Adsorption of malachite green dye composites based on MWCNT-COOH-cellulose as new adsorbent: kinetics and thermodynamic study

Two or more materials are combination for the composites synthesis that exhibit different physical and chemical properties than the primitive materials. Today, the use of nanocomposites as adsorbents for the treatment of dusts of dye-producing factories, due to their physical and chemical properties, is one of the fields of interest for researchers. In this study, the kinetics and thermodynamics of the green malachite dye were investigated by two nanocomposite adsorbents including carboxylated multi-wall carbon nanotube, cellulose, and magnesium nano-oxide particles. For this purpose, the first-order kinetic model, four types of second-order kinetic models (type I, II, III, and IV) and the Elovich kinetic model were investigated. Also, Gibbs free energy changes, enthalpy and entropy of the adsorption process were investigated. A kinetic study showed that the process performed with the second-order pseudo-second kinetic model (type II) was better. Also, thermodynamic functions, such as ΔG°, ΔH°, and ΔS° were calculated and it reveals that the adsorption MG dye on both surfaces was spontaneous and endothermic in nature.