In situ growth of hierarchical Al₂O₃ nanostructures onto TiO₂ nanofibers surface: super-hydrophilicity, efficient oil/water separation and dye-removal

Abstract

Developing a facile strategy to synthesize template-free TiO membrane with stable super-hydrophilic surface is still a daunting challenge. In this work, super-hydrophilicity (close to 0°) and underwater super-oleophobicity (165°) have been successfully demonstrated on a hierarchical AlO/TiO membrane, which is prepared via a facile electrospinning method followed by simple calcination in air. The precisely-tuned AlO heterojunctions grew in situ and dispersed uniformly on the TiO surface, resulting in an 'island in the sea' configuration. Such a unique feature allows not only achieving super-hydrophilicity by maximizing the surface roughness and enhancing the hydrogen bonding, but also improving the adsorption capacity toward different toxic dyes utilizing the abundant adsorption sites protected by the hierarchical nanostructure during sintering. The new AlO/TiO nanofibrous membrane can serve as a novel filter for gravity driven oil/water separation along with dye removal, achieving 97.7% of oil/water separation efficiency and 98% of dye capture, thanks to their superb wettability and the sophisticated adsorptive performance. Our presented fabrication strategy can be extended to a wide range of ceramic materials and inspires their advanced applications in water purification under harsh liquid-phase environments.

Rapid, Selective Adsorption of Methylene Blue from Aqueous Solution by Durable Nanofibrous Membranes

“…Chemical Structures. Solid-state 13 C NMR spectra of specimens were recorded to investigate the chemical structures of β-CD, CM-β-CDP, and PBSST-g-β-CDP nanofibrous membranes. As shown in Figure 1a, an obvious peak observed at 177.15 ppm (C10) corresponded to carboxyl groups on the carboxylic acid substituent of CM-β-CDP.…”

“…Characterization. Chemical structures of specimens were investigated through 13 C magic angle spinning NMR spectroscopy (Bruker AVANCE 400, Switzerland). The functional groups of specimens were examined by Fourier transform infrared spectroscopy (FTIR Spectrum Two, PerkinElmer, UK) in the range of 4000−400 cm −1 .…”

“…It is a great challenge to effectively dispose of industrial wastewater, which generally contains various organic pollutants. Organic dyes, especially cationic dye methylene blue (MB) and anionic dye methyl orange (MO), have been widely applied as colorants in textile, paper, and printing industries, but their residues in industrial wastewater can bring out a serious threat to aquatic organisms and even human health as typical organic pollutants. − Until now, the adsorption technique has been identified as a right way to capture or enrich organic dyes from industrial wastewater because of its low cost, wide adaptability, low harmful secondary products, and easy regeneration. , Nanofibrous membranes are attractive to remove the organic dyes from the industrial wastewater as an adsorbent because of their inherent high porosity and large specific surface areas. − Recently, various nanofibrous membranes coupled with β-cyclodextrin (β-CD) and its derivatives were fabricated and applied in the wastewater treatment because of their ecofriendliness and special cavity structure. The introduction of a cavity structure into the nanofibrous membranes contributes to the formation of host–guest inclusion of the membranes with dye molecules and thus increases their adsorption capacity to dyes. ,− …”

Coupling of Hierarchical Al2O3/TiO2 Nanofibers into 3D Photothermal Aerogels Toward Simultaneous Water Evaporation and Purification

“…4b. The super-hydrophilic performance of Al 2 O 3 /TiO 2 nanofibers can be attributed to their favorable hierarchical and hetero-structures, which can powerfully draw water toward nanofibers by capillary forces [25]. These interconnected nanofibers with superb wettability formed abundant 1D channels for rapid and continuous water wicking from bulky water.…”

Preliminary Study of Ultrasonic Welding as a Joining Process for Electrospun Nanofiber Mats

“…Such nanofiber mats can be used for a broad variety of applications, e.g., for biotechnological or medical purposes [ 1 , 2 , 3 , 4 ], antibacterial and antifouling surfaces [ 5 ], as catalyzers [ 6 ], or filters [ 7 , 8 , 9 ]. They can be produced from diverse biopolymers [ 10 , 11 , 12 , 13 ], man-made polymers [ 14 , 15 , 16 ] or blends with other materials [ 17 , 18 , 19 ].…”