Development of amine-functionalized magnetic mesoporous carbon for dyes removal from single and binary: adsorption performance and mechanism

Amine-functionalized magnetic mesoporous carbons (AFMMC) were prepared by a casting process using hard template, and ammonia gas and ferric salt as the nitrogen and iron source, which exhibited excellent adsorbents properties for the removal of anionic dye orange II (O II) or cationic dye methylene blue (MB) from aqueous solution. The AFMMC showed a higher adsorption capacity of two dyes than origin mesoporous carbon (MC), the improved adsorption capacity of AFMMC can be mainly attributed to the successfully introduction of the basic nitrogen-containing functional groups on the surface of mesoporous carbon. As isolated compounds and as a mixture of both of systems, equilibrium adsorption isotherms and kinetics were studied. During single dye solution system, the adsorption data of two dyes could be better described by the Langmuir model and pseudo-second-order model. Moreover, for AFMMC, the maximum adsorption capacities of 389.6 and 325.3 mg g(-1) for O II and MB dyes in single dye solutions, respectively. The thermodynamic studies reveal that the adsorption of two dyes onto the MC and AFMMC were spontaneous and exothermic. The binary-component system was better described with Langmuir-Freundlich isotherm models. The results indicated that the presence of competitive adsorption between O II and MB dye occurred in binary systems, the maximum adsorption amount of O II or MB dye in two dyes binary-mixture systems is less than that of the single dye system. In addition, the removal ability of O II or MB dye after desorption not significantly decreased, demonstrating an excellent regeneration ability of AFMMC. The as-prepared AFMMC materials have the potential to be used for the efficient removal of organic pollutants.