Study of adsorption of Congo red on ferric oxide@straw magnetic composites

Abstract

In this paper, citric acid-modified corn stalk and Fe3O4 were used to make magnetic straw adsorbent to realize rapid separation of adsorbent and wastewater. The influences of pH, dosage, reaction time, and initial stress on the Congo red adsorption rate were investigated. Then, we used adsorption kinetics and isothermal linear adsorption adjustment to explore the adsorption mechanism. Studies have shown the increasing doses of magnetic adsorbents on straw. When the dose was 8 g/L, the commercial adsorption rate was 95%. The adsorption process of magnetic straw adsorbent for Congo red was exothermic. Adsorption was mainly chemisorption, and the adsorption process was relatively fast, reaching adsorption equilibrium after about 90 min.