Oil Adsorption Capacity Research Articles

Multifunctional carboxylated cellulose nanofibers/exfoliated bentonite/Ti3C2 aerogel for efficient oil adsorption and recovery: The dual effect of exfoliated bentonite and MXene

Discharge of oily wastewater with poor fluidity could cause serious environmental pollution. Therefore, rapid and efficient removal and recovery of oil is still a global problem. Currently, two-dimensional (2D) Ti3C2 MXene materials with high photothermal performance have attracted extensive attention in photothermal-assisted crude oil wastewater treatment. However, the poor stability of Ti3C2 severely limits the application in the development of photothermal aerogels. In this study, porous CNF-C/BTex/Ti3C2 aerogel was constructed by synergistically introducing cost-effective exfoliated bentonite (BTex) and Ti3C2 MXene combined with carboxylated cellulose nanofibers (CNF-C) through a simple in situ co-precipitation coupling with microwave hydrothermal and solution impregnation processes. The introduced BTex efficiently restrained the oxidation of Ti3C2 during the preparation process, and synergistically enhanced the structural stability, mechanical and adsorption properties of aerogel. Specifically, CNF-C/BTex/Ti3C2 exhibited excellent stability (structural, thermal and chemical stability), thermal resistance, hydrophobic properties (water contact angle was 149°), and mechanical properties (full recovery at 60% strain), which was conducive to adsorption of common oils (up to 46–90 times than its original weight). In addition, CNF-C/BTex/Ti3C2 has outstanding photothermal conversion efficiency (light absorption efficiency was 99% and the surface temperature reached up to 75.2 °C under 1-sun irradiation:1 kW·m−2) and thermal conductivity (104 mW/m·K), which allows CNF-C/BTex/Ti3C2 to adsorb more than 48 times than its original weight of crude oil (adsorption capacity up to 48 g·g−1) under 1-sun irradiation (1 kW·m−2) within 25 s. Furthermore, enhanced adsorption mechanisms for common oils and high-viscosity crude oil have been proposed. The study provides a new option for the development of efficient and stable cellulose-based adsorbents for oily wastewater remediation by introducing low-cost bentonite and MXene.

Nano graphite platelets/Cu (BDC) MOF coating on polyurethane sponge: A superhydrophobic self-extinguishing adsorbent for static and continuous oil/water separation

The discharge of toxic organic solvents and industrial oil into water is one of the major problems that threaten marine ecology and human health. In this work, a flexible superhydrophobic/superoleophilic polyurethane (PU) sponge was modified by decorating Cu-benzene dicarboxylic acid metal-organic framework (Cu (BDC) MOF) as a flame retardant and nano graphite platelets (NGPs) as a superhydrophobic agent. These materials were attached to the sponge skeleton by poly (styrene-co-butyl acrylate). The PU-Cu (BDC)-NGPs sponge showed high thermal, mechanical, and chemical stability. Moreover, this composite possessed excellent oil/water separation efficiency. The prepared composite showed excellent superhydrophobicity with a water contact angle of 154° and possessed self-extinguishing properties with a limiting oxygen index (LOI) of 24.46%. The oil adsorption capacity at a static state and oil separation efficiency at a continuous oil/water separation process for PU-Cu (BDC)-NGPs sponge were 43.5–132 g/g and 96%, respectively. Moreover, PU-Cu (BDC)-NGPs sponge had excellent stability in harsh conditions and exhibited good compressibility and reusability. Overall, the Cu (BDC) MOF-NGPs coated PU sponge can be a highly efficient sorbent with durability and flame retardancy.

