Treatment of high-salinity organic wastewater by advanced oxidation processes: Research progress and prospect

Even though regarded as one of the mainstream solutions for organic wastewater, the performance of advanced oxidation processes (AOPs) in high-salinity organic wastewater treatment has been widely questioned. Some common inorganic anions can weaken or even quench free radicals, resulting in a 41 ± 9 % loss in reaction rate. In addition, due to the possible generation of toxic by-products represented by halides, direct contact of free radicals, organic pollutants and anions also brings additional environmental risks. Recently, researchers have found a fallback option—free radical pathways are being replaced by non-free radical pathways represented by singlet oxygen, but the efficiency decline and toxic byproducts seem difficult to completely avoid. In this work, the research progress on the application of AOPs in the treatment of high-salinity organic wastewater was reviewed. In addition, an idea based on the negatively charged catalyst was proposed, in which the anions will be driven away from the catalyst surface by electrostatic repulsion to avoid contact and quench the free radicals. This review is expected to provide guidance and new ideas for the treatment of high-salinity organic wastewater.