REPDIGITS AS DIFFERENCE OF TWO PELL OR PELL-LUCAS NUMBERS

Abstract

Abstract: Bismuth vanadate (BiVO4)-cement composites were coated on concrete surfaces, which were fabricated with differing amounts of BiVO4 (0, 20, and 40 wt%) in Portland cement. The photocatalytic methylene blue (MB) dye degradation using BiVO4 coated on concrete pellet was investigated. The influence of the BiVO4 quantity on photocatalytic dye degradation percentage was studied. Characterization of the proposed materials was assessed using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The existence of BiVO4 and concrete was confirmed using XRD. X-ray electron diffraction spectroscopy (EDS) built-in the SEM was used to discover the elemental composition. UV–Vis–NIR spectrophotometry was utilized to analyze the BiVO4 absorption spectra. During the photocatalytic experiment, the MB dye degradation capability showed enhancement with BiVO4 content in BiVO4-concrete pellets. The 40 wt% BiVO4-concrete pellets attained ~ 58% MB dye degradation efficiency with respect to 0 wt% BiVO4-concrete pellets (~ 27%) in 240 min of the photocatalytic experiment. The MB dye disintegration follows the pseudo first-order kinetic model showing the largest k value of 0.00328 min-1. A phytotoxicity study using the germination index was carried out using Vigna radiata seeds. It was noticed that an alkaline condition of pH aided in attaining a better degradation efficiency. A scavenger experiment suggests that the O2.- radical is the principal active species for commencing photocatalytic MB dye disintegration. Graphical Abstract: [Figure not available: see fulltext.] © 2023, The Minerals, Metals & Materials Society.