Adsorption mechanism of azophloxine in water by Fe3O4-chitosan composite material

Abstract

Fe3O4-chitosan composite material was synthesized as adsorbent. The effect of solution pH value, initial concentration of azophloxine and adsorption time on the adsorption of azophloxine onto adsorbent was studied. The results show that Fe3O4-chitosan composite material can be magnetically separated before and after adsorbing azophloxine. It was found that the peak intensity of azophloxine was the strongest under weak acidic conditions, and the peak position hardly shifted. In the process of adsorption, it was found that Fe3O4-chitosan composite material adsorbing azophloxine by the surface electrostatic attraction. The optimum equilibrium adsorption capacity is at initial solution pH 6, and the equilibrium adsorption capacity is very close under weak acidic conditions. The pseudo first-order and pseudo second-order kinetic models were applied to experimental data. The adsorption process followed the pseudo-first-order kinetic model, which implied that the adsorption process was physical adsorption. The correlation coefficient for the first-order kinetic model was obtained greater than 0.99571 at room temperature, and the theoretical equilibrium adsorption capacity qe,cal value also agreed very well with the experimental equilibrium adsorption capacity qe value in the case of pseudo first-order kinetics. It is suggested that Fe3O4-chitosan composite material has a wide application prospect in the removal of dyes as adsorbent.