Removal Of Oil Pollutants Research Articles

Magnetic PVA/GO-based aerogel for efficient removal of oil pollution

Magnetic PVA/GO-based aerogel for efficient removal of oil pollution

Wood sponge with photothermal, magnetically driven, and superhydrophobic characteristics for high-viscosity oil–water separation

In this work, naturally degradable porous balsa wood was used as a raw material to prepare a highly elastic wood sponge (WS) substrate using a two-step chemical method and a freeze-drying method. The surface hydrophobic modification of Fe3O4 nanoparticles using the fluorine-free material octadecyltrimethoxysilane (C18TMS) solved the problem of agglomeration caused by the high nanoparticle surface energy. Polydopamine (PDA), hydrophobically modified Fe3O4 (C18TMS/Fe3O4), and low-surface-energy polydimethylsiloxane (PDMS) were sprayed onto WS substrates using a simple spraying method. An environmentally friendly adsorption sponge with photothermal, magnetically driven, and superhydrophobic properties was prepared for the first time using this method. The prepared sponge had a water droplet contact angle of 156.8° and exhibited excellent oil–water separation performances. Due to the addition of PDA and Fe3O4, the modified sponge exhibited excellent photothermal performance, rapidly heating to 63.4°C under a sunlight intensity of 1 kW m−2. The superhydrophobic WS prepared in this experiment provides a more environmentally friendly and low-cost way for high viscosity oil–water separation and targeted removal of oil pollution.

Bifunctional hybrid magnetic colloidal clusters for efficient oil sludge recovery

Oil contamination of water bodies due to oil spills, industrial waste discharge, oil leaks, etc. poses a major threat to the quality of groundwater, soil, and living organisms. To combat this issue through effective environmental remediation, efficient and cost-effective materials and innovative strategies are required. Here, we report a novel bifunctional magnetic material for efficient oil sludge removal using superparamagnetic colloidal nanocrystal clusters(BSPM-CNC) of nickel ion doped iron oxide with a shell of nitrogen-activated carboxymethyl cellulose char. The BSPM-CNC is synthesized by using a single-step procedure using water as a solvent. The crystallite and cluster size were tuned by varying Ni2+ ion concentration, carboxymethyl cellulose, and urea ratio. The cluster size was found to increase, when the carboxymethyl cellulose and urea ratio was reduced, due to insufficient stabilization of the capping agent that allowed the formation of secondary structures. X-ray photoelectron spectroscopy results confirmed the presence of nitrogen in the shell because of the condensation of OH and carbonyl groups of CMC with amine groups of urea, sp2-type carbon, C-O/N and O-CO bonding states. Laser Raman spectra of the char showed two major bands G and D bands, originating from the sp2 bonds and sp2 microdomains of the bond angle disorder caused by the sp3 hybridizations, respectively. The BSPM-CNC was found to be very efficient for oil sludge removal, where an oil removal efficiency of ∼ 98% was achieved with a cluster loading of 16 mg/L. The mechanism of sorption of oil are π-π interaction between aromatic hydrocarbons and graphitic domains of BSPM-CNC, Lewis-acid base interaction between nitrogenous char and delocalized electron cloud, and absorption into the pores of clusters. Our new approach provides a new platform to produce magnetic nanoclusters for the efficient removal of oil pollutants.

Amphiphilic polyimide-graphene nanoplatelet aerogel composites with high mechanical stability and enhanced thermal insulation properties for oil sorption applications

