Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

49ACTA FACULTATIS ECOLOGIAE, 16: Suppl. 1, 49 – 52 Zvolen (Slovakia), 2007GENERATION OF SINGLET OXYGEN BY MODIFIEDNATURAL ZEOLITES AND MONTMORILLONITESFrantišek Šeršeň 1 – Stanislava Pavlíková 1 – Karol Jesenák 2 – Gabriel Čík 31Institute of Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina,842 15 Bratislava, Slovak Republic, e-mail: sersen@fns.uniba.sk;2Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava,Mlynská dolina, 842 15 Bratislava, Slovak Republic, e-mail: jesenak@fns.uniba.sk;3Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology,Slovak University of Technology in Bratislava, Radlinského 9, 812 37 Bratislava, Slovak Republic,e-mail: gabriel.cik@stuba.skABSTRACTŠeršeň F., Pavlíková S., Jesenák K. & Čík G. Generation of Singlet Oxygen by Modified Natural Zeolitesand MontmorillonitesThis work deals with the generation of singlet oxygen by modified natural zeolites and montmorollonites.In the work natural zeolite from the deposit of Nižný Hrabovec (Slovak Republic) and montmorillonitefrom the deposit of Stará Kremnička – Jelšový Potok (Slovak Republic) were used. Both natural aluminosilicateswere doped with Fe 3+ and thiophene or pyrrole. It was found that all four forms of preparednatural alumininosilicates are able to produce singlet oxygen in chloroform suspensions under visible light.It was also found that all prepared forms of natural aluminosilicates decomposed 4-chlorophenol in watersurroundings. We suppose that the singlet oxygen formation causes decomposition of 4-chlorophenol. Thiseffect of thus modified natural zeolites and montmorillonites can be exploited to decontamination of theenvironment polluted by chlorophenol compounds.Key words: chlorophenol decomposition, montmorilonote, singlet oxygen, zeoliteINTRODUCTIONSinglet oxygen ( 1 O 2) belongs to reactive oxygenspecies. Essentially, it is an oxygen moleculeO 2in excited state. 1 O 2, despite not being a radical,is very reactive and easily initiates various radicalreactions. 1 O 2can be generated by several physical,chemical, photochemical or biological reactions[1]. Photoexcitation is the most frequently usedmethod for generation of 1 O 2. Because, molecularoxygen does not exhibit serious absorption in UV–VIS radiation, its excitation is carried out indirectlyby photosensible compounds [2]. For that purpose,organic dyes [3] or oligomers of thiophene derivatives[4] are used.Zeolites are porous aluminosilicates with netsof channels and cavities, which are composed ofthe AlO 45–and SiO 44–tetrahedrons [5]. Montmorillonitebelongs to dioctahedral phylosilicates. Itsstructure is composed of two tetrahedron and one–octahedron layers; the negative charge of the layersis compensated by various cations (for instanceNa + , Ca 2+ , Mg 2+ , Fe 3+ ) [5]. It is known that iron dopedzeolites form thiophene oligomers in channelsor cavities and on the surface of the zeolite [6,7].Also, montmorillonites are able to form thiopheneoligomers [8].The goal of this work is to demonstrate the possibilityof generation of singlet oxygen by modifiednatural zeolites and montmorillonites and their usefor photodecomposition of 4-chlorophenol in watersolution.