Kinetic adsorption of hazardous methylene blue from aqueous solution onto iron-impregnated powdered activated carbon

Abstract

© 2019, Faculty of Environment and Resource Studies,Mahidol University. All rights reserved. In this study, iron-impregnated powdered activated carbon (Fe-PAC) prepared using chemical co-precipitation techniques was used as an adsorbent for methylene blue (MB) removal in a batch experiment. The analysis of transmission electron microscopy, scanning electron microscopy with energy dispersive spectroscopy showed that iron oxide particle was substantially distributed into the surface of the adsorbent, suggesting that Fe-PAC was successfully synthesized. The results showed that fast and efficient adsorption of MB by Fe-PAC was achieved, with a relative short contact time of 10 min and MB adsorption capacity of 51 mg/g. The kinetic adsorption of MB on Fe-APC adsorbent was well described by a pseudo-second-order model. Concurrently, the analysis of intraparticle diffusion model suggests that intraparticle diffusion is not the only rate-limiting step of MB molecules adsorption by Fe-PAC adsorbent. The elevated temperature conditions also improved the removal efficiency of MB. Thermodynamic parameters exhibited by the MB adsorption process onto Fe-PAC were endothermic and spontaneous. The findings of the present work indicate that Fe-PAC can be a potentially effective adsorbent for MB removal in wastewater due to its fast and efficient MB adsorption, and separation in wastewater treatment systems.