High Oil Absorption Capacity Research Articles

Kapok fibre as potential oil-absorbing material: Modification mechanism and performance evaluation

Kapok fibre has gained considerable attention as a potential oil-absorbing material due to its lipophilicity, hydrophobicity, and configuration of its central lumen which is the key component of its high oil absorption capacity. However, the weak structural integrity of the fibre greatly retards its application. This study aims to develop a reinforcement method for kapok (Ceiba pentandra) fibre to enhance its reusability and oil recovery. Oil-sorption capacities of several modified kapok fibres have been evaluated to resolve the oil-polluted water issues. Oxidation using sodium chlorite (NaClO2) followed by sol-gel coating with tetraethylorthosilicate (TEOS) and sponge formation via freeze-drying method successfully enhance the structural integrity of the fibre without significantly reduce its hydrophobicity. Further coating the sponge with dodecyltrimethoxysilane (DTMS) using the chemical vapor disposition method results in superhydrophobic fibre. The best performance achieves an oil-sorption capacity of 48.6 g-oil/g-fibre and can maintain 62.6% of its oil-sorption capacity even after ten reuse cycles.

Cellulosic sponges with pH responsive wettability for efficient oil-water separation

To obtain efficient oil-water separation materials with responsiveness, cellulosic porous materials with switchable wettability in response to pH changes were developed by reacting cellulose acetoacetate sponges with alkylamines of varying carbon chain length via dynamic covalent enamine bonds. The resulting sponges reversibly changed between being superhydrophilic (θwater = 0°) and highly hydrophobic (maximal θwater = 146°) under suitable pH conditions while maintained the favorable porous structures. Notably, the functionalized sponges exhibited high and selective oil absorption capacity (40–80 g/g) and satisfying desorption ability of 80%, and could efficiently separate oil-water mixtures and emulsions with extremely high efficiency (> 99%) in a controllable manner. With the three-dimensional micro/nano porous structure, switchable wettability and intrinsic environmentally friendliness, the pH responsive cellulosic sponges developed here hold great potential in controllable oil-water separation and oily wastewater purification.

Effect of Germination on Nutritional Composition and Functional Properties of Fenugreek (Trigonellafoenum-graecum Linn) Seed Flour

This study evaluated the effect of germination on the chemical composition and functional properties of fenugreek seed flour. The study was conducted at Addis Ababa Institute of Technology in Food Engineering laboratory. Fenugreek seed was germinated for 0, 24, 48 and 72 hrs. Germinated fenugreek flour had higher crude protein 29.89% in fenugreek flour germinated for 72 hrs followed by 29.36% in fenugreek flour germinated for 48 hrs and 27.42% in raw fenugreek flour. The crude fiber ranged from 11.349 to 14.70%. But as the time of germination increased the crude fiber content slightly decreased. Fenugreek flour germinated for 48 hrs proved to be more beneficial in most mineral content than the rest of the germination periods (p<0.05). Germinated fenugreek flour for 72 hrs had significantly lower contents of anti-nutritional factors. The phytate content decreased significantly (p<0.05) from 64.22 to 18.99 with 53.96% reduction. The study showed that fenugreek flour germinated for 72h proved to be the best for highest nutrient content. The reduction of bulk density further increased as germination time increased. The control fenugreek flour have higher amount of water absorption capacity (401.86%). On germination the water absorption capacity decreased to 250.07, 248.13, and 245.15% at 24, 48, 72 hrs germination, respectively. The processed fenugreek flour had a higher oil absorption capacity in the range of 346.13-398.40 ml/g, which was significantly (p<0.05) higher than that of control flour. Therefore, the use of processed fenugreek seed flour can be exploited in functional foods as well as a therapeutic agent on a regular basis.

