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Oily wastewater treatment is a major problem for a large variety of industrial sectors. Membrane filtration is quite promising for oil-in-water emulsion treatment by virtue of numerous eminent advantages. Here, microfiltration carbon membranes (MCMs) were prepared by the blends of phenolic resin (PR)/coal as precursor materials for efficient removal of emulsified oil from oily wastewater. The functional groups, porous structure, microstructure, morphology and hydrophilicity of the MCMs were analysed by Fourier transform infrared spectroscopy, bubble-pressure method, X-ray diffraction, scanning electron microscope and water contact angle, respectively. The effect of coal amount in precursor materials on the structure and properties of MCMs was mainly investigated. Under operation at 0.02 MPa for trans-membrane pressure and 6 mL min−1 for feed flowrate, the optimal oil rejection and water permeation flux are correspondingly attained to 99.1% and 21,388.5 kg m−2 h−1 MPa−1 for MCMs made by the precursor containing 25% coal. Besides, the anti-fouling ability of the as-prepared MCMs is greatly improved in comparison with the one merely made by PR. In summary, the result indicates that the as-prepared MCMs are very promising for oily wastewater treatment. [ABSTRACT FROM AUTHOR]

In this novel attempt to enhance the removal of oils and organic solvents from wastewater, making water safer and cleaner for use, poly(ethylene-co-vinyl acetate was blended with organically modified montmorillonite (OMMT) nanoclay following a green pathway by melt blending in a Brabender plasticoder. The prepared nanocomposites exhibited excellent adsorption capacity for various oils and organic solvents. To further increase the adsorption capacity of the nanocomposites, NaCl was added as a porogen in the melt mixing process, followed by the leaching of NaCl in water to generate a highly porous nanocomposite material. The adsorption tests revealed excellent efficiency, with an adsorption capacity of 40 g g−1 in dichloromethane (DCM), 11 g g−1 in gasoline, and 5 g g−1 in crude oil. The nanocomposites demonstrated excellent recycling capability and could be reused for more than 30 adsorption–desorption cycles. FTIR, XRD, SEM, and TEM analyses were conducted to delineate the structure and morphology of the nanocomposite. [ABSTRACT FROM AUTHOR]

Oil and grease are one of the elements that are poisonous and easily pollute the environment, especially water and soil. Adsorption techniques use natural adsorbents that do not damage or pollute the environment. The raw kapok was chosen as an adsorbent because it is a technology to overcome the problem of oil produced globally. The experiment was conducted with two types of dosage which are 5g and 15g of raw kapok to absorb the oil and the results stated that raw kapok can absorb the cooking oil that is still not used more than the cooking oil that has been used. Due to the density of the oils, it affects the ability of raw kapok to absorb and hold oil. In addition, this absorbed oil restores several water parameters such as dissolved oxygen (DO), pH, temperature and turbidity. [ABSTRACT FROM AUTHOR]

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Because switchable water is difficult to apply directly for oil removal, an enhanced approach to improve oil removal is proposed using a surfactant-free microemulsion (SFME) containing switchable water. The SFME is formed using switchable water (aqueous N, N-dimethylethanolamine (DMEA) or N,N-dimethylbutylamine (BDEA)) and a hydrophobic amine (N - butyldiethanolamine (DMBA)). The single-phase region for preparing the SFME is determined using a ternary phase diagram, and the microstructure types are distinguished using the conductivity method. The pH changes and dynamic laser scattering test results demonstrate that the SFME exhibits irreversible transformation behavior regulated by CO2. Moreover, the recovered SFME containing BDEA has a microstructure with a smaller particle size after removing the CO2 by bubbling N 2 at 65 °C, which is attributed to the higher proportion of DMEA than that of BDEA. In addition, dodecane and diesel oil are shown to dissolve in the SFME, and the oil solubility of the SFME increases with increasing oil phase (DMBA) content. The interface free energy theory reveals that the oil is more easily detached with the addition of SFME than with switchable water only owing to the reduced interface free energy of oil on the solid surface. Thus, an enhanced approach for removing oil is proposed to wash oil sands, where the oil removal efficiency of switchable water can be improved by using SFMEs containing switchable water. [ABSTRACT FROM AUTHOR]

In this study, our aim was to estimate the adsorption potential of three families of aerogels: nanocellulose (NC), chitosan (CS), and graphene (G) oxide-based aerogels. The emphasized efficiency to seek here concerns oil and organic contaminant removal. In order to achieve this goal, principal component analysis (PCA) was used as a data mining tool. PCA showed hidden patterns that were not possible to seek by the bi-dimensional conventional perspective. In fact, higher total variance was scored in this study compared with previous findings (an increase of nearly 15%). Different approaches and data pre-treatments have provided different findings for PCA. When the whole dataset was taken into consideration, PCA was able to reveal the discrepancy between nanocellulose-based aerogel from one part and chitosan-based and graphene-based aerogels from another part. In order to overcome the bias yielded by the outliers and to probably increase the degree of representativeness, a separation of individuals was adopted. This approach allowed an increase in the total variance of the PCA approach from 64.02% (for the whole dataset) to 69.42% (outliers excluded dataset) and 79.82% (outliers only dataset). This reveals the effectiveness of the followed approach and the high bias yielded from the outliers. [ABSTRACT FROM AUTHOR]

Several oil spills in aquatic environments have been reported over the last few years, and a great effort has been made to develop new techniques for collecting and removing oil from water on a large scale to prevent environmental pollution by this contaminant. In view of the various problems involving traditional methods, such as the generation of secondary pollution, high costs and complexity of synthesizing material and expenses to transport equipment, among others, new technologies have been developed for removal of oil from water. Among these, the use of magnetic polymeric nanocomposites has presented promising results, since they have high oil adsorption efficiency, ease of material removal through an external magnetic field, low cost of synthesis and possibility of reusing the material for several cycles, among others. However, a lack of studies about these promising systems exists regarding this technology and its procedures. Therefore, here we present a brief bibliographic review of the synthesis routes to obtain magnetic polymeric nanocomposites containing superparamagnetic iron oxide nanoparticles developed for oil removal from water and report future trends and perspectives for progress of this technology. [ABSTRACT FROM AUTHOR]

