Catalytic Ozonation Of Chlorophenol Pollutants In Water Using Natural Copper Ores

Chlorophenols are typical organic pollutants in industrial wastewaters,which threat human health and ecological environment.Catalytic ozonation is an effective advanced treatment technology for organic wastewater,but the high-cost catalysts limit its application.Cheap natural copper ores show the potential to replace the high-cost catalyst.In this study,chalcopyrite and chalcocite are selected as the research objects.Based on the comprehensive characterization of their composition and structure,their degradation and mineralization efficiency of chlorophenols are evaluated.In addition,the catalytic ozonation mechanisms and degradation path of chlorophenols are explored,which provides technical support and theoretical basis for the efficient and low-cost removal of chlorophenol pollutants.Chalcopyrite and chalcocite are mainly composed of Cu Fe S₂ and Cu₂S,respectively.The main elements in chalcopyrite and chalcocite have different valence states.Chalcopyrite and chalcocite contain other associated ores.The two copper ores showed stable and high catalytic activity in ozonation system,and the TOC removal rate of chlorophenol solution was about 90%in multiple evaluation rounds,which was about 1.6-1.7 times higher than that of single ozonation system.By adjusting the initial p H of chlorophenol solution to 11 and controlling p H>7 of the solution during the reaction,the dissolution of Cu²⁺can be controlled<1 mg/L.The degradation of chlorophenols is contributed by both direct and indirect ozonation,but the mineralization is mainly completed by reactive oxygen species produced by indirect oxidation.During ozonation,the two kinds of copper ores mainly promote the decomposition of ozone to produce·OH,·O₂^-and ¹O₂ through surface hydroxyl groups and electron transfer between Fe²⁺/Fe³⁺,Cu⁺/Cu²⁺and S elements.The ¹O₂ yield of chalcopyrite is relatively high,while·O₂^-yield of chalcocite is relatively high.Under the attack of ozone molecules and reactive oxygen species,chlorophenols first undergo the substitution reaction of hydroxylation and dichlorination and form phenolic compounds,then the benzene ring is opened and carboxylic acid are generated.Finally,under the attack of reactive oxygen species,chlorophenols are completely degraded and mineralized into CO₂ and H₂O.