posted on 2024-01-03, 08:30authored byJade Nadine
S. Ang, Ali Y. Chahine, Thomas J. Raeber, Stuart R. Batten, David R. Turner
Due
to the continuous growth rate of the electronic industry, hi-tech
companies depend on mining and extracting precious metals to meet
the public demand. The high turnover of modern devices generates an
alarming amount of electronic waste (e-waste), which contains more
precious metals than mined ores and therefore needs efficient recovery
procedures. A highly stable homopiperazine-derived Cd-MOF, poly-[Cd(H2L)]·9H2O,
with a protonated amine ligand core, exists as a twofold interpenetrated
3D framework with 1D channels into which the N+–H
bond is directed. The geometry of these channels appears to be suitable
to host square planar metalate complexes. Under acidic conditions,
[MCl4]x− anions containing
Au, Cu, Ni, and Pt, representing common components of e-waste under
extraction conditions, were tested for capture and recovery. Cd-MOF exhibits remarkable selectivity and uptake performance
toward Au with an adsorbent capacity of 25 mg g–1ads and shows a marked selectivity for Au over Cu in competitive
experiments. The adsorption mechanism of Au appears to be predominantly
physical adsorption at the surface of the material.