A fog-collecting surface mimicking the Namib beetle: its water collection efficiency and influencing factors

Nanoscale ◽  
2020 ◽  
Vol 12 (13) ◽  
pp. 6921-6936 ◽  
Author(s):  
Jun Lei ◽  
Zhiguang Guo
Keyword(s):  
Surface Structure ◽  
Influencing Factors ◽  
Collection Efficiency ◽  
Surface Wettability ◽  
Namib Desert ◽  
Surface Distribution ◽  
Collection Rate ◽  
Water Collection

In the Namib Desert, beetles can obtain water by fog-basking. In this review, we discussed the water collection rate of surfaces inspired by beetles from three aspects: surface wettability, surface structure and surface distribution.

scholarly journals Effect of Mesh Wettability Modification on Atmospheric and Industrial Fog Harvesting

2021 ◽  
Vol 9 ◽  
Author(s):  
Jong Hoon Kang ◽  
Jeong-Won Lee ◽  
Ji Yeon Kim ◽  
Jong Woon Moon ◽  
Hyeon Seo Jang ◽  
...  
Keyword(s):  
Water Resources ◽  
Collection Efficiency ◽  
Surface Wettability ◽  
Water Harvesting ◽  
Cooling Towers ◽  
Water Crisis ◽  
Industrial Water ◽  
Simple Method ◽  
Water Collection ◽  
Alternative Water

Freshwater shortage has been receiving considerable attention, and water harvesting is one of the potential solutions to this water crisis. Several researchers have tried to improve the harvesting capabilities by changing mesh wettability for atmospheric fog harvesting. However, the wettability effect on water harvesting from white plumes has not yet been investigated thoroughly, despite industrial cooling towers being considered as alternative water resources, because of the large amounts of fog plumes generated. In this study, surface wettability was modified with a robust and simple method for practical scaled-up applications, and we explored the influence of mesh wettability on atmospheric and industrial fog harvesting. In atmospheric fog harvesting, both superhydrophilic meshes (SHPMs), and superhydrophobic meshes (SHBMs) were found to improve the harvesting performance, with superhydrophobic treatments providing the best collection efficiency. In contrast, only superhydrophilicity improves the performance in industrial fog harvesting with flat mesh screens. We hypothesize that this research will be useful for mesh design, as it analyzes the influence of mesh wettability on the performance of water collection in both atmospheric and industrial water harvesting.

Optimizing Water Harvesting on Bioinspired Surfaces: A Mesoscopic Perspective

2021 ◽  
Author(s):  
Souparna Chakraborty ◽  
Abhirup Chaudhuri ◽  
Chirodeep Bakli
Keyword(s):  
Pressure Gradient ◽  
Water Transport ◽  
Tilt Angle ◽  
Transport Process ◽  
Collection Efficiency ◽  
Md Simulations ◽  
Laplace Pressure ◽  
Water Harvesting ◽  
Collection Rate ◽  
Water Collection

Abstract The water crisis affects the lives of millions over the world. Minimizing water losses in major water-consuming industries like power plants is of utmost importance. Since cooling towers lead to huge amounts of water loss, implementing modifications for recovering a fraction of this lost water in the exhaust has been a topic of active research. These modifications are often inspired by biological species, especially in arid regions, which have adapted in different ways by collecting water from fog, and hence biomimetic has become popular for water harvesting techniques. We revisit the fog collection technique most commonly used in nature and compare the relative merits of the same with surface texture and wettability. Arrays of spines of three different configurations were considered in this study — namely cuboidal, cylindrical and conical shapes. A theoretical model is developed to carry out a comparative analysis of these configurations considered. The effects of Laplace pressure gradient, gravity, topography and tilt angle on droplet transportation along the spines were explored to decipher the most efficient water transport and collection route. The observations are explained by performing extensive Molecular Dynamics (MD) simulations to bring out the interplay of surface tension and roughness at the contact line verifying the proposed formulations. The conical-shaped spines exhibited maximum transport and collection efficiency for zero tilt angle. Both cuboidal and cylindrical shaped spines showed little or no water collection when the spines are oriented horizontally. This is due to the Laplace pressure gradient which arises from varying radii of curvature of the conical shaped spine which drives the water droplets towards the base but is absent for the other two cases considered. On the contrary, when there is some finite tilt angle, the contribution of gravity comes into consideration and the water collection rate of the conical and cylindrical spines becomes comparable. Both Laplace pressure gradient and gravity help in water transport in the conical case whereas only gravity assists the water transport process for cylindrical spines. Still, the water collection rate is almost the same for these two scenarios due to enhanced coalescence of liquid droplets for the cylindrical case as is observed from MD simulations. As the droplets coalesce, they get larger and gravity aids the transport process by overcoming the solid-liquid interaction strength. Cuboidal shaped spines show the least efficiency with only gravity to assist the transport process and no coalescence is observed in this case. Moreover, the geometrical disparity makes the tips of conical spines more hydrophobic compared to the others which further ameliorates the water collection efficiency.

