Study On The Preparation And Characterization Of Fenton-like Catalyst And Degradation Of Tetracyclic Antibiotic In Water

The harm and potential threat of antibiotics in the environment have been widely concerned,among which antibiotics,especially tetracyclic antibiotics,wastewater is one of the main forms.Antibiotic residues in water are difficult to degrade and have the characteristics of biological toxicity,etc.As a result,this kind of wastewater has become a difficult problem and research hot spot in the field of water treatment.Fenton technology is efficient,green and economical.The treatment effect of antibiotic wastewater that is difficult to be degraded is worth expecting.The research results have good reference value and significancer for enginering application.In paper,based on the preparation and characterization of Fenton catalysts,Tetracycline hydrochloride in water was taken as the treatment object.Hydrogen peroxide and sodium persulfate as oxidants in Fenton,The effects of the process on the removal of organic compounds were investigated by single factor and orthogonal experiment,such as initical p H,Co Fe₂O₄@PDA dosage,initial concentration of tetracycline hydrochloride in water,temperature,etc.The operating conditions of UV/Fenton process were preliminarily determined.Based on the response surface method,the above Fenton process was further optimized,the COD removal rate model was established and the optimal process paprameters were determined.The model was verified under the optimal working conditions,and degradation mechanism of tetracycline hydrochloride by catalyst was discussed.The main research contents and conclusions in this paper are as follows:?1?Co Fe₂O₄was synthesized by hydrothermal method,Co Fe₂O₄@PDA was Co Fe₂O₄coated by self-polymerization.The catalyst Co Fe₂O₄@PDA was prepared and characterized by XRD,SEM,EDS,FT-IR,VSM.Through the preparation and modification experiment,it is known that Co Fe₂O₄samples with high purity can be prepared under weak alkaline condition?p H=8.5?.when the concentration of dopamine hydrochloride reached 0.5mg/L,the self-polymerization time was 8h,and the prepared Co Fe₂O₄@PDA had the best catalytic performance.Through physical characterization,it was proved that the synthetic sample was Co Fe₂O₄,and the sample was successfully coated with dopamine hydrochloride,that is,Co Fe₂O₄@PDA was prepared.?2?When hydrogen peroxide as oxidant,Through the orthogonal test,the degree of influence of various factors on the oxidation effect of Fenton was obtained as follows:temperature>initial p H>Co Fe₂O₄@PDA dosage>H₂O₂dosage>initial tetracycline concentration.The effects of wavelength of ultraviolet light,initial p H,hydrogen peroxide dosage,Co Fe₂O₄@PDA dosage,initial concentration of tetracycline in water,temperature and reaction time on COD removal rate.The appropriate of operating conditions are obtained:UV wavelength of 185nm,the initial p H is 3,H₂O₂dosing quantity?30%wt?is150mmol/L,Co Fe₂O₄@PDA dosing is 10g/L,tetracycline concentration is 0.2g/L,water temperature is 50?,reaction time is 120mins.The above single-factor degradation process were fitted by first-order kinetic equation,and the corresponding apparent kinetic equation was established.?3?When sodium persulfate as oxidant,The effects of initial p H,sodium persulfate dosage,Co Fe₂O₄@PDA dosage and reaction time on absorbance removal rate of experimental wastewater.The optimal operating conditions of UV/Fenton process were obtained through the single factor influence experiment mentioned above:the initial p H is4,sodium persulfate dosing?1mol/L?quantity is 25ml/L,Co Fe₂O₄@PDA dosing is 10g/L,reaction time is 180mins.The above single-factor degradation process were fitted by first-order kinetic equation,and the corresponding apparent kinetic equation was established.?4?Based on the response surface methodology?RSM?,UV/Fenton process optimization experiment was designed by using Box-Behnken model and Design Expert software.a regressive model for COD removal efficiency in terms of p H,H₂O₂dosage,Co Fe₂O₄@PDA dosage was developed by Design Expert.It was significant.The effect of p H on COD removal efficiency was greatest,and the interactive effect of H₂O₂dosage and Co Fe₂O₄@PDA dosage was significant.The optimal process conditions as follows:p H=3.12,Co Fe₂O₄@PDA dosage is 0.12g/L,H₂O₂?30%wt?dosage is 129.99mmol/L.The relative error between the experiment value and the predicted value was 1.8%,and the B/C value was increases from 0.11 to 0.28.?5?Mechanism investigation showed that the Fe²⁺in the traditional Fenton reagent was replaced by Co Fe₂O₄@PDA,and ultraviolet light was introduced into the Fenton reaction system.The complex of Co³⁺and OH^-in water has the potential to generate�OH,and Co²⁺can react with H₂O₂to produce�OH.This process significantly improves the solubility of�OH in the system without affecting other reactions in the Fenton system,and leads to the degradation of teteacycline hydrochloride.