Vol. 10, Special Issue 5 (2021)

Author(s):
K Nagaraju, TNVKV Prasad, V Munaswamy and Y ReddiRamu

Abstract:
The present study emphasized on the differences in the spectrochemical and optical characteristics of clay particles extracted from various regions of Andhra Pradesh which were categorized into black and red soils. From the DLS analysis, no significant differences were noticed in the size of the particles (ranged from 9.8 to 47.8 nm) as well as in their viscosity (range from 0.892-0.895) in both types. However, we have observed a wide range of difference in the zeta potential. The nanoclay particles extracted from black soil were observed to be less stable with a least zeta potential of + 22.5 mV and red soil with high stability and dispersion with a highest zeta potential of -69 mV. FTIR data revealed presence of carboxylic acid salts (1523 cm-1), phosphate (900 cm-1) and silicon ions (1100 cm-1), thiols/ethers (684 cm-1) were commonly present in all the samples irrespective of black and red soils but alkyl carbonates (1742 cm-1) were seen in all black soil samples and also exclusively in the red soil. The crystal structure analyses revealed that Kaolin was present exclusively in the clay samples of coastal regions (7 Å spacing) and rectorite characteristic to 25.0 Å spacing was seen in both types of soil and also Montmorilonites (17.7 Å) was detected in some samples. Electron microscopic images showed curved and matted flakes and a combination of spiny and flocculating flakes shaped nanoclay particles extracted from black soils. Curved and matted flakes and a combination of spiny and flocculating flakes shaped nanoclay particles have been observed which were extracted from the red soils.