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Arsenic sorption onto laterite iron concretions: temperature effect
Journal of Colloid and Interface Science
|March 19, 2008
Summary
Laterite iron concretions effectively remove arsenic from drinking water. This low-cost material shows enhanced arsenic sorption with increasing temperature, making it ideal for tropical climates.
Area of Science:
- Environmental Science
- Geochemistry
- Water Treatment
Background:
- Arsenic contamination in drinking water poses a significant global health risk.
- Low-tech, natural materials are sought for effective arsenic removal in developing regions.
- Laterite iron concretions (LIC) were investigated for arsenic sorption properties.
Discussion:
- Sorption capacity for arsenite and arsenate increases with temperature, with arsenite sorption being higher.
- Langmuir model fits sorption isotherm data, indicating suitability for arsenic removal.
- Sorption occurs across a wide pH range, with arsenite sorption peaking at pH 7.
Key Insights:
- LIC exhibits an inner-sphere sorption mechanism for arsenate (As V) and an outer-sphere mechanism for arsenite (As III).
- Thermodynamic analysis (negative DeltaG°, positive DeltaH°, positive DeltaS°) indicates spontaneous, endothermic sorption with high affinity.
- LIC demonstrates advantages over commercial materials, including cost-effectiveness and broad pH applicability.
Outlook:
- LIC is a promising natural material for low-tech arsenic water treatment, particularly in tropical regions.
- Positive temperature dependence enhances sorption in warmer climates and geothermal areas.
- Further research could optimize LIC for large-scale arsenic remediation.
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