Environmental Engineering Reference
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biosorption (Volesk, 2007), where certain types of biomass are able to bind
and concentrate metals from even very dilute aqueous solution. A biosorption
process offers a number of advantages when compared to the conventional
methods currently used.
5. I NERTIZATION /B IOSORPTION BY B IOMATERIALS
Removal of toxic heavy metals using conventional treatment technologies
is not economical and also generates a large quantity of toxic chemical sludge.
In this context, biosorption is emerging as a possible alternative to remove
toxic heavy metals from aqueous solutions. The major advantages of
biosorption over conventional treatment technologies are: low cost, high
efficiency, minimization of chemicals or biological sludge, regeneration of
biosorbents and possibility of metal recovery (Sud et al., 2008)(Figure 6).
Figure 6. Advangtages of Biosorption.
The significant sources formetal biosorption are cellulosic agricultural
materials. The main functional groups present in agricultural waste biomass
which are involved in the removal of toxic heavy metals are acetamido,
alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. These
functional groups have affinity for heavy metal ions to form metal complexes
or chelates. The mechanism of biosorption process includes chemisorption,
complexation, adsorption on surface, diffusion through pores and ion
exchange etc.
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