Degradation of Polystyrene by Mediated Electrochemical Oxidation

The huge amount of plastic waste that resulted from mega polymer production units give rise to serious environmental concerns, as plastic does not degrade and remains in themunicipal for decades. Incineration of waste polymers and thermal pyrolysis of polymers to liquid fuels (PTL) take placeat high temperature (above 900 oC). Toxic or carcinogenic emissions including dioxins, furans, polyaromatic hydrocarbons are generally formed during these processeswhich are threats to the environment [1]. On the other hand, mediated electrochemical oxidation (MEO) as a new and clean technique has been proposed mainly fordestruction of organic wastes. In this process, the hazardous, radioactive or mixed organic waste streams can be destructedat low temperature (<100 oC) due to the high redox potential of the silver redox couple, low cell voltage, low pressure andbeing amenable to control. No toxic or carcinogenic discharges were reported during the MEO process [2]. The mediator oxidants such as Ag(I) or Ce(III) are regeneratedcontinuously to Ag(II) or Ce(IV) by an electro-membrane cell to minimize the production of secondary wastes and they arebrought in contact with the organic waste. Unfortunately, the number of studies on degradation of polymer materials by MEO is scarce [3]. Initial studies onpolyolefins have shown a slow reaction with the mediators hindering the technique as a practical means for bulk plastic destruction [3, 4]. The aim of the present study is thus to shed more lights on this issue by investigating degradation of polystyrene using silver-MEO technique.