EXTRACTION AND CHARACTERIZATION OF NANOCLAY PARTICLES FROM BLACK AND RED SOILS OF ANDHRA PRADESH
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Date
2018
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Acharya N.G. Ranga Agricultural University
Abstract
The present investigation was carried out to study “Extraction and
Characterization of Nanoclay Particles from Black and Red Soils of Andhra
Pradesh”. For this, ten surface soil samples (0-20 cm) were collected in
different districts of Andhra Pradesh covering black and red soils. The soil
samples were analyzed in the laboratory for physical, physico-chemical,
electro-chemical and Extraction and Characterization of Nanoclay Particles.
Five samples of black soils were collected from Kurnool, East Godavari,
West Godavari, Krishna and Guntur districts and five soil samples of red soils
from Anantapur, Kadapa, Chittoor, Vizianagaram and Visakhapatnam districts
Andhra Pradesh. Clay particles from these soil samples were collected using
the International Pipette method.
The texture of black soils in the study area ranged from clay loam to
sandy clay loam whereas the textures of red soils were sandy clay loam. The
black soils in the study area were very acidic to very slightly alkaline (5.5 to
8.0) in reaction and the red soils were neutral to very slightly alkaline (6.51 to
7.9) in reaction. The black and red soils were non saline in nature.
The cation exchange capacity of black soils in the study area were
ranged from 32.3 to 42.1 cmol (p+) kg-1 soil with a mean value of 37.6 cmol
(p+) kg-1 soil, while in red soils ranged ranged from 15.6 to 17.2 cmol (p+) kg-1
soil with a mean value of 16.32 cmol (p+) kg-1 soil.
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The present study emphasized on the differences in the spectrochemical
and optical characteristics of clay particles collected 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 proven to be less stable with a least zeta potential of +22.5 mV
(Kambaladinne) and red soil with high stability and dispersion with a highest
zeta potential of -69 mV (Utukur).
In black and red soils of Andhra Pradesh, the peak corresponding at 242
nm revealed the presence of Kaolin mineral in the samples of Garikapadu, Lam
farm, Maruteru, Vizianagaram, while the peak corresponding at 245 nm
revealed the presence of Montmorillonite mineral in the samples of Anakapalli
and Rajamahendravaram, while the peak corresponding at 250 nm revealed the
presence of Vermiculite mineral in the samples of Kambaladinne, Rekulakunta,
Utukur, Tirupati.
Further, the 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 but
Montmorilonites (17.7 Å) was detected only in the samples of Anakapalli and
Rajamahendravaram.
Electron microscopy showed curved and matted flakes in black soils of
Garikapadu, Kambaladinne and Maruteru while that of Lam farm,
Rajamahendravaram, Garikapadu have shown a combination of spiny and
flocculating flakes. The red soils of Anakapalli have shown curved and matted
flakes while that of Rekulakunta, Vizianagaram, Tirupati and Utukur have
shown a combination of spiny and flocculating flakes.
Description
D5736
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