• Copolymers with dual functions of oil removal and sterilization were synthesized. • The optimal preparation parameters of copolymers were determined using RSM. • PAANa and DA enhance the copolymer's oil removal and sterilization capabilities. • The oil flocs in oil- E. coli binary systems assist in E. coli removal. • SEM and 3D-EEM confirm the copolymer's bactericidal effect against E. coli. In treating complex sewage containing microorganisms, flocculation and disinfection typically occur as distinct stages, involving the addition of flocculants and disinfectants separately. To integrate oil removal and disinfection, a novel quaternary ammonium-hydrophobic ternary template polymer, TPAMA-DA, was engineered with capabilities for both flocculation and sterilization functions. Optimal copolymer characteristics were determined through Response Surface Methodology of the preparation parameters for TPAMA-DA. The copolymer prepared was applied to model wastewater, and the results indicate that, in emulsified oil and E. coli single systems, TPAMA-DA achieved removal rates of 95.71 % and 97.19 % for emulsified oil and OD 600 (residual OD 600 = 0.0239), respectively, showcasing superior oil removal and antibacterial capabilities compared to TPAMA and PAMA. Meanwhile, TPAMA-DA exhibited excellent oil removal efficiency across a broad range of pH environments, contrasting sharply with its pH-sensitive antibacterial properties. Surprisingly, applying TPAMA-DA to the oil- E. coli binary systems, it not only maintained high efficiency in oil removal but also showed certain pH adaptability in antibacterial activity, suggesting TPAMA-DA's outstanding ability for simultaneous oil removal and antibacterial action in oil- E. coli binary systems. Impressively, SEM and 3D-EEM analyses confirm that TPAMA-DA disrupts the bacterial cell, resulting in the death of E. coli. These findings may pave the way for new avenues in the development of multi-functional, efficient, low-consumption, and environmentally friendly high-performance copolymers with dual capabilities for oil removal and sterilization. [ABSTRACT FROM AUTHOR]

The highly efficient removal of oils such as oils or dyes from wastewater has aroused wide concern and is of great significance for clean production and environmental remediation. The synthesis of a novel aerogel (designated as HEC/LS) is reported herein, achieved through a sol-gel method followed by freeze-drying utilizing loofa and hydroxyethyl cellulose as the raw materials. The new HEC/LS aerogel exhibits excellent porosity and specific surface area, with a porosity of 88.70 %, a total pore area of 0.607 m2 g−1, and a specific surface area of 230 m2 g−1. The prepared HEC/LS aerogel exhibits exceptional hydrophilicity and self-floatability, facilitating its rapid absorption of water up to 21 times its own weight within a mere 3 s. Additionally, it demonstrates good adsorption performance for methylene blue (MB), with a maximum adsorption capacity of 83.30 mg g−1. Subsequently, a new hydrophobic microorganisms-loaded composite aerogel (namely, Bn-HEC/LS) was obtained by doping microorganisms into the as-prepared HEC/LS in multiple enrichment followed by a hydrophobic and oleophilic surface modification. Based on its rich porous structure and oleophilic wettability, the as-synthesized Bn-HEC/LS exhibits excellent selective adsorption and degradation properties for the oil contamination, the diesel oil could be selectively absorbed in the Bn-HEC/LS and degraded by the loaded microorganisms. Among them, B 5 -HEC/LS displays the highest removal efficiency of 94.50 % within 180 h, while free microorganisms and HEC/LS aerogels show degradation efficiencies of only 21.70 % and 48.10 %, respectively. The fixation of microorganisms in the aerogel increases their number within the material and enhances the relative microorganisms removal capacity. The hydrophobic and lipophilic modifications improve the selective adsorption performance of the aerogel on diesel oil, resulting in a significantly high removal rate of Bn-HEC/LS for diesel oil. The results indicate that the immobilization of microorganisms into aerogel improves the activity of microorganisms, and the hydrophobic and oleophilic modification enhances the selective adsorption performance of aerogel to diesel oil, thus resulting in a very high removal rate of Bn-HEC/LS for diesel oil. This study is expected to provide a now possibility for the green and efficient bioremediation of oils. [Display omitted] [ABSTRACT FROM AUTHOR]

In an attempt to develop the methodologies used for oil spill clean-up, polyurethane sponge was modified by deposition of NiFe2O4 nanoparticles on the surface of the original polyurethane sponge under ultrasonic treatment. The fabrication process was facile and low-cost. The as-prepared magnetic sponge exhibited remarkable features including great porosity, high oil adsorption capacity, hydrophobicity, and reusability. In addition, the magnetic property of the modified sponge facilitated the process of oil-water separation. Indeed, the hydrophobicity of the modified sponge contributed to the adsorption of different types of oil and organic solvent on the sponge surface. The modified sponge exhibited the same characteristic peaks as those of the NiFe2O4 magnetic nanoparticles, ascertaining the formation of the crystalline nickel ferrite nanoparticles. The XRD and FTIR results proved the formation of the composite. FESEM images of the nanocomposite showed a highly porous mulberry-like structure with a rough skeleton. More importantly, the oil and water contact angle measurements proved the hydrophobicity of the modified sponge. [ABSTRACT FROM AUTHOR]

Water pollution is one of the biggest problems in the world and treatment is very important. ZIF-8 is a promising nanomaterial for water treatment. In this study, zinc imidazolate framework-8 (ZIF-8) nanoparticles were prepared via a solvothermal method. The synthesized were characterized by using several techniques and applied in emulsified oil/water separation and reuse. A combination of techniques (XRD, BET, SEM) showed that the crystalline phase of the ZIF-8 was successfully obtained by the solvothermal method. ZIF-8 exhibits a high surface area of 1146 m2/g and an average nanoparticle size 47 ± 4.6 nm. ZIF-8 exhibits a very high adsorption capacity reached 2811.1 mg/g and it was regenerated by the ethanol-washing method. The process of regeneration of ZIF-8 has proved to be efficient. ZIF-8 was regenerated by a simple ethanol-washing method; the regenerated ZIF-8 exhibited more than 98% of regeneration efficiency over three cycles. [ABSTRACT FROM AUTHOR]