Study on the sorption capacity of the adsorbent based on polyurethane and chitin to remove oil spills

Nowadays, oil and its derivatives were considered one of the major energies and they also have been one of the main sources of environmental pollution, especially for water pollution. The tendency in this time of researchers was to find new adsorption, that has high sorption capacity, economical and easy production. By accordance with the present trend, in this study, chitin was used with the dose up to 50% as a filler in the composition of adsorbents basic on polyurethane foam (PUF). The effect of the size (small size: 1-3 mm and large size: 5-10 mm) and the dose (10, 20 and 50%) of filler in the foaming composition to technological parameters of the collected adsorbent, as well as to its absorption capacity were investigated. The results showed that the adsorbents filling with a lower dose of chitin (10 and 20%) were better foaming than the one containing a higher dose of filler. At the same time, the adsorbents containing small chitin also formed the foam better than one filling large size. For 2 types of PUF, the adsorbent from elastic PUF has higher sorption capacity than the semi-elastic adsorbent with the same dose of the filler. For the results of sorption effectivity of the adsorbents presented that the adsorbent with the small size of filler observed greater the absorbency than the one with large size. In which, the elastic adsorbent containing 10% chitin with small size has the highest oil absorption capacity, which reached 13.13 g/g. To compare the sorption capacity of the adsorbent between relation to oil and water, it shown that its oil capacity is significantly higher than the sorption capacity of water.

Facile fabrication of wood-inspired aerogel from chitosan for efficient removal of oil from Water

Aerogels that derived from biomass have long been attractive as absorbents for oil clean-up. However, it remains a significant challenge to prepare fully bio-based oil absorbents that combines fast oil/water separation capacity, adequate mechanical robustness and easy recyclability through green and facile strategy. Inspired by the fascinating structure of wood, here we report a highly porous and anisotropic bio-based aerogel by taking advantage of the directional freezing technology, followed by a freeze-drying and silylation process. Due to the directional growth of ice crystals along the vertical direction, a special spring like morphology was obtained, which is mainly composed of well aligned low-tortuosity channels that seamlessly connected to bottom layer. Superior mechanical properties that allow for high mechanical compressing and fast elastic recovery were consequently acquired. Moreover, the silylated CS aerogel displays a rather high oil absorption capacity of 63 g g−1, together with excellent recyclability via simple hand squeezing. By virtue of such hierarchical morphology, a device that could continuously separate oil from water was successfully designed. Given the natural abundance of raw material as well as the easy processability, this work would lay solid foundation for further fabrication of bio-based oil absorbents toward low-cost, high-performance and large-scale commodities.

Fabrication of Superhydrophobic Magnetic Sawdust as Effective and Recyclable Oil Sorbents.

In this paper, a novel superhydrophobic magnetic sawdust (SMSD) was fabricated as an oil sorbent. The SMSD was functionalized with Fe3O4 nanoparticles using melamine formaldehyde resin (MFR) as a coupling agent and subsequently hydrophobically-treated with hexadecyltrimethoxysilane (HDTMS). The SMSD showed excellent superhydrophobicity with the water contact angle of 155.3 ± 0.9°. Meanwhile it had remarkable environmental durability, long-term stability, and mechanical durable properties. Taking advantage of its magnetic characteristics, the SMSD could be easily controlled to absorb oil to separate oil–water mixtures with high oil absorption capacity and good reusability. Moreover, the emulsion was successfully separated by SMSD, including water-in-oil and oil-in-water emulsions. This study developed an effective oil absorbent, which was low cost and environmentally-friendly.

A Scalable Chemical Approach for the Synthesis of a Highly Tolerant and Efficient Oil Absorbent.

