BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...

Table 3.2. Elemental composition of biosorbents in terms of C, H, N, and S
Biosorbents % C % H % N % S
Dunaliella salina 40.19 5.79 9.19 0.76
Oocystis sp. 47.66 7.18 5.49 0.57
Porphyridium cruentum 14.45 3.11 1.30 1.57
Scenedesmus protuberans 47.52 7.02 7.18 0.66
3.1.4. Thermo Gravimetric Analysis (TGA)
Thermal stability of the algae was investigated using TGA in which the mass
loss of the sample is monitored as a function of temperature. The solid samples were
heated from 25ºC to 750ºC in 10 minute intervals in N2 atmosphere. The plots are given
in Figure 3.3–3.6.
In Figure 3.3, the first mass loss of Dunaliella salina which is less than 10% in
the temperature range of 25ºC-100ºC is due to the release of bound water molecules.
The largest loss can be seen in 240ºC-560ºC, and then in 560ºC-630ºC which can be
attributed to the decomposition of the organic part of the sample.
Figure 3.3. TGA decomposition curve of Dunaliella salina
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