Catalytic Ozonation Of Oxytetracycline With Activated Carbon Supported Copper Oxide

With the extensive use of antibiotics in animal husbandry, the pollution of veterinaryantibiotics in animal manure and wastewater from livestock farms are getting worse.Without properly removing, these antibiotics will inevitably result in a serious threat tothe ecological environment. The purpose of this study is to find a simple and effectivetreatment method to remove veterinary antibiotics in wastewater from livestock farms.Ozonation is widely used in water treatment applications, but its disadvantage is theselective oxidation. Catalytic ozonation technology utilizes the free radical oxidation andgreatly improves the efficiency of ozone oxidation. With the loading of metal oxide onthe carbon surface, the catalyst not only has adsorption characteristics, but also has a highcatalytic activity. So it is a promising catalyst for ozonation of wastewater due to itseconomy and efficiency. In this experiment, activated carbon was used as the catalystsupport and the oxytetracycline (OTC) was used as the target pollutant, the activity ofloaded activated carbon on ozonation of oxytetracycline was investigated.Fe/AC, Mn/AC, Co/AC, Cu/AC, Ni/AC catalysts were prepared by impregnationmethod. The activity of these five different metal supported catalysts on ozonation ofOTC wastewater was compared. Results showed that Cu/AC catalyst has the highestcatalytic activity. At60min, TOC removal efficiency was72.2%. Removal efficiencies ofOTC for all three processes of AC+O3,O3and Cu/AC+O3were nearly100%in10min,indicating that oxytetracycline could rapidly oxidized by ozone.The influence of amount of metal loading and calcination temperature on preparingsupported catalyst was investigated. Results showed that loading and calcinationtemperature showed greater impact on the activity of the catalyst. Optimum preparedconditions were loading5wt%and400℃calcination temperature.The influence of different operation conditions on the catalytic reaction was also investigated, including the initial concentration of OTC, the reaction temperature, catalystdosage and pH value of the solution. An optimal reaction condition was1g/L of catalystdosage, initial pH ranging from7.0to10.0and in the temperature of20℃. And repeatedexperiments showed that Cu/AC catalyst has a good stability.The structure and active components of catalysts were characterized by BET, XRDand XPS. Results show that active component on the activated carbon catalyst surfacewas in the form of CuO. XPS results indicated that Cu2+existed on the surface of thecopper oxide-loaded catalyst. The analysis of intermediates suggested that the OTCdegradation by catalytic ozonation was mainly through electrophilic substitution reactionand OH radical chain reaction.