Oil sorption and retention capacities of thermally-bonded hybrid nonwovens prepared from cotton, kapok, milkweed and polypropylene fibers

3D Oleophilic Sorbent Films Based on Recycled Low-Density Polyethylene

Recycling low-end, one-time-use plastics-such as low-density polyethylene (LDPE)-is of paramount importance to combat plastic pollution and promote sustainability in the modern green economy. This study valorizes LDPE waste by transforming it into 3D oleophilic swellable thin films through a process involving dissolution, phase separation, and extraction. These films are subsequently layered using a customized polypropylene (PP) based nonwoven fabric separator and securely sealed in a zigzag pattern. The zigzag-shaped seal enhances the adhesion of pollutants to the sorbent by providing wire curvatures that increase retention time and uptake capacity. As a result, the sorbent exhibits impressive oil uptake capacities, with immediate and equilibrium values of 120 g/g and 85 g/g, respectively. Notably, the as-prepared sorbent demonstrates low water retention and high selectivity for oil, outperforming commercially available oil sorbents. The unique design involving a 3D-film structure, superposed films, and a zigzag-shaped seal offers a sustainable and value-added solution to the issues of LDPE waste and oil spills on water surfaces.

Enhanced oil-water emulsion separation through coalescence filtration utilizing milkweed fiber: a sustainable paradigm

Over the past few years, the environment and public safety have suffered due to the detrimental effects of oily industrial effluents. Natural fibers have gained popularity for their affordability, reusability, and effectiveness in separating oil from oily wastewater. Milkweed fibers were characterized using FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and contact angle techniques. With four porosities (0.90, 0.92, 0.95, and 0.98), deep bed coalescence filters were built at three different filter bed heights (10 mm, 20 mm, and 30 mm). Using milkweed coalescence filtering technology, a novel oil separation method is described along with a method to calculate oil film thickness following emulsified oily water saturation. By combining a bed height of 30 mm and a porosity of 0.98, a maximum oil separation of 99.73% and an optimized D50 droplet ratio were achieved. Throughout a prolonged operational period lasting 250 min, the filter bed, possessing a depth of 30 mm and a porosity of 98%, exhibited no discernible fouling indications. Following five cycles, the milkweed filter bed measuring 30 mm in depth and featuring a porosity of 98% displayed an impressive oil separation efficiency of 91.5%. This study found that using a milkweed deep bed filter, coalescence filtering effectively removes oil from oily effluent. Furthermore, milkweed is a natural and biodegradable fiber that is easy to dispose of after use and does not harm the environment.

Kapok fiber-supported liquid extraction for convenient oil samples preparations: A feasibility and proof-of-concept study

In this study, a novel kapok fiber-supported liquid extraction (KF-SLE) method was developed for conveniently extracting analytes from oil samples. Natural kapok fiber without any pretreatment was directly used as an oil support medium. The extraction device was conveniently constructed by directly packing some kapok fibers into a syringe tube. Due to the fibrous property of the kapok fiber, no filter plate was needed. The cost of a KF-SLE device was as low as 0.5 CNY. The KF-SLE process was conveniently conducted using a simple three-step protocol: (1) the oil sample without any pretreatment including dilution was added directedly; (2) then, the oil-immiscible extractant was added; (3) after waiting a certain time for static extraction, the extractant was eluted out by pressing the kapok fibers with the syringe plunger. The extractant could be directly transferred for subsequent instrumental detection. For the feasibility and proof-of-concept study, the method was applied to quantify four synthetic flavor chemicals in edible oils. Satisfied quantification results were obtained with the correlation coefficient (R²) being greater than 0.996, the relative recoveries ranging from 92.90% to 107.53% and intra- and inter-day RSDs being less than 7.56%. All in all, for the first time, the SLE technique was expanded to process oil samples and the method has the characteristics of low cost, environmental friendliness, high sample processing throughput and ease of automation, offering a promising approach for edible oil sample preparations.