Effects of thermal and chemical modification on the physical properties of Ugandan Mutaka Kaolin

This study investigates the impact of thermal treatment at temperatures ranging from 600 ​°C to 1050 ​°C and chemical treatment using (COOH)2·2H2O and Al2(MoO4)3 ​at concentrations of 0.01 ​M, 0.05 ​M, and 0.1 ​M. The modified kaolin samples’ pH, oil adsorption capacity, refractive index, specific gravity, and viscosity were examined. Comprehensive analyses were performed to characterize the modified kaolin samples. The spectrum results revealed dealumination, with a corresponding increase in silicon content due to chemical treatment, while the aluminum content decreased compared to thermal treatment results. As observed with the calcined kaolin sample, a significant portion of the OH stretch groups vanished with disappearance stretches along the bands at 1229.6 and 1009.2 ​cm−1, corresponding to Si–O stretching vibrations. The specific gravity of calcined kaolin was observed to be relatively lower than TiO2. Furthermore, the obtained pH of 4.0 or lower, or a pH of 9.0 or higher, is classified as corrosive. The ideal temperature range for achieving optimal oil absorption lies within the 800 ​°C–900 ​°C range, where metakaolin properties favor effective oil uptake. The chemical concentration had a notable impact on the dispersion of kaolin powders, in contrast to calcined kaolin. At 800 ​°C, calcined kaolin attained an almost ideal refractive index for water-based paints, closely aligning with the refractive index of water.

Versatile CO2-responsive Sponges Decorated with ZIF-8 for Bidirectional Separation of Oil/Water and Controllable Removal of Dyes.

The complex wastewater containing water-soluble dyes and water-insoluble oils has given rise to significant environmental concerns that demand urgent remediation. Herein, a novel "smart" multifunctional sponge (ZIF-8@PMS) stepwise decorated with ZIF-8 nanoparticles and CO2-responsive copolymer (poly(2-(diethylamino) ethyl methacrylate-co-3-(trimethoxysilyl)propyl acrylate-co-stearyl methacrylate) was successfully prepared for CO2 controllable oil/water separation and dyes removal. The results revealed that the sponge coated with CO2-responsive copolymer for three cycles (ZIF-8@PMS-3) exhibited optimal comprehensive properties. The ZIF-8@PMS-3 had excellent compressive-resilient characteristics and chemical stability. As expected, it displayed tunable wettability and charged state under the regulation of CO2. Based on these features, ZIF-8@PMS-3 presented highly efficient removal of oil and dyes, even for the dye-containing oil/water emulsions, via a synergistic combination of adsorption and separation methods. The adsorption capacity for oil and various organic solvents ranged from 21.3 to 50 g g-1. The maximum adsorption capacities toward anionic dyes: methyl orange with 1205.89 mg g-1 and methyl blue with 880.00 mg g-1 in the presence of CO2 through electrostatic interaction. In the absence of CO2, it achieved maximum adsorption capacities for cationic dyes, including malachite green with 1246.15 mg g-1 and rhodamine B with 203 mg g-1, primarily driven by π-π interactions. According to distinct adsorption mechanisms, ZIF-8@PMS-3 could selectively adsorb either anionic or cationic dyes by exploiting CO2 as a trigger. Furthermore, the separation efficiencies for both types of oil/water emulsions surpassed 99.9%, with respective fluxes of 1566.99 L m-2 h-1 (water-in-oil emulsion) and 310.37 L m-2 h-1 (oil-in-water emulsion). Additionally, the as-prepared sponges exhibited remarkable antibacterial properties and exceptional recyclability. Therefore, the ZIF-8@PMS-3 holds substantial promise for potential applications in practical industrial wastewater treatment.

Preparation of aerogels from corn stalks and research on their properties and gelation behavior

Corn straw is a kind of agricultural biomass waste produced by the corn crop. It is a question of how to make effective use of this waste resource. Biomass aerogel is a good adsorbent which can be used to deal with water pollution. The direct use of non-component separated maize straw as the raw material in this paper can effectively reduce the experimental cost, simplify the experimental procedures and make efficient use of maize straw compared to traditional cellulosic raw materials. The inorganic salt lithium bromide (LiBr) solution was used as the solvent, and the environmentally friendly corn stover whole component aerogels (CA) with excellent performance were prepared by solvent replacement and freeze-drying. The optimum process for the preparation of aerogels was obtained using a single factor test method: 1:200, 150 ℃, 40 min, 70 wt% LiBr. The full-component aerogels from maize straw contained cellulose, hemicellulose and lignin, which indicated that the maize straw was effectively utilised. CA has a three-dimensional network pore structure, mainly composed of micropores and mesoporous pores. It has ultra-low density (9 mg/cm3) and excellent adsorption capacity for methylene blue and soybean oil (123.59 mg/g, 103.58 g/g). At the same time, the Rheolaser Master Microrheological (RMM) analyzer of French Formulaction Company was used to investigate the changes in solution gel process. The mean azimuth shift (MSD) curve of the sample was measured by optical microrheometer. The elastic factor (EI), macroscopic viscosity factor (MVI), solid-liquid equilibrium point (SLB), and photon free path (I*) values of the samples were calculated to explore the microstructure and rheological characteristics of the samples during the gel process. The gel behaviour and processes have been explored based on the analysis of these parameters. Potential applications of whole-component aerogels from corn stalks include building insulation, thermal insulation, light-blocking materials, and packaging materials.