The commercial importance of natural surfactants is evidenced from the increasing trends in their production and the number of industrial applications due to its potential physicochemical properties. Currently, these compounds are moving several industries in the food, chemical and pharmaceutical sectors in which they demand the development of technologies in the industrial and environmental areas. The objectives of the present study were to evaluate the surfactant properties of the Artocarpus heterophyllus plant extract and its application in oil removal of solid surface. Studies on the surfactant properties analyses performed were the surface tension, emulsification activity using different hydrocarbons and vegetable oils, the haemolytic activity, the surface tension stability in different temperatures, pH and addition of salt, test of dispersion, toxicity test, the critical micelle concentration and the ion charges. To evaluate the capacity of this surfactant on oil removal in engine parts, small-scale tests conducted using steel nuts of different sizes. The results showed that this surfactant of vegetable origin obtained from fruit extract exhibited surfactant properties due to the presence of the haemolytic activity and the reduction of the surface tension of water from 72.00 ± 0.14 mN / m to 26.90 ± 0.20 mN / m, with the critical micelle concentration of 0.050 g / L with the increase values of the emulsification activity ranging from 42 ± 0.12% and 100 ± 0.05% on all hydrophobic compounds (corn oil, sunflower oil, soybean oil, petroleum, n-hexadecane, diesel and motor oil). The results also showed a considerable stability of these biosurfactants derived from fruit extract submitted to different temperature (stability of 26.11 ± 0.23), pH (stability of 25.63 ± 0.21) and the salt concentrations (stability of 25.79 ± 0.08). And in the result of oil displacement test demonstrated that the biosurfactant vegetable could remove 1.872 cm² the motor oil. With the characteristic of low toxicity (germination index with values of 100 at 98%) of biosurfactant and the efficient oil removal on a solid surface between 82.6 ± 0.5 a 78.4 ± 0.6%, can be considered new perspectives with potential to be marketed and replace the application of chemical surfactants. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A chemical-free method with MBs was developed for cleaning oil-contaminated sands. • More than 90% of oils could be removed from contaminated sands within 40 min. • Seawater instead of fresh water could be used as medium for generation of MBs. • The proposed method with MBs might be extended to clean oil-contaminated soils. Abstract Oil spill-contaminated sands caused by marine oil spillage could severely impact aquatic and terrestrial ecosystems. In this work, self-collapsing microbubbles (MBs)-based method was explored as a chemical free approach for remediation of oil spill-contaminated sands. Tap water and saline water with 32 g/L of sodium chloride were employed as the media to generate MBs. Results showed that almost all oils were removed from the oil spill-contaminated sands after the 40-min treatment with MBs generated in tap water. The oil removal efficiency of MBs in saline water was slightly lower than that in tap water, while more than 90% of oil removal efficiency was still achieved after the 40-min treatment. The analyses by FTIR and UV spectra further confirmed the oil removal from oil spill-contaminated sands by MBs. Consequently, self-collapsing MBs showed a great potential as an environmentally friendly technology for high-efficiency remediation of oil spill-contaminated sands. [ABSTRACT FROM AUTHOR]

The production of organic effluents derives from several industry areas, and the increase of this production accompanied those industries growth. The components of those effluents have high toxicity, which may cause serious damages to the affected environment. For this reason, the research for alternative materials (derived naturally or from industrial residues) for wastewater treatment has increased. Thus, biopolymers, such as chitosan, are a sustainable alternative, since they come from renewable and biodegradable sources. Chitosan has properties, such as adsorption capacity and flocculation and coagulation abilities, which allow it to replace, partially or completely, synthetic materials. Several methods have been applied for the treatment of those organic effluents in order to achieve their maximum limit for wastewater disposal or reuse set in each country. Among those treatments, adsorption can be considered the most advanced and efficient for residual treatment, removing selectively several organic compounds. Therefore, this paper reviewed the applicability of chitosan in phenol and oil removal from industrial effluents. Several authors highlighted its use as an environmentally friendly alternative, once chitosan presented a pollutant removal capacity similar or even better than those commonly used materials. The majority of the studies reviewed indicated the best condition for adsorptive capacity of natural or modified chitosans at acidic pH, due to the great influence of the electrostatic attraction mechanism. In addition, the review encourages further researches for more in-depth studies such as those of mechanism of adsorption, simultaneous pollutant adsorption and industrial-scale process. [ABSTRACT FROM AUTHOR]

Highlights • The particle are synthesized by high temperature carbonization method. • Particle preparation using environmentally friendly raw materials. • The structure and morphology were characterized. • The oil-absorbent capacity of the Fe 3 O 4 @C/Cu MNCs was investigated. Abstract In this paper, we provided a low-cost, high-efficiency and reusable core-shell magnetic sub-micron composite particles (MSMCs) based on Fe 3 O 4 magnetic sub-micron particles (MSMPs) and glucose that was synthesized by hydrothermal method and high temperature carbonization method. Several techniques such as scanning electron microscope, transmission electron microscope, Fourier transform infrared, vibrating sample magnetometer, and thermogravimetric analysis were used in the characterization of the materials. The results indicated that the MSMCs has good dispersion and uniform particle size. It also can floating on the surface of water. The saturation magnetization of the MSMCs is 34 kA/m and the coercive force is 84Oe which make it recover easily under the magnetic field. Its excellent temperature resistance can easily remove absorbed oil on its surface by low temperature fractionation. Those separated particle powder can be reused for many times after drying and oscillation. The MSMCs adsorption capacity of kerosene, diesel and engine oil is 3.05 g/g, 3.25 g/g and 3.38 g/g, and its oil-absorption speed is high. With the above characteristics, the MSMCs can effectively remove oil on a wide ocean surface and avoid secondary pollution. [ABSTRACT FROM AUTHOR]

Abstract A novel macroporous and oleophilic Natural Rubber (NR) foam is prepared through a vulcanization process using methanol (CH 3 OH) as solvent at different compositions of crosslinking agent (Disulphur Dichloride, S 2 Cl 2). NR was firstly modified to reduce its molecular weight by photochemical oxidation method to produce Liquid Natural Rubber (LNR). This spongy-like foam made of LNR was firstly reported here, has produced interconnected open-cell structures with pore volume ranged from 1.83 mL/g to 4.28 mL/g and diameter sizes between 2.09 μm and 13.24 μm. The absorption capability of LNR-foam resembled to the cotton fiber-based sorbent where it absorbed most of oil products by up to 9.39 g/g. The porous materials reached the saturation limit within 5 min of low-viscosity oils, and 15 min for higher-viscosity oils. In a simulated oil slick system, this LNR macroporous and hydrophobic foams maintained its high oil absorption capacity in the ranged of 3.54 g/g to 9.39 g/g. About 90% of absorbed oil is being recovered and the LNR-foams are able to perform up to 20 absorption cycles which demonstrated a good reusability. Hence, this new type of natural-based modified absorbent has the potentials to be commercialized. Highlights • This research proposed facile method of preparing foams made of LNR. • The absorbent efficiency is comparable to the commercial items. • The LNR foams absorb more than 10 types of oils. • The reusability of LNR foams up to 10 cycles. [ABSTRACT FROM AUTHOR]