This study presents the fabrication of new polyimide (PI) aerogel composites through incorporation of graphene nanoplatelet (GNP) in PI matrix. A series of PI aerogel composites with various GNP concentrations were synthesized in a three-step gel preparation method, followed by a supercritical drying procedure. The role of GNP in tuning and optimizing various properties of aerogel composites including physical, thermal, and mechanical properties was discussed. The fabricated aerogel samples showed a significant reduction of shrinkage from 16% for pristine PI aerogel to only 6% in the presence of 0.5 wt% GNP. Further characterizations showed that incorporation of 0.5 wt% GNP also resulted in the highest pore volume (3.5 cc/g), highest surface area (404.5 m2/g), lowest density (∼ 0.04 g/cm3), and outstanding thermal insulation property (thermal conductivity of only 25.47 mW/m.K). When GNP was incorporated into the solid backbone, it was noticed that even at a very low concentration of 0.1 wt%, the modulus was increased over two times, and the maximum modulus of around 8 MPa was obtained. Such an enhancement in mechanical properties showed that GNP with ultrahigh aspect ratio can not only control and tailor the nanostructured assembly of PI aerogel composites but also due to the better entanglement with polymer chains, a stronger 3D porous network was formed, and thus, GNP can act as a reinforcing filler. Eventually, the sorption capacity and kinetics were determined using various solvents including methanol, acetone, toluene, hexane, and diesel to demonstrate the application of aerogel composites in oil sorption. The results showed that the highest sorption capacity was obtained for PI aerogels with 0.5 wt% GNP, and it could reach 7.3 ± 0.2 g/g for diesel which was significantly higher than the one for pristine PI aerogels. Unlike the previously reported PI aerogel composites where the enhancement of a specific property would often be associated with the deterioration of several other properties, this study showed that various properties of PI aerogel composites can be improved and optimized through the incorporation of GNP and the control of the aerogel synthesis. The proposed materials can therefore be used as high-performance thermally insulating materials and hold great potential for the removal of oil pollutants and organic solvents.

An Overview on the Treatment of Oil Pollutants in Soil Using Synthetic and Biological Surfactant Foam and Nanoparticles.

Oil-contaminated soil is one of the most concerning problems due to its potential damage to human, animals, and the environment. Nanoparticles have effectively been used to degrade oil pollution in soil in the lab and in the field for a long time. In recent years, surfactant foam and nanoparticles have shown high removal of oil pollutants from contaminated soil. This review provides an overview on the remediation of oil pollutants in soil using nanoparticles, surfactant foams, and nanoparticle-stabilized surfactant foams. In particular, the fate and transport of oil compounds in the soil, the interaction of nanoparticles and surfactant foam, the removal mechanisms of nanoparticles and various surfactant foams, the effect of some factors (e.g., soil characteristics and amount, nanoparticle properties, surfactant concentration) on remediation efficiency, and some advantages and disadvantages of these methods are evaluated. Different nanoparticles and surfactant foam can be effectively utilized for treating oil compounds in contaminated soil. The treatment efficiency is dependent on many factors. Thus, optimizing these factors in each scenario is required to achieve a high remediation rate while not causing negative effects on humans, animals, and the environment. In the future, more research on the soil types, operating cost, posttreatment process, and recycling and reuse of surfactants and nanoparticles need to be conducted.

Recyclable magnetic carbon foams possessing voltage-controllable electromagnetic shielding and oil/water separation

Lightweight carbon foams with high-performance electromagnetic interference (EMI) shielding have attracted extensive attentions. However, it is challenging for researchers to effectively regulate the EMI shielding of carbon foams independent on shield's thickness. Herein, we proposed a macroscopic magnetic carbon foams through a chemical engineering strategy under the synergies of nickel ion reduction and in-situ growth of carbon nanotubes on carbon frameworks derived from carbonized woods. The macroscopic magnetic carbon foams present high-performance EMI shielding with absorption-dominant mechanism, and the removal of oil pollutants for water purification. Magnetic properties favor the manipulation of oil absorption without direct mechanic contact. After burning, the magnetic carbon foams can be re-used in EMI shielding and oil absorbency. Furthermore, we used a novel electric voltage-driven strategy to upgrade EMI shielding performances of magnetic carbon foams. By the increase in applied voltages, the enhanced absorption-dominant EMI shielding and fast oil absorbency due to the decrease viscosity of crude oil could be simultaneously obtained. The strategy developed here may lead a new avenue toward the design of porous magnetic carbon foams with the enhanced voltage-driven multifunctionalities for practical applications.

Green Preparation of Robust Hydrophobic β-Cyclodextrin/Chitosan Sponges for Efficient Removal of Oil from Water.

