Superhydrophobic Sponge Research Articles

Multiple Energies-Assisted All-Weather Recovery of Crude Oil by Magnetically Superhydrophobic Sponge

Multiple Energies-Assisted All-Weather Recovery of Crude Oil by Magnetically Superhydrophobic Sponge

Mechanically Durable Anti-Bacteria Non-Fluorinated Superhydrophobic Sponge for Highly Efficient and Fast Microplastic and Oil Removal

Mechanically Durable Anti-Bacteria Non-Fluorinated Superhydrophobic Sponge for Highly Efficient and Fast Microplastic and Oil Removal

Fast self-healing superhydrophobic sponge with all-weather heating and anti-fouling properties

The loss of superhydrophobicity due to mechanochemical damage is critical for superhydrophobic surfaces, and rapid self-healing is significant in maintaining surface durability. Herein, a novel, fast, self-healing superhydrophobic sponge capable of all-weather heating was polymerized in an eco-friendly aqueous system and dip-coated using fluorine-free and non-toxic reagents. Benefiting from the photothermal and Joule-heating performance of polyaniline (PANI) and multiwalled carbon nanotubes (MWCNTs), all-weather heating could be achieved. The equilibrium surface temperature (EST) of the as-prepared sponge could rapidly reach 105°C under irradiation of 1.0 kW/m2 for 20 s, and the EST exceeded 120°C with supplementary 18 V treatment. Impressively, after O2 plasma etching for 1 min or after being immersed in hydrogen peroxide (H2O2) solution for 24 h, the water contact angle (WCA) of self-healing superhydrophobic polyurethane (PU) sponge (SHSPS) can be restored to 155°C under simulated sunlight for 2 min because of the rapid migration of low surface energy polydimethylsiloxane (PDMS) chains, which is the fastest recovery achieved to the best of our knowledge. In addition, the modified sponge exhibited a significant antifouling capability for particulate contaminants and organic pollutants, extending service life. Our preliminary results demonstrated that the modified sponge prepared in the current work is fully qualified in multiple applications, including oil-water separation, viscous oil treatment, seawater evaporation and desalination, de-icing, and anti-icing.

Fabrication of PDMS@Fe3O4/MS Composite Materials and Its Application for Oil-Water Separation.

The discharge of oily wastewater and oil spills at sea are the current difficulties in water pollution control. This problem often leads to terrible disasters. Therefore, the effective realization of oil-water separation is a very challenging problem. Superhydrophobic sponge is a promising oil-absorbing material. In this article, we reported a superhydrophobic sponge with nano-Fe3O4 for oil-water separation. The addition of nano-Fe3O4 allows the sponge to be recycled under the action of magnetic force. The sponge has the advantages of low cost, simple preparation and efficient oil-water separation. This kind of sponge is very worthy of promotion for the treatment of oily wastewater and marine oil spill accidents.

Superhydrophobic MS@CuO@SA sponge for oil/water separation with excellent durability and reusability

We present a superhydrophobic material based on commercially melamine sponge (MS) with great durability, recyclability, and excellent sorption performance. The fabrication process of this sponge is facile without using toxic reagents or sophisticated equipment and therefore it is simple to scale up. The CuO layer utilized to give a rough surface of the substrate (MS) was successfully prepared in a commercial microwave to seed copper nucleuses in an alkaline medium. Stearic acid (SA) plays a role as the self-assembled monolayer on the surface of the sponge skeletons. Throughout this study, the properties of the modified sponge were fully characterized, and the changes in wettability were carefully examined. Water contact angle (WCA) measurements revealed the excellent superhydrophobicity of the material with high static WCA of 165.1° and low dynamic WCA of 8°. Furthermore, the as-prepared sponge demonstrated high efficiency in separation (over 99.0%) of different oils from water. Notably, several unique properties of as-modified material were found, consisting of ultrafast sorption capacities of up to 32–52 times of its own weight by using 80 mL of each oil, outstanding reusability with good sorption capacity even after 40 cycles. Even under various harsh environments, the novel materials proved its outstanding durability and ultrafast sorption capacity of oils. The durability, recyclability, and superhydrophobic properties of the novel superhydrophobic sponge provide it a solid basis for oil-water separation applications through an ultrafast sorption capacity of oils as well as quick recovery of the oil by easy squeezing process.

