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A model to describe Cr(VI) kinetics biosorption
Jordi Poch1, Isabel Villaescusa
1Department of Applied Mathematics, Escola Politècnica Superior, Universitat de Girona, Avda. Lluís Santaló, s/n, 17071 Girona, Spain. jordi.poch@ima.udg.edu
Journal of Hazardous Materials
|November 26, 2009
Summary
Controlling pH significantly impacts chromium(VI) sorption onto grape stalks, especially at lower temperatures. A new model accounts for chromium sorption, reduction to chromium(III), and pH changes during the process.
Area of Science:
- Environmental Chemistry
- Adsorption Science
- Waste Valorization
Background:
- Chromium(VI) is a toxic pollutant requiring effective removal methods.
- Grape stalks represent an abundant lignocellulosic waste material.
- Understanding sorption kinetics is crucial for designing efficient remediation systems.
Purpose of the Study:
- To investigate the effect of pH control on chromium(VI) sorption kinetics onto grape stalks.
- To develop and validate a kinetic model that incorporates pH variations.
- To assess the influence of temperature on the sorption process.
Main Methods:
- Sorption experiments conducted at constant pH (controlled by Programmable Logic Controller) and evolving pH.
- Experiments performed across a temperature range of 5-50°C with precise temperature control.
- Development of a complex reaction sequence model including sorption and reduction steps.
Main Results:
- pH control significantly influences chromium(VI) sorption kinetics, particularly at lower temperatures (5-10°C).
- The proposed kinetic model accurately describes the experimental data, considering pH evolution.
- Chromium(VI) reduction to chromium(III) and subsequent sorption are integral parts of the process.
Conclusions:
- Grape stalks show potential as a biosorbent for chromium(VI) removal.
- Kinetic modeling considering pH changes provides a more realistic understanding of the sorption mechanism.
- The study highlights the importance of pH management in optimizing chromium removal using agricultural waste.
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