Speaker
Description
With the tremendous increase of hydrogen production via water electrolysis technology, the development of a recycling process for valuable raw materials is emerging as an important issue for a functional circular economy. Since the size range of the active materials used in polymer electrolyte membrane (PEM) water electrolyzers is well below 100 µm, the development of mechanical separation technologies has not been well established. Conventional mechanical separation processes, such as flotation, are not effective for particles in the submicron scale. According to previous investigations, each material on both electrodes shows a contrast in surface properties in terms of (de)wett(ing)ability. For this study, pure particle fractions of carbon black and titanium oxide are used as representative materials.
Oil agglomeration is one of the widespread technologies to recover hydrophobic particles. As reported by Kim Van Netten in 2017, the separation of fine coal particles from a suspension was achieved by developing hydrophobic binder comprising only 5 % of organic liquid. In this study, this novel organic emulsion system is applied to separate ultra-fine carbon black particles selectively from the particle mixture and to assess the functionality of the emulsion to develop a process for PEM recycling. The degree of particle agglomeration was determined depending on the agitation time and single dosage of the hydrophobic binder. Furthermore, the impact of the hydrophobic binder on the process of separating particles by flotation is investigated. The experimental results are compared with those of a typical reagent e.g. Kerosene (Escaid 110). In contrast to the economic advantages of hydrophobic binder in the paper from Kim Van Netten, in our study, there was no significant difference in effectiveness between binder and kerosene.
References
Kim van Netten et al., 2016, Selective agglomeration of fine coal using a water-in-oil emulsion, Chemical Engineering Research and Design,
| Keywords | Water electrolyzer, PEM, Agglomeration, Recycling, particle interaction |
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