Vacuum-ultraviolet based advanced oxidation and reduction processes for water treatment

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Photochemistry

Background:

• Vacuum-ultraviolet (VUV) photolysis is an emerging technology for water treatment.
• It shows high efficacy in degrading refractory organic contaminants and eliminating oxyanions.
• Understanding reactive species is crucial for optimizing VUV-based processes.

Purpose of the Study:

• To provide a concise overview of VUV photolysis in water treatment.
• To summarize reactive species in VUV-AOPs and VUV-ARPs.
• To explore factors influencing VUV photolysis efficiency.

Main Methods:

• Review of VUV irradiation principles.
• Identification and summary of primary reactive species (˙OH, H2O2, O3, e-aq, ˙H).
• Analysis of influencing factors: VUV dose, catalysts, dissolved gases, water matrix, and pH.

Main Results:

• VUV-AOPs primarily involve hydroxyl radicals (˙OH), hydrogen peroxide (H2O2), and ozone (O3).
• VUV-ARPs are driven by hydrated electrons (e-aq) and hydrogen atoms (˙H).
• VUV irradiation dose and catalysts enhance degradation; DOM and inorganic anions inhibit it. pH significantly impacts both VUV-AOPs and VUV-ARPs performance.

Conclusions:

• VUV photolysis offers a promising approach for advanced water treatment.
• VUV-AOPs and VUV-ARPs exhibit distinct reactive species and optimal operating conditions.
• Further research into influencing factors can optimize VUV processes for contaminant removal.