Advances and challenges of photocatalytic technology for air purification

With the acceleration of the urban industrialization process,air pollutant emission has increased sharply,which seriously endangers the ecological environment and human beings.Solar-driven photocatalysis has the broad-spectrum activity for various inorganic to organic pollutants at ambient temperature without harsh reaction conditions,which shows a very broad application prospect in air purification.However,the photocatalysis technology suffers from the unrevealed reaction me-chanism and the deactivation of photocatalysts,which severely limits its practical application.Currently,there is still a huge gap between basic research and industrial application in the field of photocatalytic air purification.This review summarizes recent progress on photocatalytic degradation of air pollutants and categorizes them based on the types of photocatalytic materials and air pollutants,with a focus on photocatalytic reaction mechanisms and the application scenarios of photocatalytic air purification to identify this gap.We also critically discussed the major challenges for promoting applications of photo-catalytic technology and put forward the development prospect.

Research Progress on the Bismuth Containing Complex Oxide in Photocatalystic Technology

The photocatalytic degradation on the bismuth containing complex oxide was revised in detail including the synthesis and classification of photocatalyts, and then the photocatalytic reaction, scavenger, and the mechanism of reaction. In particular, the perspectives of photocatalytic degradation on the bismuth containing oxide were analyzed in detail.

Advanced Treatment of Biologically Treated Chemical Comprehensive Wastewater by Nano-TiO2 Photocatalytic Oxidation

Nano-TiO2 photocatalytic oxidation was used to perform the advanced treatment of biologically treated chemical comprehensive wastewater. The effects of reaction time,nano-TiO2 dosage and initial p H of the wastewater on the removal rate of COD were tested. The GC/MS and EEM techniques were used to qualitatively analyze organic compounds in the wastewater before and after treatment. The result showed that after the biologically treated chemical comprehensive wastewater was treated by nano-TiO2 photocatalytic oxidation under the conditions of reaction time 3 h,nano-TiO2 dosage 8 g/L,and pH 8. 0,the effluent COD was 61. 9 mg/L and its removal rate was 63. 8%. Additionally,the species of organic pollutants reduced from 12 to 6. Meanwhile,the content of humic-like and fulvic-like substances dropped dramatically.

Efficient photocatalytic degradation of statin via optimization on ZnIn_(2)S_(4)/Bi_(2)WO_(6) Z-scheme heterostructure

Statins are widely used in the treatment of hyperlipidemia disease,which are refractory in the municipal sewage treatment plant.The photocatalytic degradation of statins by the Z-scheme heterostructured photocatalyst is confirmed,but the degradation mechanism of statins needs to be further revealed.In this study,the effects of photocatalyst dosage,solution pH and humic acid(HA)on the photocatalysis of fluvastatin by ZnIn_(2)S_(4)/Bi_(2)WO_(6) Z-scheme heterostructured photocatalyst(ZIS/BWO photocatalyst)were investigated and the degradation mechanism was proposed.Results showed that adsorption of fluvastatin was improved with the increase of photocatalyst dosage,but photoinduced desorption and light scattering resulted in the decrease of the removal of fluvastatin with high dosage.0.2 g/L of the ZIS/BWO photocatalyst was optimal dosage.65.21%of fluvastatin was removed at pH=9,because high concentration of OH^(-)was conducive to produce·OH.The change of pH,competition of photons and active sites,and trapping of reactive oxygen species(ROS)by carboxyl group of HA combined to inhibit the photocatalysis of fluvastatin in the presence of HA.The C–C,C=C and C–N bonds of fluvastatin were attacked by a variety of ROS to generate degradable intermediates that were easily mineralized to H_(2)O and CO_(2).