Molecular simulation study of the adhesion characteristics of β-phosphogypsum product surface to mold biomolecules

Abstract

The adhesion of β-phosphogypsum product (M-β-PG) to mold is one of the factors affecting its mildew，and the possible structure and mechanism of the interaction between mold adsorbed on M-β-PG surface remain unclear. From the point of view of the interaction between the main biomolecular (Z) on the surface of mold cell wall and the main component of M-β-PG gypsum (G), the adsorption characteristics and interaction mechanism of Z on G surface were studied by means of molecular simulation and experiment. Using X-ray diffraction, gypsum phase composition analysis, X-ray fluorescence spectroscopy, scanning electron microscopy, microbial diversity detection and other tests, the object of molecular simulation modeling was determined. By analyzing the fourier infrared spectroscopy (FTIR) functional group test, the geometric optimization, the band structure and the density of states calculated by quantum mechanics; the adsorption heat, interaction energy, adsorption isotherm, adsorption bond length and mean square displacement calculated by molecular mechanics, the interaction mechanism between G and Z is studied. The results showed that the adsorption occurred primarily between the hydroxyl and carboxyl O atoms and amino N atoms of Z and Ca, S and H atoms in G. The forms of interaction were hydrogen bonding and van der Waals force interaction, which belonged to physical adsorption. On the surface of G, the most and least adsorbed were β-glucan and galactosamine, respectively, whereas the strongest and weakest adsorbed were galactomannan and galactosamine, respectively. This study provides some indication for the interaction mechanism between mold and phosphogypsum surface.