Carbofuran degradation by the application of MW-assisted H₂O₂ process

Abstract

Carbofuran removal performance of a microwave (MW)-assisted H₂O₂ system under different MW-power levels (300-900 W) was investigated. Batch experiments were conducted at 100 mg/L carbofuran concentration using a modified-MW reactor with 2450 MHz of fixed frequency. As a precursor, control experiments were carried out with H₂O₂ alone, MW alone and conventional heating (CH). A maximum carbofuran removal of 14 % was observed in both H₂O₂ alone and CH systems. On the other hand, only 2 % removal was observed in the MW alone system irrespective of the operation-mode, i.e. continuous or pulsed. The combination of MW and H₂O₂ produced 100 % carbofuran removal in all the MW-assisted experiments. The MW-assisted system operated under continuous-mode and at 750 W has showed rapid carbofuran degradation, i.e. 30 sec, with the highest first-order removal rate constant of 25.82/min. However, 97 % carbon oxygen demand (COD) removal was observed in the same system only after 30 min. On the other hand, 100 % carbofuran removal and 49 % COD removal were observed in the pulsed-mode MW-assisted H₂O₂ system after 10 and 30 min, respectively. Carbofuran mineralization in the system was evidenced by the formation of ammonium and nitrate, and carbofuran intermediates.

Keywords:

• Carbofuran
• microwave
• advanced oxidation
• mineralization
• pesticides