Semiconductor oxides are widely used to achieve photocatalytic removal of NOx(NO and NO2) species. These materials also exhibit enhanced oxidation ability in thermally assisted photocatalysis;however, many of them ten...Semiconductor oxides are widely used to achieve photocatalytic removal of NOx(NO and NO2) species. These materials also exhibit enhanced oxidation ability in thermally assisted photocatalysis;however, many of them tend to be deactivated at high relative humidity(RH) levels. In the case of the benchmark P25 TiO2 photocatalyst, we observe a significant decrease in non-NO2 selectivity from 95.02% to 58.33% when RH increases from 20% to 80%. Interestingly, the porous TiO2(B) microspheres synthesized in this work exhibit 99% selectivity at 20% RH;the selectivity remains as high as 96.18% at 80% RH. The high humidity tolerance of the TiO2(B) sample can be ascribed to its strong water desorption capacity and easy O2 adsorption at elevated temperatures, which reflects the fact that the superoxide radical is the main active species for the deep oxidation of NOx. This work may inspire the design of efficient photothermal catalysts with application in NOx removal in hot and humid environments.展开更多
Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time an...Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time and temperature on drying characteristics and red pigments content of line pepper were investigated.Results showed that after a 3-min SSIB pretreatment at 110℃ the pepper epidermis covered with wax coat was damaged.In addition,the drying time was extensively decreased and the loss of red pigments of dried products was reduced.Results showed that the whole drying process took place in the falling rate period,which indicated that diffusion was the dominant physical mechanism governing moisture movement in the samples.Therefore,the second Fick’s law of diffusion was used to determine the effective moisture diffusivity(Deff)of line pepper,which increased from 1.193×10^-10 to 3.128×10^-10 m^2/s with increasing of the drying temperature and air velocity.The drying activation energy(Ea)of pretreated samples was 34.31 kJ/mol,which decreased by 3% compared with the non-pretreatment group.The findings of this work indicate that SSIB is very promising pretreatment technique as it not only enhances drying process but also improves bioactive substance preservation of red pepper.展开更多
文摘Semiconductor oxides are widely used to achieve photocatalytic removal of NOx(NO and NO2) species. These materials also exhibit enhanced oxidation ability in thermally assisted photocatalysis;however, many of them tend to be deactivated at high relative humidity(RH) levels. In the case of the benchmark P25 TiO2 photocatalyst, we observe a significant decrease in non-NO2 selectivity from 95.02% to 58.33% when RH increases from 20% to 80%. Interestingly, the porous TiO2(B) microspheres synthesized in this work exhibit 99% selectivity at 20% RH;the selectivity remains as high as 96.18% at 80% RH. The high humidity tolerance of the TiO2(B) sample can be ascribed to its strong water desorption capacity and easy O2 adsorption at elevated temperatures, which reflects the fact that the superoxide radical is the main active species for the deep oxidation of NOx. This work may inspire the design of efficient photothermal catalysts with application in NOx removal in hot and humid environments.
基金the National Natural Science Foundation of China(Grant No.31360399)for the financial support.
文摘Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time and temperature on drying characteristics and red pigments content of line pepper were investigated.Results showed that after a 3-min SSIB pretreatment at 110℃ the pepper epidermis covered with wax coat was damaged.In addition,the drying time was extensively decreased and the loss of red pigments of dried products was reduced.Results showed that the whole drying process took place in the falling rate period,which indicated that diffusion was the dominant physical mechanism governing moisture movement in the samples.Therefore,the second Fick’s law of diffusion was used to determine the effective moisture diffusivity(Deff)of line pepper,which increased from 1.193×10^-10 to 3.128×10^-10 m^2/s with increasing of the drying temperature and air velocity.The drying activation energy(Ea)of pretreated samples was 34.31 kJ/mol,which decreased by 3% compared with the non-pretreatment group.The findings of this work indicate that SSIB is very promising pretreatment technique as it not only enhances drying process but also improves bioactive substance preservation of red pepper.
