Investigators at the University of Missouri – Kansas City (UMKC) and Southern Methodist University (SMU) will investigate how to retrieve gold ions from waste streams using porous polymers. Recovering gold from electronic waste (e-waste) has significant environmental and financial benefits. The global e-waste recycling market reached around $55.3 billion in 2022, with gold recovery accounting for the most value. Adsorption technology is regarded as a highly effective, simple, economical, and environmentally benign separation method. However, current adsorption-based gold recovery technology suffers from low adsorption capacity, slow adsorption rates, and low selectivity. This project will develop adsorbents for the effective and efficient recovery of gold and other metal ions essential for rechargeable battery applications, promoting the United States’ global leadership in the energy and defense sectors. This project supports the interdisciplinary training of graduate and undergraduate students. The investigators have partnered with UMKC’s Multicultural Student Affairs Office and SMU’s Engaged Learning, McNair Scholars, and Hamilton Undergraduate Research Scholars programs to recruit students from underrepresented and underserved groups in STEM. The research results will be broadly disseminated in peer-reviewed journals, conferences, and online outlets. <br/><br/>Systematic experimental and theoretical studies will be conducted to gain fundamental insights into the interactions between gold ions and novel adsorbents based on intrinsically porous triazine-crosslinked polyethyleneimine (TCPEI) networks. Four research tasks will be completed: (1) design and synthesize three series of TCPEIs with dramatically different distributions of the various types of amine nitrogen; (2) experimentally and theoretically study the gold ion adsorption capacities and energies of the three sets of TCPEIs; (3) experimentally and theoretically determine adsorption and desorption kinetics; and (4) explore the gold adsorption selectivity of TCPEIs over other metal ions commonly found in e-waste such as lead, mercury, nickel, cobalt, manganese, cadmium, chromium, iron, and copper. The research is expected to lead to advanced adsorption-based gold recovery technology. The fundamental knowledge gained through this study may also be applied to develop adsorbents for other metal ions, including critical metals. The graduate and undergraduate student researchers will be trained to synthesize these unique polymers, measure and characterize the polymers’ metal ion adsorption properties, and perform theoretical studies to understand adsorption processes and polymer properties.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.