Biomedical subjects

D Mehandjiev

Publications and source records attributed to D Mehandjiev.

4 recordsLinked to original sources

PubMed2005

Adsorption of NO on alumina-supported oxides and oxide-hydroxides of manganese.

The adsorption capacity for NO of alumina-supported oxides and oxide-hydroxides of manganese have been studied. Two series of samples have been prepared by precipitation on gamma-alumina and appropriate thermal treatment. The samples have been characterized by adsorption methods, magnetic methods, electronic paramagnetic resonance (EPR), transient response technique, and temperature-programmed desorption (TPD). The influence of the concentration of the initial manganese-containing solution has been investigated. The sample, prepared with a solution with Mn concentration of 4 g/100 ml, has been shown to be the best adsorbent for NO under the conditions of the experiment. It has been found that the presence mainly of Mn3+ ions on the surface of the support is probably responsible for the enhanced adsorption capacity.

Adsorption↗

PubMed2003

Copper oxide supported on carbon modified alumina as catalyst for reduction of NO with CO.

Carbon-modified alumina-supported copper oxide catalysts have been investigated. The samples have been prepared by modified incipient techniques. The gamma-Al(2)O(3)-supported carbon phase permits sufficient modification of the chemical nature of the support surface in the region of low carbon contents without changing the specific surface area and the mesoporous character of the samples as compared to those of initial gamma-Al(2)O(3). In addition, the surface oxygen groups of the carbon phase, similar to the hydroxyl groups of the alumina surface, affect the formation and type of copper oxide phase. It has been established that the catalysts investigated have high activity in the reduction of NO with CO, the highest activity belonging to the Cu17AC/AL catalyst, which contains the largest amount of carbon. This sample is also active with respect to the direct decomposition of NO.

Journal Article↗

PubMed1999

Study on Active Carbon-Supported Two-Component Catalysts for NO Conversion.

The impregnation of active carbon with two-component aqueous solutions of Cu and Co nitrates has been investigated and different deposition degrees of copper and cobalt ions have been established. Adsorption analysis has shown modification of the active carbon texture after impregnation with solutions whose concentration of Cu and Co ions exceeds 3%. A catalyst with a high activity in the reduction of NO with CO at 100 degrees C has been obtained. All samples are found to catalyze the complete reduction of NO to N2. A correlation between the catalytic activity and the Cu:Co ratio in the supported phase has been established. Copyright 1999 Academic Press.

Journal Article↗

PubMed1997

Study of Ni-Impregnated Active Carbon

The reduction of NO with CO on Ni-impregnated active carbon catalysts (AC/Ni) has been investigated. High activity toward NO reduction can be achieved on an AC/Ni catalyst obtained by thermal decomposition of the precursor nitrate at 200°C. The role of active carbon in the catalytic reduction of NO with CO at different temperatures has been discussed. At low temperatures (below 200°C), when there is no substantial gasification of the carbon, dissociative adsorption of NO along with N2 evolution and oxygen accumulation on the carbon surface has been observed. The active sites occupied by the oxygen evolved during the NO decomposition are regenerated by the CO reducing agent. At high temperatures the C-O complexes evolved from the carbon surface participate in NO reduction as a second reducing agent. The effect of the oxygen-containing functional groups and the available nitrate groups on catalyst activity has been discussed. Copyright 1997Academic Press

Journal Article↗