Abstract Oil/water separation with superwetting mesh is an emerging method for removing oil from wastewater, but the adopted meshes at present are not reliable in practical applications due to their poor pressure-bearing capacity. A TiO 2 -deposited and coated mesh (TDCM) with underwater superoleophobicity and transformable micro-nano structure is reported to separate oil/water mixtures with efficiencies >99%. Due to the compactness of deposited porous TiO 2 aggregates triggered by pressure, the TDCM can bear applied pressures of ≥12.6 kPa dependent on oil types and achieve ultrafast water transportation driven by retentate accumulation or other applied pressure without oil breaking through. The feature of the pressure-induced surface structure transformation will not damage the surface wettability and oil/water separation performance of the TDCM and is demonstrated effectively in mitigating the theoretical trade-off between water flux and pressure-bearing capacity. Furthermore, the TDCM has good self-cleaning performances for particulate and organic pollutants before and after surface structure transformation with the aid of oil and ultraviolet illumination. As a novel mesh for oil/water separation, the TDCM shows great potential in real applications and provides a brand-new perspective of developing advanced materials for oil removal from water in complicated situations. Graphical abstract Unlabelled Image Highlights • An underwater superoleophobic mesh is reported for efficient oil/water separation. • High water flux is obtained driven by oil accumulation or other applied pressure. • The mesh reconfigures its surface structure to bear high pressure. • The mesh's separation performance cannot be damaged by surface transformation. • Transformable surface mitigates tradeoff between flux and pressure-bearing ability. [ABSTRACT FROM AUTHOR]

A variety of materials with superwetting property are fabricated for separation of immiscible oils/organic solvents and water mixture. However, the complex fabrication process, requirement of sophisticated equipment, and associated toxicity strongly limit the development of the superwetting materials. In this paper, a simple two-step dip coating strategy is demonstrated to prepare polydopamine-octadecanethiol modified 3D porous sponge with superhydrophobic and superoleophilic properties (a water contact angle of 156.8° ± 2.5° and an oil contact angle of nearly 0°) through the combination of enhanced surface roughness and low surface energy coating for separation of oil/water mixture. The as-prepared superhydrophobic sponges possess high porosity (greater than 99.2%), low density (below 10 mg/cm3), and 3D porous network structure, which meet well with the needs for adsorption of the actual oil pollutions. More importantly, in situ continuous removal of oil from oil/water mixture is successfully accomplished via a vacuum-assisted system, even in the corrosive environments including turbulent situation, heat, acidic, alkaline, seawater, and glacial water. The continuous oil collection system could avoid the limit in adsorption saturation effectively. We believe that the superhydrophobic sponge with easy large-scale production, economical, and environmentally friendly characteristics can be a superior candidate for the treatment of oily wastewater and practical oil spill accidents. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel electrocoagulation (EC)-carbon membrane coupling with electrochemical anodic oxidation (CM/EAO) integrated system was designed and constructed for oily wastewater treatment. Abstract A novel electrocoagulation (EC)-carbon membrane coupling with electrochemical anodic oxidation (CM/EAO) integrated system was designed and constructed for oily wastewater treatment. Electrocoagulation was adopted as a primary unit, and the effects of many parameters, including current density, electrolyte concentration, initial pH, feed oil concentration, and operating time on pretreatment performance were investigated and optimized. Subsequently, CM/EAO was set as a secondary unit for further deep purification of the EC effluent. The results showed the integrated system had great potential for oil removal from wastewater. The EC unit could remove nearly half of COD and TOC in the feed, and the following CM/EAO unit further degraded the EC effluent, and the COD, and TOC were reduced to 13 mg/L and 22 mg/L, respectively. The mechanisms involved in each stage were proposed. A large proportion of oil droplets in oily wastewater were firstly removed by electrocoagulation process, and the remaining oil droplets were further decomposed into small molecules or even into CO 2 and H 2 O by hydroxyl radicals generated from electrochemical anode oxidation reactions. The degraded intermediate products including various n-alkanes and polycyclic aromatic hydrocarbons were identified by GC MS. [ABSTRACT FROM AUTHOR]

Abstract Currently, roasting-leaching is the main treatment process of spent hydrodesulfurization (HDS) catalyst, but it will produce impurities, such as nickel molybdate and cobalt molybdate (NiMoO 4 or CoMoO 4), which is adverse to recover valuable metals. In this paper, a combined ultrasonic-microwave method was developed to remove oil and recover molybdenum (Mo) from the spent HDS catalyst. Firstly, ethanol was used to extract the surface oil of the spent MoNiCo/Al 2 O 3 catalyst with ultrasonic assistance. Effects of temperature, ultrasonic time, liquid-solid ratio and ultrasonic power on the oil removal rate were investigated systematically and the process conditions were optimized using response surface methodology (RSM). The results showed that the oil removal rate was over 99% under the optimum conditions of temperature 55 °C, ultrasonic time 2 h, liquid to solid ratio 5:1, and ultrasonic power 600 W. After oil removal, the sample was roasted in microwave field at 500 °C for 15 min. The generation of toxic gas could be effectively avoided and no hardest-to-recycle impurity CoMoO 4 was found. At last, the roasted sample was subjected to ultrasonic leaching with sodium carbonate (Na 2 CO 3) solution for recovering Mo. Extraction of Mo of the deoiled sample after microwave roasting reached 94.3%, which is about 7% higher than that of oily sample. Moreover, microwave roasting method resulted in a much higher Mo extraction than traditional method for both the oily and deoiled spent catalyst. It was concluded that the ultrasonic-microwave assisted method could remarkably improve the recovery of Mo and greatly shorten the processing time. [ABSTRACT FROM AUTHOR]

Abstract Pseudomonas sp. sp48, a marine bacterium isolated from Bahary area (Alexandria, Egypt), showed a high potency for oil degradation up to 1.5%. Additionally, it showed an ability to consume aromatic hydrocarbons (phenol & naphthalene) and aliphatic (pentadecane) reaching to 79; 73; 62%, respectively. In the current study, Plackett-Burman factorial design was applied to evaluate culture conditions affecting the degradation potency. Analysis of Plackett-Burman design results revealed that, the most significant variables affecting oil removal were magnesium sulfate, inoculum size, glucose and Triton X-100. To optimize the levels of these significant variables Response Surface Methodology (RSM) was followed. In this respect, the three-level Box–Behnken design was employed and a polynomial model was created to correlate the relationship between the three variables and oil removal. The optimal combinations of the major constituents of media that was evaluated from the non-linear optimization algorithm of EXCEL-Solver was as follows: (w/v%) 1 crude oil, 0.5 peptone, 0.5 yeast-extract, 1 ammonium chloride, 0.7418 D-glucose, 0.5 MgSO 4 ·7H 2 O, 0.1 Triton X-100 and inoculums size 4.18 ml% in natural sea water at pH 7; 30 °C incubation temperature, 200 rpm for 6 days. The predicted optimum oil removal was 89%, which is 2.4 times more than the basal medium. [ABSTRACT FROM AUTHOR]

