Thermal stability and oil absorption of aluminum hydroxide treated by dry modification with phosphoric acid

The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders were investigated. The results show that the increase of mass ratio of phosphoric acid to aluminum hydroxide, the decrease of mass concentration of phosphoric acid and prolongation of mixing time are favorable to the improvement of thermal stability of aluminum hydroxide; when the mass ratio of phosphoric acid to aluminum hydroxide is 5:100, the mass concentration of phosphoric acid is 200 g/L and the mixing time is 10 min, the initial temperature of loss of crystal water in aluminum hydroxide rises from about 192.10 to 208.66 ℃, but the dry modification results in the appearance of agglomeration and macro-aggregate in the modified powders, and the oil absorption of modified powders becomes higher than that of original aluminum hydroxide.

Study on Performance and Mechanism of Oil Absorption Materials

Both the commonly used and the PHBV based oil absorption materials were studied and the absorption mechanism was analyzed. The results show that the oil pick up ratios and the absorption rates of molded PHBV are almost the same as that of oil absorption polypropylene felt. In addition, the oil keeping ability of molded PHBV is superior to the latter. So the PHBV is a valuable and bio degradable oil absorption material.

Tailoring surface features and pore structure by carbon spiral fibers to construct the high-strength carbon foams for the fast and cyclic photo-thermal oil absorption

Two key limitations affecting the commercial application of carbon foams for fast clean-up of varied oils are the complex synthesis process and poor mechanical stability.In this work,an effective method is reported to fabricate the efficient oil-absorbing materials(CSF@MCF)of carbon spiral fibers(CSFs)anchored on melamine carbon foam(MCF)with superior mechanical properties and excellent photothermal con-version.The interwoven CSFs can not only provide extra rigidity but also reduce the stress concentration of the carbon skeleton,which greatly improves the mechanical properties with 6.3 times maximum compression stress and 4.5 times ultimate tensile strength than MCF.In addition,the pure carbon component can reduce the interface resistance and excite the free electrons more easily,thus realizing high-efficiency photothermal conversion in a wide range of wavelengths.Under light irradiation,the CSF@MCF can be quickly heated up to 70℃and achieve ultra-high absorption of crude oil,up to 62 g g_(-1),due to its low density and large absorption volume.Meanwhile,the CSF@MCF exhibits impressive absorption stability with persistent superhydrophobicity and a high recovery efficiency of over 85%.Superadding its simple preparation process,low production cost,and excellent acid-alkali resistance,the CSF@MCF shows great commercial potential for effectively absorbing varied oils.

Fabrication of intra porous PVDF fibers and their applications for heavy metal removal,oil absorption and piezoelectric sensors

Intra porous fibrous membranes have enhanced metal ionic adsorption and oil separation abilities than those of intra nonporous fibrous membrane.In this paper,we prepared highly intra porous fibrous poly(vinylidene fluoride)(PVDF)membranes using an innovated water-mediated electrospinning approach.FTIR-ATR and XRD techniques confirmed the conversion of non-polarα-phase to polarβ-phase in electrospun membranes.The porous fibrous membrane M–16 had adsorbed oil almost 120%and metal adsorption around 15%,12%,5%,13%respectively for Pb^(2+),Cd^(2+),Cu^(2+)and Zn^(2+),which are larger than the counterpart of nonporous M–18.The nonporous fibrous membranes have better peak to peak output voltage(Vp-Vp)2 to 3 times than the porous fibrous membranes(M–16).The results show apparent potential applications in wastewater/oil spill treatment as well as piezoelectric sensors.

Electrical Conductivity,Oil Absorption and Electric Heating of Carbon Black-modified Carbon Nanofibers

Carbon-black-modified carbon nanofibers were prepared by electrospinning,and the effects of the carbon black content and processing temperature on the physical and chemical properties of the resulting composites were investigated.The results showed that the conductivity of carbon-black-modified nanofibers increased with the carbon black content.The addition of carbon black in a 20%mass ratio increased the conductivity of the composite(0.75 S/cm)by 230%compared with the undoped nano-fiber(2.47 S/cm),while the adulteration with 5%CB allowed the preservation of the mechanical properties of the composites.The fabricated carbon-black/carbon-nanocomposite fibers exhibited excellent oil absorption and electrothermal conversion performance.Furthermore,the conductivity and oil absorption capacity increased with increasing carbonization temperature.With a carbonization temperature of 1000℃(5%carbon black),the voltage was 31 V,the current was 0.66 A,and the surface temperature of the composite reached 234.1℃.The overall enhancement in physical properties upon the addition of even low amounts of carbon black makes these composites advantageous for future industrial applications.