A critical review in electrocoagulation technology applied for oil removal in industrial wastewater

EC process, which stands for Electrocoagulation, is considered a widespread wastewater remediation method that is investigated widely for an extensive variety of wastewater resources, based on its flexibility, easy setup, eco-friendly nature, and low footprint. The critical operative factors in the EC process and the crucial relation between EC and the typical chemical coagulation approach had been thoroughly evaluated because they are the main variables that govern the process of contaminant elimination. As a result, the EC process requires further investigations for scale-up simulations in the manufacturing scopes and optimization of operational parameters. Furthermore, the current paper studies the novel integrated separation methods with the combined EC process and also their limitations for improved wastewater remediation process for cleaner wastes, recycling processes, and water recovery. In this paper, the EC enhancement processes toward oil removal from wastewater have been reviewed which includes a concise representation of the source and features of oily wastewater. Additionally, the advanced remediation methods for oil-contained wastewater and the electrocoagulation process are presented. This review summarized the present utilization of electrocoagulation to eliminate oil from wastewater. Besides the process optimization and modeling investigations, the parameters that significantly affect the electrocoagulation remediation effectiveness are evaluated. Finally, the cutting-edge and sophisticated methods of electrocoagulation process for oil removal are presented.

Combined Treatment (Alkali + Thermal) of Calotropis procera Fiber for Removal of Petroleum Hydrocarbons in Cases of Oil Spill

The objective of this study was to evaluate the Calotropis procera fiber treated with NaOH combined with heat treatment as sorbent material for removal of petroleum and derivatives in cases of oil spill. The effects of oil viscosity, fiber/oil contact time, and the type of sorption system (oil and oil/water) were evaluated by experimental planning. The fiber obtained was characterized by Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (SEM-FEG), thermogravimetric analysis (TG/DTG), contact angle, and wettability. The fiber treated by combining NaOH and heat treatment (CPNaOHT) exhibited a large structure with an internal diameter of 42.99 ± 3.98 μm, roughness, and hydrophobicity on the surface with a contact angle of 101 ± 2°. The sorption capacity of oil ranged from 190.32 g/g to 98.9 g/g. After five cycles of recycling, the fiber still maintains about 70% of its initial sorption capacity and presented low liquid desorption (0.25 g). In this way, it can be used as an efficient sorbent to clean up spills of oil and oil products.

Using polypropylene needle punch nonwoven sorbents as the interceptor for oil in static and dynamic water experiments

This work was to determine the impact of pore size and thickness of sorbents besides the influence of oil properties on the performance of sorbents used as an interceptor barrier for oils in Static and dynamic water experiments. polypropylene needle punch sorbents were used. SEM test showed the porous structure of sorbents. Oil sorption test investigated that with sorbents had same thickness N1 absorbed oil 8.89 g/g of soybean oil and 7.15 g/g of motor oil. Meanwhile, sorbents with the same pore size, N6 absorbed oil 6.11 g/g of soybean oil and 5.13 g/g of motor oil. All sorbents showed a retention rate of over 75% after 24 h of dripping. Dynamic oil spreading revealed that smaller pore size and higher thickness exhibited higher height wicking. The static performance experiment showed motor oil and soybean oil started to leak at 38 and 32 min for N1, then prolonged with reducing pore size with intercepting efficiency around 70% after 600 min for motor oil and 540 min for soybean oil. In comparison, The motor oil and soybean oil started to leak at 49 and 40 min for N4 and then prolonged with increased thickness with intercepting efficiency around 70% after 480 min for motor oil and 360 min for soybean oil. Under the dynamic experiment, oils spilled quicker with initial leakage of sorbents N3 and N6 at rate flow 55.65 ml/s for motor oil and soybean oil were (41 min, 36 min) and (50 min, 41 min) while intercepting efficiency was (99%, 98.40%) and (99.33%, 98.40%).