Ultrasonic technology is a promising tool for washing oily sludge to remove oil, however, little information has been provided on the pilot scale application of ultrasonic washing. In this study, the ultrasonic conditions were optimized based on the pilot trial of the effects of ultrasonic properties on oil removal from oily sludge. An ultrasonic power of 0.24 w/cm 2 was necessary to overcome the energy threshold for oil washing at the frequency of 25 kHz. The removal rate was changed from 46.0% to 60.7% with oily sludge content from 25.0% to 42.0%, respectively. The addition of surfactants could improve oil recovery, and the optimizing content for sodium petroleum sulfonate and Span 80 was 0.3% and 0.03%, respectively. A series of pilot scale test indicated that the oil removal rate could be 82–90% by ultrasound assistant with surfactants (Span 80). Thin-layer chromatographic flame ionization detection showed that the removal rate by ultrasonic wash was dropped with the increase of composition polarity. However, under the assistance of surfactants (Span 80), all compositions could be effectively removed. This pilot study will greatly improve the application of ultrasonic technology in oily sludge treatment. [ABSTRACT FROM AUTHOR]

Highlights • MIL-101 @ nanoporous Graphene composites were prepared by a solvothermal method. • Introduction of nanoporous graphene contents in different contents (30, 60, and 90 wt%) could enhance the surface area and improve the pore volume. • The proposed composite was used successfully for adsorption of crude oil (14 g/g) in water samples. • Reusability study with solvent extraction method and hydrophobicity nature of synthesized composite were studied. Abstract The marine environment is being more and more polluted by oil spills on a daily basis, posing a serious threat to humans. The substances possessing high adsorption capacity and hydrophobic nature, generally play an important role in crude oil adsorption from aqueous solutions. The synthesis of new porous materials has attracted attention of many researchers in a large number of systems. Metal Organic Frameworks such as MIL-101(Cr) with high surface area and pore volume have been widely investigated to use in many applications such as separation. To enhance the MIL-101′s properties, hybrid composites with high specific surface area and pore volume have been considered. MIL-101 and MIL-101@ nanoporous graphene (NPG), which have been fabricated for the first time, with different nanoporous graphene contents (30, 60, and 90 wt%) were herein synthesized via a solvothermal method.The prepared adsorbents were characterized using field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectroscopy, thermal gravimetric analysis (TGA), adsorption of nitrogen at 77.4 K, and contact angle (CA). The high oil adsorption capacity (14 g/g) was achieved for the synthesized adsorbents with the high surface area of MIL-101 (4293 m2/g) and MIL-101@NPG 60 wt% (4642 m2/g), and the high pore volume of MIL-101 (2.42 cm3/g) and MIL-101@NPG 60 wt% (2.62 cm3/g). The results show that the crude oil adsorption capacity enhanced by adding NPG to the virgin MIL-101, which is higher than that of previous scientific reports. The conformity of various adsorption models, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D-R) to the equilibrium data were evaluated, and among which Freundlich isotherm model gave the best fitting result. The synthesized adsorbents can be further reused for several times, with no significant adsorption loss capacity and hydrophobicity. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Deep bed filtration is commonly used to remove oil from oily wastewater. The wettability of the filter media greatly influences the oil removal efficiency. A filter with a strong hydrophobicity and oleophilicity results in a higher oil removal efficiency. To improve the hydrophobicity and oleophilicity, ZnO nanoparticles and octadecyltrichlorosilane (OTS) were coated on quartz sand filter media. SEM, FTIR and XPS were used to study the morphology and chemical composition of the filters, and adsorption capacity and oil removal efficiency experiments were performed to assess the oil removal performance. The results show that the OTS molecules are grafted onto the surface of the quartz sand filter through chemical bonding, and the OTS/ZnO-coated quartz sand filter is superhydrophobic and oleophilic, with a water contact angle of 154.1° and an oil contact angle of 0°. The OTS/ZnO-coated quartz sand filter has very high mechanical stability and acid resistance. The oily wastewater treatment performance is greatly improved after application of the OTS/ZnO coating, and the superhydrophobic quartz sand filter media can potentially be used to filter oily wastewater and achieve high oil removal efficiency. [ABSTRACT FROM AUTHOR]

Mechanical recovery of oils using oil sorbents is one of the most important approaches to manage marine oil spills. However, the properties of the oils spilled into sea are influenced by external environmental conditions. In this study, we present a graphene-based (GB) sponge as a novel sorbent for crude oil removal and compare its performance with that of a commercial sorbent sheet under various environmental parameters. The GB sponge with excellent superhydrophobic and superoleophilic characteristics is demonstrated to be an efficient sorbent for crude oils, with high sorption capacity (up to 85–95 times its weight) and good reusability. The crude-oil-sorption capacity of our GB sponge is remarkably higher (about 4–5 times) than that of the commercial sheet and most other previously reported sponge sorbents. Moreover, several challenging environmental conditions were examined for their effects on the sorption performance, including the weathering time of oils, seawater temperature, and turbulence (wave effect). The results show that the viscosity of the oil increased with increasing weathering time or decreasing temperature; therefore, the sorption rate seemed to decrease with longer weathering times and lower temperatures. Turbulence can facilitate inner sorption and promote higher oil sorption. Our results indicate that the extent of the effects of weather and other environmental factors on crude oil should be considered in the assessment of the effective adsorption capacity and efficiency of sorbents. The present work also highlights the widespread potential applications of our GB sponge in marine spilled-oil cleanup and hydrophobic solvent removal. [ABSTRACT FROM AUTHOR]

Modified Hummer’s method has been used in this study to synthesize graphene oxide (GO) solution that was utilized for the fabrication of three-dimensional (3D) graphene sponges and their subsequent functionalization through a low-cost and facile vapor-based surface enhancement approach. The functionalized 3D-graphene sponge is an excellent absorbent, which can remove more than 3300 wt.% of crude oil (calculated with respect to the original sorbent mass). The functionalization of the obtained graphene sponges with trichloro (1H,1H,2H,2H-perfluorooctyl)silane enhanced their wettability properties due to the super-hydrophobic nature of the resulting materials characterized by the contact angles in water greater than 150°. Furthermore, their elastic compression modulus (estimated by conducting a series of compression tests) was about 22.3 kPa. The equilibrium modeling of the oil removal process, which was performed by plotting Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms, confirmed the properties of the fabricated 3D graphene sponges as exceptional absorbents for crude and diesel oil, which could be attributed to the oleophilic nature of graphene. Moreover, the obtained 3D graphene sponges could be regenerated via heat treatment, which was conducted to release the adsorbed species. After five adsorption-desorption cycles, the sorption capacity of the produced 3D graphene sponges towards crude oil reached 95% of the initial value. [ABSTRACT FROM AUTHOR]

