Characterization of Flame Retardancy and Oil-Water Separation Capacity of Superhydrophobic Silylated Melamine Sponges

A silylated melamine sponge(SMS)was prepared by two simple steps,namely,immersion and dehydration of a melamine sponge coated with methyltrichlorosilane.The silylated structure of SMS was characterized by FT-IR(Fourier-transform infrared)spectroscopy,SEM(Scanning electron microscopy)and in terms of water contact angles.Its oil-water absorption and separation capacities were measured by FT-IR and UV-visible spectrophoto-metry.The experimental results have shown that oligomeric silanol covalently bonds by Si-N onto the surface of melamine sponge skeletons.SMS has shown superhydrophobicity with a water contact angle exceeding 150°±1°,a better separation efficiency with regard to diesel oil(by 99.31%(wt/wt%)in oil-water mixture and even up to 99.99%(wt/wt%)for diesel oil in its saturated aqueous solution.Moreover,SMS inherited the intrinsicflame retardancy of the melamine sponge.In general,SMS has shown superhydrophobicity,high porosity,excellent selectivity,remarkable recyclability,and better absorption capacity for various oils and organic solvents,and a high separation efficiency for oil in saturated aqueous solutions.

Preparation of Silica Nanosphere with Vertical Pore and Its Application in Oil-water Separation

Uniform monodispersed mesoporous silica nanospheres with vertical pores were successfully synthesized using chiral amphiphilic small molecule L-16Ala5PyClO4and solvents as dual templates via solgel transcription.The morphologies and pore sizes of silicas are adjustable by changing the type and amount of solvents in the reaction systems.With the increase of the organic solvent content,the morphologies of the obtained silica changed from nanospheres with vertical pore structures to nanosheets structures.When 1 mL of benzene,cyclohexane or toluene were used as solvents,only silica nanospheres were obtained,the BET surface areas of silica nanospheres reached 600.7,669.5,and 560.8 m^(2)/g,respectively.The pore sizes were 3.51,3.54,and 3.46 nm,respectively.Significantly,these ordered silica nanospheres/poly(vinyl alcohol-co-ethylene)(PVAco-PE)nanofiber membranes have high separation efficiencies(>99%)for n-hexane/water mixtures.

Preparation of Hydrophobic Fly Ash by Surface Modification and Oil-water Separation Devices

A simple and effective superhydrophobic mesh was designed and made to separate oil-water mixture. Alkali-activated fly ash reacted with 1-bromooctadecane to prepare superhydrophobic modified fly ash (MFA) with low surface energy through Williamson ether synthesis. The MFA powder was then coated uniformly on a stainless steel mesh (SSM) along with the epoxy resin E44 and curing agent T31 to give the superhydrophobic MFA-modified stainless steel mesh (MFA-SSM). The MFA-SSM has a high static water contact angle (CA) of 150.1°and can separate various oil or organic solvent from water with>95%separation efficiency. The oil-water separation efficiency remained high after 30 runs of petroleum ether/water separation.The developed superhydrophobic stainless steel mesh is expected to have wider use in oil-water separation.

Robust,fluorine-free and superhydrophobic composite melamine sponge modified with dual silanized SiO_(2) microspheres for oil-water separation

Massive oily wastewater discharged from industrial production and human daily life have been an urgent environmental and ecological challenge.Superhydrophobic materials have attracted tremendous attention due to their unique properties and potential applications in the treatment of wastewater.In this study,a novel superhydrophobic/superoleophilic composite melamine sponge modified with dual silanized SiO_(2) microspheres was fabricated simply by a two-step sol-gel method using vinyltriethoxysilane and hexadecyltrimethoxysilane as functional agent,which exhibited a water contact angle of 153.2°and a water sliding contact angle of 4.8°.Furthermore,the composite sponge showed the excellent oil adsorption performance and the compressive elasticity reaching up to 130 g·g^(-1) of dichloromethane and 33.1 kPa of compressive stress.It was worth noting that the composite sponge presented the excellent separation efficiency(up to 99.5%)in the processes of continuous oil/water separation.The robust superhydrophobic composite melamine sponge provided the possibility with the practical application for oil-water separation.

Simultaneously spray-assisted assembling reversible superwetting coatings for oil-water separation

Here,superhydrophobic cuprous oxide(Cu2O)with hierarchical micro/nanosized structures was synthesized via sprayassisted layer by layer assembling.The asprepared superhydrophobic meshes with high contact angle(159.6°)and low sliding angle(1°)are covered with Cu_(2)O "coral reef"like micro/nanosized structures.Interestingly,the superhydrophobic mesh surfaces became superhydrophilic again due to the oxidization of Cu_(2)O to CuO by annealing at a higher temperature(300℃).And the superhydrophobic properties would be recovered by heating at 120℃.Furthermore,the superwetting meshes were applied to design a miniature device to separate light or heavy oil from the wateroil mixtures with excellent separation efficiency.These superwetting surfaces by simultaneously sprayassisted layer by layer assembling technique show the potential application in universal oilwater separation.

