Study of zinc biosorption on natural and chemically modified rice husks
Date
2022-01
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Abstract
Heavy metal contamination is one of the greatest risks to water courses because these pollutants are
difficult to eliminate due to their non-biodegradable and persistent nature. Numerous technologies
have been developed to solve this environmental problem, being biosorption one of the most widely
used alternatives due to its efficiency, low cost and the possibility of using natural materials as
biosorbents. Agricultural residues are an important source of biomass that can be used in this type
of process. Therefore, the objective of this study was to analyze the physicochemical factors that
affect the sorption of zinc in solution using rice husk as biosorbent, either natural or chemically
modified with potassium hydroxide or phosphoric acid. This is a highly available residue in the
province of Entre Ríos, Argentina.
Sorbents were characterized by infrared spectroscopy and by determining the pH at the point zero
charge.
The chemical treatment with potassium hydroxide improved significantly the removal of the
pollutant, while the acid activation did not show improvements regarding to the use of the natural
husk. The removal levels were favoured by the increase in pH up to 5 and biosorbent dosage, while
they decreased by the rise in zinc concentration.
For the systems being evaluated it was found that the equilibrium of the process was reached quickly
and adjusted to pseudo-second order kinetics. For the adsorbents used, a monolayer sorption with
homogeneous binding sites would be presented.
Description
Keywords
Zinc, Biosorption, Rice husk, Alkali activation
Citation
Brazilian Journal of Animal and Environmental Research, v. 5, nº 1, p. 124-139.
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