Adsorption of water-soluble organic dyes on ferrofluid-modified sawdust

Abstract

Abstract A magnetically responsive composite material based on lignocellulose and magnetic nanoparticles has been prepared. Spruce sawdust was magnetically modified by contact with water-based magnetic fluid stabilised with perchloric acid. Electron spin resonance and transmission electron microscopy measurements indicated the presence of both individual magnetic nanoparticles and clusters precipitated on the surface of sawdust particles. The material prepared was used to study the adsorption of selected water-soluble organic dyes. The adsorption isotherms followed Langmuir, generalised Freundlich, generalised Langmuir, and Langmuir-Freundlich adsorption patterns. Maximum adsorption capacities for acridine orange, Bismarck brown, crystal violet, malachite green, methyl green, Nile blue, safranin O and Saturn blue LBRR 200 ranged between 34 and 59 mg g-1 dry adsorbent. A change in pH value can increase the dye adsorption. Ferrofluid-modified sawdust is thus an interesting material for further study and potential applications.