Preparation of adsorbed bismuth-based visible light photocatalytic materials and their effects on the performance of cement-based materials

Abstract

In order to effectively solve the problem of pollutant degradation in cement-based materials, the BiVO₄ was introduced into the reconstruction of the water-encountered MgAl-LDHs layer after calcination utilizing the memory effect of MgAl-LDHs which successfully prepared the highly adsorbable visible light photocatalytic material, BiVO₄/MgAl-LDHs. Its layered structure results in a large specific surface area with more active sites, promotes the growth and development of crystal nuclei, and thus accelerates cement hydration. Also, the nanofilling effect can optimize the microstructure and improve the mechanical properties of the cement paste. It is noteworthy that excessive BiVO₄/MgAI-LDHs will weaken the aforementioned promotions due to the reduction in the number of active species and heterogeneous defects. In the self-cleaning performance test, the specimens prepared by the coating method showed better behavior, whose degradation outcome was close to that of BiVO₄/MgAl-LDHs on methylene blue (MB) solution with a degradation rate of up to 89.2 %, once again confirming that BiVO₄/MgAl-LDHs possesses good chemical stability. The test for the durability of photocatalytic efficiency demonstrated that the specimens produced by the polyvinyl chloride (PVC) film loading method performed better. The above two performance tests illustrate that the number of BiVO₄/MgAl-LDHs molecules on the paste surface plays a major role in the degradation of MB solution.