Progress on mechanism and efficacy of heterogeneous photocatalysis coupled oxidant activation as an advanced oxidation process for water decontamination

Dissolved Organic Matter-Mediated Photosensitized Activation of Monochloramine for Micropollutant Abatement in Wastewater Effluent

“…Notably, the excited state energies of 3 duroquinone* ( 3 DQ*, 235 kJ/mol) and 3 2-acetonaphthone * ( 3 2-AN*, 249 kJ/mol) are lower than the dissociation energy of the N–Cl bond of NH 2 Cl molecule (256 kJ/mol). , Accordingly, the energy transfer between 3 DQ* (or 3 2-AN*) and NH 2 Cl, which leads to the homolytic cleavage of the N–Cl bond of the NH 2 Cl molecule (e.g., NH 2 Cl + 3 sensitizer* → Cl · + NH 2 · + 1 sensitizer), is unfavorable. , Instead, the reactions of 3 DQ* and 3 2-AN* with NH 2 Cl (Supplementary Figure 8) provided evidence for the electron transfer between triplet states ( 3 DOM*) and NH 2 Cl. Moreover, 3 DOM* is likely to serve as a reductant in the reaction with NH 2 Cl because (1) k 3 sensitizer*,NH 2 Cl showed no relationship with the reduction potentials of triplet state sensitizers (Figure a) and (2) the reaction is thermodynamically favorable when considering the oxidation potential of triplet states (e.g., E ° *( 3 benzophenoone*/ benzophenoone · – ) = −0.85 V (SHE)) and the reduced potential of NH 2 Cl ( E ° *(Cl – /NH 2 Cl) = 0.75–1.4 V (SHE)). , Accordingly, the reaction between 3 DOM* and NH 2 Cl is proposed as eq . NH 2 Cl + DOM 3 * → NH · 2 + Cl − + DOM · + …”

“…• + 1 sensitizer), is unfavorable. 48,49 Instead, the reactions of 3 DQ* and 3 2-AN* with NH 2 Cl (Supplementary Figure 8) provided evidence for the electron transfer between triplet states ( 3 DOM*) and NH 2 Cl. Moreover, 3 DOM* is likely to serve as a reductant in the reaction with NH 2 Cl because (1) k 3 sensitizer*,NHd 2 Cl showed no relationship with the reduction potentials of triplet state sensitizers (Figure 4a) and ( 2) the reaction is thermodynamically favorable when considering the oxidation potential of triplet states (e.g., E°*-…”

Integrated Taylor–Couette Reactor Model for Heterogeneous Photocatalytic Degradation of AO7

“…Heterogeneous photocatalysis technology (HPCT) utilizes semiconductor photocatalysts to generate photoelectron–hole pairs under light excitation and provides oxidation and reduction conditions for the catalyzed substances. − Due to its advantages, such as green environmental protection, low cost, low energy consumption, and mild reaction conditions, HPCT has been widely used in the fields of wastewater treatment, CO 2 reduction, H 2 production, solid waste treatment, and microbial disinfection . As a promising technology, HPCT has been extensively studied by many researchers, from mechanisms to applications.…”

Electrocatalytic Generation of Singlet Oxygen via ROS-Mediated Redox Chain Reaction for Efficient Disinfection

“…Harmful microorganisms in environmental water have been posing risks to ecosystems and human health. − Advanced oxidation processes (AOPs) can effectively inactivate harmful microorganisms by producing reactive oxygen species (ROS), such as hydroxyl radicals ( • OH), singlet oxygen ( 1 O 2 ), and superoxide radicals ( • O 2 – ). − Compared to short-lived and nonselective • OH, the relatively stable 1 O 2 has unoccupied π* orbitals and a mild oxidizing ability, making it highly selective toward electron-rich substances such as drugs, unsaturated organics, and microbial pathogens. , Consequently, 1 O 2 -targeted reactions showed a high potential for the inactivation of harmful microorganisms in wastewater treatment such as in industrial or medical fields. − …”