Magnetic Wood-based Superhydrophobic Aerogel for Efficient Oil-Water Separation

The fabrication of directionally driven oil-water separation materials has great significance for the removal of oil spills and organic pollutants.In this study,an oil-water separation aerogel capable of directionally adsorbing oil was designed using an anisotropic wood aerogel with a layered structure and a top-down fabrication strategy.Specifically,a magnetic wood-based superhydrophobic aerogel(methyltrimethoxysilane(MTMS)/Fe_(3)O_(4) wood aerogel)was developed through the in situ coprecipitation of Fe_(3)O_(4) nanoparticles and chemical vapor deposition.Owing to its highly porous structure,lipophilicity,hydrophobicity(water contact angle of 160°),and high compressibility,the MTMS/Fe_(3)O_(4) wood aerogel exhibits excellent oil-water separation performance and compression cycle stability.Additionally,the Fe_(3)O_(4) endows the material with excellent magnetic and photothermal conversion capabilities.These excellent properties make MTMS/Fe_(3)O_(4) wood aerogel a promising recyclable and sustainable oil-water separation material.

Electrospinning Nanofiber Membrane Reinforced PVA Composite Hydrogel with Preferable Mechanical Performance for Oil-Water Separation

Nowadays hydrogels have been attracting the massive interest in oil-water separation due to their robust hydrophilicity and fantastic underwater oiliness features.However,the weak toughness and tensile strength shortcomings of hydrogels have thus inhibited their actual applicability.For this reason,we successfully fabricated the electrospun nanofiber membrane-reinforced PVA composite hydrogels.The PVA-PAN composite hydrogel has exhibited the excellent tensile strength and friction performance,separately enhancing 174.2%of the tensile strength,and reducing 20.7%of the friction coefficient and 58.7%of wear volume relative to the neat PVA hydrogel.Furthermore,the pull-out experiments indicated that the PAN nanofiber membrane exerted a stronger interface bonding effect with PVA hydrogel.The oil-water separation evaluation test showed that the separation efficiency reached up to 97.6%for treating the SA-100 lubricating oil/water system.

NIR-responsive Collagen-based Sponge Coated with Polydimethylsiloxane/Candle Soot for Oil-Water Separation

To fabricate an oil-water separation material that is rich in source,eco-friendly,and responsive,in this study,we successfully developed a collagen-based sponge for application to oil-water separation based on a green and facile strategy.In this design,widely-available collagen(COL)was used as the substrate:it was immersed in polydimethylsiloxane(PDMS)suspension with candle soot(CS)nanoparticles,followed by hot curing.The resultant sponge(CS/PDMS-COL)possessed good hydrophobicity with a water contact angle of 148.3°under a low PDMS concentration of 2%.The results from field emission scanning electron microscope,Fourier transform infrared spectrometer,X-ray photoelectron spectrometer,and X-ray diffractometry demonstrated the successful coating of CS and PDMS on the surface of COL substrate.The CS/PDMS-COL can adsorb eight oils,with the adsorption capacity for trichloromethane reaching 95 g/g.With benzene as the target adsorbent,the separation efficiency was maintained at no less than 95%even after recycling 20 times.CS/PDMS-COL was also used to separate oil-in-water emulsion.Moreover,the sponge killed bacteria effectively due to its excellent near-infrared photothermal responsiveness.This study provides new insight into the preparation of facile oil-water separation materials based on naturally occurring biomaterials effortlessly.

Superhydrophobic magnetic Fe_(3)O_(4) polyurethane sponges for oil-water separation and oil-spill recovery

The effective and affordable separation of oil and water,a crucial process in the safe han dling of environmental disasters such as crude oil spills and recovery of valuable resources is a highly sought-after yet challenging task.Herein,superhydrophobic PU sponge was fab ricated for the fast and cost-effective adsorptive separation of oil and different organic sol vents from water.Octadecyltrichlorosilane(OTS)-functionalized Fe_(3)O_(4)@SiO_(2)core-shell mi crospheres were dip-coated on the surface of porous materials via a dip-coating process thereby endowing them with superhydrophobicity.Owing to the hydrophobic interaction between OTS molecules and oil and increased capillary force in the micropores,the result ing superhydrophobic sponge served as a selective oil-sorbent scaffold for absorbing oil from oil-water mixtures,including oil-water suspensions and emulsions.Remarkably,after the recovery of the adsorbed oil via mechanical extrusion,these superhydrophobic materials could be reused multiple times and maintain their oil-water separation efficacy even afte 10 oil-water separation cycles.

