Surfactant-assisted flocculation for the efficient removal of aqueous dyestuff: A sustainable approach

Abstract

This work is focused on designing a suitable methodology for the fast and effective treatment of wastewater containing reactive dyestuff. The efficiency of surfactant-based flocculation is evaluated with a scope to produce water that can be reused for industrial purposes. The biodegradable anionic surfactants, along with the polyvalent salt, have been used in different concentrations and experimental conditions to access the optimized parameters for achieving maximum removal of the dye reactive blue 21 (RB-21). During the micellization process, surfactant molecules have the potential to capture dye molecules from the aqueous phase. The flocculant contributes by aggregating the surfactant micelles and often by forming complexes with dye molecules that later adsorb at the micelle-water interface. Calculations were performed to determine the removal efficiency and adsorption characteristics. The experimental data were used in different isotherm models to determine the mechanism. Furthermore, the nature and stability of the process were also evaluated by fitting data in different kinetic models and thermodynamic equations, respectively. The results revealed that micellar flocculation is a simple and sustainable method for removing colorants with high efficiency, i.e., around 99 %. The process needs no pH adjustment, higher temperature, and expensive membranes. Moreover, the process only takes a few minutes to complete.