Electrochemical removal of pentachlorophenol in a lab-scale platinum electrolyzer

摘要

This study is focused on the removal of pentachlorophenol from its aqueous phasenby electrochemically induced degradation with Pt electrodes. The objective of this study wasnto contrast the electrochemical removal of pentachlorophenol at the oxidative and thenreductive potentials, and further to understand how to apply the electrochemical treatment onnPCP degradation. Lab experiments were conducted in a Pt electrolyzer, and the voltage sourcenwas supplied and precisely controlled by an electrochemical analyzer. In these experiments,nthe variables including electrolyte species, pH, voltage supply, and reaction time werenexamined to compare the efficiency of pentachlorophenol removal. Experimental results showednthat pentachlorophenol was completely degraded after being electrolyzed for 1 h at 2 1.5 V inna 0.5M KCl solution, while the removal of pentachlorophenol is negligible under the similarncondition when 0.5M NaNO3 or Na2CO3 was used as the electrolyte. The electrolytenconcentration below 0.5M is unfavourable for the electrochemical removal of pentachlorophenol.nThe removal efficiency of pentachlorophenol is slightly affected by pH, and the strong basicnenvironment might impede the degradation of pentachlorophenol. Comparing with thosenunder positive potentials, the experiments conducted under negative potentials havenshown a better removal of pentachlorophenol with a higher current efficiency. It impliesnthat pentachlorophenol degradation followed the reductive pathway. Based on thenanalysis of GC/MS, the intermediates of pentachlorophenol degradation were identifiednas 1,2-dichlorocyclohexane and 2-chlorocyclohexanol.