A Robust Superhydrophobic Polyurethane Sponge Loaded with Multi-Walled Carbon Nanotubes for Efficient and Selective Oil-Water Separation.

The influence of different coupling agents and coupling times on the wettability of a polyurethane (PU) sponge surface were optimized. Octadecyltrichlorosilane (OTS) was selected as the optimal coupling agent to prepare the superhydrophobic sponge. The superhydrophobic sponge was prepared in one step, which has the advantages of simple operation and enhanced durability. The superhydrophobic sponge was characterized by scanning electron microscopy, Teclis Tracker tensiometry, and Fourier transform infrared (FT-IR) spectrophotometry. The water contact angle increased from 64.1° to 151.3°, exhibiting ideal superhydrophobicity. Oils and organic solvents with different viscosities and densities can be rapidly and selectively absorbed by superhydrophobic sponges, with an absorption capacity of 14.99 to 86.53 times the weight of the sponge itself, without absorbing any water. Since temperature affects the viscosity and ionic strength of oil, and influences the surface wettability of the sponges, the effect of temperature and ionic strength on the oil absorption capacity of the superhydrophobic sponges was measured, and its mechanism was elucidated. The results showed that the absorptive capacity retained more than 90% of the initial absorptive capacity after repeated use for 10 times. Low-cost, durable superhydrophobic sponges show great potential for large-scale oil-water separation.

Fully organic and biodegradable superhydrophobic sponges derived from natural resources for efficient removal of oil from water

• A fully organic and biodegradable superhydrophobic sponge is rationally constructed. • All of raw materials are derived from cheap renewable natural resources. • The sponge presents great separation performance for immiscible oil/water mixtures. • Multi-layer compressed porous structure achieves gravity-driven high-flux emulsion separation. Facile fabrication of functional superhydrophobic porous materials with full biodegradability for efficient removal of oily pollutants from water has been of considerable interest for its great significance in environmental protection. Herein, a fully organic and biodegradable superhydrophobic sponge is fabricated with carnauba wax (CW) via dip-coating, nonsolvent induced phase separation and spraying processes on a freeze-dried pomelo peel. The as-fabricated sponge was covered with flower-shaped patterns aggregated by CW nanosheets, and presented great water repellency with a contact angle of 154°. Thanks to the 3D porous architecture and superhydrophobicity/superoleophilicity, the sponge exhibited great oil absorptive capacity, oil selectivity, separation efficiency and reusability for immiscible oil/water mixtures. Interestingly, the multi-layer compressed sponges realized gravity-driven surfactant-stabilized water-in-oil emulsion separation with high permeation flux of up to 5729 L·m −2 ·h −1 and excellent efficiency of oil purity larger than 99.9%. Importantly, the superhydrophobic sponge was derived from cheap renewable natural resources, and capable of being completely biodegraded after discarding. The findings conceivably stand out as a new tool to fabricate superhydrophobic materials with sustainability and biodegradability for oil accidents and industrial sewage emissions.

Superhydrophobic sponges based on green deep eutectic solvents for spill oil removal from water