STUDY ON THE GRAVITATION SEPARATION OF SKARN-TYPE WOLLASTONITE ORE FOR PURIFICATION

This paper introduces the common paragenetic minerals of skarn-type wollastonite ore and its principle of gravitation separation for purification. Through the separation experiment of concentrating table on the wollastonite ore from Xiaojipu Wollastonite Mine of Hubei province, the product has reached the reguirement of wollastonite powder used as the ceramic raw material.

分离变量法求解椭球星体的重力势增量

尝试利用电动力学中常用的求电势的方法“分离变量法”求解椭球星体的重力势增量.

Simple and Ultrahigh Efficient Superhydrophilic Polydopamine-coated TiO_(2) Cotton for Oil-water Separation

Oil–water mixing has brought many problems to a society, and it is of great significance to develop a simple, convenient, efficient, and durable separation material to solve the problem of oil–water mixing. In this paper, modified cottons were successfully prepared using polydopamine as the in situ mineralization site of TiO_(2) nanoparticles combined with synergistic crosslinking with KH550. A large number of hydrophilic groups endowed the cotton with superhydrophilic ability, which greatly shortened its water spreading time. The prepared modified cotton could be successfully separated from oil and water, and still had a separation efficiency of 99.999% after 50 cycles. In addition, after 24 h immersion in 1 M HCl, NaOH, and NaCl solutions and 50 abrasion experiments, the modified cotton showed excellent oil–water separation ability, and the separation efficiency was above 99.990%. Successfully provided a simple preparation method to prepare high-efficiency and clean cottons for oil–water separation.

Separation Problem in Satellite Gravimetry

The problem of separating gravitation from inertia is discussed in very general sense, and the conclusion is positive: man can separate gravitation from inertia, if various observation techniques are applied for. The accelerometer's position problem in satellite gravimetry is investigated, and the additional acceleration effect due to the position error of an instrument as well as the difference between the mass center and the gravity center is explored.

Produced-water treatment: Application and research of combined fiber coalescence technique in offshore oilfield

When the process of extraction of oil from an offshore oilfield enters the advanced stages,the water content in the extracted fluid can be above 90%.The water quality is complex with many types of pollutants and highly emulsified water.Therefore,a key consideration in the production process of offshore oilfields is the efficient and economical treatment of the oil-containing produced water to make it suitable for discharge and recover oil pollutants.In this study,we developed a hydrophilic and hydrophobic combined fiber coalescence separator with composite fiber shapes using fiber induction and X/Uweaving.The separator is designed based on experimental observations of the mechanism of structure coalescence in the physical oil removal method.A pilot test was performed on an oil exploration platform in the Bohai Sea.At the designed flow rate,the separator reduced the total concentration of petroleum in the produced water from 2000 to 3000 mg/L to below 60 mg/L,with an average oil removal efficiency of 98.24%.Furthermore,it effectively reduced the number of organic compounds present in the water from 120 to 17 and removed 70% of the SS.The test results show that the proposed device can be used fr produced-water treatment on offshore platforms.

Fabrication of Bioinspired Structured Superhydrophobic and Superoleophilic Copper Mesh for Efficient Oil-water Separation

Oily water treatment has attracted the attention of many researchers. The development of effective and cheap oil/water separation materials is urgent for treating this problem. Herein, inspired by superhydrophobic typical plant leaves such as lotus, red rose and marigold, superhydrophobic and superoleophilic copper mesh was fabricated by etching and then surface modi- fication with 1-dodecanethiol （HS（CH2）IlCH3）. A rough silver layer is formed on the mesh surface after immersion. The ob- tained mesh surface exhibits superhydrophobicity and superoleophilicity and the static water contact angle was 153~ ＋ 3~. In addition, the as-prepared copper mesh shows self-cleaning character with water and chemical stability. The as-prepared copper foam can easily remove the organic solvents either on water or underwater. We demonstrate that by using the as-prepared mesh, oils can be absorbed and separated, and that high separation efficiencies of larger than 92% are retained for various oils. Thus, such superhydrophobic and superoleophilic copper mesh is a very promising material for the application ofoil spill cleanup and industrial oily wastewater treatment.

