BTEX and MTBE adsorption onto raw and thermally modified diatomite.
The removal of BTEX (benzene, toluene, ethyl-benzene and xylenes) and MTBE (methyl tertiary butyl ether) from aqueous solution by raw (D(R)) and thermally modified diatomite at 550, 750 and 950 degrees C (D(550), D(750) and D(950) respectively) was studied. Physical characteristics of both raw and modified diatomite such as specific surface, pore volume distribution, porosity and pH(solution) were determined, indicating important structural changes in the modified diatomite, due to exposure to high temperatures. Both adsorption kinetic and isotherm experiments were carried out. The kinetics data proved a closer fit to the pseudo-second order model. Maximum values for the rate constant, k(2), were obtained for MTBE and benzene (48.9326 and 18.0996 g mg(-1)h(-1), respectively) in sample D(550). The isotherm data proved to fit the Freundlich model more closely, which produced values of the isotherm constant 1/n higher than one, indicating unfavorable adsorption. The highest adsorption capacity, calculated through the values of the isotherm constant k(F), was obtained for MTBE (48.42 mg kg(-1) (mg/L)(n)) in sample D(950).
Technical University of Crete, Department of Environmental Engineering, Laboratory of Toxic and Hazardous Waste Management, University Campus, P.C. 73100, Chania, Crete, Greece.
Maria
M
Aivalioti
Ioannis
I
Vamvasakis
Evangelos
E
Gidarakos
D000327:Adsorption; D000465:Algorithms; D001554:Benzene / Q000737:chemistry; D001555:Benzene Derivatives / Q000737:chemistry; D002849:Chromatography, Gas; D007692:Diatomaceous Earth / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry*; D007700:Kinetics; D008738:Methyl Ethers / Q000737:chemistry*; D010578:Petroleum / Q000032:analysis; D016062:Porosity; D052617:Solid Phase Microextraction; D012996:Solutions; D013499:Surface Properties; D013816:Thermodynamics; D014050:Toluene / Q000737:chemistry; D014865:Waste Disposal, Fluid; D014992:Xylenes / Q000737:chemistry
D001555:Benzene Derivatives; D006838:Hydrocarbons; D008738:Methyl Ethers; D010578:Petroleum; D012996:Solutions; D014992:Xylenes; C043243:methyl tert-butyl ether; D014050:Toluene; D007692:Diatomaceous Earth; C033787:diatomite; D001554:Benzene; C004912:ethylbenzene