The paper described a new method for crude oil-water separation by means of superhydrophobic melamine sponges impregnated by deep eutectic solvents (MS-DES). Due to the numerous potential of two-component DES formation, simple and quick screening of 156 non-ionic deep eutectic solvents using COSMO-RS (Conductor-like Screening Model for Real Solvents) computational model was used. DES which were characterized by high solubility of hydrocarbons and the lowest water solubility were synthesized and embedded on melamine sponges. The new sponges were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and goniometer. Several parameters affecting the crude oil-water separation (i.e. type and amount of DES, density and porosity of sponges, water contact eagle) were thoroughly studied. In order to studies of MS-DES affinity to the selected groups of crude oil i.e. Saturated, Aromatic, Resins, Asphaltenes (SARA) the thin layer liquid chromatography-flame ionization detection (TLC-FID) was used. The obtained results indicate that the melamine sponges impregnated by DES composed of eucalyptol and menthol in 1:5 molar ratio have high real crude oil absorption capacity in the range of 96.1 – 132.2 g/g and slightly depends on crude oil compositions, superhydrophobic properties (water contact angle 152°), low density of 9.23 mg/cm3, high porosity of 99.39%, and excellent reusability which was almost not changing even after 80 cycles. The outcomes indicate that new MS-DES materials could be excellent alternatives as absorbents for the cleanup of crude oil-polluted water.

Durable superhydrophobic melamine sponge based on polybenzoxazine and Fe3O4 for oil/water separation

Oil/water separation through superhydrophobic sponges is an important method for oily wastewater and organic solvents pollution treatments, and developing a simple and eco-friendly approach to fabricate superhydrophobic sponge is still very urgent and valuable. In this work, Fe3O4 and bio-benzoxazine based on cardanol and long-chain aliphatic amine were successively loaded on melamine sponge (MS) through a simple dip-coating method, which was thermally cured to obtain superhydrophobic MS. The as-prepared superhydrophobic MS (P15C-O/Fe3O4/MS) not only exhibited high oil absorption capacity from 65.8 to 136.2 times its own weight for various oils and organic solvents, but also showed excellent recyclability with a water contact angle (WCA) of about 149° after 50 absorbing-squeezing cycles and an absorption retention of more than 92% after 100 cycles. Moreover, P15C-O/Fe3O4/MS also possessed outstanding chemical stability, whose WCA almost kept unchanged after touching with strong acid (pH = 1) and alkali (pH = 13) as well as NaCl solutions for 48 h. The outstanding recyclability and stability of P15C-O/Fe3O4/MS were from the stability of polybenzoxazine and strong adhesion between the coating and sponge, due to the formation of coordination interactions between Fe3+ and N, O atoms as well as hydrogen bonds between polybenzoxazine and sponge. In addition, P15C-O/Fe3O4/MS could be used for continuous oil-water separation and driven remotely by a magnetic force. These advantages make P15C-O/Fe3O4/MS a potential candidate for large-area oil-spill cleanup and oily wastewater treatment, especially under some dangerous conditions.

Interfacial assembly of micro/nanoscale nanotube/silica achieves superhydrophobic melamine sponge for water/oil separation

The regulation of surficial micro/nanoscale architecture assisted by interfacial assembly with nanomaterials is effective for the attainment of superhydrophobic surface, thus promising for fractionation of surfactant-containing oil/water mixtures. However, the pricey materials and elaborate preparation procedures make it infeasibility for mass production. In this work, a superhydrophobic/superoleophilic melamine sponge (MS-PAF-HNTs/SiO2) is prepared by combining an interfacial polymerization (IP) technique for halloysite nanotubes (HNTs) loading with superhydrophobic silicification derived from in situ tetraethoxysilane (TEOS) and octadecyl trimethoxysilane (ODTMS)-hydrolyzed condensation. The integration of naturally occurring micro-scale HNTs and nanoscale SiO2 endows the modified sponge with ridge-and-valley configuration and low-surface-energy, thus contriving a robust superhydrophobic/superoleophilic sponge evincing an extremely wetting selectivity for water and oil phases with a high water contact angle (WCA) of 158° and low water adhesion with a sliding angle of 5°. In this context, the MS-PAF-HNTs/SiO2 sponge displays superior separation performance with 99.99% and 99.58% separation efficiency toward immiscible oil/water mixtures and oil-in-water emulsions, respectively. The superhydrophobic sponge also features remarkable absorption capacity (169.7 times of its own mass) and exceptional compressibility which could withstand 1000 cycles compression without backbone collapsing. Furthermore, the as-prepared superhydrophobic sponge inherits the fire resistance property of pristine melamine sponge, which decreases the risk of flame and explosion when being employed for practical oil/water separation activities. This study provides a facile strategy containing moderate formation conditions and low-priced materials for design of superhydrophobic surface with an enhanced oil/water separation efficiency.