The superhydrophobic sponge decorated with Ni-Co double layered oxides with thiol modification for continuous oil/water separation

In this paper, the superhydrophobic polyurethane sponge(SS-PU) was facilely fabricated by etching with Jones reagent to bind the nanoparticles of Ni-Co double layered oxides(LDOs) on the surface, and following modification with n-dodecyl mercaptan(DDT). This method provides a new strategy to fabricate superhydrophobic PU sponge with a water contact angle of 157° for absorbing oil with low cost and in large scale. It exhibits the strong absorption capacity and highly selective characteristic for various kinds of oils which can be recycled by simple squeezing. Besides, the as-prepared sponge can deal with the floating and underwater oils, indicating its application value in handling oil spills and domestic oily wastewater. The good self-cleaning ability shows the potential to clear the pollutants due to the ultralow adhesion to water. Especially, the most important point is that the superhydrophobic sponge can continuously and effectively separate the oil/water mixture against the condition of turbulent disturbance by using our designed device system, which exhibit its good superhydrophobicity, strong stability.Furthermore, the SS-PU still maintained stable absorption performance after 150 cycle tests without losing capacity obviously, showing excellent durability in long-term operation and significant potential as an efficient absorbent in large-scale dispose of oily water.

Plugging performance and mechanism of an oil-absorbing gel for lost circulation control while drilling in fractured formations

Lost circulation of drilling fluid is one of the most common engineering problems in the drilling process of fractured formations.In this study,an oil-absorbing polymer gel synthesized using compound monomers with rigid and flexible chains was applied to control the oil-based drilling fluid loss while drilling.The microstructure,oil-absorbing performance,and plugging performance the gel was investigated.A large number of dense pores on the surface of the gel were observed,which allowed the oil molecules to enter the internal space of the gel.The initial oil absorption capacity of the gel was fast,and it increased with the increase in the temperature and decrease in the particle size,reaching 20.93 g/g at140℃.At a high temperature of 140℃,the bearing pressure capacity of the gel formula containing particles of different particle sizes reached 7.6 MPa for a fracture of a width of 3 mm,showing that the oil-absorbing gel have excellent plugging performance at high temperature.Plugging mechanism of the gel was investigated through visualized fracture plugging experiments.Results show that the dynamic migratio n,particle-swelling,particle-bridging,particle-aggregation,deformation-filling,and compaction-plugging contribute to the whole lost circulation control process,reflecting that the plugging performance can be effectively enhanced by improving the aggregation and filling degrees of the gel with different particle sizes.

Influence of Partial Drying on Oil Uptake ＆ Quality Attributes of French Fries

Today＇s customers are looking for non-fat or low-fat containing products. One of the methods to reduce oil absorption in fried products is partial drying before frying. In this study, influence of partial drying （10 min, 20 min, 30 min） on oil absorption and quality attributes of three potato cultivars （Agria, Satina, kenebek） was evaluated. Our results reveled that in Agria, partial drying leads to an increase in oil absorption compared with non-dried sample （p〈0.05）. In kenebek, partial drying reduced the oil absorption and improved the texture and color of the produced French fries （p〈0.05）. Similar results were observed with Satina as with kenebek. In all three varieties, partial drying increased the dry matter, color quality and required cutting force of the French fries （p〈0.05）.

Study on Process Conditions of Preparation of Microporous Potatoes Starch by Complex Enzyme Method

[Objective] The technology of using c-amylase and glucoamylase to prepare microporeus potato starch was studied.[ Method ] Taking potato starch as raw materials, starch hydrolysis rate and the oil absorption as a measure of index, the influences of the reaction temperature, two enzymes proportion, the quantity of enzyme, the chroma of substrate, buffer solution pH and reaction time on microporous potato starch were inves- tigated. [ Result] The experimental results showed that the best technological conditions were reaction temperature 45 ℃, enzyme ratio （ glucoamy- lase/α-amylase）6, the quantity of enzyme （amount of enzyme and starch quality than） is 1.0%, the substrate quantity chroma of 0.14 g/ml, buffer solution pH 4, the reaction time 8 h. In such process condition, the oil adsorption rate of hydrolyzed potato starch was as high as 70.2%, starch hydrolytic ratio was 34.16%. [ Condmion] The study provided a basis for the development and utilization of microporous starch. Key words Microporous starch; Hydrolysis rate; Oil absorption rate; Preparation; Complex enzyme method; China

Structure and Potential Application of Konjac Glucomannan Nano Microfibril Aerogel

An ultra-light and high porosity nano microfibril aerogel was prepared from konjac glucomannan（KGM） by the electrospinning and freeze-drying. The structure of aerogel was analyzed by scanning electron microscopy（SEM） and X-ray diffraction（XRD） while the density and compressive strength of the samples were studied separately. Results reveal that porous network structure of the KGM nano microfibril aerogel is constructed by intermolecular hydrogen bonds in random and interpenetrate way. The nano microfibril structure presents in the KGM aerogel,which is an important reason of its high density and compressive strength. There is a potential application for this unique nano microfibril aerogel in the absorption of biodegradation bacteria to solve problems in marine oil spill pollution.