In the past, bio-inspired extreme water repellent property has been strategically embedded on commercially available sponges for developing selective oil absorbents. However, most of the reported materials lack physical and chemical durability, limiting their applicability at practically harsh settings. Herein, a stable dispersion of polymeric nanocomplexes was exploited to achieve a chemically reactive coating on the highly compressible melamine foam. A superhydrophobic melamine foam (SMF) was achieved after post-covalent modification of the reactive coating through 1,4-conjugate addition reaction at ambient conditions. The durability of the embedded extreme water repellent property in the as-modified melamine foam has been elaborately demonstrated through exposing it to severe physical manipulations, chemically harsh aqueous media including pH 1, pH 12, surfactant contaminated water, river water, seawater and prolonged UV irradiation. Thus, the highly tolerant SMF was utilized as an efficient oil absorbent wherein oils of varying densities could be selectively recovered from an oil/water interface with high (e.g., 137 g g-1 for chloroform and 83 g g-1 for diesel) oil absorption capacity. Moreover, the selective oil absorption capacity of the as-synthesized material remained unaffected at practically relevant severe chemical and physical settings, and the extreme water repellency of the material remained unaltered even after repetitive (at least 50 cycles) use for oil/water separation.

Peat moss: A hyper-sorbent for oil spill cleanup - a review

Peat moss, a well-known hyper-sorbent is now gaining attention for its utilization in oil-spill cleanup techniques because of its cost-effectiveness, biodegradability and relatively high oil absorption capacities. This review mainly emphasis on the characteristic features of the peat moss such as high porosity and large surface area which make it an efficient natural sorbent material for cleaning up oil spills. There are several products which have been developed from the peat moss and are commercially available in the market for oil spill cleanup.

Superhydrophobic and Superoleophilic Fiber from Waste Bamboo Processing Residues for Oil/water Selective Separation

Biomass materials have attracted increasing attention as oil absorbents for oil/water separation duo to their renewability, biocompatibility and biodegradability. However, many separation materials preparations are either rather time consuming or have suffered from the need of harsh conditions. In the present study, bamboo fiber was successfully modified to acquire simultaneously super-hydrophobic and super-oleophilic properties by just two steps: delignification and chemical vapor deposition (CVD). The morphology and properties of MTMS-bamboo fiber were characterized by SEM, FT-IR, XPS and the oil/water contact angles. Moreover, the durability, recyclability and the practical application of selective separation were studied. The analysis results disclosed that the special surface wetting properties of MTMS-bamboo fiber resulted from the silanization of the bamboo fiber surface, notably, from its water contact angle being 153° and oil contact angle 0°. The fiber so prepared exhibited excellent durability in several kinds of chemical solutions. The absorbed oil can be recovered by simple mechanical squeezing and the bamboo fiber maintained a high oil absorption capacity after multiple squeezing-absorption cycles. The modified fiber acted as an absorbent for hot water oil/water separation and demonstrated also a high oil separation capacity. The continuous separation efficiency of the MTMS-bamboo fiber was investigated.

Superhydrophobic nanoporous polymer-modified sponge for in situ oil/water separation

Developing an efficient and environmentally friendly strategy for oil–water separation is extremely important for practical application. In this study, a superhydrophobic and superoleophilic melamine sponge loaded with cross-linked and swellable polydivinylbenzene was successfully fabricated by a facile and effective one-step impregnation–curing method with adhesion of polydimethylsiloxane. The prepared sponge not only exhibited high oil absorption capacity, but it also enabled rapid oil collection in situ, which could be extended to practical application. Moreover, the modified superhydrophobic sponge showed excellent mechanical resistance and chemical stability. The surface morphology and chemical composition were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. This material has great development potential for large-scale oil spill clean-up and chemical spill accidents.