3D MXene Sponge: Facile Synthesis, Excellent Hydrophobicity, and High Photothermal Efficiency for Waste Oil Collection and Purification

Photothermally assisted superhydrophobic sponges play a vital role in the fields of waste oil collection, oil purification, and solar desalination. However, the widely reported superhydrophobic sponges with photothermal efficiency usually suffer from a post-/premodification process of harmful materials, high loading content of photothermal agents, and low photothermal efficiency. Herein, an MXene-based melamine sponge (MS) was facilely fabricated by hydrogen bonding interaction between the amino groups on the skeleton of the MS and the polar groups on the surface of the as-exfoliated 2D MXene Ti3C2Tx nanosheets. Interestingly, the as-fabricated MXene sponge exhibits excellent hydrophobicity and high photothermal efficiency under an extremely low loading of MXene Ti3C2Tx nanosheets (0.1 wt %). Moreover, the highly hydrophobic sponge also possesses a high oil absorption capacity as high as 176 times of its own weight and keeps stable under multiple absorption/desorption cycling tests. Surprisingly, the surface temperature of the MXene sponge can quickly reach 47 °C under illumination and has good reproducibility during multiple light on/off cycles. The excellent photothermal performance and large oil absorption capacity of the MXene sponge endow the highly hydrophobic sponge with fast solvent evaporation speed and high-purity waste oil collection (99.7 wt % dichloromethane) under illumination, which holds great promise for oil/water separation, leaked oil collection, and photo-driven waste oil collection and purification applications. It is envisioned that this work can open a new strategy for new designs of 3D multifunctional sponges for high-performance waste oil collection and purification.

Facile synthesis of superhydrophobic MS/TiO2/PDMS sponge for efficient oil-water separation.

To obtain a kind of superhydrophobic sponge with high oil and water selectivity, the MS/TiO2/PDMS sponge was prepared via a two-step hydrophobic fabrication based on the melamine sponge (MS), tetrabutyl titanate (TBOT), and polydimethylsiloxane (PDMS). The effects of modification time, the concentrations of TBOT and PDMS on the properties of the MS/TiO2/PDMS sponge were studied, and the separation mechanism was also discussed based on the interaction between the oil and the surface of the MS/TiO2/PDMS sponge. The results suggest that under optimal conditions, the MS/TiO2/PDMS sponge show superhydrophobicity. The contact angle and adsorption capacity for oil of the MS/TiO2/PDMS sponge are 149.2° and 98.5 g·g-1, respectively, and they can be recycled for about 25 cycles after oil-water separation test. This study prepares a new composite material with high oil-water selectivity, which is a good foundation for the development and research of new oil adsorbents.

Facile fabrication of 3D hierarchical micro-nanostructure fluorine-free superhydrophobic materials by a simple and low-cost method for efficient separation of oil-water mixture and emulsion

In this paper, a simple, environmentally friendly, fluorine-free, economical and effective hydrophobic modification method for melamine sponge (MS) with cobalt oxyhydroxide (CoOOH) and stearic acid (STA) was developed. The 3D pine needle-like hierarchical micro-nanostructure CoOOH coated onto the framework of MS as superhydrophobic materials were successfully constructed and synthesized by low temperature hydrothermal method. By combining the high porosity, superior elasticity, and mechanical stability of the MS with the nanometer scale roughness of CoOOH and low surface energy of STA, the modified CoOOH@STA@MS not only has superhydrophobic surface with the water contact angle of 155°, but also shows outstanding adsorption performance towards the various organic solvents/oils (absorption weight ranging from 20 to 50 times of its own) and excellent recyclability. Additionally, the modified MS can be used as an efficient oil pollutant removal equipment for continuous oil-water separation with the help of peristaltic pump. Furthermore, the CoOOH@STA@MS could be able to separate immiscible oil-water mixture as well as surfactant-stabilized water-in-oil emulsions. All the advantages indicate that the superhydrophobic sponge is the ideal material for oil spills treatment and environmental control.

