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

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.