Degradation Of Rhodamine B And Dibutyl Phthalate By Urea-hydrogen Peroxide Catalyzed With Iron-nitrogen Co-doped Biochar

Organic dyes and phthalates have the characteristics of difficult degradation,bioaccumulation and high toxicity.Emission into the environment will not only pollute the atmosphere,water and soil,but also cause serious harm to human health due to the“three-inclusive”effect,which is a common two major categories of pollutants in the environment.Therefore,the prevention and control and elimination of organic dyes and phthalates have become an important part of pollution prevention and control.Advanced oxidation method has become one of the preferred methods for pollution control due to its advantages of low repair cost,high efficiency and short cycle.It is a method for the degradation of organic pollutants by the decomposition of oxidants to produce active groups under the action of activated materials,in which the selection of oxidants and catalytic reactions are the key.Urea-hydrogen peroxide（UHP）has the characteristics of hydrogen peroxide and urea,and has been used for the degradation of organic pollutants.However,the existing transition metal salts(such as Fe²⁺,Mn²⁺,etc.)and other activated materials are unstable,which reduces the activation efficiency of UHP.The combination with low cost,adjustable structure and performance of modified biochar becomes an effective measure to improve the activation efficiency of activated materials.In this paper,Fe-N co-doped biochar was prepared by one-pot method as a catalyst for the degradation of rhodamine B（Rh B）and dibutyl phthalate（DBP）by urea peroxide.The main contents are as follows:（1）Degradation of rhodamine B by urea-hydrogen peroxide catalyzed with iron-nitrogen co-doped biochar.Iron-nitrogen co-doped biochar was prepared by using grapefruit peel powder as carbon source,urea as nitrogen source and Fe Cl₃·6H₂O as iron source.The biochar was characterized by SEM,FT-IR,XRD and XPS.The results showed that the surface of iron-nitrogen co-doped biochar was rich in C=O,C-O-C,Fe-O and other functional groups.Fe and N were uniformly dispersed on the surface of biochar,and had large specific surface area and porosity.The results of different influencing factors on Rh B degradation showed that the degradation rate of Rh B reached 99.31%within 30 min under the conditions of Rh B concentration 50 mg/L,calcination temperature 500℃,catalyst 100 mg/L,UHP 50 mg/L,ambient temperature 20℃and degradation solution p H=6.Free radical quenching and electron spin resonance detection showed that superoxide radical（O₂·^-）and hydroxyl radical（·OH）were generated during UHP catalyzed by Fe-N co-doped biochar,which were the main active species in Rh B degradation process.（2）Degradation of dibutyl phthalate by urea-hydrogen peroxide catalyzed with iron-nitr-ogen co-doped biochar.The effects of catalyst concentration,oxidant concentration,environmental temperature and p H value on the degradation of dibutyl phthalate in water were investigated.The results showed that the degradation rate of dibutyl phthalate reached 93.23%under the conditions of catalyst 0.6 g/L,urea-hydrogen peroxide 0.8 g/L,ambient temperature30℃,p H=4 and initial concentration of 10 mg/L in water for 24 h.The results of the degradation experiment of dibutyl phthalate in soil showed that the degradation rate of dibutyl phthalate in soil reached 92.53%after 48 h under the conditions of dibutyl phthalate 10 mg/kg,catalyst 10 g/kg and UHP 10 g/kg.The iron-nitrogen co-doped biochar activator prepared by a simple one-pot method can efficiently activate urea-hydrogen peroxide to degrade organic pollutants,which provides a solution for the treatment of organic pollutants and has a good application prospect in the treatment of organic pollution.