Abstract: Electrochemical oxidation of polyethylene glycol (PEG) in an
acidic (pH 0.18 to 0.42) and high ionic strength electroplating solution was
investigated. The electroplating solution is a major source of wastewater in
the printing wiring board industry. A paraffin composite copper
hexacyanoferrate modified (PCCHM) electrode was used as the anode and a bare
graphite electrode was used as the cathode. The changes in PEG and total
organic carbon (TOC) concentrations during the course of the reaction were
monitored. The efficiency of the PCCHM anode was compared with bare graphite
anode and it was found that the former showed significant electrocatalytic
property for PEG and TOC removal. Chlorides present in the solution were found
to contribute significantly in the overall organic removal process. Short chain
organic compounds like acetic acid, oxalic acid, formic acid and ethylene
glycol formed during electrolysis were identified by HPLC method. Anode surface
area and applied current density were found to influence the electro-oxidation
process, in which the former was found to be dominating. Investigations of the
kinetics for the present electrochemical reaction suggested that the two stage
first-order kinetic model provides a much better representation of the overall
mechanism of the process if compared to the generalized kinetic model.
Keywords: polyethylene glycol(PEG), paraffin composite copper hexacyanoferrate modified (PCCHM)
electrode, electroplating solution, two stage first-order kinetic model, generalized kinetic model