Application of Response Surface Methodology for Optimization of the Biosorption Process from Copper-Containing...

Copper-containing wastewater is a significant problem in the water industry. In this work, biosorption of copper ions on alginate beads have been considered as a promising solution. The effective diffusion coefficient D_e is the parameter describing the diffusion of copper ions in calcium alginate granules. Granules with a wide spectrum of alginate content from several to several dozen percent (0.6-20%) were tested. The granules with an alginate content of 20% were produced by a new method. The conductometric method was used to determine D_e. The study determined the D_e values depending on the process parameters (temperature and pH of copper solutions) and the alginate content in the granules. The RSM method was used to analyze the obtained results. The conducted research proved that all analyzed factors significantly affect the value of the diffusion coefficient (R² = 0.98). The optimum operating conditions for biosorption of copper ions from CuCl₂ salt, on alginate beads obtained by RSM were as follows: 0.57% of alginate content in the granules, temperature of 60.2 °C, and pH of 2. The maximum value of D_e was found to be 2.42·10^-9 m²/s.