Catalytic electrochemical pre-treatment for the degradation of persistent organic pollutants

Electrochemical advanced oxidation processes have been widely explored for the total degradation of biorecalcitrant compounds such as some pesticides and pharmaceuticals. More recently, coupling processes involving an electrochemical pre-treatment followed by a biological process have been proposed as cost-effective and reliable remediation methods for the mineralization of persistent compounds. This open the way to more selective electrochemical methods than those involving hydroxyl radicals since the aim of the pre-treatment is no more to achieve the total mineralization of non-biodegradable species, but is only the improvement of their biodegradability focusing on functional groups known to reduce it. In this context, catalytic electrochemical reductions and oxidations can find their place in a coupling process for the remediation of biorecalcitrant compounds as selective and well-controlled methods. This review summarizes some relevant and recent work on catalytic electrochemical processes performed in aqueous medium that have been used to improve the biodegradability of persistent organic pollutants.