Synergistic effect of coupling ozonation/adsorption system for toxic dye efficient removal: chemometric optimization by Box-Behnken response surface methodology

This work aims to optimize the ozonation/adsorption coupling system as an advanced technique for the removal of the dye crystal violet (CV) in the presence of new innovative material based on the Capparis spinosa L waste (CSLW). Data from operational parameters such as adsorbent dose (X1), CV concentration (X2), and oxygen flow rate (X3) were used to optimize the dye removal rate (Y) by the Box-Behnken design (BBD) response surface methodology. Under the ideal conditions of X1 (2 g center dot L-1), X2 (100 mg center dot L-1), and X3 (4 L center dot min-1), the rate Y exceeded 99.75%. The complete removal of the CV dye by the ozonation/adsorption coupling results from the selective interactions between the surface groups of the CSLW material, the ozone, and the various charges present in the solution. The coupling mechanism indicates that ozonation partially degrades the CV dye and the adsorption process significantly increases the percentage of removal due to the different adsorbent-adsorbate interactions. Due to the low power consumption of the oxygenator and ozonator and the lack of CSLW cost, the treatment of CV by the ozonation/adsorption coupling could cost about $1.8518 L-1. Thus, this process could be generalized through an industrial pilot-scale application.