Microbiological and physicochemical properties of fermented and unfermented sweet potato flour

This research accesses the suitability of using processed flours from fermented and unfermented yellow-fleshed sweet-potato as alternative flour based on their physiochemical and microbiological properties. Raw yellow sweet potato tubers were obtained from a local Nigerian market and processed into fermented and unfermented sweet potato flours. Their microbiological and physiochemical (proximate and functional) properties were analyzed using standard methods. The microbiological results identified six bacterial genera; (Bacillus, Klebsiella, Micrococcus, Staphylococcus, Lactococcus, and Enterobacter) and five fungal genera (Aspergillus, Penicillium, Mucor, Candida, and Saccharomyces). Bacillus and Aspergillus spp. were the most dominant bacterial and fungal genera respectively. The physiochemical result reveals that fermenting sweet potato flour resulted in improved protein, moisture content, and water and oil adsorption capacities compared to the unfermented flour. The pH also decreased from 8.8 to 5.0 after 72 h of fermentation. Most of the microorganisms isolated are associated with plants, water, environment, and fermentation, they are generally recognized as safe (GRAS) organisms and their potentials can be further exploited in the food industry. These findings highlights the potentials of incorporating fermentation techniques in enhancing the nutritional and techno-functional attributes of sweet potato flour as a healthy alternative gluten-free flour-based staple diet.

Macroporous fibers electrospun from dual‐good solvent system

AbstractThe polymer/solvent/nonsolvent ternary solutions have been previously used for fabricating electrospun macroporous fibers, in which the nonsolvent was expected to induce a liquid–liquid phase separation that leads to formation of pores after drying. In this study, we demonstrate that the poly(styrene‐co‐acrylonitrile) (SAN)/chlorobenzene (CB)/dimethyl sulfoxide (DMSO) system can be successfully electrospun into highly uniform macroporous fibers with pore size >50 nm at CB/DMSO volume ratio ~7/3 though both CB and DMSO are good solvents to SAN. The results imply that a premixed nonsolvent is not necessary for the formation of macropores. We find that it is the water droplets condensed from the atmosphere that work as the nucleation sites to trigger the phase separation while water‐miscible DMSO plays a supporting role to expand the solvent‐rich phase and the resultant pore size. Instead of solvent quality, the distinct volatilities and water miscibilities of the solvents are the keys. The macropores throughout the fibers provide high surface areas and large openings on surface such that the fibers show a significant improvement in oil adsorption capacity in comparison to the smooth and mesoporous ones.

One‐pot synthesis of bio‐polyol from vegetable oil for preparation of bio‐polyurethane based porous sorbent with high oil adsorption capacity

AbstractIn the present work, bio‐polyol has been synthesized via controlled hydroxylation from sunflower oil in one conversion step using a mixture of hydrogen peroxide and formic acid. The influences of various reaction conditions for bio‐polyol synthesis such as reaction time, temperature, the dosage of hydrogen peroxide, and formic acid were investigated. The bio‐polyol was obtained from sunflower oil with hydroxyl number of 180 mg KOH/g, and functionality of 3.5 OH groups/mol. The as‐synthesized sunflower oil‐based polyol was then used for replacing fossil‐based polyol in synthesis of bio‐based polyurethane (PU), which was then simultaneously combined with coir biomass filler to fabricate the porous material with high oil adsorption capacity. The oil adsorption capacity of the new bio‐based sorbent material was relatively high, up to 14.89 g/g. In comparison with pristine PU or lignocellulosic materials, the new sorbents had higher oil adsorption capacity.

