Implementation of laser flash photolysis for radical-induced reactions and environmental implications

Chu, Chu; Yan, Yiqi; Ma, Junye; Jin, Shengye; Spinney, Richard; Dionysiou, Dionysios D.; Zhang, Haijun; Xiao, Ruiyang

doi:10.1016/j.watres.2023.120526

Cited by 12 publications

(3 citation statements)

References 122 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Advancements of time-resolved laser flash photolysis (LFP) have opened up new horizons for transient species kinetic investigations, including improved features such as better temporal resolution (∼10 –9 s), rapid response speeds, and lower detection limits (absorbance less than 5 × 10 –5 ). − For environmentally relevant studies, LFP was widely exploited to investigate the transformation of micropollutants triggered by radicals and other reactive species ( e.g. , excited triplet states of compounds). , In particular, Canonica and von Gunten made many pioneering and significant contributions to characterize the photochemical transformation of micropollutants in sunlit natural waters. − The gradual recognition of its implementation inspires potential utilization for real-time visualization of transient species and direct determination of their italicΦ values in radical-based treatment processes.…”

Section: Introductionmentioning

confidence: 99%

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Yan,

Meng,

Miu

et al. 2024

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The absolute radical quantum yield ( italicΦ ) is a critical parameter to evaluate the efficiency of radical-based processes in engineered water treatment. However, measuring italicΦ is fraught with challenges, as current quantification methods lack selectivity, specificity, and anti-interference capabilities, resulting in significant error propagation. Herein, we report a direct and reliable time-resolved technique to determine italicΦ at pH 7.0 for commonly used radical precursors in advanced oxidation processes. For H2O2 and peroxydisulfate (PDS), the values of italicΦ •OH and normalΦ normalSO 4 • − at 266 nm were measured to be 1.10 ± 0.01 and 1.46 ± 0.05, respectively. For peroxymonosulfate (PMS), we developed a new approach to determine normalΦ • normalOH normalPMS with terephthalic acid as a trap-and-trigger probe in the nonsteady state system. For the first time, the normalΦ • normalOH normalPMS value was measured to be 0.56 by the direct method, which is stoichiometrically equal to Φ SO 4 • − PMS (0.57 ± 0.02). Additionally, radical formation mechanisms were elucidated by density functional theory (DFT) calculations. The theoretical results showed that the highest occupied molecular orbitals of the radical precursors are O–O antibonding orbitals, facilitating the destabilization of the peroxy bond for radical formation. Electronic structures of these precursors were compared, aiming to rationalize the tendency of the italicΦ values we observed. Overall, this time-resolved technique with specific probes can be used as a reliable tool to determine italicΦ , serving as a scientific basis for the accurate performance evaluation of diverse radical-based treatment processes.

show abstract

Section: Introductionmentioning

confidence: 99%

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Yan,

Meng,

Miu

et al. 2024

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…4,5 The benchmark AOT is the combination of ultraviolet (UV) light and hydrogen peroxide (H 2 O 2 ), an inexpensive and readily available chemical. 6,7 The photochemical formation of OH • from H 2 O 2 is triggered by UV irradiation. 8 However, the UV molar extinction coefficient (ε) of H 2 O 2 is remarkably low (19.6 M −1 cm −1 at 254 nm), 9 indicating that UV irradiation is inefficient in initiating the OH • formation reaction.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Hydroxyl radical (OH • )-based advanced oxidation technologies (AOTs) are able to remove organic pollutants and control pathogenic microorganisms, and they are considered an effective way to improve the quality of reclaimed water. , The benchmark AOT is the combination of ultraviolet (UV) light and hydrogen peroxide (H 2 O 2 ), an inexpensive and readily available chemical. , The photochemical formation of OH • from H 2 O 2 is triggered by UV irradiation . However, the UV molar extinction coefficient ( ε ) of H 2 O 2 is remarkably low (19.6 M –1 cm –1 at 254 nm), indicating that UV irradiation is inefficient in initiating the OH • formation reaction.…”

Section: Introductionmentioning

confidence: 99%

Bimolecular versus Trimolecular Reaction Pathways for H₂O₂ with Hypochlorous Species and Implications for Wastewater Reclamation

Luo,

Zhou,

Jiang

et al. 2023

Environ. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The benchmark advanced oxidation technology (AOT) that uses UV/H2O2 integrated with hypochlorous species exhibits great potential in removing micropollutants and enhancing wastewater treatability for reclamation purposes. Although efforts have been made to study the reactions of H2O2 with hypochlorous species, there exist great discrepancies in the order of reaction kinetics, the rate constants, and the molecule-level mechanisms. This results in an excessive use of hypochlorous reagents and system underperformance during treatment processes. Herein, the titled reaction was investigated systematically through complementary experimental and theoretical approaches. Stopped-flow spectroscopic measurements revealed a combination of bi- and trimolecular reaction kinetics. The bimolecular pathway dominates at low H2O2 concentrations, while the trimolecular pathway dominates at high H2O2 concentrations. Both reactions were simulated using direct dynamics trajectories, and the pathways identified in the trajectories were further validated by high-level quantum chemistry calculations. The theoretical results not only supported the spectroscopic data but also elucidated the molecule-level mechanisms and helped to address the origin of the discrepancies. In addition, the impact of the environmental matrix was evaluated by using two waters with discrete characteristics, namely municipal wastewater and ammonium-rich wastewater. Municipal wastewater had a negligible matrix effect on the reaction kinetics of H2O2 and the hypochlorous species, making it a highly suitable candidate for this integration technique. The obtained in-depth reaction mechanistic insights will enable the development of a viable and economical technology for safe water reuse.

show abstract

Highly efficient activation of ferrate (VI) via corncob biochar assisted by electrochemistry for the removal of sulfamethoxazole from water

Deng,

Zhu,

Zeng

et al. 2024

Chemical Engineering Journal

View full text Add to dashboard Cite

Implementation of laser flash photolysis for radical-induced reactions and environmental implications

Cited by 12 publications

References 122 publications

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Bimolecular versus Trimolecular Reaction Pathways for H₂O₂ with Hypochlorous Species and Implications for Wastewater Reclamation

Highly efficient activation of ferrate (VI) via corncob biochar assisted by electrochemistry for the removal of sulfamethoxazole from water

Contact Info

Product

Resources

About

Implementation of laser flash photolysis for radical-induced reactions and environmental implications

Cited by 12 publications

References 122 publications

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Direct Determination of Absolute Radical Quantum Yields in Hydroxyl and Sulfate Radical-Based Treatment Processes

Bimolecular versus Trimolecular Reaction Pathways for H2O2 with Hypochlorous Species and Implications for Wastewater Reclamation

Highly efficient activation of ferrate (VI) via corncob biochar assisted by electrochemistry for the removal of sulfamethoxazole from water

Contact Info

Product

Resources

About

Bimolecular versus Trimolecular Reaction Pathways for H₂O₂ with Hypochlorous Species and Implications for Wastewater Reclamation