A hydrophobic/oleophilic chitosan-based sorbent: Toward an effective oil spill remediation technology

Shellfish chitosan as one of the most abundant biopolymers on earth was converted to an ultralow-density hydrophobic/oleophilic sorbent aerogel via a new facile synthesis strategy. The aerogel demonstrated properties of very high oil absorption and retention capacities, excellent oil-water selectivity, and recycling ability. Equilibrium absorbencies of 41.7 and 48.3 g g−1 were achieved for two light crude oils with densities of 0.823 and 0.942 g cm−3 at ambient temperature, exceeding the absorption capacities of many synthetic oil sorbents reported so far. The oil absorption kinetics studies performed for both crude oils via pseudo first- and pseudo second-order models revealed that the latter model could better describe the experimental data. The wicking process as well as the absorption dynamics was investigated and described via Lucas-Washburn’s model and the effects of all important factors on the sorption process were pinpointed and discussed. By comparing the data acquired through Gravimetric Absorbency Testing (GAT) experiments with the predictions made by Lucas-Washburn’s model, it was inferred that the sorption process affected largely by two parameters i.e., the capillary force and the structural swelling. While the network swelling can improve the oil retention ability of sorbent, it could significantly lower the absorption rate, particularly for viscose organic liquids.

Preparation of biomass carbon/polyurethane foams for selective oil/water absorption

Although the preparation of polyurethane foam (PUF) composites for oil absorption have attracted increasing research attention, the preparation process of PUF composites are still a thorny problem due to the nonrenewable raw materials. Proposed herein is an environmentally friendly method to prepare the biomass carbon/PUF composites. In this proposal, the biomass carbon with superhydrophobicity was prepared by using the cellulose of bamboo as precursors. Then, the biomass carbon/PUF composites were synthesized using one step foaming technology using the biomass carbon as modifier. This facile synthesis technique has the advantages of scalable fabrication of porous PUF composite for versatile water–oil separation. The PUF composites are mainly composed of hollow microspheres with holes on their surfaces. The PUF composite show very high efficiency in oil separation and quickly absorb edible oil from the glass surface and heavy oils under water. The resulting PUF composites exhibited high oil absorption capacities in the range from 8.59 to 37.10 times of their own weight for various organic solvents. Importantly, recovery oils absorption for PUF composites was obtained for 5 consecutive cycles without a significant decrease in the oil absorption properties. This study suggests potential environmental advantage in using biomass materials in improving the oil absorption properties of oil-absorbing resin for recovering oils from oily wastewater.

Facile fabrication of superhydrophobic polyurethane sponge towards oil-water separation with exceptional flame-retardant performance

In this article, a superhydrophobic polyurethane (PU) sponge with exceptional flame-retardant property, was fabricated by coating polydopamine (PDA) through one-step polymerization and surface treatment with hexamethyl disilazane (HMDS). Specifically, dopamine was polymerized in an alkaline solution to generate PDA nano-aggregates as hierarchically rough structure on PU sponge skeleton. After the sponge was further treated with HMDS, the obtained PU-PDA-HMDS sponge surface was transformed from hydrophilic into superhydrophobic with a water contact angle about 153°. The Fourier-transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurement results demonstrated that the PDA nano-aggregates layer was successfully coated onto PU skeleton, and HMDS molecules were grafted onto PDA nano-aggregates layer by forming silicyl groups on sponge. When the superhydrophobic PU-PDA-HMDS sponge was used towards oil-water separation, it exhibited high oil absorption capacity and stable absorption performance even after cyclic absorption-desorption process. Meanwhile, the sponge exhibited good elastic property and recovery ability under compression test. Furthermore, the thermal stability and flame-retardant property of the sponges were measured, and the results showed the resulting PU-PDA-HMDS sponge exhibited superior thermal stability and flame-retardant property to the pristine PU or PU coated with PDA alone. Even encountering a flame attack, the PU-PDA-HMDS sponge would be self-extinguished and remained its structure integrity due to the formation of silica-hybrid char residue layer during combustion process. The formation process of silica-hybrid char residue layer and what role it exerted on enhancing flame-retardant property were proposed and discussed. Therefore, this work not only provided a simple strategy for fabricating the superhydrophobic porous composites for oil-water separation, but also opened a door to protect the combustible porous composites from fire with exceptional flame-retardant performance.