A low cost and high performing hybrid ceramic/carbon symmetric membrane has been fabricated and tested. The hybrid membrane was fabricated by mixing alumina powder with high surface area powdered activated carbon (PAC). The hybrid Al 2 O 3 /AC membrane has a developed complex network of micro and nano channels which enhanced the porosity of the membrane two fold compared to a pure Al 2 O 3 membrane. Furthermore, due to enhanced pore size and porosity, the hybrid membrane exhibited super-hydrophilic characteristics with the contact angle being close to zero. The increase in the membrane roughness enhanced the surface area of the membrane, which created an increase in the membrane surface area for the filtration path. The membrane exhibited a very high removal efficiency and retention (more than 99%) of oil from an oil-in-water emulsion stabilized by a surfactant. The membrane performance has been tested under harsh conditions such as a high oil concentration in a concentrated saline feed and no change in the separation efficiency or performance was observed with time. The membrane proved to be a good candidate for applications such as the treatment of oily wastewater or oil separation from seawater or from produced-water. [ABSTRACT FROM AUTHOR]

High performance diatomite hybrid microfiltration carbon membranes (MFCMs) were developed for oil removal from oily wastewater. The thermal stability, functional groups, microstructure, morphology of the membranes were analyzed by thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscope, respectively. The effects of diatomite amount, oil concentration, operation time and regeneration on the removal efficiency of MFCMs were investigated. Results show that the addition of diatomite can effectively adjust the microstructure and property of MFCMs. The oil rejection elevates by increasing the diatomite amount in starting materials or the oil concentration in feed stream. The maximum oil rejection is achieved at 98.2% for 200 mg/L oily wastewater using MFCMs prepared from the precursors with diatomite content of 15 wt%, together with all the oil concentration beneath 10 mg/L in the penetrating stream within the scope of this work. After regeneration of MFCMs by simple water backwashing, the permeation flux could be almost completely recovered. [ABSTRACT FROM AUTHOR]

Using oil-degrading bacteria (Acinetobacter spB11) as the reference strain, this article explored the effect of a low-strength magnetic field on strain B11 for oil removal. The magnetic field had a positive effect on the degradation of n-alkanes by microorganisms, especially short-chain hydrocarbons. Under the premise of not destroying the cell membrane, lower magnetic fields (15–25 mT) enhanced the permeability of the cell membrane and improved the activity of the oil-degrading bacteria. In the 25-mT magnetic field, the hydrophobicity and oil-spreading diameter of the B11 cells were increased by 6.7% and 21.9%, respectively, and the surface tension was decreased by 6% compared with that measured when bacteria were applied without magnetic field application. A test of the bio-surfactant levels showed that the magnetic field increased the surfactant content released by the microorganisms but had no significant impact on the surfactant properties. [ABSTRACT FROM AUTHOR]

The technology of producing an adsorbent, which have magnetic properties, for the oil removal from waste water and surface water bodies by the controlled magnetic field, is proposed. A method of the magnetic adsorbent producing includes the mixing of magnetite and the absorbent material which is degradable steel slag. The weight ratio of slag: magnetite = 1 : (1.5-2.0). Optimal particle size of the components is 70-100 microns. Application of a magnetic treatment with the treated water prior acidification to pH = 3 ÷ 4 improves the efficiency of oil removal from waste water up to 1.5 times. To remove spills of petroleum products by the proposed magnetic adsorbent we developed diagram of the device, which is mounted on board a catamaran - type oil skimmers. The device includes a body, which is open to the entry and exit of treated water, the bottom of which is made in the form of endless moving belt. Above the tape at the end of its movement is set oil-gathering magnetic drum system. Adding oil adsorbent layer is made from a hopper disposed at the front of the vessel and provided with a drum feeder which provides a predetermined flow of the adsorbent depending on the thickness of the oil layer. Due to the high bulk density is a quick dip in the adsorbent layer of mineral oil. Large flocs, lost buoyancy deposited onto a moving belt and move to the oil-gathering drum. Removal of saturated adsorbent is carried out with the drum surface scraper, passing into a trough in which is located a rotating auger. [ABSTRACT FROM AUTHOR]

There are large amounts of oily wastewater produced by industrial production processes and daily life, and oily wastewater is one of the most widespread environmental issues. These effluents contain a large amount of emulsified oil/water mixtures. However, separation of stabilized oil/water emulsions is difficult and a global challenge. Oily wastewater is not only harmful to the environment but it also affects human health. Thus, development of materials that can effectively solve this problem is of great interest. Here, a smart surface with antifouling property and pH-controllable oil wettability in aqueous media is reported. The smart surface on a porous anodic aluminum oxide (PAAO) membrane (pore size < 1 µm) shows switchable superoleophilic/superoleophobic performance in different pH aqueous media. The smart surface was fabricated by modifying the PAAO membrane with the pH-responsive poly(4-vinylpyridine) and hydrophobic/oleophilic polystyrene block copolymer. The as-prepared PAAO membrane can effectively separate stabilized oil-in-water and water-in-oil emulsions by adjusting the pH of the aqueous medium (3.0 and 7.0). Furthermore, the as-prepared membrane with superior antifouling capacity and could be used at least 10 times with high separation efficiency (99.95%). The present study suggests that PAAO membranes have potential applications for separation of stabilized oil/water emulsions. [ABSTRACT FROM AUTHOR]

A simplified adhesive-free strategy for fabricating robust superhydrophobic polyvinylidene fluoride (PVDF) oil/water separation membranes was developed. SiO 2 nanoparticles were strongly fixed to the surface of the “adhesive” PVDF membranes via delayed phase inversion. Oil/water filtration membranes with micro–nano coarse structures and low surface energies were obtained by adjusting the SiO 2 concentration in a coagulation bath. The membrane structure was analyzed via Fourier transform IR and X-ray photoelectron spectroscopy. The evolution of the morphology, performance of the membranes, and the filtration properties were investigated using scanning electron microscopy and confocal scanning microscopy, among other techniques. The obtained SiO 2 -nanoparticle decorated PVDF membrane has a water contact angle of 157 ± 2° and an oil contact angle of 0 °. The superhydrophobic PVDF membranes had extremely high chloroform fluxes, over 10,000 L/(m 2 h) at 0.9 bar, and could be used for the separation of oil–water mixtures and surfactant-stabilized water-in-oil emulsions. The separation efficiency (approximately 99.95% in terms of the oil purity in the filtrate) was high. Furthermore, the fabricated PVDF oil/water filtration membranes exhibited good stability and excellent recyclability (over 20 cycles). The proposed eco-friendly and straightforward strategy provides new insights for the development of practical oil/water filtration membranes. [ABSTRACT FROM AUTHOR]

Being cost-effective, synthetic materials were initially used abundantly for the removal of oil. Gradually, however, awareness of the use of dispersants like Corexit, which makes water resources more toxic than oil, has changed the scenario for the treatment of spilled oil. The removal of spilled oil from water resources is still a very topical issue. An eco-friendly and sustainable approach towards the environment has introduced many low-cost, non-toxic and biodegradable materials along with different biomasses to make micro-to nano-sized materials, membranes, sponges/aerogel, etc. for the removal and recovery of oil from water resources. Additionally, the reusability of these materials after the recovery of oils has added one more step towards sustainability. This review comprises the work conducted by various researchers in the field of the removal and recovery of spilled oils using various biomasses and polymers, either in the form of sorbents or separators. [ABSTRACT FROM AUTHOR]

