Multiple Photocatalytic System Efficiently Removes Rhodamine B And VOCs

With the development of industrialization,a large amount of waste water,waste gas and solid wastes are discharged into the natural environment,which result in environmental pollution and seriously threatens human health.Photocatalytic materials can transform light energy in nature into usable chemical energy,and have the advantages of non-toxicity and low cost,so they have a broad prospect in environmental pollution control and solving world energy problems.At present,photocatalytic technology has been widely used in the field of pollutant removal,but traditional photocatalysts,such as Ti O₂,can only absorb ultraviolet light due to their wide band gap,and the activity of the catalysts is limited due to the easy recombination of photocarriers,thus limiting the application of photocatalysis.Therefore,it is of great significance for environmental governance and utilization of natural energy to improve photocatalytic performance.In recent years,piezoelectric catalysis and single atom catalysis have become a new research focus and are also expected to become a new method to improve the performance of photocatalysis,because of their advantages of high efficiency,good stability.However,the related research has been rarely reported.The purpose of this paper is to coupling piezoelectric catalysis,single atom catalysis and photocatalysis and make up for the deficiency of existing research by synthesizing new catalysts and building a coupled multi-catalytic system.In this study,piezoelectric catalysis and single atom activation PMS technology were used to improve the performance of the catalyst.Then rhodamine B（Rh B）and VOCs,as typical pollutants in waste water and exhaust gas respectively,were used to investigate the catalytic performance of the catalyst,and the mechanism of reaction was explored.In a word,this thesis mainly consists of the following two parts:（1）Coupling piezoelectric and photocatalytic fuel cells improves the catalytic performance of catalysts.Finally,rhodamine B was used as the target pollutant to evaluate the reaction system.The experimental results show that the system can provide good conditions for catalysis,and achieve efficient removal of rhodamine B by coupling of piezoelectric catalysis and photocatalysis fuel cells.The effects of different conditions,such as doping ratio,external resistance,electrolyte concentration,on the removal rate of rhodamine B were investigated in this system.The results showed that under the optimal conditions,the removal rate of Rhodamine B could reach 98.7%within 50 min,and the rate constant was 0.081,which was7.13 times and 5.26 times of pure Ba Ti O₃ and pure Bi₂WO₆,respectively.Repeatability experiments showed that the removal rate of rhodamine B remained 96.3%after repeated use for 4 times,showing good stability.（2）Coupling monatomic catalysis and photocatalysis to improve the catalytic performance of the catalyst.Single atom Co was loaded onto photocatalyst g-C₃N₄ by calcination.Through HFAAD-STEM characterization of the material,it was confirmed that monatomic Co was successfully prepared and uniformly dispersed on the surface of g-C₃N₄.The system was constructed by coupling Co-g-C₃N₄ activated peroxymonosulfate（PMS）,photocatalysis and microbial fuel cell（MFC）to constantly removal VOCs.The effect of different Co doping amount on VOCs removal was tested,and the optimal Co loading was Co CN-2（0.14 wt%）.When the external resistance in the system is 1000Ω,the removal efficiency is the highest（VOC can be stably degraded within 120 min,and the removal rate is 100%,the average removal capacity is 356.4 g/m³/h）,and the output voltage is 500 m V.It has good environmental and economic benefits.