Electrochemical polymerisation of phenol in aqueous solution on a Ta/PbO2 anode

Abstract

This paper deals with the treatment of aqueous phenol solutions using an electrochemical technique. Phenol can be partly eliminated from aqueous solution by electrochemically initiated polymerisation. Galvanostatic electrolyses of phenol solutions at concentration up to 0.1 mol dm -3 were carried out on a Ta/PbO 2 anode. The polymers formed are insoluble in acidic medium but soluble in alkaline. These polymers were filtered and then dissolved in aqueous solution of sodium hydroxide (1 mol dm -3 ). The polymers formed were quantified by total organic carbon (TOC) measurement. It was found that the conversion of phenol into polymers increases as a function of initial concentration, anodic current density, temperature, and solution pH. The percentage of phenol polymerised can reach 15%.

Electropolymerization of phenol on a vitreous carbon electrode in acidic aqueous solution at different temperatures

“…Cyclic voltammetry and chronoamperometry were performed at different temperatures (25,40,60,75, and 85°C) in aqueous solution containing 1 mol L -1 of sulfuric acid and 1 or 4 mmol L -1 of phenol. Chronoamperometric measurements were carried out at constant potentials chosen either in the region of water stability or oxygen evolution.…”

“…Results of bulk electrolysis conducted on Ta/bPbO 2 at high anodic current density and high temperature have shown that 39% of the starting phenol was removed as polymer under the best operating conditions [39,40]. It was also shown that the fraction of starting phenol converted into polymers increased substantially with temperature and that no electrode passivation (in that no noteworthy tensioncell increase happened) was observed over electrolysis [40].…”

“…In our previous study [39,40], we have studied the electrochemical removal of phenol from aqueous solution based on anodic polymerization as a possible route that could improve the electrochemical wastewater treatment process. Results of bulk electrolysis conducted on Ta/bPbO 2 at high anodic current density and high temperature have shown that 39% of the starting phenol was removed as polymer under the best operating conditions [39,40].…”

Effect of electropolymerisation conditions on the permeability of polyphenol films deposited on a vitreous carbon electrode

“…The main advantage in proceeding by electropolymerisation is the low consumption of the electric charge compared with electrochemical mineralisation [1]. In this way, the removal of phenols from aqueous solutions by electrochemical polymerisation was conducted on granular activated carbon [2], carbon fibre [3], Ta/␤-PbO 2 [1,4] and polyaniline/glassy carbon electrodes [5]. Nevertheless, electropolymerisation of phenolic compounds leads to the deposition of a non-conductive film that blocks the electrode activity and prevents further removal of phenol [6][7][8][9][10][11].…”

“…The aim of our previous works [1,4,20,21] was to find the operating conditions that allow electropolymerisation to proceed as long as a current is supplied to the electrode; thus, the polymeric film inevitably deposited on the electrode surface must have the highest permeability for phenol molecules. The main operating conditions were described in Ref.…”