Gamma radiation-induced pstructural changes in PP-films studied by small-angle X-ray scattering

X-ray scattering methods at large and small angles were used for the determination of structural changes induced by high energy -radiation (⁶⁰Co) in modified polypropylene films     

Sorption and desorption of Fe(III) on natural and chemically modified zeolite

The Fe(III) uptake from aqueous solutions by natural and chemically modified zeolites was investigated using a gradual radioexchange method and AAS technique. The leachability of Fe(III) from loaded zeolites was studied too. The Fe-uptake reached the value of 60 mg·g⁻¹ for the zeolite chemically treated with 6 mol·l⁻¹ solution of NaOH and it is more than twelve times higher than that of the raw zeolite. The leachability of the loaded zeolite samples in water and alkaline solution was up 5%. The leachability of the same zeolites in acid solution depended on the concentration of modifying solution. The leachability at pH=2.6 in the range 2–20% at pH=1.9 was many times higher. The results of the radioexchange and AAS methods were compared.     

Adsorption and Desorption of Cr(III) on Natural and Chemically Modified Slovak Zeolites

Natural and chemically modified zeolites from the Slovak Republic and Ukraine have been investigated as the adsorbents for the uptake of Cr(III). Model water solution of low radioactivity was used. The adsorption and desorption kinetics of chromium were established with the gradual radioexchange technique (tracer ⁵¹Cr) and flame AAS. The effect of the factors studied are examined and explained. The sorption coefficient , distribution coefficient K _D , sorption capacity , sorption rate S, and leachability of Cr were calculated in neutral, alkaline and acidic aqueous solutions. The sorption capacity of the modified zeolites was found to be greater by a factor of 2 to 16 than that of the unmodified ones depending on the modifying solution applied. The leachability of chromium from loaded zeolites into the neutral solution was negligible. The leachability into alkaline and acidic solutions increased over 40%.     

Developing iron nitrosyl complexes as NO donor prodrugs

A novel class of water-soluble iron nitrosyl complexes has been developed for use as NO donor prodrugs. To elaborate these NO prodrugs various water-soluble ligands were used such as P(CH2OH)3, 1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane (PTA), 1,2-bis[bis(hydroxymethyl)phosphino]ethane (HMPE), 1,2-bis[bis(hydroxymethyl)phosphino]benzene (TMBz), cysteamine, cysteamine hydrochloride, L-cysteine ethyl ester hydrochloride (LCEE) and pyrimidine-2-thiol (pyrim). The mononuclear complexes Fe(NO)2P(CH2OH)3Cl , Fe(NO)2(P(CH2OH)3)2, Fe(NO)2(PTA)2, Fe(NO)2HMPE , Fe(NO)2TMBz , [Fe(NO)2pyrimI] , [Fe(NO)3P(CH2OH)3][X] (X=PF6, SbF6, BF4) and the dinuclear species [Fe(NO)2S(CH2)2NH3Cl]2, [Fe(NO)2S(CH2)2NH3I2] , [Fe(NO)2LCEE]2 and [Fe(NO)2pyrim]2 were obtained. Complexes , , , , , , and are water-soluble. , and were identified as nitroxyl and , , , and as nitric oxide donors by applying an EPR NO-trap assay. To determine the amount of nitric oxide which was released from the nitric oxide donors, an additional electrochemical methodology was used. The equilibrium release or the trapping concentration of NO was also studied by a UV-vis method, which allowed the rate constant of NO release to be determined.     

The Use of Radio-Release Methods for the Determination of Some Water Pollutants

Water pollution is a global problem of expanding concern, not only because of an ever larger number of chemicals being added by man to the hydrologic cycle, but also because of the greatly increased need for larger and larger amounts of useable water. The latter factor has required multiple reuse in many parts of the world, and hence placed greater demands on pollution control technology. At the same time, we are gradually becoming more aware of the sometimes subtle and complex effects of pollutants on the behavior of the hydrologic cycle itself; problems of accelerated eutrophoication, long-term contamination of underground water, and unexpected effects of sediment contamination are only a few examples. A potentially far-reaching factor is the surprisingly recent realization that we have inadequate information about the environmental behavior and ultimate fate of many pollutants; e.g. the heavy metals.     

Neutron absorptiometric titration

A method is outlined for detection of two-phase titration end-points by means of an abrupt change in the neutron-absorption characteristics of one of the phases. One of the components of the precipitate must have a large neutron absorption cross-section, and the disappearance or appearance of neutron absorption by the supernatant liquid from the precipitation reaction then marks the completion of precipitation.