Speed up the absorption of viscous crude oil spill by Joule-heated sorbent design

Although ocean crude-oil spill accidents did not frequently happened in the past, it really caused great damage to the ma- rine ecosystem once it happened. Because of the spreading and weathering, crude-oil spill usually covers a large area of water surface and its viscosity is very high, which brings hu- man great trouble to clean it up. Dispersant and in-situ burn- ing were frequently used in the past crude-oil spill accidents, but these two methods suffered from the drawbacks includ- ing being toxic to marine lives, causing air pollution, disabil- ity of recovering the crude oil. Oil skimmers could recovery the oils, but their handling capacities are rather limited. Re- cently, porous hydrophobic and oleophilic materials （PHOM） have been demonstrated as low-cost, efficient and ecofriendly materials for the oil spill cleanup [ 1 ]. Nevertheless, their poor absorption speed to viscous oil spill hinders their practical ap- plication.

Preparation and properties of a silver particle-coated and 1-dodecanethiol-modified superhydrophobic melamine sponge for oil/water separation

A Ag particle-coated and 1-dodecanethiolmodified melamine sponge(Ag-DDT-MS)was prepared through surface roughness by coating silver particles and subsequent grafting of a hydrophobic long hydrocarbon chain.Superhydrophobic and 3D porous Ag-DDT-MS was characterized by Fourier transform infrared spectroscopy,scanning electron microscope,energy-dispersive X-ray spectroscopy,and X-ray diffraction.The water contact angle of Ag-DDT-MS reached 159.2°.Ag-DDT-MS exhibited excellent absorption capacity for high viscous oils and organic solvents,ranging from 42.8 to 105.2 g∙g−1.The absorbed oils can be easily collected by the mechanical pressing process,and the oil recovery rate was satisfactory,more than 90%after 20 recycles.Ag-DDT-MS material also demonstrated good stability and excellent compressionrecovery ability,keeping 88.6%of the initial height after ten compression-release cycles.

Downy feather-like para-aramid fibers and nonwovens with enhanced absorbency,air filtration and thermal insulation performances

Fiber morphology with off-standing branches,as found in nature,e.g.,in goose downy feather,provides exquisite functions that can be barely achieved by man-made fiber systems.In this work,we develop a simple and scalable method for generating downy feather-like para-aramid fibers and assemblies.Through treating commercial para-aramid microfibers with mild alkaline solution(low concentration of NaOH),a synergistic effect of chemical hydrolysis and physical shearing is successfully triggered to generate abundant nanofiber branches on the surface of para-aramid fibers.When compared with conventional monotonous structures,nonwovens composed of downy feather-like fibers exhibit a typical multiscale fiber morphology,larger specific surface area and smaller pore size,thus showing enhanced particles adsorption capacity(over twice of the pristine nonwoven),excellent oil absorption capacity(increased by~50%),improved air filtration performances(doubled the filtration efficiency)and effective thermal insulation(thermal conductivity=26.1 mW·m^(−1)·K^(−1)).More attractively,the intrinsic flame-retardant nature of para-aramid is well inherited by the downy feather-like fibers,and the fabrication process requires neither sophisticated equipment,nor tedious procedures,making us believe the strong competitiveness of these fibers and assemblies.

Enhanced Mechanical Properties of Poly(arylene sulfide sulfone)Membrane by Co-electrospinning with Poly(m-xylene adipamide)

The mechanical properties of poly(arylene sulfide sulfone)(PASS) electrospun membrane were significantly enhanced by coelectrospinning with semi-aromatic nylon poly(m-xylene adipamide)(MXD6), another engineering plastic with high thermal stability and good mechanical properties. The tensile strength of PASS membrane increased with increased incorporation of MXD6, and was tripled when 20%MXD6 was incorporated. The mechanism of the mechanical property improvement is the existence of hydrogen bonding interaction between PASS and MXD6 and between adjacent fibers at the intersections. Thermal properties of the PASS/MXD6 membranes were evaluated by differential scanning calorimetry(DSC) and thermogravimetric analysis(TGA), which showed that the membranes could be stably utilized up to180 °C without any change in appearance and without decomposition. Contact angle measurements of all the membranes showed hydrophobic character. To demonstrate the potential applications of PASS/MXD6 blend membranes, their oil absorption capacities were evaluated with three oils of different viscosities, which proved that the PASS/MXD6 membranes are better absorbents than commercial non-woven polypropylene fibers. Therefore, PASS/MXD6 fibrous membranes produced by electrospinning have a great potential in practical applications.