Mesoporous carbonaceous materials (Starbon®) for metal adsorption and energy storage

Humankind heavily rely on electrical and electronic devices which require precious metals and energy, the latter typically derived from fossil fuels. Increasing concern for the environment has led to the search for renewable sources of energy (i.e. solar, wind) and sustainable ways to utilise metals. Porous carbons have been widely used as adsorbents to recover metals from waste streams, and as electrodes for energy storage devices (i.e. electrochemical double layer capacitors).
Starbon® are mesoporous carbonaceous materials derived from starch. A method for the preparation of Starbon® monoliths has been developed. In turn, the potential of Starbon® for the adsorption and recovery of precious metals from solution was investigated. Starbon® were capable of adsorbing Pd, Pt and Au, reaching adsorption capacities of up to 600 mg·g-1 for Au. The application of Starbon® to complex mixtures of metal waste showed preferential adsorption of Au, leaving the other metals (i.e. Cu, Fe, Ni) in solution. In addition, monoliths allowed for the adsorption of gold in flow regimes.
A method for the preparation of Starbon®-graphite composites was also developed. These materials combined the good porosity of Starbon® and the high conductivity of graphite. These composites were shaped as small discs which allowed them to be tested as electrochemical double layer capacitors. The electrochemical characterisation showed the good performance of these Starbon®-graphite composite capacitors. The composites were shaped as discs without the need of a binder, which can negatively affect the properties of the material.