Evaluation of polypropylene melt blown nonwoven as the interceptor for oil

The present study aims to evaluate PolyPropylene meltblown nonwoven sorbents as interceptor barrier for oils (motor oil - soybean oil). Experiments carried out in oil-water bath under both static and dynamic conditions. Among tested sorbents, sorbent P3 with porosity 85.93% show high sorption capacity. In which it achieves the highest absorption values 13.13 and 11.91 g/g for motor oil and soybean oil, respectively. Followed by sorbent P2 with porosity 88.30% and sorbent P1 with porosity 91.46%. Besides, results show that sorbent P1 registered the highest oil retention rate followed by sorbent P2 and sorbent P3, respectively. The SEM observation indicates that pore size and porosity play a significant role in deciding oil sorption and retention. At static condition, oil interception performance was evaluated. oil begins to break through the interceptor barrier in sorbent P3 at 29 min for motor oil with intercepting efficiency 98.00% and at 22 min for soybean oil with intercepting efficiency 96.57%. As the thickness of the interceptor barrier increases the time for initial leakage prolonged. After oil leakage, steady oil spillage took place. The typical oil leaking rate was divided into three phases in which oils leaks sharply increased rate, decrease rate and finally gently. Under dynamic conditions, quickly oil leakage happens compared to a static condition. With water flow rate 166 ml/s, the initial oil leakage for sorbent P3 shortens at 16 min for motor oil and 7 min for soybean oil, with Interception efficiencies at 93.42% and 90.00%, respectively.

Sorbent-based devices for the removal of spilled oil from water: a review

Always, oil spills do cause serious and dire consequences for the environment, nature, and society that it consumes much time and socio-economic resources to overcome such consequences. Oil spills, hence, posed a big challenge in searching the advanced technologies and devices to recover spilled oil rapidly and efficiently. Indeed, sorbents have been found to play an extremely critical role in the spilled-oil remediation processes. Recently, a large number of various advanced sorbents and sorbent-based oil-collecting devices/technologies have been developed to enhance the oil-recovery capacity. Therefore, it is necessary to have a comprehensive assessment of the application of sorbent-based oil-collecting devices/technologies in recovering spilled oil. Due to this reason, this paper aims to provide a comprehensive review of the advanced technologies of the combination of sorbents and oil-collecting devices in the oil cleanup strategies. Two main oil-collecting devices such as booms and skimmers that could conjunct with sorbents were critically evaluated on the basis of the applicability and technological features, indicating that the capacity of oil spill recovery could achieve 90%. Moreover, oil-storage and oil-collecting devices were also completely mentioned. Last but not least, technical directions, concerns over the application of sorbents in oil recovery, and existing challenges relating to storage, transport, and disposal of used sorbents were discussed in detail. In the future, the automatic process of spilled oil recovery with the conjunction between advanced devices and environmentally friendly high-efficiency sorbents should be further investigated to minimize the environmental impacts, reduce the cost, as well as maximize the collected oil spill.

Carbon Nanotubes and Polydopamine Modified Poly(dimethylsiloxane) Sponges for Efficient Oil-Water Separation

In this paper, effective separation of oil from both immiscible oil-water mixtures and oil-in-water (O/W) emulsions are achieved by using poly(dimethylsiloxane)-based (PDMS-based) composite sponges. A modified hard template method using citric acid monohydrate as the hard template and dissolving it in ethanol is proposed to prepare PDMS sponge composited with carbon nanotubes (CNTs) both in the matrix and the surface. The introduction of CNTs endows the composite sponge with enhanced comprehensive properties including hydrophobicity, absorption capacity, and mechanical strength than the pure PDMS. We demonstrate the successful application of CNT-PDMS composite in efficient removal of oil from immiscible oil-water mixtures within not only a bath absorption, but also continuous separation for both static and turbulent flow conditions. This notable characteristic of the CNT-PDMS sponge enables it as a potential candidate for large-scale industrial oil-water separation. Furthermore, a polydopamine (PDA) modified CNT-PDMS is developed here, which firstly realizes the separation of O/W emulsion without continuous squeezing of the sponge. The combined superhydrophilic and superoleophilic property of PDA/CNT-PDMS is assumed to be critical in the spontaneously demulsification process.

