Application and enhancement of mediumpressure ultraviolet activated peroxydisulfate in treating incineration leachate

Herein, a special medium-pressure ultraviolet (MPUV) reaction device was designed, in which MPUV-activated peroxydisulfate system (MPUV/PDS) was used to treat incineration leachate, and the treatment performance and mechanism after introducing catalysts were also investigated. The results indicated that organic pollutants were efficiently degraded, and the degradation regularity was similar when incineration leachate at different concentrations was treated in MPUV/PDS system. In addition, different transition metal ions diversely affected MPUV/PDS system, among which Cu²⁺ exhibited the most excellent activation property, and in view of this result, copper-loaded activated carbon (Cu-GAC), which was successfully synthesized by using dipping method, was applied to further enhance the treatment effect as a heterogeneous catalyst. The results showed that under optimal operation conditions, CODcr and DOC removal rates in Cu-GAC/MPUV/PDS system respectively reached 91.83% and 93.67%, which were 11.65% and 16.86% higher than those in MPUV/PDS system under the same reaction conditions, and almost all dissolved organic matters in incineration leachate were mineralized or decomposed into lower molecular weight organics within 180 min. Furthermore, it was demonstrated that Cu-GAC maintained a high catalytic performance throughout the four repetitive experiments. As revealed by mechanism analysis, three pollutants removal pathways (adsorption, radical-based and non-radical oxidation) existed in Cu-GAC/MPUV/PDS system, and various reactive species, including HO^·, SO₄^∙-, O₂^∙- and ¹O₂, exerted important contributions in organics removal.