A relatively straightforward green method to fabricate robust hydrophobic sponges for effective removal of oil pollutants and other organic contaminants was developed. These sponges were constructed from bio-sources: citronellal and palmitic acid-modified aminoethyl cyclodextrin-sodium phytate-chitosan (ACCTCS). The modified sponge exhibited desirable mechanical properties and strong hydrophobicity with a water contact angle (WCA) of 147.8°. Scanning electron microscopy showed that the ACCTCS sponge had a highly porous structure that was particularly suitable for organic component absorption. The sponge exhibited excellent absorption capacities for n-hexane, trichloromethane, vacuum pump oil, and peanut oil (47.9, 32.3, 32.6, and 32.2 g/g, respectively). The removal rate of oil was more than 80% (>26.2 g/g) after 10 absorption-desorption cycles. The ACCTCS sponge also showed good oil/water and organic components/water separation performance. The bio-source materials, green preparation method, and new absorbed-oil recovery strategy provided a novel pathway to construct multifunctional absorbents for oil/water separation in industrial wastewater.

Removal of Oil Pollution in water using hydrophobic silica

Nowadays the contamination in waters by oily substances turns out to be a problem of world-wide scope and although some methods of removal of oils in water exist; these present some limitations; therefore, this project proposes the use of hydrophobic silicas as absorbent materials for oily substances. Modified silicas (R-SiO2) were synthesized using the Stöber method, modifying the surface by co-condensation. Tetraethyl-orthosilicate (TEOS) and two surface modifiers were used as silica former: Methyl-trimethoxysilane (MeTEOS) and n-octyl-triethoxysilane (nOctyl-TEOS). The R-SiO2 were characterized by infrared spectroscopy identifying the modifying groups and their hydrophobicity was qualitatively evaluated according to the change in solubility in water. Finally, the removability of an automotive motor oil was evaluated by determining the amount of oil removed per gram of modified silica.

SYNTHESIS OF CELLULOSE AEROGEL FROM KAPOK FIBER FOR CLEANING THE WASTE OF LUBRICANT OIL

Cellulose aerogel is known to be superior in removal of oil pollutants and organic solvent. This research developed the synthesis of cellulose aerogel from kapok fiber, application as an adsorbent for lubricating oil waste and its reusability. Chemical delignification was carried out by immersing the kapok fibers in NaOH 6% solution at 100oC for 1h to obtained a cellulose of 65.5% (SNI-2009). The effect of urea concentration on adsorbent products was studied in the range of 8-16w%. Whereas the effect of cellulose was studied at a concentration range of 0.5-1.5w%. The gelation stage was carried out by adding cellulose in a NaOH/urea solution accompanied by stirring (1000rpm) for 15minutes. The mixture was cooled at 0 oC for 48h to form a gel. The formed gel is dried by the freeze drying method at -45°C. The cellulose aerogel from kapok fiber with a density of 0.11g/cm3 and porosity of 92.46% had an absorption capacity of up to 11.987g/g in the first cycle. The use of each aerogel cellulose sample to absorb lubricant oil waste reached a maximum of three cycles. DOI : https://doi.org/10.33005/jurnal_tekkim.v15i1.2305

Highly efficient photocatalytic degradation of oil pollutants by oxygen deficient SnO2 quantum dots for water remediation

