Predation of a sand-dwelling mysid crustacean Gastrosaccus sanctus by plover birds (Charadriidae)

The plovers Charadrius hiaticula and C. alexandrinus feed on the mysid shrimp Gastrosaccus sanctus (van Beneden, 1861). They hunt at random along the sandy seashore, on the sites of the densest mysid population, regardless of the size of the mysids.     

Amorphous oxides of manganese as new sorbents of strontium ions

Samples with the best adsorption properties are selected as a result of investigations conducted on synthesis of manganese-dioxide-based materials and study of their physicochemical properties. Materials were selected on the basis of their low cost and the simplicity of their production technology. In the laboratory the synthesis and analyses of materials was carried out for selected samples. The sorption of a series of elements is studied for a more detailed investigation of materials obtained. The results obtained will promote the synthesis of materials with improved adsorption properties with the aim of their application for purification of water from strontium. It is shown that the most promising way for amendment of manganese oxide is modification of this material using acid-resistant oxides. These oxides are also less expensive than existing sorbents for strontium.     

Oxidative degradation of 2,4-xylidine by photosensitization with 2,4,6-triphenylpyrylium: homogeneous and heterogeneous catalysis

The possibility of using zeolites containing the 2,4,6-triphenylpyrylium cation as photocatalysts for the degradation of pollutants has been tested on aqueous xylidine (2,4-dimethylaniline) solutions as models for contaminated wastewaters. The influence of the photocatalyst and substrate concentrations on xylidine oxidation has been investigated in homogeneous solution, by performing a series of experiments chosen according to the experimental design methodology (Doehlert uniform array). The empirical models and the corresponding response surfaces obtained from data analysis have been used for simulating and predicting degradation efficiency. The results have shown that conversion increases with increasing amounts of photocatalyst and decreasing concentration of the model pollutant. The fluorescence of 2,4,6-triphenylpyrylium was quenched by xylidine with a rate constant k(q) of 3.1x10(9)M(-1)s(-1). This result suggests a direct electron transfer between the excited pyrylium salt and xylidine. Because of the limited stability of the photocatalyst in homogeneous media, a pyrylium containing Y-zeolite has been tested for the photocatalytic oxidation of xylidine under heterogeneous conditions. The results suggest that the supported catalyst has a much improved stability and that xylidine oxidation rates remain nearly constant during the whole reaction time. An additional advantage of the pyrylium containing zeolite photocatalyst is that it can be recycled and used for further experiments.     

Amorphous oxides of manganese as new sorbents of strontium ions

Samples with the best adsorption properties are selected as a result of investigations conducted on synthesis of manganese-dioxide-based materials and study of their physicochemical properties. Materials were selected on the basis of their low cost and the simplicity of their production technology. In the laboratory the synthesis and analyses of materials was carried out for selected samples. The sorption of a series of elements is studied for a more detailed investigation of materials obtained. The results obtained will promote the synthesis of materials with improved adsorption properties with the aim of their application for purification of water from strontium. It is shown that the most promising way for amendment of manganese oxide is modification of this material using acid-resistant oxides. These oxides are also less expensive than existing sorbents for strontium.