Biomimetic Superoleophobicity of Cotton Fabrics for Efficient Oil–Water Separation

Abstract

dispersal oil using chemical dispersants, in situ burning, and so on. [4][5][6][7][8] The option for oil collection using filtration was considered as an attractive choice because of its simplicity for the proper disposal of free and dispersed oil in water body.In the last decade, textile materials have gained much attention as membranes or sorbents for oil-water separation due to their high flexibility, moderate absorption capability, low density, reasonable price, and excellent biocompatibility. Typically, two types of membranes, e.g., hydrophilic/oleophobic and hydrophobic/ oleophilic textiles, have been developed and studied for the collection of water or oil from oil-water mixture/emulsion. [4][5][6][7][8] For example, Zhang et al. [6] developed a switchable superoleophilic and superoleophobic material by grafting poly(2-vinylpridine) and oleophilic/hydrophobic polydimethylsiloxane (i.e., P2VP-b-PDMS) on nonwoven textile (cloth-like wipes). The P2VP segment showed an altered wettability and conformation via protonation and deprotonation, and this behavior was further improved by the flexible PDMS block on textile, endowing the material high capability for oil-water separation. Palama et al. demonstrated a switchable wettability of cotton substrate with a coating consisting of zinc oxide nanorods and diamond like carbon. [7] The changeable interfacial behavior (i.e., altered from superoleophilicity to superoleophobicity) was due to the complete wetting of hierarchical surface of cotton by water. In another study, Li et al. [8] prepared a durable robust flower like TiO 2 deposited cotton fabrics with superhydrophobic/oleophilic properties by hydrothermal method. The as prepared member exhibited high flexibility and stability for separating oil-water mixture with excellent separation efficiency. While significant efforts have been made in this field, there were still many issues to be considered and optimized for the materials during the practical cleanup of oil spills, such as chemical and energy cost of membrane, mechanical and thermal stability in air and water conditions, fouling and concentration polarization due to the selective oil adsorption, as well as recyclability and reusability of materials. [8][9][10] Development of sustainable and cost-effective materials by a facile method is highly desirable to satisfy the above requirements.Generally, three distinct interfaces, e.g., air-water-solid, airoil-solid, and water-oil-solid, are considered for describing wettability and interfacial phenomena of water and oil droplets on hydro-philic/phobic or oleo-philic/phobic surfaces, Textile materials have gained much attention as membranes for oil-water separation. However, traditional membranes are suffered by either energyintensive preparation method or the fouling during the practical application. Motivated by the biomimetic surface of fish, this paper reports the modification of cotton fabrics using a single-step hot alkali treatment, which creates roughened morphologies in micro-and nanoscale on fiber surfa...

Direct Assembly of Silica Nanospheres on Halloysite Nanotubes for “Green” Ultrahydrophobic Cotton Fabrics

“…Fabrics treated with 0.1% and 0.3% Si-HNT particle concentration show that much of the cotton fiber surface is bare and does not contain many Si-HNT particles, while fabric treated with 0.5% Si-HNT particle concentration shows most of cotton fiber surface covered with particles. [5] The tensile data presented in Figure 8a While the results of an earlier study had indicated that the fatty acid grafting on cotton fabrics using microwave causes 47% and 50% strength loss in the warp and weft directions, respectively, due to the high temperature caused by microwave treatment, no such strength loss was found in this study. Whereas fabric treated with pure HNT particles and fatty anhydride results in ultrahydrophobic fabric at first, but the water drop gets absorbed in just a few seconds.…”

“…[5][6][7] Ultrahydrophobic surfaces found in nature such as lotus leaves, cicada wings, and many others show a unique combination of the hierarchical rough structure with a hydrophobic waxy layer present on the surface. Some of the other applications of ultrahydrophobic cellulose include anti-biofouling, separating oil from water for cleaning oil spills in offshore oil fields or tanker vessels, cellulose films used in packaging, and improving interfacial bonding of cellulosic fibers or micro and nanofibrils for use in nonpolar resins for fabricating fiber reinforced composites or simply obtaining high strength resins.…”

Energy‐Efficient Oil–Water Separation of Biomimetic Copper Membrane with Multiscale Hierarchical Dendritic Structures

“…The BMCM showed an average mean square roughness (Ra) of 25.952 nm, which is much higher than that of stainless steel mesh (17.486 nm) within the same area scanned. This is due to the existence of dendritic structures on the BMCM surface, which could increase the surface roughness and hierarchy . Chemical composition analysis of BMCM was carried out using EDS and XRD.…”

“…This is due to the existence of dendritic structures on the BMCM surface, which could increase the surface roughness and hierarchy. [42,43] Chemical composition analysis of BMCM was carried out using EDS and XRD. Figure 7e www.small-journal.com solution and SNWF was modified by stearic acid successfully.…”

Janus Copper Mesh Film with Unidirectional Water Transportation Ability toward High Efficiency Oil/Water Separation

“…[13] The second type is films with superhydrophilicity/underwater superoleophobicity,s uch as hydrogel-coated metal films, [33] porousn itrocellulose membranes, [34] and Cu(OH) 2 -coated copperm esh films, [35] that can separate water from the mixture. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] Notably,a ll these films can only separatec ertain types of oil/water mixture, either light oil/water mixtures (1 oil < 1 water )o rh eavy oil/water mixtures (1 oil > 1 water ). Briefly,i ns uperhydrophobic/superoleophilic films that can removeo il from mixtures, light oil/water mixtures (1 oil < 1 water )a re unfavorable because the water can sink down and accumulate on the film as ab arrier layer,w hich thusb locks oil permeation.…”