The use of membrane technology for produced oily water treatment has become an active area of research for both academia and industry. The search for membranes with enhanced efficiency and prolonged life time during oily water treatment has been a rallying point for many scientists. The focus of this review is on the advancement of polymeric and ceramic membrane technologies, membrane modification strategies used to mitigate membrane fouling and optimization of permeate flux, particularly for oily water systems. In addition, recent methodologies used for modeling the permeate flux decline are also highlighted. [ABSTRACT FROM AUTHOR]

Abstract: In this study, extracellular lipase was produced by Serratia marcescens wild type and three mutant strains. The maximum lipase activity (80 U/mL) was obtained with the SMRG4 mutant strain using soybean oil. Using a 22 factorial design, the lipase production increased 1.55‐fold (124 U/mL) with 4% and 0.05% of soybean oil and Triton X‐100, respectively. The optimum conditions for maximum lipase activity were 50 °C and pH 8. However, the enzyme was active in a broad range of pH (6–10) and temperatures (5–55 °C). This lipase was stable in organic solvents and in the presence of oxidizing agents. The enzyme also proved to be efficient for the removal of triacylglycerol from olive oil in cotton cloth. A Box–Behnken experimental design was used to evaluate the effects of the interactions between total lipase activity, buffer pH, and wash temperatures on oil removal. The model obtained suggested that all selected factors had a significant impact on oil removal, with optimum conditions of 550 U lipase, 45 °C, pH 9.5, with 79.45% removal. Biotransformation of waste frying oil using the enzyme and in presence of methanol resulted in the synthesis of methyl esters such as methyl oleate, methyl palmitate, and methyl stearate. [ABSTRACT FROM AUTHOR]

Due to increased production, transportation, and use of oils and toxic organic solvents, the possibility of spills that cause serious environmental threats and pollution has grown. As a result, effective removal of oils and organic pollutants from water at low cost has become a global challenge. Here, we report the simple, cost-effective fabrication of a free-standing carbon nanofiber-polydimethylsiloxane (CNF/PDMS) nanocomposite block via a solution process using one-step vacuum filtration. The block showed excellent superhydrophobicity and superoleophilicity (water contact angle = 163° and oil contact angle = ∼0°), high mechanical stability, good absorbance capacity, and recyclability. It also exhibited rapid, selective absorption of several types of oils and organic liquids floating on the water surface, as well as heavy oils sunken in water. These findings suggest that the CNF/PDMS block is a promising material for practical applications of oil spills clean up. [ABSTRACT FROM AUTHOR]

The integration of microbubbles (Sauter diameter: 80 μm) and macrobubbles (Sauter diameter: 0.9 mm) in a flotation system were proposed to enhance oil removal efficiencies. The role of the microbubbles as a secondary collector for macrobubbles was studied in the static bubble interaction studies in terms of attachment time, contact angle and visualization of contact area. Results showed that the presence of microbubbles could decrease the attachment time between macrobubbles and oil layer by 82%, and improve the contact angle and surface area of attachment by 40.3% and 54.5% respectively. Macrobubbles, on the other hand were able to improve the floatability of oil contaminant as suggested from the dynamic bubble interaction study. The presence of macrobubbles was able to increase the volumetric rate of micro-macrobubbles captured from 0.47 μL/s to 4.5 μL/s. The results demonstrated that the coalescence phenomena between bubbles could provide the necessary lifting force to further aid the oil flotation. The interaction between microbubbles and macrobubbles is particularly advantageous in an integrated bubble flotation system. Application of the integrated micro-macrobubbles demonstrated a significant increase in oil removal to 68.6% under oil-wet conditions while almost all of the oil contaminants were removed from water-wet sands. An increase of 28% was observed upon implementation of integrated micro-macrobubble flotation compared to the single bubble flotation for oil removal. Results indicated that the integration of microbubbles and macrobubbles in the flotation cell is a simple modification to a flotation system that would enhance the removal of oil contaminant from contaminated sand. [ABSTRACT FROM AUTHOR]

Due to the unique properties of subcritical water (marked change in water's dielectric constant and viscosity), the extraction by subcritical water offers a great opportunity to remediate soil contaminated with organic pollutants as an alternative and green remediation method. In this study, subcritical water extraction is proposed as an efficient remediation technique for the Gulf War oil spill contaminated soil. The subcritical water extraction experiment was carried out in a lab-scale continuous flow apparatus. The three major operating factors, temperature, time and water flow rate, were evaluated in terms of optimum removal efficiency. The results show that crude oil removal depended largely on water temperature, whereas an extraction run time higher than 1 h and a water flow rate higher than 1.5 mL/min marginally or negatively affected removal efficiency. During subcritical water treatment at 300°C for 1 h at a flow rate of 1.5 mL/min, removal efficiency was almost 95%. Under these operating conditions, the subcritical water treatment demonstrated a similar removal efficiency to those of organic solvents like acetone. In contrast, the efficiency of oil recovery decreased with an increase in extraction temperature, due to degradation by a water self-oxidizing agent. Several degradation products identified in the treated soil and in the effluent sample (which initially were absent in the contaminated soil) were oxygen-containing aromatic compounds, confirming the oxidation-degradation. [ABSTRACT FROM AUTHOR]

Reusable absorbents with high absorption capacity, good selectivity, and low cost are highly demanded for efficient removal of oil spills and organic leakages from water. We discover that ZnO produced by atomic layer deposition (ALD) is hybridized with carbon moieties, and consequently exhibits an appreciable hydrophobicity. By taking this advantage, we develop a "dry" process to produce high-performance oil absorbents. Originally amphiphilic polymeric foams are directly turned into strongly hydrophobic oil absorbents simply by ALD of ZnO and exhibit excellent absorption capacity, selectivity and reusability. Such absorption capacities and reusability are better than most foam-based oil absorbents. Surprisingly, we find that ALD-deposited ZnO can reverse the wettability of polymeric foams depending on the foam porosities. This ALD-enabled surface functionalization is expected to find important applications in the synthesis of many other interfacial materials. [ABSTRACT FROM AUTHOR]

