Facile synthesis of magnetic-activated nanocomposites for effective removal of cationic and anionic dyes in an aqueous environment: An equilibrium isotherm, kinetics and thermodynamic studies

Contamination of wastewater with dye ions is a serious threat to the environment, thus making its removal exigent, for which adsorbent has proved very useful. In this study, magnetized activated carbon (MAC) was synthesized from eucalyptus leaves with simultaneous magnetization with K2CO3 and FeCl3 that increased the surface area and porosity of eucalyptus carbon (EC). The adsorption behavior of methyl orange (MO) and methylene blue (MB) by MAC was investigated and characterized before and after the adsorption to investigate the effects of pH, initial dye ion concentration, MAC dose, adsorption time and temperature on the adsorption effect. The results showed that the amount of MO adsorbed on MAC increased from 50 mg/g to 205 mg/g, and the amount of MB adsorbed increased from 50 mg/g to 289 mg/g with the increase of the initial concentration. The results of the fitted adsorption process are consistent with the pseudo-secondary, Langmuir and D-R models, which indicate a predominantly chemisorption accompanied by physical adsorption and monolayer adsorption, a spontaneous heat absorption process that may occur through ion exchange, electrostatic interaction and surface complexation. The high adsorption capacity and magnetic properties of MAC make it a potential adsorbent for dye wastewater treatment.