Adsorption of BTX from aqueous solutions by Na-P1 zeolite obtained from fly ash

Abstract

Abstract The adsorption of BTX (benzene, toluene, o- and p-xylene) from aqueous solution by synthetic zeolite Na-P1 obtained from fly ash was examined. The adsorbent was characterized by scanning electron microscope (SEM-EDS) and X-ray diffraction (XRD). Surface area and pore volume distribution were determined using a nitrogen adsorption/desorption isotherm. BTX adsorption tests, including the influence of contact time, sorption isotherms and the influence of initial concentration, were performed in a batch multicomponent system. The sorption capacity followed the order xylenes > toluene > benzene, and the removal efficiency decreased with an increase in initial BTX concentration. The process kinetics was evaluated using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The adsorption equilibrium was reached within 24 h and followed pseudo-second-order kinetics. The Langmuir, Freundlich and Temkin models were used to evaluate the adsorption capacity of Na-P1. The Langmuir model was found to be the most suitable for all BTX sorption from a multicomponent system. The calculated maximum adsorption capacities of Na-P1 (qmax) for benzene, toluene, o- and p-xylene were 0.032, 0.050, 0.147 and 0.129 respectively.