Low-temperature carbonization synthesis of carbon-based super-hydrophobic foam for efficient multi-state oil/water separation

In view of the complexity and diversity of multi-state oils, the development of green and low-cost materials with high selectivity to oils has important ecological significance in the polluted water treatment. Herein, a simple method was proposed to develop large-scale production of superhydrophobic sponges (CPMF200 sponges) for high-efficiency oil/water separation under different complex environments. The as-prepared CPMF200 sponges possessed many superior properties, including high roughness, well-developed porosity, good thermal stability, excellent chemical stability, and superhydrophobic properties (water contact angle is 152°), which is conducive to high oil adsorption capacity (up to 70–179 times of its own weight) and oil-water separation. More importantly, the CPMF400 sponge has an excellent photothermal conversion capability to improve the fluidity of high viscosity oil for oil recovery. Based on a simple synthesis method, it exhibits high-efficiency absorption of multi-state oils and excellent oil-water separation performance and strongly proves their application prospects in treating oily wastewater.

The simple preparation of superhydrophobic sponge with fluorinated graphene and carbon nanotube

Nanomaterials have been developed to solve kinds of water pollution problems. Fluorinated graphene (FG) and multi-walled carbon nanotubes (MWCNTs) are used to improve the efficiency of oil/water separation of sponge via forming MWCNTs/FG/PU sponge in this work. The tests show that the two-dimensional FG can be adsorbed on the PU sponge, and one-dimensional MWCNTs can intertwine on the FG nanosheets as threads to fix on the skeletons of the PU sponge, which will form the micro-nano hierarchical structures and low surface energy surface. The surface contact angle of the MWCNTs/FG/PU sponge comes to the point of 158°, which indicates the MWCNTs/FG/PU sponge is superhydrophobic. The superhydrophobic MWCNTs/FG/PU sponge has outstanding ability to separate various oil/water mixtures effectively, and the corresponding absorbency of oils and organic reagents is over 15 g/g.

Unexpected Superhydrophobicity on a Wide Range of Substrates via a One-step Immersion in Aqueous Solution without Hydrophobic Agent

Superhydrophobic surfaces were unexpectedly constructed by immersing a variety of substrates (aluminum sheet, melamine sponge, cotton fabric, and wood) into an aqueous solution containing tea polyphenols and metal ions (Fe2+, Ag+, Ce3+) and the potential applications in corrosion resistance for superhydrophobic aluminum, water absorption resistance for superhydrophobic wood, oil/water separation for superhydrophobic sponge and self-cleaning for superhydrophobic fabric were investigated.

Application of Nano-Hydroxyapatite Derived from Oyster Shell in Fabricating Superhydrophobic Sponge for Efficient Oil/Water Separation.

The exploration of nonhazardous nanoparticles to fabricate a template-driven superhydrophobic surface is of great ecological importance for oil/water separation in practice. In this work, nano-hydroxyapatite (nano-HAp) with good biocompatibility was easily developed from discarded oyster shells and well incorporated with polydimethylsiloxane (PDMS) to create a superhydrophobic surface on a polyurethane (PU) sponge using a facile solution–immersion method. The obtained nano-HAp coated PU (nano-HAp/PU) sponge exhibited both excellent oil/water selectivity with water contact angles of over 150° and higher absorption capacity for various organic solvents and oils than the original PU sponge, which can be assigned to the nano-HAp coating surface with rough microstructures. Moreover, the superhydrophobic nano-HAp/PU sponge was found to be mechanically stable with no obvious decrease of oil recovery capacity from water in 10 cycles. This work presented that the oyster shell could be a promising alternative to superhydrophobic coatings, which was not only beneficial to oil-containing wastewater treatment, but also favorable for sustainable aquaculture.

