca²⁺/Mg²⁺-mediated cation bridging and cation–π interactions on montmorillonite. Maize straw-CDOM (mixed –COOH, –NH₂, –SO₃H) was retained through synergistic ligand exchange, cation bridging, and electrostatic/H-bonding. Concentration-dependent fractionation shifted from H-bonding/electrostatic attraction (small polar molecules) to hydrophobic/cation–π interactions (large aromatic molecules) with increasing concentration. This framework provides mechanistic context for pyrogenic carbon sequestration and contaminant mobility in clay-rich environmental matrices. 2026-09-29T00:00:00Z Text Journal contribution 10.1021/acs.est.6c07762.s001 https://figshare.com/articles/journal_contribution/Molecular_Fingerprint-Dependent_Retention_and_Fractionation_of_Combustion-Derived_Dissolved_Organic_Matter_on_Kaolinite_and_Montmorillonite/34028743 CC BY-NC 4.0