200

13 Biosorption of Heavy Metals and Metal-Complexed Dyes Under the Influence

Cl

Cl

O

CO

O

N

N

N

N

N

N

N

N

H2NO2S

SO2NH2

Na⁺

–

Figure 13.5

Formazan dye.

Source: Freeman et al. [36].

–

O

O

O

N

N

N

N

Cr

O

H3CO2S

H3CO2S

Na⁺

Figure 13.6

Irgalan dye. Source: Based

on Freeman et al. [36].

synthesized by the diazotization of o-aminophenol derivatives coupled with ben-

zaldehyde derivatives such as benzaldehyde phenylhydrazones and benzaldehyde

phenylhydrazone-4-sulfonic acid thrived by iron(II) sulfate [36].

The Irgalan dyes are chromium MCDs formed by complexation of metal and acid

dyes. It has six coordination sites in which three coordination atoms are utilized

by dye and the remaining atoms complexed by the water molecules at acidic pH or

hydroxyl ion at basic pH. To improve the solubility of dyes and fastedness character-

istics, it was modified by blending with non-hydrophilic methyl sulfonyl sulfomide.

The solubilizing effects were enhanced due to electron sharing (covalent bonding)

between water and sulfonyl oxygen groups in Irgalan dyes (Figure 13.6) [36].

13.9

Biosorption of Metal-Complexed Dyes

The fungal biomass is one of the most facilitated microbial sources for the removal

of synthetic or metal-complexed dyes. During the biosorption process, the cell