Exploring the Micellar-Enhanced Ultrafiltration Process for Manganese Removal from Aqueous Solutions Using Cellulose Acetate Membrane: Response Surface Methodology

In this study, the efficacy of the improved micellar-enhanced ultrafiltration method for the removal of Mn2+ metal using a cellulose acetate membrane was assessed through Response Surface Methodology (RSM) and Box-Behnken design. The membrane, fabricated in the laboratory through the phase inversion method at a room temperature of 25±1°C, was morphologically characterized using Field Emission Scanning Electron Microscopy (FE-SEM). Additionally, (ATR-FTIR) was utilized to examine functional groups and bonds within the membrane structure. Subsequently, surfactants with a Tween 80/SDS ratio of 0.3 were employed to generate micelles. The impact of three crucial parameters, including surfactant concentration, molar ratio of surfactant to metal, and pH, as well as their interactions on the removal percentage and permeate flux, was investigated. Analysis of the graphs revealed that an increase in pH and the surfactant-to-metal ratio led to increased rejection. However, the concentration of surfactant exhibited a nuanced relationship: rejection increased up to a value of CS=9.2 mM, beyond which rejection decreased. Concerning seepage flux, each operational parameter's increase contributes to its decrease, with the lowest flux occurring when all parameters simultaneously reach their maximum values. In the optimization phase, the highest rejection value was 99.156%, accompanied by a flux of 5.411 mL/m2. s. Simultaneously, at CS=8.052 mM, S/M=8.476, and pH=7.29, a removal rate of 95.679% and a permeate flux of 4.151 mL/m2.s was observed. Consequently, MEUF technology and the test design method with the fabricated cellulose acetate (CA) membrane provided Mn2+ removal efficiency of 99% and a flux of 5.411 mL/m2.s, demonstrating effective Mn²⁺ removal and high membrane flux.