Facile Oxygen-Enriched Hierarchical Porous Carbon Particles Based on Biomass Wastes for Improving the Adsorption of Malachite Green From Aqueous Solutions

Abstract

The abundance of active groups and the surface areas of adsorbents used for the removal of contaminants such as dyes are very important for the effective adsorption process. For this purpose, the high surface area-activated carbon was obtained by activation of agricultural waste chestnut shells as carbon precursor(CSAC) with sodium hydroxide in the first stage of this study. In the second stage, the doping of oxygen atoms with nitric acid was carried out to further improve the surface properties of this activated carbon (O-doped CSAC). The obtained oxygen-rich activated carbon sample was used as an adsorbent to remove a cationic dye malachite green (MG). EDS, SEM, XRD, FTIR and nitrogen adsorption analyses were used for the characterisation of these activated carbon samples. FTIR, elemental analysis and EDS analyses showed a significant increase in the amount of oxygen groups on the surface. The BET surface area obtained for CSAC had a high surface area of 1548 m(2)/g. Kinetic, thermodynamic and isotherm parameters for the adsorption of MG with O-doped CSAC were determined. The qe values obtained for MG adsorption with O-doped CSAC showed an adsorption efficiency of about 90 %. An adsorption capacity of 284.6 mg g(-1) was obtained at 298 K with the Langmuir isotherm. The adsorption mechanism of MG with O-doped CSAC was also investigated.