Application and Modifications of Ordered Mesoporous Carbon (OMC) for BTEX Removal: Characterization, Adsorption Mechanisms, and Kinetic Studies

Chemical and petrochemical industries produce substantial amounts of wastewater every day. This wastewater contains organic pollutants such as benzene, toluene, ethylbenzene and xylenes (BTEX) that are toxic to human and aquatic life. Ordered Mesoporous Carbon (OMC), an adsorbent that possesses the characteristics of an ideal adsorbent was investigated to understand its properties and suitability for BTEX removal. Adsorption isotherms, adsorption kinetics, the effects of BTEX initial concentrations, and temperatures on the adsorption process were studied. The OMCs were characterized using surface area and pore size analyzer, transmission electron microscopy (TEM), elemental analysis, thermogravimetric analysis (TGA), and fourier transform infrared spectroscopy (FTIR). The results suggested that the Langmuir isotherm and pseudo-second-order models described the experimental data. The thermodynamic parameters, Gibbs free energy (ΔG), the enthalpy change (ΔH), and the entropy change (ΔS) of adsorption indicated that the adsorption processes were physical, endothermic, and spontaneous. In addition, OMC had 27% higher total adsorption capacities compared to GAC. Physical modifications on OMC were performed by varying the ratios of boric acid to sucrose. The BTEX adsorption capacities were improved from 8% to 15% with the addition of boric acid. The highest total adsorption capacity was 116.6 mg g -1 using OMC-2. Chemical modification of OMC using citric acid showed increase in adsorption capacity by 21.7% compared to OMC-2