Simple fabrication of superhydrophobic PLA with honeycomb-like structures for high-efficiency oil-water separation

Polylactic acid(PLA) is one of the most suitable candidates for environmental pollution treatment because of its biodegradability which will not cause secondary pollution to the environment after application.However,there is still a lack of a green and facile way to prepare PLA oil-water separation materials.In this work,a water-assisted thermally induced phase separation method for the preparation of superhydrophobic PLA oil-water separation material with honeycomb-like structures is reported.The PLA material shows great ability in application and could adsorb 27.3 times oil to its own weight.In addition,it could also be applicated as a filter with excellent efficiency(50.9 m^3 m^(-2) h^(-1)).

Preparation of PDVB/TiO2 composites and the study on the oil-water separation and degradation performances

The traditional superhydrophobic materials are not ideal for treating residual pollutants after oil-water separation. In this paper, a simple and economical method was developed for the fabrication of multi-functional superhydrophobic materials PDVBx/TiO2 composites, through in situ polymerization. The performance of the superhydrophobic composite was studied. The results showed that the low surface energy of PDVB2.5/TiO2 composite with the micro-nano scale roughness would result in excellent superhydrophobicity. In addition, the PDVB2.5/TiO2 composite exhibits optimum effect on the degradation of methyl orange(MO) with the degradation efficiency of 97.8%. What is more, the applications of the composite materials could be expanded to other fields, such as the degradation of drug ciprofloxacin hydrochloride(CIP). Finally, we expanded the application of the PDVBx/TiO2 composites to tribology, and found its excellent performance in reducing wear and antiwear.

SIMULATION OF OIL-WATER TWO PHASE FLOW AND SEPARATION BEHAVIORS IN COMBINED T JUNCTIONS

The combined T junctions used for the oil-water separation have the advantages of compactness in structure, consistency in effects and economy in cost. The mixture k- ε turbulence model and the Eulerian multi-fluid model are used to simulate the flow and phase distribution in the combined T junctions. The effects of structural parameters such as the branched pipe interval and height on the flow distribution and the separation behaviors are studied. The results show that the combined T junctions under fixed inlet and outlet boundary conditions form a single hydraulic equilibrium system in which the fluid energy distributes freely till a balance is achieved. The split-flow promotes the separation of the immiscible oil and the water. The separation efficiency increases with the increase of the branched pipe interval and changes slightly with the increase of the branched pipe height. The structural change of the combined T junctions may change the flow direction in the branched pipes. Simulation results can provide some guidance for the design of the combined T junctions as one kind of oil-water separator.

One-step Condensation/copolymerization of VTES and DVB for Self-assembly Bionic Superhydrophobic Surface Coating and Study on Oil-water Separation

Mimicry of nature drives the development of bionic materials.Bionic superhydrophobic materials are a kind of high-efficiency materials to handle oil spills and water pollution.However,the stability of surface coatings of the superhydrophobic materials remains a challenge.Herein,a new category of self-assembly bionic superhydrophobic surface coating was prepared via one-step condensation/copolymerization of vinyltriethoxysilane(VTES)and divinylbenzene(DVB),which realized the close combination of covalent bonds between organic(e.g.DVB)and inorganic matter(e.g.VTES),and avoided the swelling of polydivinylbenzene(PDVB)in the process of collection of oil from water.This organic-inorganic hybrid polymer could self-assembly deposit on the surface of sponge even other substrates.For example,P(VTES-DVB)-Si0_(2)/MS obtained by assembling P(VTES-DVB)-Si0_(2)on the surface of Melamine Sponge(MS)exhibited superhydrophobicity with a Water Contact Angle(WCA)of 157.3,the optimal adsorption capacity of 77 g g 136 g g-1 for diverse oils,and an excellent separation efficiency of 99.3%.Besides,the excellent acid and alkali resistance of P(VTES-DVB)-Si0_(2)/MS suggested the potential value in practical oil-water separation.P(VTES-DVB)-Si0_(2)showed the outstanding hydrophobic performance by using as coating on different substrates.This work provided a new idea about the stable combination of organic and inorganic matter in the surface modification.

An unusual superhydrophilic/superoleophobic sponge for oil-water separation

Development of porous materials with anti-fouling and remote controllability is highly desired for oil-water separation application yet still challenging. Herein, to address this challenge, a sponge with unusual superhydrophilicity/superoleophobicity and magnetic property was fabricated through a dip-coating process. To exploit its superhydrophilic/superoleophobic property, the obtained sponge was used as a reusable water sorbent scaffold to collect water from bulk oils without absorbing any oil. Owing to its magnetic property, the sponge was manipulated remotely by a magnet without touching it directly during the whole water collection process, which could potentially lower the cost of the water collection process. Apart from acting as a water-absorbing material, the sponge can also be used as affiliation material to separate water from oil-water mixture and oil in water emulsion selectively, when fixed into a cone funnel. This research provides a key addition to the field of oil-water separation materials.