Enhanced Recovery of Au(III) under Neutral pH Conditions Using Polysulfide-Porphyrin Polymers

Abstract

Adsorbents capable of high extraction of gold from complex sources, especially electronic waste (EW) and seawater, are needed for gold resource sustainability and effective recycling. Herein, polysulfide-porphyrin polymers (S-PPors) that can effectively extract gold from complex matrices have been successfully developed. Among them, S-PPor-1 exhibited an adsorption rate of 97.59% at pH = 6.0. The adsorption capacity of S-PPor-1 for Au(III) reached 833.33 and 2000.00 mg/g, respectively, at 25 and 55 °C under the environment of pH = 6, which was more suitable for the adsorption of Au(III) under neutral conditions. The optimum adsorption effect occurs at 55 °C and pH 6. The high adsorption rate mainly depends on the complexation and oxidation–reduction. When 10 mL of eluent was selected, the adsorption rate of S-PPor-1 remained above 85% after seven cycles. Finally, S-PPor-1 selectively and efficiently extracted Au(III) from high-salt solutions as well as EW leaching solutions, showing great potential for the recovery of gold from these substrates.

An N-Rich Polymer for the Selective Recovery of Gold from Wastewater

“…Among these, adsorption is a commonly used and advantageous method because of its simple synthesis of adsorbent materials, ease of operation, and low cost. Numerous adsorbent materials, such as resin [11,12], covalent organic frameworks (COFs) [13,14], metal-organic frameworks (MOFs) [15][16][17], and polymers [18,19], have been employed for adsorption. Polymers are commonly used as adsorbent materials for gold recovery.…”