Page 37 - PR 2014 2016 07 Nuclear Science and Technology

Nuclear Science and Technology | Progress Report 179

analyzing the crystals, through instrumental of them reaching up to 50 meters in height.
neutron activation analysis (INAA). These trees can be found scattered through-
out the Amazon region. The fruits, known to
The samples were provided by the Labora- Brazilians as Castanha do Pará, are charac-
tory of the Radiation Detector at IPEN that teristically a spherical capsule, with a thick,
was developing the BiI crystals growth to be hard, dark brown surface. From the capsules
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used as radiation semiconductor detector. For are extracted the edible seeds, the Brazil nut,
purification, BiI crystals have been grown by considered as one of the most valuable prod-
3
the vertical Bridgman technique, based on ucts harvested from a tropical forest. In the
the melting and nucleation phenomena. After extraction process, large amounts of residues
completion of the growth step, some crystals formed from Brazil nut shell and bur fibers are
were selected from the bottom, middle and generated. In this case, the project consisted in
top of the system, for analysis of impurities. making the physical and chemical characteri-
Another part was reprocessed, i.e. the entire zation of these residues. Instrumental neutron
process was repeated. Several repetitions were activation analysis (INAA) was used to make
made in order to obtain the crystal with a high the mineral characterization of the extraction
degree of purity. by-product. The inorganic composition found
in Brazil nut shell and bur fibers were Br, Cl,
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In this case, INAA demonstrated to be a sen- Cs, Na, Rb (at μg g ) and Co, Sb, Sc, Se and Th
sitive analytical technique useful to identify (at μg kg ).
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and quantify the impurities: Ag, As, Br, Cr,
K, Mo, Na and Sb in BiI crystals in order to Applications of neutron
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distinguish the segregation of the impurities activation analysis in the
along the crystal and, to evaluate the reduction
of the trace impurities, after each purification study of human health

number.
Analysis of medicinal clays
Characterization of Brazil Nut Fibers
In order to meet the demands of the National
The agro-industry generates innumerable Policy on Integrative and Complementary
sources of biomass that are neither sufficiently Practices of the Ministry of Health that ad-
nor adequately utilized. The use of lignocel- vocates encouraging research in these field,
luloses fibers and their constituents as raw including the social thermalism and medicinal
materials in the production of polymeric and plants, with a view to evaluating the effi-
composite materials represent an exceptional ciency, effectiveness and safety of care, the
opportunity for sustainable technological de- nuclear analytical techniques are used in the
velopment. In order to think about potential characterization of the chemical, mineralogi-
and future exploitation and applications of cal and radiological composition of clays with
lignocellulosics, properties and performance of therapeutic and cosmetic application, elemen-
fibers under environmental or other conditions tal composition determination of medicinal
must be known. plants, studies of the soil elemental composi-
tion influence on the production of secondary
Brazil nuts (Bertholletia excelsa, family Le- metabolites, verification of the adequacy on
cythidaceae) grow on wild trees with some the trace elements contents to the ingestion