Oil absorption stability of modified cellulose porous materials with super compressive strength in the complex environment

AbstractThe occurrence of oil spills has severe damage upon both the environment and human health. Hence, the development of a green, recyclable, complex environment resistant, and efficient oil–water separation aerogel is required in order to effectively absorb marine or industrial oil. In this study, modified cellulose/N,N'-methylenebisacrylamide/tannin (PCMT) composite porous materials were prepared utilizing the sol–gel method and were modified with tertbutyl acrylate. PCMT possesses a three-dimensional interpenetrating porous structure, exhibiting remarkable oil–water separation performance and excellent compressive strength (PCMT can capable of bearing 7000 times its own weight; PCMT can endure 290.3 kPa pressure at 80% strain when the amount of tannin is 0.2 g). The unique pore structure of PCMT engenders differential oil adsorption capacities (PCMT0, PCMT0.05, PCMT0.1, and PCMT0.2 evince higher adsorption capacities for petroleum ether and dichloromethane, n-hexane and dichloromethane, toluene, and toluene and dichloromethane, respectively). Of critical import, PCMT demonstrates exceptional adaptability to complex environments, wherein the porous materials maintain good hydrophobicity and oil absorption capacity under conditions of vigorous stirring, a wide pH range (1–14), a wide temperature range (4–160 °C), ultraviolet irradiation (8 h), and tape peeling (10 times). Moreover, the porous materials may be employed for the recovery of oil through simple mechanical extrusion, thus demonstrating certain economic significance and the application potential in the treatment of oil spills.

Integrating genetic-engineered cellulose nanofibrils of rice straw with mild chemical treatments for enhanced bioethanol conversion and bioaerogels production

Cellulose in crop straws represents an abundant biopolymer convertible for biofuels and bioproducts, while the inherent recalcitrance of lignocellulose limits these applications. By selecting desirable rice mutant (cesa7) from site-mutation of the OsCESA7 isoform essential for cellulose biosynthesis, this study examined much improved lignocellulose recalcitrance such as reduced cellulose crystallinity, polymerization and nanofibril length for increased lignocellulose porosity and accessibility. Compared with its wild type, the cesa7 mutant showed a near-complete biomass saccharification with hexose yields of over 96% (% cellulose) for bioethanol production raised by 58%− 71% under three green-like pretreatments performed. Meanwhile, the cellulose substrate of cesa7 mutant was applied to produce aerogels with high porosity and large specific surface under less-intensity ultrasonic treatment, and its further mild chemical modification led to significantly raised oil adsorption capacity by 55%, mainly due to higher proportion of nanofibrils and the honeycomb-like fibers structure observed. It has thus provided an applicable approach for high-yield bioethanol and high-quality aerogels by integrating genetic-modified cellulose substrates with cost-effective process technology.

Facile fabrication of hydrophobic covalent organic framework decorated melamine sponge for efficient separation of immiscible oil-water mixture and water-in-oil emulsion

Frequent oil spills and oily sewage have caused serious environmental problems. Sponges have attracted great attention in oil-water separation due to their low cost and high porosity, but it still remains challenge to hydrophobic modification of sponge in facile and scalable manner. Here is reported a facile fabrication of porous and hydrophobic sponge composite (MS@COF) with effective oil-water separation by in-situ growth of hydrophobic TFB-BD(Me)2 COF on the surface of melamine sponge. Combining the porous structure of the sponge and hydrophobicity of COF, the composite can separate oil-water mixture and water-in-oil emulsions in a fast way. The prepared MS@COF showed oil adsorption capacity up to 160 g g-1. In addition, continuous separation of oil-water mixture was demonstrated using a peristaltic pump with a separation rate of 50 mL min-1. More importantly, the composite could separate surfactant-stabilized water-in-oil emulsions with separation efficiency of 98.8%. The oil-water mixture and oil-water emulsion separation ability of the composite persisted after 50 separation cycles thereby demonstrating good recyclability. The composite also showed good chemical stability, mechanical and flame retardancy. This work introduces a new approach for the synthesis of hydrophobic sponge decorated with COF nanoparticles for oily wastewater treatment and organic pollutant removal on water surfaces.

