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

1.6.1.2. Entrapment in Polymeric Matrices
The polymers matrices used are calcium alginate (Babu et al. 1993, Costa and
Leite, 1991, Peng and Koon, 1993, Gulay Bayramoglu et al. 2002), polyacrylamide
(Macaskie, et al. 1987), polysulfone (Veglio, et al. 2003, Bai and Abraham 2003).
Gel particles are obtained from immobilization in calcium alginate and
polyacrylamide. The materials obtained from immobilization in polysulfone and
polyethyleneimine are the strongest.
1.6.1.3. Covalent Bonds to Vector Compounds
Silica gel is the most common vector compound (carrier). In this technique,
the form of materials are gel type particles. It is generally utilized for algal
immobilization (Holan, et al. 1993).
1.6.1.4. Cross-Linking
The addition of the cross-linker leads to the formation of stable cellular
aggregates. This technique was found useful for the immobilization of algae (Holan,
et al. 1993, Valdman and Leite 2000). The most common cross linkers are:
formaldehyde, glutaric dialdehyde, divinylsulfone and formaldehyde - urea mixtures.
1.7. Aim of this Study
The aim of this study was primarily based on the biosorption of aqueous Pb 2+ ,
Cd 2+ , and Ni 2+ by the algae (biosorbents) such as Dunaliella salina, Oocytis sp.,
Poprhyridium cruentum, and Scenedesmus protuberans and investigate the
biosorption ability of the biosorbents towards the metal ions.
In this sudy, biosorption experiments were with respect to the pH of the metal
ion solution, sorption time, initial metal ion concentration, and the amount of the
biosorbent used. The desorption of the metals from the biosorbents and the repetitive
usability of the biosorbents were also studied. In addition, competitive performance
of the metals were also studied in the presence of the other metal ions.
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