The oil spill pollution has become one of the most significant threats to the marine environment and coastal ecology. An efficient way is urgently expected to remove the oil pollutants at this last stage of the petroleum age. In this work, the oxygen vacancy-rich SnO2 quantum dots (QDs) are prepared in aqueous solution via a facile bottom-up self-assembly route. The QDs are applied to the photocatalytic degradation of oil pollutants in water. A high degradation efficiency of 91.9% for octane is obtained within 48 h under the ultraviolet–visible irradiation and the excellent performance is able to be maintained within a period of 90 days. The primary reactive radical is superoxide anion (O2•−) in the degradation process, where the oxygen supply is essential to the photocatalytic removal of oil pollutants. The optical characterizations conclude that the QDs have 16.7% of oxygen vacancies and a band gap of 4.2 eV. Based on these characteristics, a computational model is established for the first principle-based simulation, which reveals the electrical properties and demonstrates a deep energy level of oxygen vacancies at 1.4 eV below the conduction band. The proficient photocatalytic degradation efficiency is ascribed to the inherent oxygen vacancies, which build an internal Z-scheme mechanism for the electron transition. A novel strategy is therefore proposed that the deep energy levels in low dimensional semiconductors are beneficial to the enhancement of photocatalytic activity. The present oxygen vacancy-rich SnO2 QDs are prospective candidates for mass degradation of organic oil pollutants in water and they are of great significance to the development of semiconductor photocatalysts as well as the remediation of marine environment.

Popped Rice Biochar and Superhydrophobic SiO2 / Popped Rice Biochar for Oil Adsorption

A novel biochar, whose precursor is popped rice, was produced to remove oil pollution in water. Popped rice biochar is characteristic with large pores. When popped rice was carbonized at 300 °C, its oil absorption capacity for paraffin oil is up to 10.88 ± 0.51 g/g, being much higher than that of the original popped rice (4.03 ± 0.39 g/g). In order to improve the oil-water separation property of popped rice biochar to absorb oil selectively, epoxy resin was used as a binder to make superhydrophobic SiO2 coated on the surface of popped rice biochar. The water contact angle of superhydrophobic SiO2 / popped rice biochar is 153 ± 0.9°, and it has good oil-absorption capacity with low water-absorption ratio. As the oil-absorption material is environmentally friendly, it will be a good select for the removal of oil pollution.

Foam or cotton covered by superhydrophobic micro-SiO2/fiberglass cloth for oil absorption

A novel porous oil-sorption material covered by a superhydrophobic fiberglass cloth was fabricated, in which the superhydrophobic fiberglass cloth facilitated oil–water separation and the cotton or foam provided storage for the oil that permeated through the superhydrophobic fiberglass cloth. It is crucial to prepare superhydrophobic silica (SiO2) particles by the application of dodecyltrimethoxysilane. Epoxy resin was used as a binder to coat superhydrophobic silica on the surface of the fiberglass cloth. The adhesive force between the fiberglass cloth and the superhydrophobic silica was found to be strong. The water contact angle of the superhydrophobic microsilica/fiberglass cloth (modified fiberglass cloth) was 155 ± 1°, the oil contact angle was always 0° and the water–oil separation efficiency was 95.80%. The modified fiberglass cloth showed good acid–alkali resistance. Cotton or foam covered by the superhydrophobic microsilica/fiberglass cloth had good water–oil separation performance, oil-sorption recyclability and a maximum oil-sorption capacity for high-temperature oil of up to 17.07 ± 0.59 g/g. As oil-sorption materials are simple to manufacture and inexpensive, they are a good option for use in the removal of oil pollutants.

A Simple, Long-Lasting Treatment for Concrete by Combining Hydrophobic Performance with a Photoinduced Superhydrophilic Surface for Easy Removal of Oil Pollutants.

Superhydrophobic surfaces present promising applications in the protection of building materials, such as the self-cleaning effect promoted by their high water-repellent properties. However, these surfaces easily lose their properties when exposed to oil contaminants. This is a critical weak point for their application in building facades, which are exposed to environmental pollutants such as hydrocarbons and vandalism (e.g., grafitti). A viable strategy to remove oils is to produce superhydrophilic surfaces, which present underwater superoleophobic behavior. In the case of buildings, the use of this strategy can be considered counterproductive because it promotes their interaction with water, the main vehicle of most decay agents. In this work, we have successfully combined the advantages of a superhydrophilic coating with a hydrophobic impregnation treatment, which prevents water ingress into the porous structure of the substrate. Specifically, a photoinduced superhydrophilic surface was produced on concrete by simple spraying of a starting sol containing TiO2NPs, which create a Cassie-Baxter state, a silica oligomer, producing a compatible matrix promoting good adhesion to the substrate and polydimethylsiloxane as a hydrophobic agent. After being exposed to sunlight, the treated surfaces switched from superhydrophobic (SCA 160°) to superhydrophilic (SCA < 10°). These surfaces presented underwater superoleophobicity (SCA 152° with CHCl3) and oil-contaminated dust was easily cleaned without employing detergents. The photoactivation does not alter the protection against water absorption (>85% reduction). The treatment showed suitable adhesion to the substrate and good resistance to rainfall and outdoor exposure due to the presence of the hydrophobic silica matrix in the concrete pore structure.

