Synthesis of zeolite-carbon composites using high-carbon fly ash and their adsorption abilities towards petroleum substances

摘要

In this paper, high-carbon fly ash (HCFA) was used to produce the zeolite-carbon composites of faujasite and gismondite structures (named NaX-C and NaP1-C, respectively) in pilot scale using the single-step hydrothermal conversion. The possibility of using the obtained composites in the petroleum substances removal was studied. The materials were characterized by means of particle size distribution, CHN elemental analysis, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, scanning electron microscopy, X-ray diffraction, DTA/TG thermal analysis, Fourier transform infrared spectroscopy, as well as BET surface area and pore structural analysis. The adsorption performance was examined using a Westinghouse procedure towards engine oil, used engine oil and kerosene. HCFA and composites exhibited high content of carbon (28.1-44.5%), accompanied by mineral phase abundant with silica and alumina (18.2-30.2% and 10.0-13.6%, respectively). The composites revealed a presence of well-defined zeolite crystals formed onto carbonaceous surface and more developed textural parameters in relation to HCFA. Specific surface area S-BET of HCFA, zeolite-carbon composites NaP1-C and NaX-C was 46, 249 and 67 m(2)/g, respectively. The sorption capacity towards oils was 1.14-1.39 g/g for HCFA, 1.1-1.54 g/g for NaX-C, 1.32-1.69 g/g for NaP1-C depending on the oil properties as well as the particle size and pore structure of the adsorbent.