Photothermal conversion-assisted oil Water separation by superhydrophobic Cotton yarn prepared via the silver mirror reaction

A Composite Fabric with Dual Functions for High-Performance Water Purification

The dilemma of diminishing freshwater resources caused by water pollution has always impacted human life. Solar-driven interfacial evaporation technology has the potential for freshwater production via solar-driven distillation. However, in solar-driven interfacial evaporation technology, it is difficult to overcome the problem of wastewater containing various contaminants. In this work, we propose a bifunctional fabric created by depositing titanium dioxide@carbon black nanoparticles onto cotton fabric (TiO₂@CB/CF). The TiO₂@CB/CF has a coupling effect that includes the photothermal effect of CB and photocatalysis of TiO₂, and it can not only generate clean water but can also purify contaminated water. The resulting bifunctional fabric can achieve an outstanding water evaporation rate of 1.42 kg m^-2 h^-1 and a conversion efficiency of 90.4% in methylene blue (MB) solution under one-sun irradiation. Simultaneously, the TiO₂@CB/CF demonstrates a high photocatalytic degradation of 57% for MB solution after 2 h with light irradiation. It still shows a good photocatalysis effect, even when reused in an MB solution for eight cycles. Furthermore, the TiO₂@CB/CF delivers excellent performance for actual industrial textile dyeing wastewater. This bifunctional fabric has a good application prospect and will provide a novel way to resolve the issue of freshwater scarcity.

Design and fabrication of polydopamine based superhydrophobic fabrics for efficient oil-water separation

In this work, we prepare a PDMS-SiO2-PDA@fabric with high water contact angle (WCA = 155°). Combining dopamine self-polymerization and a sol-gel method, SiO2 is in situ grown on a PDA-modified fabric surface to synergistically construct micro-nano rough structures. Finally, a superhydrophobic fabric is successfully obtained after coating the fabric with a layer of PDMS. The prepared fabric can maintain superhydrophobicity after immersion in various solvents (pH = 1, 3, 5, 7, 9, 11, 13, DMF, ethanol, THF, n-hexane) for 24 h and strong ultraviolet irradiation for 60 min. Thanks to the highly reactive PDA clusters, the stronger interfacial bond between the fabric and SiO2 enables it to withstand 180 min of washing and 159.22 N tensile stress, showing strong adhesion strength. In addition, the modified fabric has excellent self-cleaning properties and is resistant to contamination such as milk, coffee and tea. More importantly, the prepared fabric can selectively repel water and adsorb oil, achieving above 90% oil-water separation efficiency even after 8 cycles.

Effect of silylating agents on the superhydrophobic and self-cleaning properties of siloxane/polydimethylsiloxane nanocomposite coatings on cellulosic fabric filters for oil-water separation

A new facile approach for preparing two nonfluorinated hybrid organic-inorganic siloxane/polydimethylsiloxane nanocomposite coatings for cotton fabrics is presented using two distinct silylating agents. The first coated fabric was prepared predominantly via trimethylsilyl modification using hexamethyldisilazane (HMDS) while higher amounts of trimethoxy(octadecyl)silane (TMOS) further enhanced the superhydrophobicity of the second coating matrix. Unlike HMDS with substituted silyl (Me3Si) groups, TMOS consists of hydrolysable trimethoxy silyl ((MeO)3Si) chemical groups that allowed for the formation of nanosilica with Si-O-Si linkages needed to foster stable coatings. After characterization and testing, these coated fabrics demonstrated varying responses to harsh solvents and thermal conditions. Both sets of coated fabrics exhibited unique capacities for self-cleaning and oil-water separation as superhydrophobic filters due to (a) their low surface energy silylated hybrid polysiloxane chemical groups, (b) their highly reduced surface wettability and (c) nanopatterned surface morphologies. In this study, coated superhydrophobic cotton fabrics revealed a higher static aqueous contact angle of more than 150° and sliding hysteresis angle of less than 5°. Coated fabrics with 30 mg TMOS/10 mg HMDS (CMF3) and 30 mg HMDS/10 mg TMOS (CTF3) exhibited optimal superhydrophobicity. Both fabrics also retained percentage separation efficiencies over 90% for both chloroform-water and toluene-water mixtures. However, CTF3 displayed with a recorded separation efficiency less than 90° after five filtration cycles.