Degradation of azo dye (direct red 89) using H₂O₂/periodate process-parameter optimization and mixture composition...

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies

Background:

• Dye contamination in wastewater poses environmental risks.
• Advanced Oxidation Processes (AOPs) are effective for degrading persistent organic pollutants (POPs).

Purpose of the Study:

• To investigate the degradation of Direct Red 89 (DR89) using a periodate (PI)-based AOP activated by hydrogen peroxide (H2O2).
• To evaluate the impact of operating parameters on the efficiency of the H2O2/PI process for DR89 degradation.

Main Methods:

• Utilized a H2O2/PI advanced oxidation process to degrade DR89.
• Investigated the effects of pH, H2O2 concentration, and PI concentration on degradation rates.
• Employed quenching experiments to identify dominant reactive species.

Main Results:

• Achieved 67% DR89 degradation within 1 minute using the H2O2/PI process.
• Acidic pH (pH 3) significantly enhanced degradation (94.31%) compared to alkaline pH (pH 11, 20.92%).
• Identified iodyl radicals (IO3•), hydroxyl radicals (•OH), singlet oxygen (1O2), and superoxide radicals (O2•−) as key reactive species.

Conclusions:

• The H2O2/PI process is a fast and efficient method for degrading DR89.
• Optimized operating conditions, particularly acidic pH, are crucial for maximizing degradation efficacy.
• This AOP shows promise for treating POPs in industrial wastewater.