Superhydrophobic carbon black-loaded polyurethane sponge for efficient oil-water separation and solar-driven cleanup of high-viscosity crude oil

In recent years, spills of petroleum and organic chemicals have frequently occurred during their transportation at sea, which has caused serious pollution for water resources. In view of this, a superhydrophobic PU/CB@FAS sponge with excellent photothermal conversion performance was prepared, and its microscopic morphology and wettability were investigated in this paper. The results showed that the skeleton of PU/CB@FAS sponge was covered with a layer of CB nanoparticles, and elements such as F and Si were found on the skeleton surface. Subsequently, the water contact angle of the PU/CB@FAS sponge was measured to be 151°and the sponge was able to separate oil-water mixtures in different ways. When the sponge was used as an adsorbent material, its saturation capacity was 27.11–59.96 g·g−1 for low-viscosity oils/organic solvents such as soybean oil. Finally, the PU/CB@FAS sponge's photothermal conversion performance was investigated at a light power density of 1 sun (1.0 kW/m2), and the sponge's adsorption capacity for crude oil was increased by 15 times compared with the condition of without light. Thus, the PU/CB@FAS sponge successfully achieved rapid oil-water separation and adsorption for high-viscosity crude oil, showing a broad practical application prospect.

Application of Functionalized Fe3O4 Magnetic Nanoparticles Using CTAB and SDS for Oil Separation from Oil-in-Water Nanoemulsions.

Using magnetic nanoparticles (MNPs) for emulsified oil separation from wastewater is becoming increasingly widespread. This study aims to synthesize MNPs using amphiphilic coatings to stabilize the MNPs and prevent their agglomeration for efficiently breaking oil-in-water nanoemulsions. We coat two different sizes of Fe3O4 nanoparticles (15-20 and 50-100 nm) using cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) with surfactant-to-MNP mass ratios of 0.4 and 0.8. We study the effect of various variables on the demulsification performance, including the MNP size and concentration, coating materials, and MNP loading. Based on the oil-water separation analysis, the smaller size MNPs (MNP-S) show a better demulsification performance than the larger ones (MNP-L ) for a 1000 ppm dodecane-in-water emulsion containing nanosized oil droplets (250-300 nm). For smaller MNPs (MNP-S) and at low dosage level of 0.5 g/L, functionalizing with surfactant-to-MNP mass ratio of 0.4, the functionalization increases the separation efficiency (SE) from 57.5% for bare MNP-S to 86.1% and 99.8 for the SDS and CTAB coatings, respectively. The highest SE for MNP-S@CTAB and the zeta potential measurements imply that electrostatic attraction between negatively charged oil droplets (-55.9 ± 2.44 mV) and positively charged MNP-S@CTAB (+35.8 ± 0.34 mV) is the major contributor to a high SE. Furthermore, the reusability tests for MNP-S@CTAB reveal that after 10 cycles, the amount of oil adsorption capacity decreases slightly, from 20 to 19 mg/g, indicating an excellent stability of synthesized nanoparticles. In conclusion, functionalized MNPs with tailored functional groups feature a high oil SE that could be effectively used for oil separation from emulsified oily wastewater streams.

A multifunctional non‐fluorinated flame retardant superhydrophobic 3‐D porous material for highly selective oil spill treatment and removal of dyes

AbstractThe environment and global healthcare are at risk from oily wastewater accumulation and spills. Hence, porous sponge materials are widely sought for remedial oil cleanups. Materials with superhydrophobic and photocatalytic characteristics are implemented for extensive use besides oil–water separation, self‐cleaning, and removal of dyes. Regardless of the various upsides, few materials display both of these features jointly. Most nanomaterial photocatalysts are susceptible to the action of ultraviolet (UV) light irradiation, which often inhibits their hydrophobicity. Here in this work, a photocatalyst such as ZnO was coated on a porous 3‐D melamine sponge (MS). To preserve the hydrophobicity without sacrificing the photocatalytic behavior, ZnO coated melamine sponge was modified with transparent polydimethylsiloxane (PDMS) to obtain MS/ZnO/PDMS. The obtained superhydrophobic photocatalytic sponge exhibits exceptional oil adsorption capacity, superior stability even under severe conditions and the ability to remove organic dyes. Remarkably, the sponge exhibits outstanding compressive strength and fire resistance properties, indicating the possible utilization in a prolonged practical execution. As a result, this technique might pave the way for the creation of a comprehensive design for an improved superhydrophobic photocatalytic sponge with high stability and recyclability.

