Microheterogeneous Concentrations of Singlet Oxygen in Natural Organic Matter Isolate Solutions

Abstract

The binding affinity of a hydrophobic singlet oxygen probe toward natural organic matter isolates was investigated. A linear phase-partitioning model was used to calculate partition coefficients and intramicellar concentrations of singlet oxygen several orders of magnitude larger than those reported by traditional singlet oxygen probes. From the obtained data, a kinetic model was developed to describe the microscopic environment experienced by hydrophobic compounds in natural water systems. Micellar radii and molecular weights were derived from the experimental data and evaluated. The data obtained provides additional support of a microheterogeneous environment within bulk natural solutions. The enhanced concentrations of photogenerated reactive intermediates within these microenvironments may improve understanding of hydrophobic pollutant degradation in the environment.

Transformation of 2,4,6-trimethylphenol and furfuryl alcohol, photosensitised by Aldrich humic acids subject to different filtration procedures

“…The properties of dissolved species can be reasonably derived by considering the 0.10 µm fraction, which had P a = 1.04⋅10 (Latch and McNeill, 2006;Grandbois et al, 2008). Hydrophobic sites should also be common in suspended particles (Appiani and McNeill, 2011).…”

Sunlight-mediated inactivation of health-relevant microorganisms in water: a review of mechanisms and modeling approaches

“…For example, studies have shown that the interaction with DOM enhanced the photodegradation of mirex, 65,66 organic probe compounds of singlet oxygen, 61,67 histidine, 68 and also mercury(0). 69 Compared to free molecules, it has proven difficult to experimentally demonstrate enhanced photoreactions for organic matter-bound microorganisms.…”

Phototransformation Processes of Emerging Contaminants in Surface Water

“…Therefore, 1 O 2 could play an important and still poorly recognised role in the photochemical transformation of hydrophobic pollutants, which would be preferentially located in CDOM hydrophobic cores rather than in solution [56,57]. Interestingly, no evidence has been found of a higher photochemical reactivity of CDOM particles compared to dissolved CDOM species, as far as 1 O 2 photoproduction is concerned [58,59].…”