Fluorescent porous hybrid silsesquioxane-based semiconductor polymer for sunlight-driven gold recovery with high efficiency and selectivity

Abstract

As an important precious metal, the recovery of gold can not only relieve the shortage of resources, but also has a high economic value. In this work, a novel silsesquioxane-based fluorescent porous hybrid polymer (PTSC) was prepared successfully by Heck coupling reaction of octavinylsilsesquioxane with a dibromated distyry-bithiophenes containing cyano groups. The structure of PTSC was fully investigated, which featured a high surface area of 455 m2 g−1, wide light adsorption band, narrow optical band gap (1.73 eV) and excellent semiconductor performance. As Au(III) adsorbent, the adsorption capacity of PTSC reached 3080 mg g−1 under light irradiation for 4 h at pH = 5, and the purity of the recovered gold in e-waste could reach 23.92 K. The adsorption mechanism showed that photoelectrons produced by PTSC could reduce all Au(III) adsorbed to Au(I) and Au(0). Moreover, a hybrid aerogel device based on PTSC and chitosan was fabricated to realize the enrichment and recovery of gold ions in wastewater. Besides, PTSC could also act as a probe to detect Au(III) with high selectivity and specificity. This study provided a new strategy for efficient recovery and detection of Au(III).