Biosorption of Organic Dyes: Research Opportunities and Challenges - Green Chemistry for Dyes Removal from Wastewater - page 306

Furthermore, SEM and EDS analysis indicated the chitosan surface cover-
age and the interaction between the sulphonate groups of the dyes and the
amino groups of the chitosan. In the work of Mirmohseni et al. [70], chito-
san hollow fibers were prepared by dry-wet spinning process, and applied
for the biosorption of Reactive Blue 19 (RB 19). They obtained chitosan
hollow fibers with high mechanical strength (47.57 MPa) which were suit-
able to remove RB19 from aqueous solutions. Wong et al. [75] evaluated
the effects of temperature, particle size and percentage deacetylation on the
biosorption of acid dyes on chitosan. They found that the biosorption was
favored by the temperature increase, particle size decrease and deacety-
lation decrease. These results were explained on the basis of the swelling
effect and changes in crystallinity. On the other hand, Piccin et al. [59], in
the biosorption of FD&C Red 40 by chitosan, verified that the process was
favored by the temperature decrease and deacetylation degree increase.
Their results were explained based on the dye solubility and increase in
chitosan protonate amino groups. Detailed information about the use of
chitosan as biosorbent can be obtained in Crini and Badot [9] and Wan
Ngah et al. [66].
8.2.5 FungalBiomass
Fungal biomass is another class of biosorbents used for the removal of
SODs from aqueous solutions [76-85]. A fungus is a member of a large
group of eukaryotic organisms that includes microorganisms such as
yeasts and molds. The fungal cell wall is composed of glucans and chitin.
Furthermore, in its internal cellular structure, there are proteins, lipids,
disaccharides, polysaccharides, alcohols and other compounds [86]. The
above compounds contain a series of functional groups such as amino,
carboxylic acid, phosphate and others [6,80-85]. These functional groups
are responsible for dye binding [80-85]. Fungi are easy to grow, produce
high yields of biomass and at the same time can be manipulated genetically
and morphologically. The fungal organisms are widely used in a variety of
large-scale industrial fermentation processes. The biomass can be cheaply
and easily procured in substantial quantities as a byproduct of established
industrial fermentation processes [87]. Table 8.5 summarizes the biosorp-
tion capacities of some fungi.
Khambhaty et al. [81] studied the biosorption of Brilliant Blue G (BBG)
from aqueous solutions by marine Aspergillus wentii . Some parameters
such as contact time (0-80 min), initial dye concentration (119.3-544.8
mg L -1 ) and pH (2-10) were evaluated. They verified that the contact time
necessary to reach equilibrium was 180 min. The BBG biosorption was
strictly pH dependent. The biosorption isotherm data fitted well to the