Changes in the structural and physicochemical characterization of pea starch modified by Bacillus-produced α-amylase

In this study, changes in structural and physicochemical properties of pea starch treated with Bacillus-produced α-amylase were determined. The results showed that enzymatically modified pea starch had lower amylose content and granule size but higher branching degree and relative crystallinity. After enzyme hydrolysis, the distribution of A and B1 chains slightly decreased, while the distribution of B2 and B3 chains increased lightly. Enzymatic hydrolysis preferentially occurred in the amorphous region and cannot change the crystalline structure of pea starch. Moreover, pea starch showed lower light transmittance, peak viscosity, breakdown viscosity, pasting temperature, shear viscosity, storage modulus and loss modulus, while the oil adsorption capacity and gelatinization enthalpy significantly increased with increasing α-amylase hydrolysis time. Correlation analysis indicated that α-amylase hydrolysis had different effects on different pea varieties. This research could provide ideas for exploring new applications for enzymatically modified pea starch in food industry. Industrial relevanceThis study found that Bacillus-produced α-amylase significantly changed the amylose content, granule size and viscosity of pea starch, which was helpful to further investigate the modified starch. This technology is expected to widen the applications of pea starch modified by Bacillus-produced α-amylase in food industry, for example as thickener, stabilizer and beverage, to improve the texture, stability and shelf-life of various food products.

Waste plastic-derived aerogel modified with graphene oxide for hygroscopic material and oil spill treatment

Plastic bags, also known as nylon bags, plastic packaging, latex bags, and bubble bags, are one of the most harmful segments of plastic waste to the ecosystem. Researchers estimate that plastic bags in natural surroundings take between 500 and 1000 years to fully decompose. Therefore, the recycling of non-biodegradable plastic products such as plastic bags is always a prime topic. In this study, plastic bags were used as raw materials for the synthesis of aerogel (PBA) and modified with graphene oxide (GO/PBA) to increase mechanical strength. Young's module results show that GO/PBA can withstand a maximum compression of about 55 N while PBA has a compressive force of only about 10 N. GO/PBA has a porous 3D structure, low density (0.026 g/cm3), and the major elements are C, O with the existence of C − O, which are suitable as hygroscopic materials. GO/PBA are able to absorb moisture up to 17 g/g compared to that of PBA with 10 g/g. Besides, GO/PBA is hydrophobically modified with PDMS (PDMS/GO/PBA) to increase selectivity in oil/water systems, oil spill treatment application with high oil adsorption capacity reaching 27 g/g, about 10 times the mass of the material. Thus, GO/PBA and PBMS/GO/PBA were successfully synthesized for the application of desiccant and oil adsorbent, respectively. The kinetics of the two adsorption processes are shown by pseudo-order first and second models.

Superhydrophobic wood sponge with intelligent pH responsiveness for efficient and continuous oil-water separation

In recent years, the leakage of crude oil and the discharge of oily wastewater in industrial production have seriously endangered the water environment and ecological safety. Adsorbent materials with excellent oil-water separation performance play an important role in water purification. In this work, we employed a simple yet effective strategy to prepare highly compressible wood sponges. And with the prepared wood sponge as the substrate, the prepared pH-responsive copolymer was coated on the surface of the wood sponge by spraying method, and the pH-responsive superhydrophobic wood sponge was successfully prepared. The experimental results show that the wood sponge has excellent pH-responsive properties and can complete the transition of surface wettability between superhydrophobicity and hydrophilicity according to the change of pH value. The wood sponge has good oil adsorption capacity (12.72 g g−1), and reusability. Continuous oil-water separation can be carried out under the vacuum pump, and the oil-water separation efficiency in one separation cycle is above 92%. It has great application potential in the treatment of oily wastewater.

Construction of Super-Hydrophobic Lignocellulosic Nanofibrils Aerogels as Speedy Oil Absorbents.

