A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi ...A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.展开更多
Maria sites are important historical sites, backing to the Byzantine period. The sites suffer from weathering noted as honeycomb, exfoliation and discoloration with white salt efflorescence at some parts. These are di...Maria sites are important historical sites, backing to the Byzantine period. The sites suffer from weathering noted as honeycomb, exfoliation and discoloration with white salt efflorescence at some parts. These are diagnostic features for salt weathering as confirmed by the laboratory investigations using thin section analysis. The salt is found to be from three sources, namely, water spray, chemical alteration of the mortar＇s carbonate content into sulfate salts by acid rain, and wet deposition of air pollutants on the surface of the stones ruins. The cracks noted in the structures of this archeological building are the results of landslides in this area. Knowledge of the archeological sites material examined can be greatly enhanced by understanding the process in their formation of degradation. This paper aims to describe the use of thin sections/micromorphology in the archeological sites. Analysis data of physical sitting, geology, geomorphology, and climate have been done to determine the main nature of hazards in this sites. Dynamic processing problems are existing along Alexandria coast including beach erosion, pollution and manmade. Thin section analysis is used to determine the factor in increasing the hazard level.展开更多
基金Supported by the National Natural Science Foundation of China(21676023,21376025)
文摘A simple and high efficient method was proposed for the synthesis of uniform three dimensional （3D） BiVO4/reduced graphene oxide （RGO） nanocomposite photocatalyst by adopting the microwave assistant and using Bi （NO3）3·5H2O, graphene oxide （GO） and NH4VO3 as precursor. The as-obtained composites were well characterized with the aid of various techniques to study the morphology, structure, composition, optimal and electrical property. In the as-obtained composites, the GO sheets were fully reduced into RGO, and monoclinic structure BiVO4 crystallized completely into butterfly-like BiVO4 lamellas and well bonded with the RGO lamellas. The length and the width of the butterfly-like BiVO4 particle were about 1.5 μm, and the thickness of the flake was about 20 nm. Photocatalytic performances of BiVO4/RGO composite and pure BiVO4 particle have been evaluated by investigating the reduction of Cr（VI） ion-contained wastewater under simulated solar light irradiation, where the BiVO4/RGO composite displayed enhanced photocatalytic activity. It is found that the pseudo-first-order rate constants （k） for the photocatalytic reduction of Cr （VI） by BiVO4/RGO composite was about 4 times as high as that of the pure BiVO4. The present work suggested that the combination of BiVO4 and RGO displayed a remarkable synergistic effect, which led to enhanced photo-catalytic activity on Cr（VI） reduction.
文摘Maria sites are important historical sites, backing to the Byzantine period. The sites suffer from weathering noted as honeycomb, exfoliation and discoloration with white salt efflorescence at some parts. These are diagnostic features for salt weathering as confirmed by the laboratory investigations using thin section analysis. The salt is found to be from three sources, namely, water spray, chemical alteration of the mortar＇s carbonate content into sulfate salts by acid rain, and wet deposition of air pollutants on the surface of the stones ruins. The cracks noted in the structures of this archeological building are the results of landslides in this area. Knowledge of the archeological sites material examined can be greatly enhanced by understanding the process in their formation of degradation. This paper aims to describe the use of thin sections/micromorphology in the archeological sites. Analysis data of physical sitting, geology, geomorphology, and climate have been done to determine the main nature of hazards in this sites. Dynamic processing problems are existing along Alexandria coast including beach erosion, pollution and manmade. Thin section analysis is used to determine the factor in increasing the hazard level.
