Highly Efficient and Selective Gold Recovery Based on Hypercross-Linking and Polyamine-Functionalized Porous Organic Polymers
Rui Ding, Yanli Chen, Yanhong Li, Yancheng Zhu, Cheng Song, Xiaomei Zhang
Abstract
With the continuous increase of electronic products, there is an urgent need to effectively recover gold from e-waste and other secondary resources other than the original mine. Here, hypercross-linking and polyamine-functionalized porous organic polymers (Pc–POSS–POP) were designed and facially synthesized based on multiple azo-coupling polymerizations between 2,9,16,23-tetraaminophthalocyanine (H2Pc(NH2)4) and octa(aminophenyl)-t8-silsesquioxane (OAPS) for the first time. The reaction requires no metal as a catalyst, thereby benefiting the purification of the product and the industrial scalability. Pc–POSS–POPs possess a hypercross-linking structure, highly conjugated frameworks, nitrogen-rich active sites, and extensively visible and near-infrared light absorption, which was utilized as an absorbent to retrieve Au (III). The results demonstrated that Pc–POSS–POPs have a high adsorption capacity (862.07 mg g–1) and a rapid adsorption rate toward gold recycling. The maximum adsorption capacity could reach up to 1026.87 mg g–1 as in the case of light irradiation. Due to the strong N coordination sites and the electronic interaction between the −NH4+ groups of Pc–POSS–POPs and AuCl4–, Pc–POSS–POPs also exhibited excellent selectivity toward gold over several coordinated metals [Cr (VI), Co (II), Cd (II), Ni (II), and Hg (II)]. These properties together with the good regenerative ability and superior recyclability demonstrated that Pc–POSS–POPs possess promising potential as hypercross-linking polymers for capturing and recycling of Au (III).