chlorobenzene degradation by electro-heterogeneous catalysis in aqueous solution
TRANSCRIPT
Chlorobenzene degradation by electro-heterogeneous catalysis in
aqueous solution: intermediates and reaction mechanism
WANG Jiade, MEI Yu, LIU Chenliang, CHEN Jianmeng
IntroductionChlorobenzene (CB)
SolventsHeat transfer agentsInsect repellentsDeodorantDegreasersIntermediates in dye and
pesticide synthesis
Introduction
CB = Pollutant
IntroductionMethods
Catalytic hydrodehalogenationThermal oxidationElectrochemical (EC) dechlorinationEC-assisted heterogeneous catalysis
ObjectivesTo identify the parameters that may affect the
electro-heterogeneous catalysis processTo further probe the catalytic dechlorination
kinetics
ExperimentApparatus
catalyzed oxidation reactor was a glass trough vessel (15 L)
β-PbO2 electrode (15 cm x 5 cm)Support electrolyte -> Na2SO4 (0–0.15 g/L)Temperature -> 25°C ± 1°CCatalyst
Mn-Sn-Sb/γ-Al2O3
AnalysisTwo similar samples were collected at 0, 30, 60, 90
and 120 min
Results and DiscussionCharacterization of the Catalyst
Results and DiscussionEffect of the Current Density
Results and Discussion
Results and DiscussionEffect of Initial pH
Results and DiscussionEffect of electrolyte Concentration
Results and DiscussionComparison of Electro-heterogeneous Catalysis
and Electrochemical Process for Degradation of Chlorobenzene
Results and DiscussionIntermediates and Possible Reaction
Mechanism
Results and Discussion
ConclusionThe degradation efficiency of CB was almost 100% with an
initial CB concentration of 50 mg/L, current density 15 mA/cm2, initial pH 10.0, electrolyte concentration 0.10 mol/L, and temperature 25°C at 90 min.
Under the same conditions, the degradation efficiency of CB was only 51% by the EC process, which showed that electro-heterogeneous catalysis was more efficient than EC alone.
The experimental results indicated that Mn-Sn-Sb/γ-Al2O3 catalyst could accelerate the degradation of CB.
Intermediate products, including phenol, benzoquinone, biphenyl, vinylbenzoic acid, and butenedioic acid were detected by GC/MS.
CritiqueThe title directly states the main purpose of the
study.The interpretation of the results can be easily
understood through figures.The objectives of the study are satisfied.
RecommendationsOther pollutants can be usedOther temperatures can be considered.Detailed mechanism of electro-heterogeneous
catalysis