Modified activated carbon as a promising adsorbent for quinoline removal

Abstract Activated carbon from coconut shell ( Elaeis guineensis ), in crude form and as forms chemically modified with concentrated solutions of HNO 3 and H 2 SO 4 , were initially tested for their ability to remove quinoline from an organic medium. The adsorbents were characterised by techniques such as adsorption/desorption of N 2 at 77 K, the point of zero charge, the Boehm method, infrared spectroscopy, thermogravimetric/differential thermal analysis, X-ray photoelectron spectroscopy and CHNOS elemental analysis. The best results of contaminant removal were achieved using sulfuric acid-treated activated carbon (SAAC). With regard to its potential in quinoline removal, SAAC was evaluated in a closed batch system by a phenomenological investigation of the adsorption process, using experimental data and mathematical modelling of kinetics and equilibrium. The maximum adsorption capacity (q max ) obtained by the Langmuir model was 56.6 mg g −1 . The kinetic results obtained for different concentrations of quinoline showed that the internal resistance model, with variable mass transfer coefficient, suitably describes the quinoline adsorption process in a batch system. Therefore, such model should be used for the optimisation and design of industrial-scale columns for the investigated, and similar, systems.