Hybrid Membrane Technology for Acid Recovery from Wastewater in Coated Steel Wire Production: A Pilot Scale Study

Area of Science:

• Environmental Chemistry
• Materials Science
• Chemical Engineering

Background:

• Spent copper plating solutions contain valuable sulfuric acid but also heavy metal contaminants.
• Recycling sulfuric acid is crucial for sustainable industrial practices and waste reduction.
• Existing methods for acid recovery may be inefficient or generate secondary waste.

Purpose of the Study:

• To develop and evaluate a hybrid membrane technology for efficient sulfuric acid recycling from spent copper plating solutions.
• To assess the feasibility of reusing the recovered acid in copper plating baths.
• To determine the optimal parameters for diffusion dialysis and electrodialysis in this application.

Main Methods:

• Utilized a hybrid membrane system combining diffusion dialysis and electrodialysis.
• Processed a real spent copper plating solution from copper-coated steel wire production.
• Anion-exchange membranes were employed for initial separation of sulfuric acid from heavy metal sulfates.
• Electrodialysis was used to concentrate the purified dilute sulfuric acid.

Main Results:

• The hybrid membrane process successfully separated sulfuric acid from ferrous and copper sulfates.
• Recovered sulfuric acid concentration met the requirements for copper plating baths after processing.
• The final solution contained 1.13 mol/L sulfuric acid, with significantly reduced levels of ferrous and copper sulfates.
• Electrodialysis concentration achieved an energy consumption of 162 W·h/mol at 400 A/m² with 16% current efficiency.

Conclusions:

• Hybrid membrane technology offers an effective solution for sulfuric acid recycling from spent copper plating baths.
• The recovered acid can be directly reused in copper plating, promoting a circular economy.
• This method presents a sustainable approach to managing industrial wastewater and conserving resources.