Chemical/Advanced Oxidation Technologies For Treatment Of Herbicide Pesticide Intermediates

3,4-Dichlorobenzotrifluoride?3,4-DCBTE?and 3-Hydroxybenzoic acid are typical herbicide pesticide intermediates which can generate lots of by-products during production.There may cause serious pollution when discharged into the environment without treatment.Experiments were employed to study the treatment of these two target pollutants with several chemical/advanced oxidation technologies.Results are as follows:1.The removal rate of 3,4-DCBTE by Fenton oxidation could reach to 93.1%under the optimal condition of 2.67 g/L H₂O₂,20?,and the ratio of H₂O₂/Fe²⁺ =15,pH =3 for 2 hours.Combined with the data analysis,We speculated that the 3,4-DCBTE was eventually degraded into chlorobenzene.3-Hydroxybenzoic acid whose removal rate could reach up to 98.2%under the optimal conditions for 60 minutes could be more easily oxidized,relatively.2.The removal rate of 3,4-DCBTE by activated carbon catalytic hydrogen peroxide could reach to 99.9%under the optimal conditions of 0.85 g/L H₂O₂,2g/L GAC,pH=3,30'C for 90 minutes.The removal rate of 3-Hydroxybenzoic acid could reach up to 96.7%under the optimal conditions of pH=3,0.87 g/L H₂O₂,1g/L GAC and 30? for 60 minutes with the same method.3.0.5 mg/L KMnO₄,pH=3 and 30? were the optimum reaction conditions when using KMnO₄ alone,and 0.3 g/L PAC was best when using PAC alone,and 3,4-DCBTE could be completely removed during the oxidation using KMnO₄/PAC combination;75mg/L KMnO₄,pH=3 and 30? were the optimum reaction conditions when using KMnO₄ alone,and 0.5g/L PAC was best when using PAC alone,and 3-Hydroxybenzoic acid could even be fully removed with the same combination method.4.3,4-DCBTE could be fully removed with ventilation 0.05m3/h,pH=3,0.11g/L H₂O₂ for only 1 minute by O₃ oxidation;3-Hydroxybenzoic acid could be fully removed with ventilation 0.025m/h,pH=3,0.028 g/L H₂O₂ for only 1 minute by the same method.5.The removal rate of 3,4-DCBTE by Fe²⁺/K₂S₂O₈ could reach to 93.6%under the optimal conditions of pH=7,135 mg/L S₂O₈^2-,2.8 mg/L Fe²⁺ and 30? for 2 hours;3-Hydroxybenzoic acid could be fully removed with pH=7,270 S₂O₈^2-,2.8 mg/L Fe²⁺ and 30? for 1h with the same method.6.Treatment of these two substances by Fenton oxidation all followed the first order kinetics equations,and the activation energies were 16.15,11.12 kJ/mol,respectively;And their activated carbon catalytic hydrogen peroxide oxidation also fitted well to the first order reaction kinetic models,and the activation energies were 27.61,56.99 kJ/mol;And the kinetic data of 3,4-DCBTE reduction by KMnO₄ accorded with the secondary reaction kinetic models,and the activation energies were27.38 kJ/mol,while 3-Hydroxybenzoic acid's kinetic data accorded with the first order kinetics models,and the activation energies were 12.08 kJ/mol;O₃ oxidation,O₃/H₂O₂ oxidation were all in good accordance with the first order kinetics equations;And the oxidation of these two substances Fe²⁺/K₂S₂O₈ fitted well to the secondary reaction kinetic models,and the activation energies were 40.74,28.60 kJ/mol,respectively.