Biomedical Engineering Reference
In-Depth Information
Yang and Cheng (2003) have also reported the metal uptake abilities of macro
cyclic diamine derivative of chitosan. The polymer has high metal uptake abilities,
and the selectivity property for the metal ions was improved by the incorporation of
azacrown ether groups in the chitosan. The selectivity for adsorption of metal ions
on polymer was found to be Ag
+
> Co
2+
>Cr
3+
. These results reveal that the new type
chitosan-crown ethers will have wide ranging applications for the separation and con-
centration of heavy metal ions in environmental analysis.
Chitosan grafted with poly(methylmethacrylate) is an efficient adsorbent for the
anionic dyes (procion yellow MX, Remazol Brilliant violet and Reactive blue H5G)
over a wide ph range of 4-10 being most at pH 7. The adsorbent was also found ef-
ficient in decolorizing the textile industry wastewater (Singh et al., 2009). Chitosan
grafted with cyclodextrin, has ability to form complexes with a variety of other ap-
propriate compounds, and are very promising materials for developing novel sorbent
matrices (Sreenivasan, 1998). Martel showed that the adsorption of textile dyes from
the effluent can be carried out with CD grafted with chitosan derivatives. Moreover
these systems have superior rate of sorption and global efficiency than that of parent
chitosan polymer and of the well-known cyclodextrin-epichlorohydrin gels (Martel
et al., 2001).
Composites of Chitosan
Silicate-chitosan composite shows the greatest adsorption of Cd(II) and Cr(II) at pH
7. When Cr(II) was evaluated, pH 4 was optimal for its adsorption (Copello et al.,
2007). Steen Kamp investigated the capacity of Cu(II) adsorption on alumina/chito-
san composite, a new composite chitosan biosorbent prepared by coating chitosan, a
glucosamine biopolymer, onto ceramic alumina (Steem Kamp et al., 2002). Chitosan
coated on alumina exhibits greater adsorption capacity for Cr(VI). The ultimate capac-
ity obtained from the Langmuir model is 153.85 mg/g chitosan (Boddu et al., 2003).
Chitosan/magnetite nano composite beads have the maximum adsorption capaci-
ties for Pb(II), and Ni(II) at pH 6 under room temperature which were as high as 63.33
and 52.55 mg/g respectively. Chitosan magnetite nano composite beads could serve a
promising adsorbent not only for Pb(II) and Ni(II) but also for other heavy metal ions
in wastewater treatment technology (Hoang Vinh Tran et al., 2010).
Chitosan/polyurethane porous composite-based on chitosan, polyether polyols,
and tolylene diisocyanate were prepared. Adsorption of Cu
2+
and Cd
2+
on CS/PU
was studied with atomic adsorption spectroscopy. The removing rate of Cu
2+
reached
96.67% the removing rate of Cd
2+
reached 95.67%; the adsorption capacity of CS/PU
for Cu
2+
and Cd
2+
was 28.78 mg/g and 25.32 mg/g, respectively. The selective adsorp-
tion of CS/PU for Cu
2+
is higher than that for Cd
2+
when Cu
2+
and Cd
2+
co-exist (Liu et al.,
2010).
Chitosan/kaolin/nanosized Ỳ-Fe
2
O
3
composites were prepared by a micro emul-
sion process and characterized by TEM, SEM, and WAXRD. Many pores and pleats
were visible on the surface of the composites and provided a good condition for dye
adsorption. Methyl orange was selected as a model anionic azo dye to examine the
adsorption behavior of the composites. About 71% of methyl orange was adsorbed
within 180 min, from 20 mg/l at ph 6 by 1.0 g/l adsorbent dosage. The composites can
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