Page 184 - 00. Complete Version - Progress Report IPEN 2014-2016

184 Nuclear Science and Technology | Progress Report

The samples were provided by the Laborato- Brazilians as Castanha do Pará, are charac-
ry of the Radiation Detector at IPEN that was teristically a spherical capsule, with a thick,
developing the BiI3 crystals growth to be used hard, dark brown surface. From the capsules
as radiation semiconductor detector. For pu- are extracted the edible seeds, the Brazil nut,
rification, BiI3 crystals have been grown by considered as one of the most valuable prod-
the vertical Bridgman technique, based on ucts harvested from a tropical forest. In the
the melting and nucleation phenomena. Af- extraction process, large amounts of residues
ter completion of the growth step, some crys- formed from Brazil nut shell and bur fibers are
tals were selected from the bottom, middle generated. In this case, the project consisted in
and top of the system, for analysis of impuri- making the physical and chemical characteri-
ties. Another part was reprocessed, i.e. the en- zation of these residues. Instrumental neutron
tire process was repeated. Several repetitions activation analysis (INAA) was used to make
were made in order to obtain the crystal with the mineral characterization of the extraction
a high degree of purity. by-product. The inorganic composition found
in Brazil nut shell and bur fibers were Br, Cl,
In this case, INAA demonstrated to be a sen- Cs, Na, Rb (at μg g-1) and Co, Sb, Sc, Se and Th
sitive analytical technique useful to identi- (at μg kg-1).
fy and quantify the impurities: Ag, As, Br, Cr,
K, Mo, Na and Sb in BiI3 crystals in order to Applications of neutron
distinguish the segregation of the impurities activation analysis in the
along the crystal and, to evaluate the reduc-
tion of the trace impurities, after each purifi- study of human health

cation number.
Analysis of medicinal clays
Characterization of Brazil Nut Fibers

In order to meet the demands of the Nation-
The agro-industry generates innumerable al Policy on Integrative and Complementa-
sources of biomass that are neither sufficient- ry Practices of the Ministry of Health that ad-
ly 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 medic-
materials in the production of polymeric and inal plants, with a view to evaluating the ef-
composite materials represent an exceptional ficiency, 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 therapeutic and cosmetic application, elemen-
of fibers under environmental or other condi- tal composition determination of medicinal
tions must be known. plants, studies of the soil elemental compo-
sition influence on the production of second-
Brazil nuts (Bertholletia excelsa, family Le- ary metabolites, verification of the adequacy
cythidaceae) grow on wild trees with some on the trace elements contents to the inges-
of them reaching up to 50 meters in height. tion limits and evaluation of the potentially
These trees can be found scattered through- toxic elements content in medicinal plants.
out the Amazon region. The fruits, known to For such, the techniques of Neutron Activa-

Instituto de Pesquisas Energéticas e Nucleares