Nano γ-Fe2O3/bentonite magnetic composites: Synthesis, characterization and application as adsorbents

Abstract Nano γ-Fe 2 O 3 modified bentonite magnetic composites (γ-Fe 2 O 3 /Bent) were synthesized via an annealing approach of the ferric oleate and bentonite compounds. The γ-Fe 2 O 3 nanoparticles with narrow size distribution and an average diameter of 32 nm were equably dispersed on the surface and between layers of the bentonite nanosheets, which mainly owed to the complete mixture of ferric oleate and hydrophobic modified bentonite. The γ-Fe 2 O 3 /Bent composites exhibited typical ferromagnetic characteristics with the saturation magnetization of 22.31 emu/g and coercivity of 209 Oe. Adsorption performance measurement indicated that the γ-Fe 2 O 3 /Bent composites are a kind of excellent adsorbent with fast adsorption rate, high adsorption capacity, 99.99% removal rate and easily magnetic separation process for the removal of cationic dye methylene blue (MB). Adsorption kinetics and isotherms were studied to describe the adsorption process, and the electrostatic adsorption mechanism was confirmed by zeta potential measurement.