Comparative adsorbtion of magnetic nano-bisorbent with single and binary reactive dyes

The single and competitive adsorption capacities of Metanil Yellow (MY) and Reactive Black 5 (RB5) by glutaraldehyde cross-linked magnetic chitosan nanoparticles (GMCNs) were studied. During the studies, various essential factors influencing the adsorption, like adsorbate concentration, pH of the dye solution, and contact time have been monitored. The equilibrium was achieved within 17 h for single dyes and 3 h for binary mixture at pH 3. The maximum adsorption capacities calculated by applying the Langmuir equation to single dye adsorption isotherms were 620 mg/g for MY and 2549 mg/g for RB5 at pH 3, 30 °C. The second-order kinetic model fits well with the dynamical adsorption behavior of a single dye and binary mixture. Moreover, competition adsorption through analysis of the intraparticle diffusion model apparently favored the RB5 dye more than the MY dye on the GMCNs in mixture solutions (mixture RB5 and MY). The GMCNs nanoparticles for the adsorption of the dyes were regenerated efficiently through the alkaline solution and were then reused 10 times for dye removal.