Page 84 - Annual Report_21-22

Mineralogical and petrological characterisation of the syenite body around the Rairakhol area,
Odisha for evaluation of its REE potential

This project was taken up for mineralogical and petrological the REE content of nepheline syenite varies from 26 to
characterization of the syenite body, around the Rairakhol 650 ppm and the higher concentration of REE is found
area, Sambalpur District, Odisha, with an objective to in the rocks having more mafic rich minerals. The major
evaluate its REE potential. Field work has been carried mineral phases are albite, microcline, hornblende, biotite
out and representative nepheline syenite samples were and nepheline. The RE bearing mineral phases are zircon,
collected from the alkaline complex. Petrographical, apatite, allanite, britholite and sphene identified through
mineralogical as well as geochemical characterisation of SEM-EDS. The grain size of the REE phases varies from 10
the samples has been done using an optical microscope, to 40 microns and they occur as inclusions as well as in the
XRD, SEM, WD-XRF and ICPOES. This study reveals that grain boundary region of the major mineral phases.

A: Nepheline syenite rock showing alternation of
mafic and felsic layers
B: SEM-BSE image showing RE bearing mineral phase -
britholite
C: EDAX spectra of RE bearing mineral phase - britholite
D: Semi quantitative analysis of britholite phase showing
the concentration of REE
Development of UV-SERS substrate for environmental monitoring

Chemically stable SnS nanostructures are excellent an excellent SERS substrate, exhibiting significant SERS
2
building blocks for semiconductor-based SERS activity with an enhancement of 2.9 × 10 and a low
2
applications. A comparative UV-SERS study of adsorbed detection limit of 10 mol/L for CV molecules under UV
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crystal violet (CV) probe molecules on 2D-layered excitation (Figure 1). This remarkable sensitivity and
tin disulfide (SnS ) nanoplates and carbon-doped enhancement are attributed to surface defects caused
2
SnS nanoflowers (SnS -C) is studied. The carbon doping in by carbon doping. Energy band engineering on the above
2
2
the SnS nanostructure plays a significant role in exciting 2D semiconductor substrate is a new approach in the SERS
2
electrons by UV laser and interfacial charge transfer (CT) field. This may pave the way for the development of novel
process through a substantial reduction in the band- SERS technology under UV excitation.
gap. The optimized carbon-doped SnS material acts as
2

Fig. 1. Raman spectra of CV dye molecules drop-casted on SnS -C substrate with decreasing concentrations
2
(10 –10 M).
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82 ANNUAL REPORT 2021-22