Multi-functional magnetic bacteria as efficient and economical Pickering emulsifiers for encapsulation and removal of oil from water

HypothesisEffective removal of oil pollutants from the surface of water is important in oil-polluted environments. Since living microorganisms can be used as particle-stabilizers for oil emulsification, magnet-responsive oil-degrading bacteria (M-Bacteria) are expected to integrate three intriguing properties, such as Pickering emulsification, magnet-responsiveness and bioactivity. Hence, by acting as an efficient Pickering emulsifier to encapsulate oil pollutants, it should be possible to eliminate oil from water under the application of an external magnetic field. ExperimentsOil-degrading bacteria, Brevibacillus parabrev, were successfully coated with a shell of magnetic Fe3O4 nanoparticles using polycations. The morphology and physicochemical characteristics of M-Bacteria were characterized by various techniques. A systematic study on Pickering emulsification of M-Bacteria and the removal of five types of oils were performed. Specific adsorption of M-Bacteria at the oil droplet surface was observed through optical, fluorescence, and scanning electronic microscopy images. The biodegradation process of oil was monitored using gas chromatography. FindingsEco-friendly M-Bacteria not only acts as an effective particle emulsifier to realize encapsulation and magnetic separation of oil contaminants but also shows a strong ability for further conversion of oil. This is the first report of oil removal via Pickering emulsification of living bacterial cells, which shows the potential of bacterial cells as functional colloidal materials in treating oily wastewater.

Surface modification and characterization of carbonaceous adsorbents for the efficient removal of oil pollutants.

In this study, the impact of different oxidizing agents on the structural integrity of activated carbon (AC) and multiwalled carbon nanotubes (MWCNTs) was studied for the removal of BTX from aqueous solution. Seven different combinations of green oxidizing agents (mild organic acids) in conjugation with NaOCl (basic oxidizing agent) were used. The modified adsorbents were analyzed by Brunauer, Emmett, and Teller (BET) surface area analyzer, Fourier transform infrared spectroscopy (FTIR), Boehm titration, Raman spectroscopy, thermal gravimetric analysis (TGA), x-ray diffraction (XRD), zeta potential, and variable pressure field emission scanning electron microscope (VPFESEM). The results suggested that the carbonaceous sorbents modified with combination of citric acid tartaric acid, malic acid and salicylic acid (CTMS-I) showed increased surface area (O-AC: 871.67 m2/g, O-MWCNTs: 336.37 m2/g) and total pore volume (O-AC: 0.59 cm3/g, O-MWCNTs: 0.04 cm3/g), with the significantly improved thermal stability. Preliminary batch adsorption experiments conducted using the present prepared O-AC and O-MWCNTs, showed an improved performance towards the adsorption of BTX, compared with other available reported adsorbents in the literature.

Acrylic acid-grafted pre-plasma nanofibers for efficient removal of oil pollution from aquatic environment

