Removing some alizarin dyes from an aqueous solution using a polyacrylic acid hydrogel

The present work utilizes polyacrylic acid beads (PAA) to remove Alizarin yellow R (AYR)] and Alizarin Red S (ARS) from its solution. The isotherms of adsorption were investigated and the factors that impact them, such as temperature, ionic strength effect, shaking effect, and wet PAA. The isotherms of adsorption of (ARS) were found obeys the Freundlich equation. The isotherms of adsorption of (AYR) were found obeys the Langmuir equation. At various temperatures, the adsorption process on (PAA) was investigated. According to our data, there is a positive correlation between the (ARS and AYR) adsorption on the PAA and temperature (Endothermic process). The computation of the thermodynamic functions (ΔH, ΔG, and ΔS) is based on the foregoing findings, and the ionic strength influence on the dyes adsorption was determined at (20 °C). It was discovered that adsorption decreases in the presence of different salt concentrations and tap water. The adsorption kinetics were investigated, and the data were examined by the Lagergren Equation and the second-order equation model. Based on the experimental data, the adsorption was pseudo first-ordered kinetics changed in response to changing conditions.