Lotus- and Mussel-Inspired PDA–PET/PTFE Janus Membrane: Toward Integrated Separation of Light and Heavy Oils from Water

Current special wetting materials designed for use with oily wastewater are usually classified as either the oil-removing type or the water-removing type, which are unifunctional and limited by the oil density. Inspired by the integrated Janus system of the lotus leaf as well as the mussel-like mollusks adhered to the lotus, we fabricated a Janus polydopamine (PDA)–polyethylene terephthalate/polytetrafluoroethylene (PET/PTFE) membrane by simple immersion and tape-peeling. This membrane shows a lotuslike Janus wettability, self-cleaning effect, and floating property. Furthermore, the Janus membrane can separate light oil (ρoil water)/water mixtures with the superhydrophilic side facing upward, while heavy oil (ρoil > ρwater)/water mixtures are separated with the hydrophobic side facing upward. The separation efficiency is outstanding even after 10 repeats (>99.10%). By aid of drainage of acetone, the separation process has avoided the use of external pressure. Moreover, integrated separations of oil-in-water and water-in-oil emulsions were achieved with high efficiency. This simply prepared PDA–PET/PTFE Janus membrane has realized an integrated separation system, overcoming the monotony of traditional special wettability separation membrane and extending the bionics field into oily wastewater treatment

Lotus- and Mussel-Inspired PDA–PET/PTFE Janus Membrane: Toward Integrated Separation of Light and Heavy Oils from Water

Current special wetting materials designed for use with oily wastewater are usually classified as either the oil-removing type or the water-removing type, which are unifunctional and limited by the oil density. Inspired by the integrated Janus system of the lotus leaf as well as the mussel-like mollusks adhered to the lotus, we fabricated a Janus polydopamine (PDA)–polyethylene terephthalate/polytetrafluoroethylene (PET/PTFE) membrane by simple immersion and tape-peeling. This membrane shows a lotuslike Janus wettability, self-cleaning effect, and floating property. Furthermore, the Janus membrane can separate light oil (ρoil water)/water mixtures with the superhydrophilic side facing upward, while heavy oil (ρoil > ρwater)/water mixtures are separated with the hydrophobic side facing upward. The separation efficiency is outstanding even after 10 repeats (>99.10%). By aid of drainage of acetone, the separation process has avoided the use of external pressure. Moreover, integrated separations of oil-in-water and water-in-oil emulsions were achieved with high efficiency. This simply prepared PDA–PET/PTFE Janus membrane has realized an integrated separation system, overcoming the monotony of traditional special wettability separation membrane and extending the bionics field into oily wastewater treatment

Lotus- and Mussel-Inspired PDA–PET/PTFE Janus Membrane: Toward Integrated Separation of Light and Heavy Oils from Water

Current special wetting materials designed for use with oily wastewater are usually classified as either the oil-removing type or the water-removing type, which are unifunctional and limited by the oil density. Inspired by the integrated Janus system of the lotus leaf as well as the mussel-like mollusks adhered to the lotus, we fabricated a Janus polydopamine (PDA)–polyethylene terephthalate/polytetrafluoroethylene (PET/PTFE) membrane by simple immersion and tape-peeling. This membrane shows a lotuslike Janus wettability, self-cleaning effect, and floating property. Furthermore, the Janus membrane can separate light oil (ρoil water)/water mixtures with the superhydrophilic side facing upward, while heavy oil (ρoil > ρwater)/water mixtures are separated with the hydrophobic side facing upward. The separation efficiency is outstanding even after 10 repeats (>99.10%). By aid of drainage of acetone, the separation process has avoided the use of external pressure. Moreover, integrated separations of oil-in-water and water-in-oil emulsions were achieved with high efficiency. This simply prepared PDA–PET/PTFE Janus membrane has realized an integrated separation system, overcoming the monotony of traditional special wettability separation membrane and extending the bionics field into oily wastewater treatment

Lotus- and Mussel-Inspired PDA–PET/PTFE Janus Membrane: Toward Integrated Separation of Light and Heavy Oils from Water

Current special wetting materials designed for use with oily wastewater are usually classified as either the oil-removing type or the water-removing type, which are unifunctional and limited by the oil density. Inspired by the integrated Janus system of the lotus leaf as well as the mussel-like mollusks adhered to the lotus, we fabricated a Janus polydopamine (PDA)–polyethylene terephthalate/polytetrafluoroethylene (PET/PTFE) membrane by simple immersion and tape-peeling. This membrane shows a lotuslike Janus wettability, self-cleaning effect, and floating property. Furthermore, the Janus membrane can separate light oil (ρoil water)/water mixtures with the superhydrophilic side facing upward, while heavy oil (ρoil > ρwater)/water mixtures are separated with the hydrophobic side facing upward. The separation efficiency is outstanding even after 10 repeats (>99.10%). By aid of drainage of acetone, the separation process has avoided the use of external pressure. Moreover, integrated separations of oil-in-water and water-in-oil emulsions were achieved with high efficiency. This simply prepared PDA–PET/PTFE Janus membrane has realized an integrated separation system, overcoming the monotony of traditional special wettability separation membrane and extending the bionics field into oily wastewater treatment

