Ag removal from e-waste using supercritical fluid: improving efficiency and selectivity

ABSTRACT

E-waste, including toxic and precious metals, requires an effective and environment-friendly disposal method. Extraction by supercritical CO₂ is attractive, being inexpensive, available, and environment-friendly. This paper reports an investigation of Ag extraction from waste printed circuit boards [WPCBs] using supercritical CO_2. Effects of temperature, pressure, dynamic time, various co-solvents, modifiers, and complex formers on the efficiency of the process are studied. The optimum reaction parameters are calculated through Response Surface Methodology (RSM). In addition, both calculated and experimental results are analysed using Design Expert software program, and the mathematical equations are presented for different parameters and experimental conditions. The optimum conditions for supercritical extraction are 217 bar, 51 ᵒC, and 40 mins, and the most appropriate ligand and co-solvent are found to be Cyanex 302 and acetone. Finally, a 98.75 Ag extraction from waste printed circuit boards was achieved using the proposed method.

KEYWORDS:

• E-waste
• WPCB
• silver
• supercritical CO₂
• recycling

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the University of Tehran.