A biological oil adsorption filter

Bio-Based Aerogels for the Removal of Heavy Metal Ions and Oils from Water: Novel Solutions for Environmental Remediation

Contamination of the aqueous environment caused by the presence of heavy metal ions and oils is a growing concern that must be addressed to reduce their detrimental impact on living organisms and safeguard the environment. Recent efficient and environmentally friendly remediation methods for the treatment of water are based on third-generation bioaerogels as emerging applications for the removal of heavy metal ions and oils from aqueous systems. The peculiarities of these materials are various, considering their high specific surface area and low density, together with a highly porous three-dimensional structure and tunable surface chemistry. This review illustrates the recent progress in aerogels developed from cellulose and chitosan as emerging materials in water treatment. The potential of aerogel-based adsorbents for wastewater treatment is reported in terms of adsorption efficacy and reusability. Despite various gaps affecting the manufacturing and production costs of aerogels that actually limit their successful implementation in the market, the research progress suggests that bio-based aerogels are ready to be used in water-treatment applications in the near future.

Environmental friendly Polyacrylonitrile nanofiber mats encapsulated and coated with green algae mediated Titanium oxide nanoparticles for efficient oil spill adsorption

Oil spill causes extreme environmental damage, from aquatic life to seabirds, disrupting the entire ecosystem. Herein, we have synthesized high scale, economical and bio-compatible, green algae mediated Titanium oxide (TiO₂) nanoparticles and Polyacrylonitrile (PAN) nanofiber mats. We have studied the effect of encapsulation and coating of TiO₂ nanoparticles over nanofiber mats for highly efficient oil spill adsorption. TiO₂ encapsulated and coated PAN (TECP) nanofibers showed a maximum of 62.34 g g^-1 adsorption capacity of petroleum oil from the water surface. Moreover, the composite mats show maximum adsorption within 45 s for up to 5 repeated cycles. Further, it has been observed that the adsorption capacity has increased by increasing the weight of the composite nanofiber mats, which confirms its commercial applicability. Thus, this work provides rapid, large-scale, economical, bio-compatible, and highly effective adsorbents for oil spill cleaning and extraction over natural waterbodies.

A Novel Graphite-Based Sorbent for Oil Spill Cleanup

The performance of an innovative material based on expanded graphite, Grafysorber^® G+ (Directa Plus), has been tested through laboratory, tank, and confinement tests for oil removal in case of an oil spill and water treatment. In addition to the ability to retain oil, the possibility of reusing this material after regeneration via squeezing was also evaluated. As a comparison, the same experimental tests were conducted using polypropylene flakes (PP), the material currently most used to deal with spill accidents. Oils with different chemical and physical properties were used, namely kerosene, diesel, and crude oil. From the laboratory tests, the capacity of Grafysorber^® G+ to retain oil was found to be directly proportional to the viscosity of the latter, with adsorption values ranging from 76.8 g/g for diesel to 50.8 g/g for kerosene, confirming the potential of the innovative material compared to the PP. Cyclical use tests have confirmed certain reusability of the material, even if its adsorbent capacity decreases significantly after the first cycle and continues to decrease in subsequent cycles, but a less marked manner. Finally, some considerations based on the adsorption capacities were found to suggest that the adoption of the new material is also economically preferable, resulting in savings of 20 to 40% per kg of hydrocarbon treated.

Enhanced Oil Spill Remediation by Adsorption with Interlinked Multilayered Graphene

The performances of an innovative material based on graphene multilayers in a 3D structure similar to expanded graphite, Grafysorber^® G+ (Directa Plus), have been tested via in field applications on a real contaminated site. Several experimental tests were performed using Grafysorber^® inside adsorbent devices (booms and pillows) to treat waters polluted by oil. The experimental campaign was carried out with the aim of comparing the performances of Grafysorber^® with those of polypropylene (PP), which is the material used worldwide in case of water oil spill clean-up activities. The results achieved have confirmed a considerably higher selective adsorption capacity of Grafysorber^® compared to PP, and configure the new material as a promising alternative to standard materials in enhancing oil spill remediation by selective adsorption.

Cyclic filtration behavior of structured cattail fiber assembly for oils removal from wastewater

Structured cattail fiber assembly was reported as the filter for removing oils from runoff. The oil-wetted filter was recovered by rotational centrifugation and reused in the next filtration. The cyclic filtration behavior of the assembly was characterized by oil removal efficiency, oil sorption capacity, influence of packing density and number of filtration cycles. The efficiency of liquid removal and oil recovery from the centrifuged filter were also investigated. Cattail filters showed an excellent oil cyclic filtration performance which was found to have a close relationship with the inner structural characteristic of the fibers. The filters removed vegetable oil and diesel completely from runoff in the initial 40-90 min and 30-60 min in the first cycle, respectively, after which the oils broke through the filter's body and 29.4-71.4 L and 21.0-46.2 L of clean water were collected. The time of breakthrough was decreased with decreasing cattail's packing density. The wetted filters which absorbed up to 693.11 g (14.81 g/g) of vegetable oil and 497.02 g (10.62 g/g) of diesel took separately 7 min and 30 s to be recovered. Seventy-five to ninety percent of liquids were removed and 70-93% of oils were re-collected.

