Preparation And Performance Of Peroxy Monosulfate Catalyst Based On Ferrite

In recent years,the supersulfate advanced oxidation process（AOPs）based on sulfate radicals（·SO₄^-）has been widely used because of its higher redox potential,wider p H application range and more accurate selectivity than the traditional advanced oxidation process that relies on hydroxyl radicals（·OH）.Among them,persulfate（PMS）molecules have an asymmetric structure,so they are easier to activate than persulfate（PDS）.PMS can be activated by a variety of methods,such as alkali activation,thermal activation,photoactivation,transition metal activation,etc.Among them,the non-homogeneous catalyst activation PMS based on transition metal oxide has the characteristics of high activity,low price and environmental friendliness,which can degrade organic pollutants well.Among them,copper,iron and manganese are commonly used metal-based catalysts.The ferrite of spinel structure has the characteristics of strong magnetism and large specific surface area,and is often used as a catalyst to activate PMS.However,it is precisely because of its magnetism and small particles,this will lead to the aglomeration of spinel ferrite particles to reduce the active site,thus reducing its catalytic activation effect.To solve these problems,we designed and introduced different metal oxides to improve their activity and proved their feasibility.The main research contents of this paper are as follows:（1）CuO/Cu Fe₂O₄composite materials are synthesized through a simple one-step hydrothermal method,and the structure of the sample is characterized by XRD and IF characterization.Explore the activity of different Fe:Cu quantity catalysts,and the final experiment proves that Fe:Cu=2:1.5 is the best proportion of the catalyst.The influence of reaction conditions on its degradation of PNP was further investigated,and the optimal reaction condition was determined when the solution p H 7,the catalyst dosage was 3 g L^-1,and PMS was 3 m M.In addition,the effect of ions and organic matter present in natural water on the reaction was also investigated.It was found that except for the input of FFA,which slightly inhibited the reaction,no other ions had an inhibitory effect on the reaction.Then,through free radical quenching experiments and EPR tests,it was found that·OH and ¹O₂were active species in the process of catalyst activation PMS degradation p-Nitrophenol（PNP）reaction.Finally,we studied the stability of the catalyst and found that it has good repeatability and is magnetic and easy to recover.In summary,the catalyst is promising to treat PNP in actual water.（2）CuO/Mn Fe₂O₄magnetic composite material was prepared by simple water bath method,and its structure,morphology and elemental components were characterized and analyzed.It was found that the prepared composite particles were smaller,with a larger specific surface area,increased active sites,and higher catalytic activation efficiency of PMS.The degradation efficiency of phenol is good.It is found that the catalyst has the best catalytic performance when the Cu:Mn molar ratio is 1:5.Subsequently,the influence of factors such as catalyst dosage,PMS dosage and initial p H on the degradation effect of phenol in the system was studied,and the best conditions for the reaction were determined.Through circular experiments,The influence experiment of coexistence ions proves the stability and universality of the catalyst.The main active groups in the degradation process were analyzed by free radical capture experiment.（3）Bimetallic MnO_x/Mn Fe₂O₄catalyst was prepared by water bath method,and its structure was characterized by XRD,BET,SEM and other technologies.Taking phenol as the target pollutant,the activated PMS performance of Mn Fe₂O₄and Mn/Mn Fe₂O₄was investigated,and it was found that the catalytic activity of MnO_x/Mn Fe₂O₄was significantly higher than that of pure phase Mn Fe₂O₄.Then the optimal reaction conditions were determined to be p H8,the PMS concentration was 20 m M,and the catalyst amount was 1 g L^-1.Free radical capture experiments and EPR tests have proved that the main active species in the degradation process are ¹O₂.Because the catalyst is magnetic and easy to recover,the metal ions are almost insoluble and the activity is almost unchanged after multiple cycles.The common inorganic ions and organic matter in water hardly inhibit the degradation of pollutants,which proves its good practical application prospects.