Superhydrophobic Candle Soot as a Low Fouling Stable Coating on Water Treatment Membrane Feed Spacers

Chidambaram Thamaraiselvan, Emily Manderfeld, Maurício Nunes Kleinberg, Axel Rosenhahn, Christopher J. Arnusch

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Membrane separation processes including reverse osmosis are now considered essential techniques for water and wastewater treatment, especially in water-scarce areas where desalination and water reuse can augment the water supply. However, biofouling remains a significant challenge for these processes and in general for marine biological fouling, which results in increased energy consumption and high operational costs. Especially in flat sheet membrane modules, intense biofilm growth occurs on the feed spacer at points of contact to the membrane surface. Here, we developed an ultrastable superhydrophobic antibiofouling feed spacer that resists biofilm growth. A commercial polypropylene feed spacer was coated with poly(dimethylsiloxane) (PDMS), and then, candle soot nanoparticles (CSNPs) were embedded into the ultrathin layer of PDMS, which resulted in a superhydrophobic nanostructured surface with a contact angle >150°. The CSNP-coated spacer was examined for inhibition of biofilm growth by a cross-flow membrane channel using Pseudomonas aeruginosa (PA01), and the coating was examined for effectiveness in marine fouling by testing the adhesion of marine bacterium Cobetia marina and diatom Navicula perminuta in a dynamic accumulation assay. In all cases, the CSNP coatings showed almost complete elimination of biofilm growth under the conditions tested. Confocal laser scanning microscopy and scanning electron microscopy indicated a 99% reduction in biofilm growth on the modified spacers compared to the uncoated controls. This effect was attributed to the superhydrophobic nanostructured surface, where trapped gasses formed a plastron on the coating. This plastron was observed to be extremely stable over time and could even be replenished at elevated temperatures. Development of similar antibiofouling coatings on feed spacers or other marine applications might lead to improvements in many industrial processes including membrane filtration where increased membrane life span and reduced energy consumption are key to implementation.

Original languageEnglish
Pages (from-to)4191-4200
Number of pages10
JournalACS Applied Bio Materials
Volume4
Issue number5
DOIs
StatePublished - 17 May 2021

Keywords

  • biofouling
  • candle soot
  • carbon nanoparticles
  • feed spacer
  • superhydrophobicity

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