An absorption process of S02 in the aqueous suspension of ilmenite has been found to be an efficient process of gas desulphurization. Practically, the complete absorption of S02 is possible at the appropriate selection of the principal process parameters: ilmenite content in the suspension, and temperature.
Twenty two scab-resistant apple cultivars, harvested in the 2007 and 2008 seasons, were analysed for phenolic compounds content and polyphenol oxidase (PPO) activity. Tyrosine content was determined in the raw juices of five selected cultivars. The results showed substantial differences in the composition between the investigated apple cultivars, particularly in the phenolic compounds contents. Their total polyphenol content ranged from 161.9 to 882.4 mg/kg f.w., with hydroxycinnamic acids as the main phenolic compounds. The level of PPO activity ranged from 5 to 240 U/g f.w. Almost half of the 22 cultivars show PPO activity below 50 U/g f.w. 'Angold', 'Selena' and 'Gold Milenium' showed the highest PPO activity; between 125-133 U/g f.w. 'Rebella', 'Sampion', 'Topaz', 'Rewena', 'Enterprise' and 'Gerlinde' showed the lowest PPO activity. Statistical analysis showed no correlation between PPO activity and total polyphenol content or hydroxycinnamic acids. No correlation can be confirmed between PPO activity and tyrosine content.
A general dependence of the enzyme catalytic rate on its mass was revealed when a statistical analysis of 17065 records from the EMP database was performed. The estimated activation energy of the catalytic process decreases asymptotically with the enzyme molecular mass increase. The proposed theoretical model postulates the existence of an intermediate complex of the enzyme and the departing product. It allows for the explanation of the discovered mass-energy relationship, as an effect of the global enzyme-product interactions during complex dissociation. Fitted parameters of the model seem to be in agreement with those widely accepted for the van der Waals energy of molecular interactions. Their values also agree with the picture of the hydrogen bonding in the catalytic process and suggest that surface walk can be the favorable way of the product departure.
The water-gas shift reaction performance of Fe2O3, Ru/Fe2O3 catalysts and the same compounds doped with sodium ions was studied. An addition of sodium was found to result in an increase of the ruthenium catalyst activity and stabilization of its surface area during the reduction with the reaction mixture. This series of catalysts was examined by XPS method. The addition of sodium and ruthenium causes an increase in the ionicity of the Fe2O3 lattice, manifested as changes in intensity of peaks of the Fe 2p band.