Study On Treatment Of High Concentration Refractory Organic Wastewater By Heterogeneous UV/Fenton-like Process

The high concentration refractory organic wastewater is a kind of waste water which can not be treated by ordinary biochemical method.The Fenton method has been paid more and more attention because of its strong oxidizing ability,fast oxidation rate and high oxidation degree.However,the traditional homogeneous Fenton method has the disadvantages of harsh pH requirement,low utilization rate of H₂O₂,formation of iron mud after the reaction.In order to overcome these shortcomings,this paper focuses on the construction of UV/Fenton process,and it is used to treat simulated coking wastewater.Firstly,Fe/Cu/Ce/silica-supported heterogeneous Fenton catalysts were prepared by impregnation method.Secondly,the catalysts were characterized by X-ray diffraction?XRD?,scanning electron microscopy?SEM?and physical adsorbents.Finally,a heterogeneous UV/Fenton process was constructed by introducing the UV light.The process was used to treat simulated coking wastewater,and the optimum operating conditions and the degradation performance was investigated.The optimum preparation conditions were as follows:n(Fe³⁺):n(Cu²⁺):n(Ce³⁺)=1:1:0.1,the concentration of immersion liquid of 2.8mmol/L,the immersion time of 16 h,the calcination time of 2 h,the calcination temperature of 20 ?.The decolorization rate of methyl orange solution was up to 99.6%under the following conditions:the methyl orange concentration of 2.0 g/L,the H₂O₂ dosage of 0.3 g/L,the initial pH of 3,the reaction temperature of 60 ? and the reaction time of 15min.Under these conditions,the catalyst was reused five times and the decolorization rate of methyl orange was 81.2%.Catalytic loading of metal dopant metal Ce can improve the catalytic performance of the catalyst.The amount of iron leaching is about 0.5 mg/L,and the amount of copper leaching is about 0.3 mg/L,which indicates that the catalyst has good stability.The optimum operating conditions of the UV/Fenton process are as followings:catalyst of 0.5 g/L,hydrogen peroxide of 8 mL/L,reaction time of 80 min and initial pH of 4 for the reaction.The removal rates of CODcr,phenol,2,4-dichlorophenol,SCN^- and NH₄⁺-N in simulated coking wastewater were reached 88.2%,94.9%,89.4%,75.5%and 56.8%respectively under the optimum operating conditions.