Naslov
Paramagnetic molecular centers in the gamma- irradiated precipitates obtained in the system AlCl3 beta-alanine NaOH

Autori
Himdan, Takialdin A. ; Noethig Laslo, Vesna ; Bilinski, Halka

Izvornik
International journal of radiation applications and instrumentation. Part C, Radiation physics and chemistry (1359-0197) 40 (1992), 3; 225-231

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
initial clay formation ; acid-Na+system ; phases

Sažetak
The presented results are the continuation of our work on paramagnetic molecular centers in the model clay compounds. Here it was attempted to incorporate beta-alanine in the aluminium hydroxide matrix. A series of precipitates were prepared with the highest ratio of beta-alanine/Al = 0.22 obtained at pH = 7. X-ray diffraction analysis revealed in addition to amorphous precipitates, microcrystalline samples of four different X-ray patterns in nine precipitates, indicating variations in the structure of aluminium hydroxide matrix with incorporated beta-alanine. Selected samples were exposed to gamma-irradiation at 77K, and at room temperature (293 K) in the presence and in the absence of air. In all the samples of amorphous structure no stable paramagnetic centers were determined by ESR after gamma-irradiation in air. In all samples of microcrystalline structure similar stable paramagnetic centers were determined by ESR after gamma-irradiation in air and in the evacuated tubes. These paramagnetic centers that we were unable to identify due to the poor resolution of the lines in the ESR spectrum can be most probably ascribed to structural defects introduced into the aluminium hydroxide matrix by beta-alanine. In all amorphous samples gamma-irradiated in the absence of air, the radical CH2CH2COOH formed by abstraction of amino group from the beta-alanine was determined by ESR. The radical was unstable in air. Thus in the absence of air beta-alanine may be considered as a storage site for the gamma-irradiation energy in the amorphous aluminium hydroxides.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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