Influence of surface wettability on electrostatic fog collection efficiency using polytetrafluoroethylene-coated carbon papers

TL;DR

This study shows that the wettability of PTFE-coated carbon papers has little effect on electrostatic fog collection efficiency, which is mainly influenced by electrostatic current.

Contribution

The study reveals that PTFE coating has minimal impact on electrostatic fog collection efficiency compared to hydrophilic surfaces.

Findings

PTFE-coated carbon papers perform similarly to hydrophilic ones in electrostatic fog collection.

Fog collection efficiency is strongly correlated with electrostatic current in an exponential manner.

Charge polarity does not significantly affect fog collection efficiency.

Abstract

Electrostatic fog collection offers a low energy cost and highly efficient method for fog collection; however, the correlation between efficiency and collector surface wettability has not yet been fully explored. This study examines the effectiveness of polytetrafluoroethylene (PTFE)-coated carbon papers in electrostatic fog collection and reveals that their performance is comparable to that of hydrophilic carbon papers. These findings suggest that PTFE coating on the carbon paper surface has a minimal influence on the electrostatic fog collection efficiency. On hydrophilic carbon paper, deposited fog droplets coalesce into a continuous water film that subsequently drains, whereas on hydrophobic carbon paper, the droplets aggregate into discrete spherical forms. This variation in wetting behaviour exerts nearly no influence on the overall fog collection efficiency. Furthermore, the efficiency of electrostatic fog collection is unaffected by charge polarity, with both negative and positive high voltages yielding comparable fog collection efficiencies. Collection efficiency is directly correlated with electrostatic current and shows an exponential relationship: collection efficiency rises sharply with increasing current before reaching a near-plateau. In addition, a thermal camera was utilized to map the zone where the fog stream is collected on the carbon paper, and it was shown that a strong electric field could cause segregation of the charged fog stream.

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