Ernő E. Kiss

Bimetallic Cobalt Based Catalysts

Highly dispersed, oxide- or zeolite-supported bimetallic catalysts are widely used in the catalytic industry, such as in catalytic reforming, nitrogen industry and gas-to-liquid technology. The paper highlights the nano-sized Co-based bimetallic system in terms of correlation between structure and reactivity/selectivity promoted by the second metal. Opposite to the bulk alloys nano-sized bimetallic catalysts are extremely sensitive to the structure, morphology, valence state of the supporting oxide material in which the nano-particles are embedded. In this case, one of the less reducible components, which strongly interact with the supports, may stabilize the second, more noble metals, and thus the latter can be stabilized in highly dispersed state. Conversely, addition of noble metal to the hardly reducible component may facilitate reduction, which causes the retardation of the deactivation process of some hydrocarbon reaction. The future trend is the application of bimetallic nano-particles although careful consideration and experimentation should be taken to elucidate the structure of such type of catalyst. The various effects of Co-based bimetallic particles, such as particle size, metal/support interface, morphology and electronic effects, on the activity/selectivity in given catalytic reactions will be discussed.

Photochemical Behavior of the Insecticide Methomyl Under Different Conditions

This article describes the photolytic and photocatalytic removal of the insecticide methomyl at low concentration from different types of water, upon UV, visible or natural solar light radiation, in the presence of TiO2 and ZnO, as well as using Fe-ZSM-5 zeolite and AlFe-pillared montmorillonite (photo-Fenton process). The rate of photodecomposition of methomyl was measured using UV spectrometry and HPLC, while its mineralization was investigated by ion chromatography (IC) and total organic carbon (TOC) analysis. The photochemical removal of methomyl is a natural and applicable model for the purification of water.

Catalytic concept of mineralizing effects

The subject of this work is the mechanism of phase transformations and chemical reactions of pure aluminas and kaolinite doped by Cu2+, Mn3+/Mn2+ and Fe3+/Fe2+ ions. Accelerated phase transformations of metastable aluminas and mullite formation of metal doped samples are explained by catalytic mechanism in terms of Jahn-Teller effect.

A study of the photocatalytic degradation of methomyl by UV light.

The photocatalytic degradation of insecticide methomyl in water, using TiO2 and ZnO (Merck), under UV (366 nm) was studied. The influence of the catalyst concentration and pH was investigated. The optimal concentration of the catalyst was found to be 2.0 g/l. It was found that ZnO is a better catalyst than TiO2 under the same reaction conditions. Also, the influence of NaCl was studied. The presence of Cl- significantly affects the photodegradation of the pollutant.

Stabilization of intermediate phases on preparing Fe/MgO catalysts

During the activation of coprecipitated catalysts both the precursor of the metal component and the precursor of the support undergo structural transformations. In certain instances the combination of processes may result in stabilization of catalytically inactive phases. In the present study stabilization of a catalytically inactive phase containing Fe4+ ions is suggested in the course of the activation of an Fe(OH)3/MgC2O4 catalyst precursor.

The influence of polychromatic light on methomyl degradation in TiO2 and ZnO aqueous suspension

AbstractThe photocatalytic degradation of the insecticide methomyl in water using TiO2 Merck Eusolex® T (anatase) under Osram ultra-vitalux® lamp light (315–400 nm, 300 W) was studied. The effect of the operational parameters, such as initial concentration of catalyst, initial methomyl concentration, initial salt concentration (NaCl), and pH, was studied. The optimal concentration of catalyst was found to be 2.0 g/L. Using the Langmuir–Hinshelwood mechanism as a base, a pseudo-first-order kinetic model was illustrated and the adsorption equilibrium constant and the rate constant of the surface reaction were calculated (KMT = 0.079 L/mg and kC = 0.134 mg/L min, respectively). The photodegradation rate was higher in acidic than in alkaline conditions. The presence of Cl– ions significantly affected the photodegradation of the pollutant. The rate of photodecomposition of methomyl was measured using UV spectroscopy and high performance liquid chromatography, while its mineralization was followed using ion chr...

Guest editorial—in memoriam Paula Putanov

The first ten articles in this issue are dedicated to the memory of Prof. Paula Putanov, member of the Serbian Academy of Sciences and Arts, a widely known and respected scientist, who passed away on 24th January 2014 after a short battle with illness. Paula Putanov was born on 14th July 1925 in Darda, The Kingdom of Serbs, Croats and Slovenes. She graduated in 1952 from the University of Belgrade, Faculty of Technical Sciences. She obtained her Ph.D. degree from the same Faculty in 1958. Her professional work started as a teaching assistant, and later become research associate at the Institute of Chemistry of the Serbian Academy of Sciences and Arts, later reorganized as the Institute of Chemistry of the Republic of Serbia and finally