Self-Locked and Self-Cleaning Membranes for Efficient Removal of Insoluble and Soluble Organic Pollutants from Water

Abstract

A feasible and efficient membrane for long-term treatment of complex oily wastewater is especially in demand, but its development still remains a challenge because of serious membrane fouling and incomplete/destructive reclamation methods. Herein, an interpenetrating TiO2 nanorod-decorated membrane with self-locked and self-cleaning properties is rationally fabricated via coaxial electrospinning and hydrothermal synthesis. The self-locked membrane shows full reinstatement of the original state and exhibits satisfactory mechanical strength, superhydrophilicity, underwater superoleophobicity, and robust solvent resistance, which endow the membrane with successful separation for 16 types of highly emulsified oil-in-water emulsions (e.g., surfactant-free; anionic, cationic, and nonionic surfactant-stabilized). Moreover, successful sequencing treatment of soluble organic emulsions using the separated “bait–hook–destroy” strategy indicates that the pristine membrane can be used to treat multipollutant wastewater with various limits. Most importantly, the fouled membrane can easily be reinstated by light irradiation without reduction of both mechanical strength and separation performance. As a proof of concept, the as-synthesized membrane shows an ultrahigh flux over 5000 L m–2 h–1 with a removal efficiency of >99.92%. The present development would provide a highly efficient strategy for the fabrication of an inorganic–organic revivable electrospinning membrane for various applications.

Multifunctional Switchable Nanocoated Membranes for Efficient Integrated Purification of Oil/Water Emulsions

“…Additionally, the space-separated tops and tightly connected tails of interlocked hybrid NRs would be beneficial for the dispersion of the loaded force, which also reinforced both fibers' strength and bonding. 34 Exactly, the ZIF-8@ZnO-PPVDF NFM exhibited superamphiphilicity in air (Figure 1c) and satisfactory mechanical strength (Figure 2 and SI Figure S4, see details in corresponding supplementary discussions). The specific surface area of the NFM was 248.29 m 2 g −1 because of the combination of the construction of internal pores in the fibers and ZIF-8@ZnO nanorods (SI Figure S11 and in the corresponding supplementary discussions).…”

“…After this step, ZnO NRs with a length/diameter of ∼0.3 μm/37 nm were converted to ZIF-8@ZnO NRs with a length/diameter of ∼0.4 μm/∼95 nm. Additionally, the space-separated tops and tightly connected tails of interlocked hybrid NRs would be beneficial for the dispersion of the loaded force, which also reinforced both fibers’ strength and bonding . Exactly, the ZIF-8@ZnO-PPVDF NFM exhibited superamphiphilicity in air (Figure c) and satisfactory mechanical strength (Figure and SI Figure S4, see details in corresponding supplementary discussions).…”

“…However, some of the filtrates were blue, which was due to the hindrance effect of turbid emulsions and low light intensity. 34 Considering the limited treatment ability of photodegradation, we decided to explore the combination of simultaneous quick adsorption-separation and photocatalytic degradation (denoted as the "bait-hook-eliminate" strategy). That is, the "bait-hook" and "eliminate" are performed in separation process and more advantageous conditions with high transmittance, respectively.…”

Superwetting Polyvinlydene Fluoride Membranes with Micro‐Nano Structure for Oil‐in‐Water Emulsion Separation

“…[ 24,25 ] Nanoparticles, such as titanium dioxide, silicon dioxide, and carbon nanotubes have been used to form micro/nanostructure on the surface of filter membrane, so it is of great practical significance to explore the application of other functional nanoparticles in oil–water separation of membrane technology. [ 26–32 ]…”

Evaluation of Sulfonic Cellulose Membranes on Oil–Water Separation: Performance and Modeling of Flux

“…The excellent antipollution performance is also one of the advantages of the superwettable membrane. It can even recover its oil–water separation performance by photocatalytic degradation of oil stains adhering to the membrane. − …”