Scalability, cost and feasibility of porous structures are prerequisites for emerging materials to be promising in industry. Recently, we reported a simpler variant of Friedel-Crafts synthesis of highly porous covalent organic polymers (COPs) based on an unprecedented solvent mediated cross-linking. Alkyl chlorides behave as both solvents and linkers in the presence of AlCl3. Studies on three classes of more than 20 different monomers using dichloromethane, chloroform, and 1,2-dichloroethane lead to produce a large family of alkyl linked COPs. The synthesized COPs exhibited structures from nonporous to highly porous morphologies with BET surface areas as high as 1685 m2 g-1. The simplest member, COP-150 is an intrinsically flexible porous polymer and easily made from benzene and 1,2-dichloroethane (materials cost as low as $1/kg), and scaled up to 2 kg in one batch. It showed a record high capture capacity of methane 0.625 g/g (294 L/L) when cycled between 5 and 100 bars. The flexibility provided both the rapid desorption and the thermal management, while its hydrophobicity along with the carbon-carbon bonded framework ensured robust use over many cycles and conditions. The alkyl linked porous polymers with porphyrin functionalities proved particularly effective in precious metal recovery, where COPs exhibited high selectivity toward gold, platinum, palladium, and silver. The gold adsorption capacities were 0.901-1.250 g g-1 with fast adsorption kinetics at low pH. COP-212 selectively recovered 95.6 % of gold from actual e-waste collected from junkyards. The findings point to significant potential in producing sustainable porous materials through simple and scalable methodology developed in our lab.

Alkyl linked porous polymers for methane storage and precious metal capture

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.