Ultralight, robustly compressible and super-hydrophobic biomass-decorated carbonaceous melamine sponge for oil/water separation with high oil retention

Abstract To address the high-cost hydrophobic modification of three dimensional commercial sponges, here natural cellulose nanocrystcals (CNCs) were employed to prepare ultralight, robustly compressible and super-hydrophobic biomass-decorated carbonaceous melamine (BCM) sponges by a facile immersing-adsorption-pyrolysis method. Due to the introduction of CNCs, originally pyrolyzed melamine sponges with super-hydrophilicity were changed into the ultralight BCM sponge (7.3 mg cm−3) with super-hydrophobicity and excellent mechanical property. Being applied to the oil/water separation, BCM sponges showed good oil selectivity, high oil absorption capacities up to 201 g/g or 94% of its own volume, and even high oil retention. Simultaneously, the excellent compressibility and good flame retardancy of BCM sponges ensured that the absorbed oil can be recovered by combustion and squeezing methods. Based on super-hydrophobicity, good flexibility and high porosity of BCM sponges, the spilled oils could be also consecutively collected from water surface to collecting vessels by our designed oil collection apparatus.

Characterization of cocoyam (Xanthosoma spp.) corm flour from the Nazareno cultivar

Abstract The present study assessed the physical, chemical, functional, and microbiological properties of cocoyam (Xanthosoma spp.) corm flour made from the Nazareno cultivar. The flour was initially submitted to a water-soaking process in order to reduce its high oxalate content. The soaked flour showed a high dietary fiber content (15.4% insoluble and 2.8% soluble fiber), and can be considered essentially an energy-rich food given its high starch content (60.5%), of which 85.04% was analyzed as amylopectin; it also showed a high potassium content (19.09 mg/g). The anti-nutritional component analysis showed low levels of oxalate (5.55 mg/g), saponins (0.10%) and tannins (0.07%), while phytates were not detected. The flour had a high water and oil absorption capacity (9 - 11 g/g at 90 and 100 °C; 1.2 g/g) and it gelatinized at between 81.81 - 89.58 °C. It was also microbiologically stable after storage for 9 months at room temperature. Development of a multipurpose flour from cocoyam corm could provide a value-added option for the local food industry.

Study oil/water separation property of PE foam and its improvement by in situ synthesis of zeolitic–imidazolate framework (ZIF‐8)

Herein, the oil/water separation property of four polyethylene (PE) foams with two different volume expansion ratios including 15 and 30 times was studied. We found that the PE‐30‐1 foam was the best absorbent materials among these four samples, which was also superior to the commercially available products. It demonstrated high oil absorption capacities, as well as high oil/water selectivity, which was due to its small average pore size and high porosity. In addition, this work also reports two rapid and straightforward methods to fabricate PE‐30‐1‐ZIF‐8 composite with enhanced compressive property, an encouraging absorption capacity for different organic solvents, reaching 59 times of its own weight for chloroform, as well as increased oil–water selectivity of the system. Comparing with the PE foam, the organic solvent absorption capacities for PE‐ZIF‐8‐sono composite foams were improved by 6.4%, 29%, 9.1%, and 12% for chloroform, acetone, toluene and oleic acid, respectively, while the corresponding improvement for PE‐ZIF‐8‐Me(OH) was about 7.5%, 28%, 14%, and 15%, respectively. These PE‐ZIF‐8 foams could reach the requirement for oil spill cleanup, suggesting its great potential for this type of application. POLYM. ENG. SCI., 59:1354–1361 2019. © 2019 Society of Plastics Engineers

Fabrication of a robust superhydrophobic polyurethane sponge for oil–water separation

ABSTRACTIn this study, a robust superhydrophobic ZnO microparticle coating was applied to the surface of a polyurethane sponge through a simple solvothermal and chemical vapour deposition method. The thickly hierarchical ZnO microparticle and the long chain alkyl of hexadecyltrimethoxysilane make the sponge exhibit excellent superhydrophobicity and superoleophilicity. By combining excellent superwetting characteristics and a larger surface area, the resulting sponges exhibited high oil-absorption capacity and selectivity for oil–water separation. The durability of the sponge was investigated by two methods, one is ultrasonication in acetone and hexane, the other is anti-resistance in acid and alkali solution. Reusability was tested by repeated absorption–desorption processes. Owing to the good adhesion between the coating and the sponge, the as-prepared sponge shows high durability and reusability. Moreover, the sponge can degrade toxic methylene blue under ultraviolet light irradiation. Therefore, this paper offers a simple and low-cost strategy for the fabrication of absorption materials.

