Degradation efficiency of imidacloprid by chalcopyrite-catalyzed electro-Fenton process and catalyst leaching behavior.

Natural chalcopyrite was used as catalyst for electro-Fenton process to treat the simulated imidacloprid wastewater and the degradation efficiency of imidacloprid as well as leaching behavior of chalcopyrite with regard to 18 elements were investigated. The results showed that the removal rate of COD and UV absorbance at 270 nm( UV270 ) after 4 h of reaction reached 64. 37% and 84. 69% respectively when the cathode was graphite plate the anode was titanium plate coated with RuO2 and Ir02the chalcopyrite dosage was 60 g/Lathe initial pH of electrolyte solution was 3the current density was 40 mA/cm2 and the plate spacing was 2. 5 cm. The results of atomic absorption and ICP-MS showed that the content of Cu ions in electrolyte solution after reaction exceeded the third-level standard value of Integrated Wastewater Discharge Standard, (GB 8978-1996). However the content of Cu ions could decrease to below the third-level standard value through chemical precipitation by adding alkali (pH to 10) and filtration treatment. Chalcopyrite may leach high levels of toxic heavy metals such as Much Cd and Pb under acidic condition which should be paid attention during the application of natural chalcopyrite as electro-Fenton catalyst for wastewater treatment. [ABSTRACT FROM AUTHOR]