Empirical Modeling by Active Central Composite Rotatable Design: Orange 16 Dye Biosorption onto Biosorbents Based on Residual Bacterial Lactobacillus sp. Biomass

Abstract

(1) Background: This research work proposes the ‘passive’ biosorption study of Orange 16 dye onto residual Lactobacillus sp. biomass immobilized in sodium alginate using an experimental modeling design. (2) Methods: It was applied the batch biosorption methodology was applied with a real-time determination of residual dye content and biosorption efficiency (Y, %). Empirical planning was used based on an active central composite rotatable design of 23 order in which three independent variables were considered, including residual biomass concentration (2.92–13.00 g/L, mean granule size of 0.7–1.0 mm) (X1), temperature (8–42 °C) (X2) and biosorption time (4–24 h) (X3), in association with the considered dependent variable (Y). The proposed mathematical model was validated using a few statistical tools. (3) Results: The batch biosorption experiments were permitted to propose a mathematical model considering a basic value and variation step for each selected independent variable and then to validate it. The maximum experimental dye removal was 79.98% when 11 g/L immobilized biosorbent was applied in an 89.76 mg/L dye-containing solution at 15 °C and 20 h. The significance of each independent variable on dye removal was investigated and, most importantly, explained. (4) Conclusions: The residual Lactobacillus sp. biomass can be applied as an alternative biosorbent for anionic dye removal from an aqueous solution.