An overview on the application of advanced oxidation processes for the removal of naphthenic acids from water

Although the exploitation of new energy sources like oil sand or shale may efficiently relieve the urgency of energy shortage, it can also have significant and adverse environmental impacts since huge volumes of oil-containing wastewaters are produced yearly worldwide due to such activities. Naphthenic acids (NAs), which are reported to be bio-recalcitrant due to their structural complexity and toxicity, are the main harmful components of oil shale fracking processes and oil sand process-affected waters. Identification techniques are being continuously improved to deal with the growing analytical need for traditional NAs and emerging ones like oxy-, aromatic, and diamondoid NAs. Meanwhile, treatment approaches focused on technical solutions have been investigated in the past decades. Among these, advanced oxidation processes are the most studied. Different oxidizing agents, like ozone, hydrogen peroxide, and persulfate, among others, have been used, giving rise to a diversity of techniques. The current work presents an updated overview of these techniques with regard to their application for the removal of NAs from water.