The effect of the sp3/sp2 carbon ratio on the electrochemical oxidation of 2, 4-D with p-Si BDD anodes. (1st January 2016) - Souza, F.L.
Highlights: The efficiency of the electrolysis of 2, 4-D depends on the sp 3 /sp 2 ratio of the diamond anode. A higher sp 3 /sp 2 ratio lowers the energy required to mineralize the pesticide. The sp 3 /sp 2 ratio influences the concentration but not the type of intermediates produced. Chlorate and perchlorate production is favored at higher sp 3 /sp 2 ratios. Abstract: Boron-doped diamond films on silicon substrates (p-Si BDD) with different sp 3 /sp 2 carbon ratios are systematically varied in electrodes used to oxidize 2, 4-dichlorophenoxyacetic acid (2, 4-D) in synthetic wastewater containing chlorides. 2, 4-D is completely mineralized during the electrolysis. A higher sp 3 /sp 2 ratio in the anode results in a more rapid and efficient oxidative removal of 2, 4-D. Chlorinated compounds such as 4-chlororesorcinol, 2-chlorophenol, and 2, 4-dichlorophenol form as intermediates during the oxidative treatment. Although these compounds are completely depleted during the electrolysis, their maximum observed concentrations decrease as the sp 3 content increases in the anode. On the contrary, higher maximum concentrations are observed for non-chlorinated intermediates, especially hydroquinone, and there is a greater formation of chlorates and perchlorates in chloride-containing solutions as the sp 3 content increases in the anode.