Solution-processed porous organic polymer for gold and platinum recovery

Porous organic polymers (POPs) constructed with aromatic conjugated backbones have been widely applied in adsorption, catalysis, energy, etc. by virtue of the good porosity and abundant functional groups. However, the form of insoluble and non-melting powders for POPs leads to poor processability and difficult recycling during applications, largly hindering industrial applications. In this paper, we develop a solution-processed POP (EDTATAB) with a large number of nitrogen atoms and carbonyl groups. The synthesized EDTA-TAB can be highly dispersed in N,N-dimethylformamide through the hydrogen bonding interaction between solvent molecules and amide/carboxyl functional groups in EDTA-TAB, possessing a maximum concentration of 5 mg mL-1, and this dispersion state can remain stable for at least 4 months without sedimentation. EDTA-TAB exhibits high adsorption capacities and fast adsorption kinetics for gold and platinum, especially for gold, reaching the maximum adsorption capacity of 2040 mg g-1, and achieving a removal efficiency of 99% within 30 min. Benefiting from the good processability brought by high dispersibility, an electrostatic spinning film (EDTA-TABPAN) composed of EDTA-TAB and polyacrylonitrile (PAN) was successfully prepared. When used to extract gold from the simulated e-waste solution, EDTA-TAB-PAN film shows good adsorption performance, reaching 98% adsorption efficiency within 30 min.