Esterified sago waste for engine oil removal in aqueous environment

Agro-waste from the bark of Metroxylon sagu (sago) was studied as a low cost and effective oil sorbent in dry and aqueous environments. Sorption study was conducted using untreated sago bark (SB) and esterified sago bark (ESB) in used engine oil. Characterization study showed that esterification has successfully improved the hydrophobicity, buoyancy, surface roughness and oil sorption capacity of ESB. Sorption study revealed that water uptake of SB is higher (30 min static: 2.46 g/g, dynamic: 2.67 g/g) compared with ESB (30 min static: 0.18 g/g, dynamic: 0.14 g/g). ESB, however, showed higher oil sorption capacity in aqueous environment (30 min static: 2.30 g/g, dynamic: 2.14) compared with SB (30 min static: 0 g/g, dynamic: 0 g/g). ESB has shown great poTENTial as effective oil sorbent in aqueous environment due to its high oil sorption capacity, low water uptake and high buoyancy.

Physicochemical and sorption characteristics of Malaysian Ceiba pentandra (L.) Gaertn. as a natural oil sorbent

Ceiba pentandra (L.) Gaertn (kapok) is a natural sorbent that exhibits excellent hydrophobic-oleophilic characteristics. The effect of packing density, the oil types and solvent treatment on the sorption characteristics of kapok was studied in a batch system. Oil sorption capacity, retention capacity, entrapment stability and kapok reusability were evaluated. Based on SEM and FTIR analyses, kapok fiber was shown to be a lignocellulosic material with hydrophobic waxy coating over the hollow structures. Higher packing density at 0.08 g/ml showed lower sorption capacity, but higher percentage of dynamic oil retention, with only 1% of oil drained out from the test cell. Kapok remained stable after fifteen cycles of reuse with only 30% of sorption capacity reduction. The oil entrapment stability at 0.08 g/ml packing was high with more than 90% of diesel and used engine oil retained after horizontal shaking. After 8h of chloroform and alkali treatment, 2.1% and 26.3% reduction in sorption capacity were observed, respectively, as compared to the raw kapok. The rigid hollow structure was reduced to flattened-like structure after alkali treatment, though no major structural difference was observed after chloroform treatment. Malaysian kapok has shown great potential as an effective natural oil sorbent, owing to high sorption and retention capacity, structural stability and high reusability.

Oil removal from water by fungal biomass: a factorial design analysis

A fractional factorial design analysis was conducted to screen the significant factors influencing removal of three emulsified oils from water, namely, standard mineral oil (SMO), canola oil (CO) and Bright-Edge 80 cutting oil using non-viable biomass of fungus Mucor rouxii rich with chitosan in its cell wall. Factors investigated were pH of the solution (3-9), temperature (5-30 degrees C), adsorbent dose (0.05-0.5 g), concentration of oil (50-350 mg/L) and rotational speed of the shaker (100-200 rpm). It was observed that pH of the solution was the most influencing parameter on the removal of all the three oils studied. Higher oil removal efficiencies (80-99%) were obtained at a pH of 3.0 by M. rouxii biomass for all the three oils studied. Temperature had an effect on SMO and Bright-Edge 80 removal while adsorbent dose was found to influence the removal of SMO. Average removals of SMO and Bright-Edge 80 were higher by 13% at a solution temperature of 30 degrees C compared to removals at 5 degrees C. Oil concentration had an effect on the removal of CO. The average removal of CO was found to be higher by approximately 15% at an initial oil concentration of 50mg/L than at 350 mg/L.

Removal of oil by walnut shell media

Studies were conducted to evaluate the oil sorption capacities of walnut shell media. Sorption capacity is the weight of oil picked up by unit weight of a sorbent. Initial oil pick-up by walnut shell media on pure oil and oil on aqueous medium was evaluated. Batch kinetic studies were conducted to evaluate the equilibrium time required by walnut shell media for sorbing oil. For pure oil medium, sorption capacities of 0.30g/g, 0.51g/g and 0.58g/g were obtained for standard mineral oil, vegetable oil and DoALL Bright-Edge oil, respectively. The results showed sorption capacities of 0.56g/g, 0.58g/g and 0.74g/g for standard mineral oil, vegetable oil and DoALL Bright-Edge oil, respectively, for oil on aqueous medium. It was found that sorbed oil could be recovered from walnut shell media by applying pressure. The study showed that walnut shell media can be used as a sorbent for oil removal.

Experimental investigation of various vegetable fibers as sorbent materials for oil spills

Oil spills are a global concern due to their environmental and economical impact. Various commercial systems have been developed to control these spills, including the use of fibers as sorbents. This research investigates the use of various vegetable fibers, namely mixed leaves residues, mixed sawdust, sisal (Agave sisalana), coir fiber (Cocos nucifera), sponge-gourd (Luffa cylindrica) and silk-floss as sorbent materials of crude oil. Sorption tests with crude oil were conducted in deionized and marine water media, with and without agitation. Water uptake by the fibers was investigated by tests in dry conditions and distillation of the impregnated sorbent. The silk-floss fiber showed a very high degree of hydrophobicity and oil sorption capacity of approximately 85goil/g sorbent (in 24hours). Specific gravity measurements and buoyancy tests were also used to evaluate the suitability of these fibers for the intended application.