Optimization and Computational Approach to Understand the Adsorption Behavior of Alizarine Red S on the Surface of Fish Scales

Abstract

The key components of fish scales are hydroxyapatite and collagen, which form a natural composite. In this present study, fish scales were used as biosorbent to uptake Alizarine Red S dyes from the wastewaters. Here, dye concentration, adsorbent amount, pH, and temperature were optimized using complete factorial design analysis. Sixteen experiments were required, and a linear mathematical model representing the influence of the different variables and their interactions was obtained. The discussion covered analysis of variance (ANOVA), normal probability plots of residuals, and surface plots. Theoretical calculations by Metropolis Monte Carlo (MC) methods, the density functional theory (DFT), and the electrostatic potential surface (ESP) analysis were achieved to obtain a more understanding of the dyes adsorption mechanism on both collagen and hydroxyapatite (HDA) surfaces. The findings results exhibited that the ARS dye presents more tendency of adsorption on the collagen than on the HDA surface.