Two-dimensional membrane and three-dimensional bulk aerogel materials via top-down wood nanotechnology for multibehavioral and reusable oil/water separation

Traditional oil/water separation materials can be divided into two types on the basis of their separation behavior: filtration materials (e.g., meshes, textiles, membranes, etc.) and absorption materials (e.g., sponges, foams, and aerogels). Both types of materials have advantages and disadvantages. Combining the filtration and absorption functions into one and the same material for oil/water separation applications presents a challenge. Prompted by the highly oriented porous structures and anisotropic architectures of wood and its hygro-responsive characteristic, two-dimensional (2D) membrane and three-dimensional (3D) bulk aerogel materials with water-responsive shape memory function, anisotropy, robustness, and superhydrophobicity are prepared using top-down wood nanotechnology for multibehavioral (absorption and filtration) and reusable oil/water separation. Wood aerogel is obtained by partially removing hemicellulose and lignin. Further, it is superhydrophobically treated using a polydimethylsiloxane (PDMS)/curing agent system. As-prepared wood aerogel/PDMS bulk materials possess high oil absorption capacity (about 20 g/g) and can be reused because of their fast water-responsive shape memory function. The prepared wood aerogel/PDMS membrane materials can efficiently separate oil/water mixtures with high separation efficiency (99.5%) and flux (around 2.25 × 104 L/m2·h) by only the driving force of gravity. Top-down wood nanotechnology is low-cost, facile, scalable, green, and efficient, exhibiting potential for application in multibehavioral oil/water separation and ability to handle industrial oily wastewater and oil spillage accidents.

Superhydrophobic sponge containing silicone oil-modified layered double hydroxide sheets for rapid oil-water separations

The demand for superhydrophobic sponges for fast oil-water separations is growing. Herein, a novel superhydrophobic sponge was developed using a facile and scalable synthetic procedure. Briefly, layered double hydroxide (LDH) sheets were first modified with polymethylhydrogen silicone oil (PMHS) to give superhydrophobic LDH sheets (SHP-LDH). Subsequently, the SHP-LDH sheets were immobilized at different loadings on a polyurethane sponge using a silane coupling agent (KH-550). A SHP-LDH-containing sponge (SHP-LDH loading of 25 wt.%) demonstrated outstanding oil-water separation performance, which can be attributed to its super-lipophilic character, high oil absorption capacity, good oil storage properties and ease-of-recovery following oil absorption. In addition, the superhydrophobic sponge also displayed excellent flame retardancy. On account of the low cost and readily available of the raw materials used in its fabrication, the simplicity of its fabrication and outstanding performance, the superhydrophobic sponge is expected to find widespread use in oil-water separations and other applications.

Flower-like hollow MoS2 microspheres/acrylic resin composites for enhanced oil contaminants removal from water

ABSTRACTIn this paper, novel flower-like hollow MoS2 microspheres (FHMs) were synthesized by a hydrothermal method using MF microspheres as template. The FHMs were hydrophobically modified and utilized as porous fillers to fabricate FHMs/acrylic resin composites through suspension polymerization. The oil-absorption tests revealed that the composite with 4 wt% FHMs had a high oil-absorption capacity, which might be due to the synergistic absorption effect of organic and inorganic components. Their high absorption capacity, rapid absorption rate, and excellent reusability make them attractive options as absorbents for practical oil/water separation.