Study on US/O3 mechanism in p-chlorophenol decomposition.

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Advanced Oxidation Processes

Background:

• p-chlorophenol is a common pollutant in industrial wastewater.
• Effective removal of p-chlorophenol is crucial for environmental protection.
• Conventional treatment methods may be insufficient for complete degradation.

Purpose of the Study:

• To investigate the efficacy of sonolysis, ozonolysis, and a combined US/O3 system for p-chlorophenol decomposition.
• To compare the degradation rates and chemical oxygen demand (CODcr) removal efficiencies of the different treatment methods.
• To elucidate the decomposition mechanism and identify key intermediates.

Main Methods:

• Aqueous solutions of p-chlorophenol were treated using sonolysis, ozonolysis, and a combined ultrasonic/ozone (US/O3) system.
• Reaction kinetics were monitored by measuring p-chlorophenol concentration and CODcr.
• Intermediate products were identified using analytical techniques.

Main Results:

• The US/O3 system achieved a 78.78% p-chlorophenol decomposition rate in 16 minutes and 97.02% CODcr removal in 120 minutes.
• Individual ozonolysis and sonolysis showed significantly lower decomposition (56.20% and 2.79%) and CODcr removal (62.17% and 3.67%) rates, respectively.
• The US/O3 system demonstrated enhancement factors of 63% for p-chlorophenol and 237% for CODcr, following pseudo-first-order kinetics.

Conclusions:

• The combined US/O3 system is highly effective for degrading p-chlorophenol and reducing CODcr in aqueous solutions.
• The synergistic effect of ultrasound and ozone significantly enhances the degradation process.
• Understanding the reaction intermediates and mechanism aids in optimizing advanced oxidation processes for wastewater treatment.