Water Vapor Condensation from Atmospheric Air by Super-Hydrophobic VACNTs Growth on Stainless Steel Pipes
- PDF / 441,201 Bytes
- 8 Pages / 432 x 648 pts Page_size
- 10 Downloads / 153 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.248
Water Vapor Condensation from Atmospheric Air by Super-Hydrophobic VACNTs Growth on Stainless Steel Pipes Pinheiro, R.A.1*, Damm, D.D.1-2, Silva, A.A.1, Volu, R.M.3, Almeida, K.F.4, Rosa, F.M.1, Trava-Airoldi, V.J.1, Corat, E.J.1 1
National Institute for Space Research, São José dos Campos, Brazil,
2
Federal University of São Paulo, São José dos Campos, Brazil,
3
Institute for Advanced Studies, São José dos Campos, Brazil
4
Federal University of Recôncavo Baiano, Feira de Santana, Brazil
*correspondence: [email protected]
Abstract
Energy-efficient condensation of steam contained in atmospheric air has emerged as a solution to the water scarcity. Academic and industrial research works that seeks to develop water collection devices with high efficiency has great relevance for the scientific community. In this work, we aim to show that modified carbon nanotubes forest can remove the condensed drops easier than a hydrophobic and a super-hydrophilic surface. In addition, this result was reached at high super saturation level which is an innovative aspect of this work. The Vertically Aligned Carbon Nanotubes (VACNTs) were grown on steel pipes. We used a CO 2 laser and an O2 plasma to perform the post treatments that changed the CNTs to superhydrophobic and super-hydrophilic, respectively. In addition, the CO2 laser treatment added a second level of roughness in the surface by etching the nanotubes walls. A polyethylene coating attached the carbon nanotubes to the substrate. We experimentally demonstrated a 24% higher vapor condensation rate at high supersaturations levels.
1929
Downloaded from https://www.cambridge.org/core. Access paid by the UCSB Libraries, on 26 Oct 2019 at 21:06:47, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.248
INTRODUCTION A severe hydric crisis would threaten fifty percent of the world population in the next two decades [1]. Although Brazil has close to twelve percent of the world’s fresh water at some regions lack water. In deserts and other arid territories of the planet the only water available is in the air humidity [2]. Emerging technologies which allow water harvesting from dew and fog may help to solve this problem [3]. As has shown recently the more efficient water collecting surfaces presented specific wetting properties that prevent water films or Wenzel’s drops formation [4]. Pinheiro et al. [5] developed a new 3D structure inspired in the Stenocara beetle [6][7], using super-hydrophobic/superhydrophilic VACNTs for fog harvesting. Some materials that present high water drop repellency can wet by moistening under a humid atmosphere. Drops which sizes are comparable to the surface roughness can nucleate and grow at top and bottom of the structure. This behavior, known as Wenzel’s state, can cause loss of super-hydrophobicity [8]. The captured water can remain heavily trapped into the structure changing it to
Data Loading...