Oily wastewater is a worldwide problem threatening the environment and humans. High flux and low-energy consumption separation of oil and water is urgently required but still faces great challenges. In this study, nanofibrous membranes with superhydrophilic and underwater superoleophobic surfaces were fabricated by grafting acrylic acid onto plasma-treated electrospun polystyrene/polyacrylonitrile (PS/PAN) membranes. The morphologies, chemical compositions, mechanical and surface properties of the membranes were examined in detail. The water contact angles of the PS/PAN membranes were 137.4°, 130.1°, 119.5°, 88.1° and 80.2°, respectively, which decreased to 76.5°, 47.9°, 34.4°, 0° and 0° after grafting treatment, proving that the modification improved the surface hydrophilicity of the membranes due to the introduction of hydrophilic groups. In addition, a gravity-driven filtration device was utilized to investigate the oil/water separation potential of the membranes. The results indicated that the grafted PS/PAN membranes separated the layered oil/water mixtures with permeate flux up to 57509 L m-2 h-1, while high fluxes of 1390-6460 L m-2 h-1 for the separation of different oil-in-water emulsions. Importantly, the membranes still maintained high flux and efficiency even after several cycles of separation. Therefore, the reusable membranes can be expected to be potential cost-effective materials for oil/water treatment.

Effective degradation of oil pollutants in water by hydrodynamic cavitation combined with electrocatalytic membrane

Hydrodynamic cavitation (HC) and electrocatalytic membrane (ECM) can be used in the oxidative degradation of oil pollutants, and a combined method with both techniques can improve the overall degradation efficiency. The results of this study show that HC could promote the dispersion and dissolution of oil in water at 35°C with an inlet pressure of 0.30 MPa and cavitation time of 2 h. Under these conditions, the oil concentration increased from initial 90 mg/L to 215 mg/L, at which point the effect of the degradation by HC could be clearly detected. Then, when the cavitation time was 5 h, the oil concentration decreased from maximal 215 mg/L to 139 mg/L. Subsequently, at a current density of 2 mA/cm2, pH 6, residence time of 3.8 min, electrode spacing of 40 mm and solution temperature of 30°C, the removal rate of oil pollutants reached up to 98.81%. Gas chromatography mass spectrometry (GC-MS) analysis shows that ECM could degrade oil pollutants more effectively. Therefore the combination of HC and ECM was demonstrated to be an efficient method for the removal of oil pollutants in water.

Biocompatible Meshes with Appropriate Wettabilities for Underwater Oil Transportation/Collection and Highly Effective Oil/Water Separation.

In this study, we prepared biocompatible superhydrophilic and underwater superoleophobic tannic acid (TA)/polyvinylpyrrolidone (PVP)-coated stainless-steel meshes that mediated extremely efficient separations of mixtures of oil and water. These TA/PVP-coated stainless-steel meshes displayed excellent antifouling properties and could be used to separate oil/water mixtures continuously for up to 24 h. Moreover, a funnel-like TA/PVP-coated stainless-steel mesh device could be used for underwater oil transportation and collection. In conjunction with our continuous oil removal system, this device allowed for the continuous collection and removal of oil pollutants from underwater environments. The high performance of these TA/PVP-coated stainless-steel meshes and their green, low-energy, cost-effective preparation suggests great potential for practical applications.

Carbon Sorbent of Destructive Type Based on Wood Biochar for Removal of Oil Pollution

Carbon Sorbent of Destructive Type Based on Wood Biochar for Removal of Oil Pollution

Preparation of magnetic hydrophobic polyvinyl alcohol (PVA)–cellulose nanofiber (CNF) aerogels as effective oil absorbents

Efficient, rapid removal of oil spills on the surface of water is technologically significant for protecting the ecological marine environment. In this work, environmentally friendly, novel, magnetic hydrophobic PVA/CNF aerogels (MHPCA) with ultralow density (13.84 kg m−3), high porosity (> 98%), magnetic responsivity and good mechanical properties were successfully prepared by vacuum freeze-drying PVA/CNF gel followed by a facile silanization reaction and dipping process. The hydrophobic but oleophilic nature of the as-prepared MHPCA (water contact angle over 138°) came from the polysiloxane coated on the fiber surface by the silanization reaction. The MHPCA had excellent oil/water selectivity, with oil absorption capacity as high as 136 g/g being observed. Additionally, the MHPCA exhibited good magnetic response and could absorb oil on the surface of water by magnetic driving. More importantly, the MHPCA showed excellent elasticity after 30 compression-release cycles, which demonstrated the reusability and durability of the super absorbent. The results of this work provide a feasible idea for easily and efficiently removal of oil pollution from the water surface.