Highly selective enrichment of Au using enaminone covalent organic polymers (COP)

The second recovery of gold has fundamental environmental and economic significance. In this study, an enaminone covalent organic polymer (COP) was synthesized and used to recover gold from secondary resources. The ketene covalent organic polymer (COP) possessed good gold adsorption performance, and the best adsorption capacity could reach up to 1945 mg g^-1 at 298 K, which was superior to traditional adsorbents. Meanwhile, the synthesized COP exhibited excellent adsorption selectivity and renewability of Au³⁺. The pseudo-second-order kinetic equation and Langmuir equation were suggested for describing the adsorption process. Moreover, this gold adsorption behavior was intended to be a spontaneous, endothermic, and entropy increasing process.