Response Surface Methodology Optimized Eriochrome Black T Dye Removal Using Alumina Beads: Isotherms and Kinetics Studies

Abstract

Numerous approaches have been investigated for the development of cheaper and more effective technologies to improve the quality of industrial effluent. However, adsorption has been one of the most simplest and economical remediation technology in the treatment of wastewaters. In this study, commercial alumina beads (Al-beads) were utilized for the adsorption of Eriochrome Black T dye. The adsorption process was optimized using the RSM model by Box-Behnken Design (BBD). From the optimization result, the most influential variables are; the initial dye concentration, the interaction between adsorbent dosage with itself, and that of adsorbent dosage with initial dye concentration. The R2 value of 0.7743 implies that 77.43% on the percent dye removal could be due to the variation in the independent variable. Whereas the Adeq. precision of 6.493, and lack of fit (0.92) implies the model can be used to navigate the design space. Up to 98.28%, dye removal was attained using the Al-beads under the conditions; pH of 12.39, adsorbent dosage (1.25 g), and initial dye concentration (175 ppm). The sorption data indicated that the adsorption process was fitted to Freundlich and Temkin isotherm models, while for the kinetics study, the pseudo-second-order model was the best fit. Furthermore, the adsorption mechanism was found to be governed majorly by intra-particle diffusion with some contribution from external mass transfer diffusion.