Electrochemical oxidation of chloramphenicol with lead dioxide–surfactant composites

Abstract

The PbO2–2 wt.% sodium dodecyl sulfate composite formed from methanesulfonate electrolyte consists of 93.1% of α‐phase PbO2 in contrast to the similar one synthesized from nitrate electrolyte, which contains 73.3% of β phase. The electrocatalytic activity of the obtained composites in the oxygen evolution reaction and oxidation of chloramphenicol was investigated. It was found that the Tafel slope significantly exceeds the theoretical value, which indicates a decrease in the degree of filling of the electrode surface with oxygen‐containing particles. In the presence of organic compound and chloride ions in the solution, irreversible adsorption of the intermediate is observed, which leads to additional blocking of active centers on the oxide surface, which are involved in the oxidation of organic substance. It was established that the maximum rate of chloramphenicol conversion is 83.5% and 85% at 50 and 80 mA cm−2, respectively, under kinetic control. The heterogeneous oxidation rate constant of chloramphenicol is 0.0035 min−1. Oxidation of chloramphenicol occurs through the formation of 4‐(‐2‐amino‐1,3‐dihydroxy‐propanyl)‐nitrobenzene with cleavage of dichloroacetic acid. Next, the amino group is oxidized to the nitro group to form 4‐(2‐nitro‐1,3‐dihydroxy‐propanyl)‐nitrobenzene. Subsequent electrolysis produces nitrobenzoic acid, which is oxidized to benzoic acid, later hydroquinone, then benzoquinone and a set of aliphatic compounds. Practitioner Points The PbO2–2 wt.% SDS composite consists of 93.1% of α phase of PbO2 in contrast to those synthesized from nitrate electrolyte. The Tafel slope indicates a decrease of surface filling with oxygen‐containing particles. Irreversible adsorption of the intermediate is observed in the presence of chloride ions.

Electrodeposition and Catalytic Performance of Hydrophobic PbO2 Electrode Modified by Surfactant OP-10

“…Electrodeposition process of PbO A large number of studies have shown that the addition of surfactants can increase the deposition of PbO 2 , however, the electrochemical behavior and deposition mechanism in the deposition process need to be further discussed. [43][44][45][46][47] On this basis, cyclic voltammetry (CV) and chronoamperometry (CA) tests were carried out in Pb(NO 3 ) 2 system with glassy carbon electrode to study the electrodeposition process of PbO 2 , then OP-10 was added to the solution to further explore the effect of OP-10 on the electrodeposition process of PbO 2 .…”