Hybrid engineered materials with high water-collecting efficiency inspired by Namib Desert beetles

2016 ◽  
Vol 52 (41) ◽  
pp. 6809-6812 ◽  
Author(s):  
Hai Zhu ◽  
Zhiguang Guo
Keyword(s):  
High Water ◽  
Namib Desert ◽  
Collection Rate ◽  
Water Collection ◽  
Self Cleaning ◽  
Desert Beetle ◽  
Engineered Materials ◽  
Collecting Efficiency

A hybrid superhydrophobic material was successfully fabricated inspired by the Namib Desert beetle, which showed the efficient fog capture with a water collection rate of 1309.9 mg h−1 cm−2. And the sample possessed favorable robustness and self-cleaning property.

scholarly journals Bio-inspired Fog Harvesting Materials: Basic Research and Bionic Potential Applications

2021 ◽  
Vol 18 (3) ◽  
pp. 501-533
Author(s):  
Kui Wan ◽  
Xuelian Gou ◽  
Zhiguang Guo
Keyword(s):  
Collection Efficiency ◽  
Basic Research ◽  
Development Trend ◽  
Water Mist ◽  
Long Distance ◽  
Biological Water ◽  
Water Collection ◽  
Transmission Area ◽  
Potential Applications ◽  
Water Transmission

AbstractWith the explosive growth of the world’s population and the rapid increase in industrial water consumption, the world’s water supply has fallen into crisis. The shortage of fresh water resources has become a global problem, especially in arid regions. In nature, many organisms can collect water from foggy water under harsh conditions, which provides us with inspiration for the development of new functional fog harvesting materials. A large number of bionic special wettable synthetic surfaces are synthesized for water mist collection. In this review, we introduce some water collection phenomena in nature, outline the basic theories of biological water harvesting, and summarize six mechanisms of biological water collection: increased surface wettability, increased water transmission area, long-distance water delivery, water accumulation and storage, condensation promotion, and gravity-driven. Then, the water collection mechanisms of three typical organisms and their synthesis are discussed. And their function, water collection efficiency, new developments in their biomimetic materials are narrated, which are cactus, spider and desert beetles. The study of multiple bionics was inspired by the discovery of Nepenthes’ moist and smooth peristome. The excellent characteristics of a variety of biological water collection structures, combined with each other, are far superior to other single synthetic surfaces. Furthermore, the main problems in the preparation and application of biomimetic fog harvesting materials and the future development trend of materials fog harvesting are prospected.

Bioinspired Dual-Tier Coalescence for Water-Collection Efficiency Enhancement

Langmuir ◽  
2018 ◽  
Vol 34 (44) ◽  
pp. 13409-13415 ◽  
Author(s):  
Barbara T. W. Ang ◽  
Choon Hwai Yap ◽  
Wee Siang Vincent Lee ◽  
Junmin Xue
Keyword(s):  
Collection Efficiency ◽  
Efficiency Enhancement ◽  
Water Collection

scholarly journals Physical Structure Induced Hydrophobicity Analyzed from Electrospinning and Coating Polyvinyl Butyral Films

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Shuo Chen ◽  
Guo-Sai Liu ◽  
Hong-Wei He ◽  
Cheng-Feng Zhou ◽  
Xu Yan ◽  
...  
Keyword(s):  
Surface Structure ◽  
Critical Role ◽  
Film Surface ◽  
Polyvinyl Butyral ◽  
Physical Structure ◽  
Surface Wettability ◽  
Practical Applications ◽  
Physical Surface ◽  
Film Forming ◽  
Surface Morphologies

Surface wettability of a film plays a critical role in its practical applications. To control the surface wettability, modification on the physical surface structures has been a useful method. In this paper, we reported the controlling physical surface structure of polyvinyl butyral (PVB) films by different film-forming methods, spin-coating, bar-coating, and electrospinning. The wettability of these PVB films was examined, and the surface morphologies and roughness were investigated. The results indicated that coating PVB films were hydrophilic, while electrospun films were hydrophobic. The physical surface structure was the key role on the interesting transition of their surface wettability. Theoretical analyses on these results found that the coating PVB films showed different mechanism with electrospun ones. These results may help to find the way to control the PVB film surface wettability and then guide for applications.

scholarly journals Designing bioinspired surfaces for water collection from fog

2018 ◽  
Vol 377 (2138) ◽  
pp. 20180269 ◽  
Author(s):  
Dev Gurera ◽  
Bharat Bhushan
Keyword(s):  
Flat Surface ◽  
Unit Area ◽  
Water Repellency ◽  
Vertical Axis ◽  
Collection Rate ◽  
Flat Surfaces ◽  
Single Cone ◽  
Water Collection ◽  
The Difference ◽  
Conical Surfaces

A systematic study is presented on various water collectors, bioinspired by desert beetles, desert grass and cacti. Three water collecting mechanisms including heterogeneous wettability, grooved surfaces, and Laplace pressure gradient, were investigated on flat, cylindrical, conical surfaces, and conical array. It is found that higher water repellency in flat surfaces results in higher water collection rate and inclination angle (with respect to the vertical axis) has little effect. Surfaces with heterogeneous wettability have higher water collection rate than surfaces with homogeneous wettability. Both cylindrical and conical surfaces resulted in comparable water collection rate. However, only the cone transported the water droplets to its base. Heterogeneity, higher inclination and grooves increased the water collection rate. A cone has a higher collection rate per unit area than a flat surface with the same wettability. An array of cones has higher collection rate per unit area than a single cone, because droplets in a conical array coalesce, leading to higher frequency of droplets falling. Adding heterogeneity further increases the difference. Based on the findings, scaled-up designs of beetle-, grass- and cactus-inspired surfaces and nets are presented. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology’.

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