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Stabilization of mercury-containing wastes using sulfide
1Department of Civil and Environmental Engineering, University of Cincinnati, ML 0071, Cincinnati, OH 45221-0071, USA.
Environmental Pollution (Barking, Essex : 1987)
|August 16, 2005
Summary
Sulfide treatment effectively stabilizes mercury, minimizing leaching. Optimal conditions include pH 6 and a 1:1 sulfide-to-mercury ratio, with added iron reducing interferences for 98% stabilization efficiency.
Area of Science:
- Environmental Chemistry
- Waste Management
Background:
- Mercury contamination poses significant environmental and health risks.
- Effective stabilization methods are crucial for managing mercury-containing wastes.
Purpose of the Study:
- To evaluate the effectiveness of sulfide-induced treatment for mercury stabilization.
- To determine optimal conditions for mercury immobilization using sulfide.
- To assess the impact of interfering ions on the stabilization process.
Main Methods:
- Investigated mercury stabilization using sulfide across various pH levels and sulfide/mercury molar ratios.
- Evaluated stabilization effectiveness using Toxicity Characteristic Leaching Procedure (TCLP) and constant pH leaching tests.
- Assessed the influence of interfering ions like chloride and phosphate on mercury immobilization.
Main Results:
- Sulfide treatment significantly reduces mercury leaching, achieving up to 98% stabilization efficiency.
- Optimal stabilization occurred at pH 6 with a 1:1 sulfide/mercury molar ratio.
- Increased sulfide and ferrous ion dosages ([S]/[Hg]=2, [Fe]/[Hg]=3 at pH=6) mitigated interferences from chloride and phosphate.
Conclusions:
- Sulfide-induced technology is a highly effective method for mercury waste stabilization.
- Specific pH and molar ratios are critical for maximizing mercury immobilization.
- The addition of ferrous ions enhances stabilization efficiency in the presence of common interfering ions.