Highly efficient reusable superhydrophobic sponge prepared by a facile, simple and cost effective biomimetic bonding method for oil absorption

Superhydrophobic sponges have considerable potential for oil/water separation. Most of the methods used for superhydrophobic modification of sponges require toxic or harmful solvents, which have the drawbacks of hazardous to environment, expensive, and complex to utilize. Moreover, the hydrophobic layer on the surface of sponge is often easily destroyed. In this paper, a highly efficient superhydrophobic sponge with excellent reusability was developed by using a facile, simple and environmentally friendly dopamine biomimetic bonding method. Different types of sponges, such as melamine, polyethylene or polyurethane sponge wastes, were used as raw materials to prepare superhydrophobic sponges, which possess the advantages of inexpensive and abundant. The effects of different dopamine polymerization time and different hydrophobic agent dosage on the hydrophobicity and oil absorption capacity of melamine sponges were optimized. The study results showed that the water contact angle of the superhydrophobic sponge could reach 153° with excellent organic solvent absorption capacity of 165.9 g/g. Furthermore, the superhydrophobic sponge retained approximately 92.1% of its initial absorption capacity after 35 reutilization cycles. More importantly, the dopamine biomimetic bonding superhydrophobic modification method can be used for different types of sponges. Therefore, a universally applicable, facile, simple and environmentally friendly superhydrophobic modification method for sponges was developed.

Techno-economic and Environmental Analyses on Reduced Graphene Oxide modified Kapok Fiber as Oil Absorbent

The industrialization of synthetic fiber has resulted in an economic depression for both domestic and global kapok fiber industries as well as the farmers. On the other hand, the development of ssthe oleochemical industry in Indonesia demands a separation process that is less cost- and energy-intensive. Supporting the sustainable development goals (SDGs) number 1, 8, 9, 12, and 13, in this study, the under-tapped kapok fiber has been utilized to show its potential value as an oil sorbent material. Despite having high oil sorption capacity and being biodegradable, the raw kapok fiber has low oil selectivity, low oil retention, and a fragile structure. The kapok fiber has been modified with reduced graphene oxide (rGO) to obtain hydrophobic-oleophilic absorbent with high absorption capacity, high oil selectivity, high oil retention, and strong structure to maximize the recovery yield. Modification has been done by soaking kapok fiber in GO supernatant and reducing them with ascorbic acid, then freeze-drying the fiber to get a robust superhydrophobic sponge. Techno-economic and life-cycle analyses have been conducted and the results indicate that rGO-KF aerogel is economically viable with a potential GPM greater than 36,27%, and environmentally beneficial as it can potentially decrease product carbon emissions by 32.8 tons/ton recovered oil.

One-pot synthesis of fluorine functionalized Zr-MOFs and their in situ growth on sponge for oil absorption

The treatment of oil spill and the separation of oil-water mixture have been widely concerned in recent years. In this work, a one-pot synthesis strategy is developed to prepare fluorine functionalized zirconium-based metal organic framework (Zr-MOFs) (denoted as UiO-66-1F) by using 4-fluorobenzoic acid as modulator and modifier and p-phthalic acid (PTA) as ligand. 4-fluorobenzoic acid can participate in the formation of frameworks structure and cause structural defects, causing larger surface area and hierarchically porous structure. The hydrophobicity of UiO-66-1F increases with increasing of the ratio of 4-fluorobenzoic acid to zirconium chloride and when the ratio is 10, the synthesized UiO-66-1F(10) shows high hydrophobicity with a water contact angle (WCA) of 122° while the WCA of original UiO-66 is only 21°. UiO-66-1F(10) also has good chemical stability over a wide pH range (pH 1∼11) and good hydrothermal stability. In addition, a superhydrophobic sponge (UiO-66-1F(10)@PDA@sponge) with a WCA of 150° was prepared via in situ growth of UiO-66-1F(10) on a polydopamine modified sponge (PDA@sponge). The resulting composite shows high absorption capacities for various oils and organic solvents ranging from 50.5 g/g (n-hexane)– 107.8 g/g (dichloromethane) and good recyclability.