Lignocellulosic nanofibrils (LCNF) aerogels have a three-dimensional structure, with large specific surface area, low density, which is promising to be developed into a new type of adsorbent with high absorption capacity. However, LCNF aerogels have the problem of simultaneous oil and water adsorption. This high hydrophilicity directly leads to low adsorption efficiency in oil-water systems. This paper suggests a facile and economical method for the synthesis of biocompatible CE-LCNF aerogels using LCNF and Castor oil triglycidyl ether (CE) was successfully established. The use of LCNF enabled aerogels to possess remarkably uniform pore size and structural integrity, while the introduction of hydrophobic silica produced stable superhydrophobicity for more than 50 days at room temperature. These aerogels presented desirable hydrophobicity (131.6°), excellent oil adsorption capacity (62.5 g/g) and excellent selective sorption property, making them ideal absorbents for oil spill cleaning. The effects of ratios of LCNF to CE composition, temperatures and oil viscosity on the oil adsorption performance of aerogels were estimated. The results displayed that the aerogels had the maximum adsorption capacity at 25 °C. The pseudo-secondary model had higher validity in oil adsorption kinetic theories compared to the pseudo-first-order model. The CE-LCNF aerogels were excellent super-absorbents for oil removal. Moreover, the LCNF was renewable and nontoxic, which has the potential to promote environmental applications.

Simple Fabrication of PDMS-Grafted Hydrophobic Iron Oxide Particles for Oil–Water Separation and Stimuli-Responsive Liquid Marbles

In this paper, poly(dimethyl siloxane) (PDMS) which is considered chemically unreactive was successfully grafted onto the surface of iron oxide particles, forming stable hydrophobic polymer-coated particles without the usage of any external stimuli like heat or UV irradiation. Here, magnetic hydrophobic particles were prepared by a facile method of coating PDMS prepolymer oil onto Fe3O4 particles via dispersion in a PDMS oil/hexane solution. The X-ray diffraction studies elucidated the successful synthesis of the magnetic particles, whereas the X-ray photoelectron spectroscopic studies ensure the successful incorporation of the polymer layer onto the particles. Two potential applications of the prepared particles were demonstrated here. The oleophilic and hydrophobic nature of the particles coated with PDMS is exploited to demonstrate the oil collection from the surface as well as in immersed conditions in an aqueous medium by using the particle-coated cotton and sponge, respectively. An oil–water separation efficiency of ∼95% was achieved for cotton and sponge against various oils with an oil adsorption capacity of 5 times and 11 times its own weight, respectively. Additionally, magnetic-responsive liquid marbles (LMs) were prepared by encapsulating liquids with the fabricated particles. Stable LMs were formed for a wide range of volumes (5–200 μL) with core liquids having different surface tensions, pH, and viscosity. The stability of the LM was tested using a dropping method and a hydrostatic pressure method.

Multifunctional hydrophobic bio-based foam toward highly efficient photothermal cleanup of high-viscosity crude oil spills, oil-water separation and aqueous organic pollutant elimination

The environmentally friendly and efficient remediation of crude oil spills is a global challenge due to its high viscosity and low fluidity at room temperature. Herein, we reported a polydimethylsiloxane (PDMS) modified biomass carbon fibers foam immobilized with Ag2O@Ag nanoparticles via the self-assembly, freeze-drying, carbonization, and hydrophobic modification processes (denoted as PAAC). The resulting PAAC foam exhibited excellent hydrophobicity (water contact angle: 147.8◦), high solar absorption capacity and excellent photothermal conversion property, which enable it to decrease the viscosity of heavy oil and achieve high adsorption capacity of heavy crude oil (60.5 g/g) and great reusable performances under 0.3 sun energy drive. In addition, the PAAC foam showed excellent adsorption capacity to organic solvents and low viscosity oils (11.3–26.4 g/g). Under visible-light irradiation, PAAC foam exhibited remarkable photocatalytic efficiency for removing crystal violet and demonstrated high stability and photocatalytic activity after five consecutive cycles. The proposed design of a solar heated sorbent presents a new potential to explore multifunctional biomass materials to solve environmental pollution problems on a large scale.