BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...
BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...
BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...
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such as 10.0, 20.0, 50.0, 100.0, and 200.0 mg were shaken with 10.0 mL solution of<br />
250.0 mg metal/L at 25ºC for 60 min, and the results are given in Figure 3.14-3.17. The<br />
results showed that the percentage sorption of Pb 2+ ions by Dunaliella salina increases<br />
20.0 mg biosorbent dose, then it stays constant from 20.0 mg to 200.0 mg biosorbent<br />
dose. The percentage uptake of Pb 2+ ions by Oocystis sp., Porpyridium cruentum, and<br />
Scenedesmus protuberans, shows an exponential growth. Cd 2+ and Ni 2+ sorption is<br />
lower in comparison with Pb 2+ . A relationship can also be given between a biomass<br />
amount and sorption due to the fact that the availability of the metal ion might be<br />
limited with increased electrostatic interactions, interference between binding sites, and<br />
reduced mixing at higher biosorbent dose. Furthermore, electrostatic interactions<br />
between cells could be considered as significant for the biomass-dependent metal<br />
uptake. With a large amount of metal ion which is biosorbed if the distance between the<br />
cells is greater, otherwords lower amount of biosorbent is used which is enough for the<br />
sorption takes place. Even though an increased biosorbent dose has an reducing role on<br />
the sorption capacity of a biosorbent, and in this study, the total removal of metal ion by<br />
a biosorbent is higher at higher biosorbent dose. Hence, this behaviour can be explained<br />
that there is no such a correlation between biosorbent amount and metal removal<br />
(Madrid and Camara 1997).<br />
Sorption (%)<br />
100.0<br />
80.0<br />
60.0<br />
40.0<br />
20.0<br />
0.0<br />
10.0<br />
20.0<br />
50.0<br />
100.0<br />
biosorbent amount (mg)<br />
200.0<br />
Pb<br />
Cd<br />
Ni<br />
Figure 3.14. Effect of biosorbent amount on biosorption of Pb 2+ , Cd 2+ , and Ni 2+ by<br />
Dunaliella salina (10.0 mL solution of 250.0 mg/L, solution pH of 6.0,<br />
sorption time of 60 min, and different amounts of biomass)<br />
Ni<br />
Cd<br />
Pb<br />
46