Two-stage batch sorber design and optimization of biosorption conditions by Taguchi methodology for the removal of acid red 25 onto magnetic biomass

Abstract

Biomagnetic material (MFC) was synthesized via simple co-precipitation and used as biosorbent for the removal of acid red 25 (AR25) under optimized conditions. The characteristics of MFC were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), Boehm titration and scanning electron microscopy (SEM). Optimum removal of AR25 was achieved at pH=5.0. The equilibrium data were well described by the Sips and Freundlich models. Taguchi methodology was employed to optimize the biosorption experiments. 411.56 mg/g and 96.8% were obtained as the biosorption capacity and removal efficiency, respectively, at the optimum conditions of ionic strength (0.5 M), influent volume (300 L) and MFC dosage (4 g). The contact time for removal of 96% AR25 in two-stage batch system is 400.8 min which is lower than the single-stage treatment process (895 min).