SYNTHESIS AND CHARACTERIZATION OF IRON NANOSTRUCTURES INSIDE POROUS ZEOLITES AND THEIR APPLICATIONS IN WATER TREATMENT TECHNOLOGIES
MIROSLAVA VACLAVIKOVA,* MAREK MATIK, STEFAN JAKABSKY, SLAVOMIR HREDZAK Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 043 53 Kosice, Slovakia GEORGE GALLIOS Lab. Gen. & Inorg. Chemical Technolgy, School of Chemistry, Aristotle University, GR-540 06 Thessaloniki, Greece
Abstract. A new sorbent with magnetic properties and anion removal ability has been produced by incorporating iron oxide based nanoparticles into the pores of zeolite crystals. The sorbent has been tested for the removal of arsenic (V) species from model aqueous solutions in batch–type equilibrium experiments. Good sorption was observed with maximum capacity of 73.32 mg of As per g of sorbent at pH 3.5. Keywords: arsenic; iron oxides; nanoparticles; magnetically modified zeolite; sorption
Nanotechnology is developing fast, with much impact on a wide variety of technological areas. Inclusion of guests into a well-organized host matrix is a powerful method to form new nano-sized materials. Nanoporous and microporous crystals, such as molecular sieves (zeolites) are ideal hosts for accommodation of organic and inorganic molecules, polymer chains, etc., because of their uniform pore size and their ability to adsorb molecular species. It is well known that zeolites possess a negatively charged surface and are therefore good sorbents of cations. The modification of their surface can create localized functional groups with a good affinity to inorganic anions too.
To whom correspondence should be addressed. Miroslava Vaclavikova, Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 043 53 Kosice, Slovakia; e-mail:
[email protected]
239 V.N. Popov and P. Lambin (eds.), Carbon Nanotubes, 239–240. © 2006 Springer. Printed in the Netherlands.
240 Iron oxide magnetic nanoparticles were synthesized by co-precipitation of Fe(III) and Fe(II) in the presence of zeolite – clinoptilolite 40-60% with particle size 0.045-0.09 mm as described in Vaclavikova et al. (2004). The new magnetic sorbent produced was tested for the removal of As(V) species from model aqueous solutions in batch–type equilibrium experiments. The test conditions were: initial As(V) concentration 20–1000 mg.L-1; sorbent dosage 2 mg.L-1; pH 3.5; sorption time 24 h in a rotary shaker; analysis of As by AAS. Figure 1 presents the adsorption isotherm for As (equilibrium concentration of As versus uptake). The solid line represents the Langmuir model and the dashed line represents the Freundlich model. The solid points represent the experimental data. Magnetically modified zeolite was found to be a good sorbent for arsenic oxyanions with sorption capacity calculated from Langmuir model to 73.32 mg As/g of sorbent. Both models Langmuir as well as Freundlich fit well the experimental data with coefficient of determination R2 of 0.96 and 0.97 respectively. 60 Arsenic removal ... pH 3.5
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Figure 1. Sorption isotherm – As uptake by sorbent.
Research presented by this paper was supported by the Science and Technology Assistance Agency under the contract No. APVT-51-017104 as well as by the NATO Collaborative Linkage Grant EST.EAP.CLG 981103. References Vaclavikova, M., Jakabsky, S., Hredzak, S., 2004, Magnetic Nanoscale particles as sorbents for removal of heavy metal ions, in: Nanoengineered Nanofibrous Materials, NATO Science Series II, Mathematics, Physics and Chemistry, 169, Kluwer Academic Book Publishers, Dordrecht, Netherlands, Ed. S. I. Guceri, Y. Gogotsi, and V. Kuzentsov, pp. 479–484.
