Study On VOCs Pollution Control And Catalytic Materials

With the advancement of industry,a huge number of synthetic toxins in waste water and gas will be produced,and can be released to the environment,posting an incredible danger to the environment.Among them,dye waste water and VOCs are respectively the representatives of waste water and waste gas.Photocatalysis being non-toxic,of high mineralization and no secondary contamination,but the electrons and hole pairs created by photocatalyst are easy to recombine,decreasing photocatalytic activity.Therefore,it is necessary to improve the catalytic efficiency by synthesizing novel catalytic materials and coupling them with other advanced oxidation technologies.In order to improve the catalytic efficiency,this study conducted two parts of exploration:the synthesis of monatomic catalyst Co-g-C₃N₄ and photocatalytic activation of H₂O₂ and PMS for the catalytic oxidation of Rhodamine B and liquid phase VOCs;Ag/Ag Br/Ti O₂-Zn O was synthesized,and tested in the microbial fuel cell was integrated with photoelectric catalysis for oxidation of liquid phase absorbed VOCs.（1）According to the characterization results,Co exists in the atomically dispersed state in g-C₃N₄,and increased the visible light range response and activity,and the doping of Co reduces the band gap.Co-g-C₃N₄/H₂O₂ and Co-g-C₃N₄/PMS systems were constructed to test the catalytic activity of Rh B degradation,with different Co doping ratios in PMS and H₂O₂ systems.The optimum Co loading capacity was 0.35 wt%.Through the catalytic experiment and performance stability test of Co-g-C₃N₄/H₂O₂ and Co-g-C₃N₄/PMS photo-Fenton like systems,Co-g-C₃N₄/PMS system performs better.In the Co-g-C₃N₄/PMS（0.1 m M PMS）and Co-g-C₃N₄/H₂O₂（9.8 m M H₂O₂）system,nearly 100%pollutant was degraded in respectively 2 min and 16 min.The kinetic rate constant of Co-g-C₃N₄/PMS is 1.57 min^-1,and the removal capacity is 6.10 g?h^-1?（catalyst g）^-1.It is found that the best operating conditions of Co-g-C₃N₄/PMS system are acidic and/or neutral,and the best operating conditions of Co-g-C₃N₄/H₂O₂ are neutral.The performance of Co-g-C₃N₄/PMS system was optimized,and the experimental conditions were determined as follows:calcination temperature 520℃,PMS concentration0.10 m M,and catalyst amount 0.4 g?L^-1.In addition,by comparing with the homogeneous catalysis method,the Co-g-C₃N₄/PMS is carried out in a heterogeneous way.The hydroxyl radical and sulfate radical are the main elements involved in the reaction in Co-g-C₃N₄/PMS system,and the hydroxyl radical in Co-g-C₃N₄/H₂O₂ system.The use of metal monatomic catalyst to activate oxidants for catalytic oxidation degradation of VOCs provides a new idea for the catalytic oxidation of VOCs.（2）By improving the traditional PEC-MFC system,the ability of microorganisms is fully utilized to achieve oxidative removal of high concentration VOCs.A single cycle electrocatalysis with microbial fuel cell system（C-EC-MFC）and a single cycle photo electrochemical catalysis with microbial fuel cell system（C-PEC-MFC）were successfully constructed,and ethyl acetate and isopropanol were treated respectively.In order to degrade the ethyl acetate and isopropanol in the solution,and make full use of the degradation ability of microorganisms,the solution and the EC-MFC system were used to form a circulating system.The double-circulating photo electrochemical catalysis with microbial fuel cell system（CC-PEC-MFC）was successfully constructed,and it was proved that the double-circulating system could rapidly degrade the ethyl acetate in the absorption solution.In summary,the composite modified catalytic materials and their pollution control research provides new ways of thinking for practical application.