Microencapsulation of zinc plating waste using silicone polymers.

Area of Science:

• Environmental Engineering
• Materials Science
• Waste Management

Background:

• Hazardous waste containing zinc and chloride poses environmental risks.
• Current stabilization methods may not be sufficiently effective for safe disposal.

Purpose of the Study:

• To develop and evaluate a two-step treatment process for hazardous zinc-bearing waste.
• To ensure safe disposal of treated waste into landfills.

Main Methods:

• Solidification using hydraulic binders followed by encapsulation with silicone polymers.
• Characterization via X-ray fluorescence, X-ray diffraction, and scanning electron microscopy.
• Leaching tests in distilled water and acidic environments (Toxicity Characteristic Leaching Procedure).

Main Results:

• The two-step treatment significantly reduced zinc and chloride concentrations in acidic extracts.
• Zinc and chloride levels decreased from 12,400 mg/L and 38,300 mg/L to 21.9 mg/L and 74 mg/L, respectively.
• Treated waste met regulatory requirements for landfill disposal; porosity was a key factor in leachability.

Conclusions:

• A two-step treatment using hydraulic binders and silicone polymers is effective for hazardous zinc-bearing waste.
• This method is superior to single-step silicone microencapsulation.
• Optimizing porosity is crucial for minimizing pollutant leaching.