To better understand the microbial oil removal enhancement process by a magnetic field, the effect of a static magnetic field (SMF) on the microscopic characteristics of highly efficient biodegradation oil-removing bacteria was studied. The Acinetobacter sp. B11 strain with a 53.6% oil removal rate was selected as the reference bacteria. The changes in the microscopic characteristics of Acinetobacter sp. B11 such as the cell surface morphology, cell permeability and cell activity of the bacteria were investigated. The results showed that low-intensity magnetic fields (15-35 mT) improved the ability of Acinetobacter sp. B11 to remove oil by 11.9% at 25 mT compared with that of bacteria with no magnetic field. Without destroying the cell membrane, the low-intensity magnetic fields increased the cell membrane permeability and improved the activity of superoxide dismutase (SOD), which effectively enhanced the oil degradation performance of the bacteria. [ABSTRACT FROM AUTHOR]

In this paper, oily sludge cleaning by using ultrasonic waves was further studied to ensure how the ultrasonic reactor, such as material, bottom thickness, diameter, and auxiliary mixing, effects oil removal from oily sludge. Oily sludge (S) with an initial oil content of 19.29% was mixed with distilled water (W) and treated in an ultrasonic cleaning tank,f = 40,000 Hz at 30°C. This paper was carried out around the ultrasonic reactor, such as material, diameter, and bottom thickness. The results show that acoustic resistance is the main factor affecting the material of the ultrasonic reactor. The larger the diameter of the reaction, the lower the thickness of the S-W mixture of the same quality; the smaller the diffusion attenuation of the ultrasonic wave, the higher the oil removal rate. In this paper, the cleaning efficiency seems to be independent of the bottom thickness of the reactor. This may be due to the hale wavelengths (λ/2) in polyethylene (λ/2 = 2.4 cm) and glass (λ/2 = 7.08 cm) being far greater than the range of bottom thickness. Proper mixing (200 rmin−1) can improve the oil removal rate (92.8%), increased by 8.69%, but when the strength is too large, the oil removal rate is reduced. [ABSTRACT FROM AUTHOR]

Oil/water separation polyurethane sponge with hierarchically structured surface similar to the chemical/topological structures of lotus leaf has been successfully developed by combining mussel-inspired one-step copolymerization approach. The chemical structure, surface topography, and surface wettability of the sponge were characterized by FTIR, SEM, and contact angle experiments, respectively. The results showed that as-prepared sponge exhibited high oil absorption rate because of the expansion in oil and collapse in water of the polymer molecular brushes. Meanwhile, it also possessed high absorption capacity (20 times of the self-weight), high oil retention (93.7%), and good recyclability. It had excellent potential in practical applications. [ABSTRACT FROM PUBLISHER]

The recovery of oil from oil-in-water emulsion has been investigated using chitosan/magnesium-aluminium layered double hydroxide hybrid composite (CS-LDHCs) by a single co-precipitation method. Resulting better adsorption efficiency of CS-LDHCs could be observed, indicating the synthesized material was effective to adsorb oil particles from oil-in-water emulsion at acidic pH (pH 3.0) than as-prepared LDH and raw chitosan. The enhancement of adsorption properties by CS-LDHCs material were attributed to the high content of LDH in chitosan, which makes the material more effective towards immobilization of oily particles. Batch experiment study has been elucidated by varying different physicochemical parameters such as time, pH, dose, initial oil concentration and temperature. The as-synthesized CS-LDHCs was characterized by various spectro analytical techniques viz., FTIR, SEM with EDAX, XRD, TGA and DSC analysis. To find out the best fit for the sorption process, the obtained adsorption equilibrium data was explained with Freundlich, Langmuir, Dubinin-Radushkevich and Tempkin isotherm models. The mechanism of adsorption process was demonstrated by calculating ΔG°, ΔH° and ΔS° values from thermodynamic parameters in order to understand the nature of sorption process. The schematic representation of oil removal using CS-LDHCs was explored in detail. This work provides an apparent proposal for the growth of oil removal technology. [ABSTRACT FROM AUTHOR]

Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) is an emerging green technology, but very few reports are available on its use for treating oily feeds, despite produced water representing a significant source of oily wastewater. Accordingly, this study was targeted at understanding the primary impediments of oily water MD by systematically investigating the influence of the key components (namely, oil-in-water emulsion, surfactant and salt) in such feeds. When the feed contained all three components typical in produced water, the MD performance severely deteriorated in terms of permeate flux and quality. Interestingly, for feeds containing oil or SDS or NaCl alone, the MD performance was reasonable, which indicates each component on its own did not impact the MD process significantly. Furthermore, the performance was also reasonable when the feed contained oil and NaCl, and improved when the feed contained oil and SDS. The adverse impact on the MD process was thereby traced to the combined presence of SDS and NaCl. Even in the absence of oil, increasing the concentrations of SDS and NaCl in the feed progressively deteriorated the permeate flux and quality. Therefore, to use MD for treating oily feeds necessitates a pre-treatment step to remove or significantly dilute either the surfactant or the salt. More understanding of the interaction between NaCl and SDS via molecular dynamics simulations would be useful to not only provide information on the interaction strength but also on means to circumvent such issues. [ABSTRACT FROM AUTHOR]

Beside several methods of membrane fouling reduction, induction of electric field in system of dielectric materials can also postpone fouling. For the first time, CFD technique is used to develop a model to predict behavior of a sample oil droplet located on the membrane surface affected by dielectrophoresis force in a good agreement with experimental data. Then experimental design is used to study the effects of electric field induction within defined ranges of system variables. In order to quantify droplet behavior, critical voltage is defined as minimum required electric potential to detach droplet from the membrane surface. Contact angle, droplet diameter, interfacial tension, membrane thickness, shear rate, pore diameter and trans-membrane pressure are system variables. Initially, screening experiments with 2-level factorial approach identify first four variables as effective factors. Subsequently, response surface methodology and central composite design were employed for critical voltage modeling and optimization. A quadratic model (R 2 = 0.997) is suggested for square root of critical voltage between 1800 and 22,000 V. Optimum or minimum critical voltage is observed at 0.01 N/m interfacial tension, 110° contact angle, 2 µm droplet diameter and 100 µm membrane thickness. The predicted value for optimum critical voltage by a second-order polynomial correlation is 1734 V which deviates about 4% from 1800 V as critical voltage calculated from the CFD model. [ABSTRACT FROM AUTHOR]

A superhydrophobic melamine sponge was fabricated by a facile method of photoinitiated thiol-ene click chemistry. The resultant sponge exhibited excellent water repellency with a water contact angle of 152.8° and could not only absorb various organic compounds with absorption capacities of 72–160 times its own weight, but also selectively and continuously remove oil from water. More importantly, the sponge still maintained a high absorption capacity after reused 16 times by sorption/squeezing. Additionally, the superhydrophobic sponge could also be used as a filter to separate oil/water mixtures successfully. These results suggest that the resultant superhydrophobic melamine sponge may provide great potential application for oil removal. [ABSTRACT FROM AUTHOR]