A Dually Charged Membrane for Seawater Utilization: Combining Marine Pollution Remediation and Desalination by Simultaneous Removal of Polluted Dispersed Oil, Surfactants, and Ions

Shortage of freshwater and deterioration of the marine environment have a serious effect on the human body and ecological environment. Here, we demonstrated a facile way to prepare a multiple-target superwetting porous material to obtain available water without cumbersome steps. Through the facile immersion and hydrothermal method, a charge-enhanced membrane material combining superwettability, electrostatic interaction, and the steric effect is prepared. Such a material breaks through the limitations of single size sieving and has a universal effect on different kinds of contaminants with accurate wettability manipulation and fluid separation control. The protonation and deprotonation of active carboxyl groups at the novel created solid/liquid interface facilitate the surface wettability and flux transition, which will bring out superior continuous separation and surface lubrication control

A Wax-Elastomer Superwetting Membrane with Controllable Permeability: Toward Separating a Crude Oil-in-Water Emulsion from an Oil Field

Smart superwetting membranes with finely tunable properties have attracted increased attention recently. However, they mostly focus on controllable wettability rather than controllable permeability. Also, the oil/water separation performance is usually tested with laboratory-simulated samples, making it hard for the materials to meet practical applications. Herein, we fabricate thermally responsive superwetting membranes with wax, polystyrene-B-poly(ethylene-ran-butylene)-B-polys (SEBS, a kind of elastomer), and polydopamine (PDA) to realize emulsion separation with controllable permeability. Benefiting from the elasticity of SEBS and the fluidity difference of wax at different temperatures, the pore size of the membrane could be readily tuned, resulting in different permeability. The separation flux is 0 at ambient temperature (pore size 0.394 μm) and is over 100 L m–2 h–1 at a high temperature (pore size 0.477 μm). The membrane could realize the separation of simulated oil-in-water emulsions with efficiency above 99.4%. Furthermore, it successfully achieved crude oil-in-water emulsion separation from the oil field with oil residues of less than 300 mg L–1 in the temperature range of 60–80 °C, which is the actual working temperature adopted in industrial production. Such a polydopamine/wax-SEBS modified membrane with unprecedented controllable permeability can promote the development of the emulsion treatment field and provide a new direction for designing smart superwetting materials

Peanut Leaf-Inspired Hybrid Metal–Organic Framework with Humidity-Responsive Wettability: toward Controllable Separation of Diverse Emulsions

Damage to the responsive superwetting material by external stimuli during the responsive process has been a ticklish question in recent years. We overcome this barrier by imitating a peanut leaf and designing a humidity-responsive MIL-100 (Fe)/octadecylamine-coated stainless steel mesh (HR-MOS). Such a material shows superhydrophilicity when ambient humidity is higher than saturated humidity, while it shows superhydrophobicity and high adhesion to water when ambient humidity is lower than saturated humidity. The peanut leaf-like two-level nanostructure of MIL-100 (Fe) is speculated as the principal factor to bring about the binary synergy wettability of the material. Accordingly, the material can realize humidity-controlled separation of at least 12 types of emulsions along with satisfactory durability. The responsive condition of the material is mild and green, which does lower damage to the material and environment. This strategy is the first to realize humidity-responsive wettability transition and provides a novel approach for manually controlled environmental protection

Peanut Leaf-Inspired Hybrid Metal–Organic Framework with Humidity-Responsive Wettability: toward Controllable Separation of Diverse Emulsions

Damage to the responsive superwetting material by external stimuli during the responsive process has been a ticklish question in recent years. We overcome this barrier by imitating a peanut leaf and designing a humidity-responsive MIL-100 (Fe)/octadecylamine-coated stainless steel mesh (HR-MOS). Such a material shows superhydrophilicity when ambient humidity is higher than saturated humidity, while it shows superhydrophobicity and high adhesion to water when ambient humidity is lower than saturated humidity. The peanut leaf-like two-level nanostructure of MIL-100 (Fe) is speculated as the principal factor to bring about the binary synergy wettability of the material. Accordingly, the material can realize humidity-controlled separation of at least 12 types of emulsions along with satisfactory durability. The responsive condition of the material is mild and green, which does lower damage to the material and environment. This strategy is the first to realize humidity-responsive wettability transition and provides a novel approach for manually controlled environmental protection