Toxicity Assessment In Aqueoues Solution During Electro-Heterogeneous Catalysis Degradion Of Chlorobenzene

Chlorobenzene (CB) is one of a persistent toxic pollutants in the water environment .This study was using electro-heterogeneous catalysis removal of CB. The optimal technological was investigated under the best degradation efficiency and TOC removal. Also, the toxicity of solution was assessed by the 96h-EC₅₀ of Chlorella vulgaris in order to get the optimal technological under the toxicity assessment.This study was performed to investigate the variables that influence the removal efficiency of chlorobenzene in aqueous solution by electro-heterogeneous catalysis. The effect of current density, pH conditions and electrolyte concentration on CB removal efficiency were determined. The maximum degradation was observed with an initial chlorobenzene concentration of 50 mg/L, current density 15 mA/cm², pH 10, and electrolyte concentration 0.1 mol/L at 90 min. The removal efficiency of TOC was slower than that of CB. The maximum TOC removal efficiency was detected under the same conditions but at 120 min.From the Purge-and-Trap chromatography-mass spectrometry (P&T/GC/MS) and ion chromatograph (IC) results, we presume that in the reaction process, the initial·OH attack can occur at the C-Cl bond of CB, yielding phenol and biphenyl with the release of Cl^-. Further oxidation of phenol and biphenyl produced p -Vinylbenzoic acid and hydroquinol. Finally, the compounds were oxidized to butenedioic acid and other small molecule acid. The 0, 30, 60, 90 and 120 min solution samples got from the technology condition of an initial chlorobenzene concentration of 50 mg/L, current density 15 mA/cm², initial pH 10, electrolyte concentration 0.15 mol/L have the minimum effect to the growth of Chlorella vulgaris. In this process, with the concentration of 0.5, 1.0, and 2.0 mL/100mL of the 90 min samples, the Chlorella vulgaris inhibition rates were 34.1, 41.0, 45.2 and 48.3%. With the concentration of 0.5, 1.0, 1.5 and 2.0 mL/100mL of the 120 min samples, the Chlorella vulgaris inhibition rates were 29.2, 35.3, 38.2 and 40.0%. All of the inhibition rates were on a downward trend and under 50%. To sum up, the electro-heterogeneous catalysis is a friendly technology to environment.