Comparative adsorption of methylene blue by magnetic baker's yeast and EDTAD-modified magnetic baker's yeast: Equilibrium and kinetic study.

• Adsorption mechanisms of methylene blue onto EDTAD-modified magnetic baker's yeast (EMB) were deeply studied. • EMB showed super-paramagnetic characteristic of nano-Fe 3 O 4 for isolation and recovery and good adsorption capacity of EDTAD for cationic dye. • Specific surface area of EMB was 94.972–499.85 m²/g which was around twice bigger than that of MB. Magnetic baker's yeast (MB) was prepared using glutaraldehyde cross-linking method and chemical modification with ethylenediaminetetraacetic dianhydride (EDTAD). The fabricated EDTAD-modified magnetic baker's yeast (EMB) was then employed to remove methylene blue. Comparative adsorption of methylene blue by EMB and MB was systematically investigated with respect to pH, contact time, initial concentration and reaction temperature. The mechanism of methylene blue adsorption by EMB and MB was investigated by SEM, FTIR and Special surface area using methylene blue method. The results revealed that Fe 3 O 4 nanoparticles were steadily cross-linked/incorporated with baker's yeast biomass and the EDTA was modified on the surface of the magnetic baker's yeast. The equilibrium adsorption data were fitted better by Langmuir isotherm, and the specific surface areas were 42.953–226.07 m²/g for MB and 94.972–499.85 m²/g for EMB, respectively. Kinetic studies suggested that the pseudo-second-order model was suitable to describe the adsorption process. Thermodynamic studies indicated that the adsorption was feasible, spontaneous and endothermic. The recovery efficiencies were above 80% by using 0.1 M HCl. [ABSTRACT FROM AUTHOR]