Switchgrass as oil and water-spill sorbent: Effect of particle size, torrefaction, and regeneration methods

Switchgrass, both raw and torrefied, was tested for its ability to sorb water or oil. The cyclic performance was also examined, utilizing centrifugal extraction as the regeneration method. Both oil and water sorption capacity increase with the decreasing size of raw switchgrass particles. Results indicate that 3 mm raw switchgrass can sorb water at a capacity of about 6 times its mass and can sorb oil at a capacity of about 3 times its mass, which makes it a suitable biodegradable sorbent. Torrefaction at 220 °C for 30 min reduces water sorption capacity by an average of 55% but does not have a statistically significant impact on oil sorption. Sorption of liquid is negatively correlated to particle size. Centrifugation is able to partially desorb either liquid from the sorbent, and subsequent sorption cycles do not display lower sorption capacity than the first cycle when calculated on a dry mass basis.

One-pot fabrication of reusable hybrid sorbents for quick removal of oils from wastewater

The leaking of harmful organic liquids into water resources has had hazardous impacts on living organisms. Herein, we demonstrated the fabrication of hybrid sorbents using s-PPG and organosilane cross-linker. The final product exhibited high, quick absorption capacity, great reusability and excellent oil separation performance from wastewater. They also selectively absorb different oils from the bottom and surface of water without any capacity change, even in harsh conditions like wavy and sub-zero water environment. Experimental results demonstrated that the obtained sorbents are efficient to successfully remove oil from water surface, even at harsh conditions, and float on the water surface before and after oil sorption without any capacity loss and structural change. Simple preparation by avoiding time consuming multistep process, initiator, solvent, activator free reaction medium, high and selective sorption characteristics and great reusability could make these sorbents a promising candidate for the cleaning of water from harmful organic liquids, by absorbing them.

Chemical Constituents and Uses of Calotropis Procera and Calotropis Gigantea – A Review (Part I – The Plants as Material and Energy Resources)

The traditional and current use of Calotropis procera and C. gigantea, two soft-wooded, xerophytic shrubs of the family Apocynaceae, are reviewed against the background of the plants' chemical constituents and their biological properties. The focus is on the usage of the plants for building materials, natural pesticides, animal feed and bioremediative purposes.

Evaluation of Thermally Treated Calotropis Procera Fiber for the Removal of Crude Oil on the Water Surface

Biosorbents have been highlighted as an alternative method for the removal of contaminants from spills or leaks of oil and its derivatives, since they are biodegradable, are highly available, low-cost, and have a good sorption capacity. This research investigated the sorption capacity of Calotropis procera fiber in natura (CP) and thermally treated (150 °C and 200 °C) for crude oil removal and recovery. The oil sorption tests were carried out in a dry and water (layer) static systems. The assays revealed that CP fiber has excellent hydrophobic-oil properties and good crude oil sorption capacity, about 75 times its own weight (76.32 g/g). The results of the treated fibers, CPT150 and CPT200, showed oil sorption capacities (in 24 h) higher than CP, between 94.31–103.37 g/g and 124.60–180.95 g/g, respectively. The results from sample CPT200 showed that it can be an excellent biosorbent for the removal of crude oil and other derivatives due to its high hydrophobicity, great reuse/resorption capacity, and ability to retain oil within the fiber lumens. Thus, it can be applied in the recovery, cleaning, and removal of petroleum products and its derivatives from spills and leaks in the future.

New composites based on starch/Ecoflex®/biomass wastes: Mechanical, thermal, morphological and antimicrobial properties

Different biomass wastes were successfully blended with starch and Ecoflex® viz. poly(butylene adipate-co-terephthalate), without glycerol addition, to obtain biocomposite materials. The mechanical properties, as well as thermal and surface properties, of the developed composites were evaluated. It was found that the tensile strength and impact strength improved upon the addition of lignin, while the water uptake capacity decreased. The presence of 5% lignin determined an increase in tensile strength of 125.4% for materials comprising celery (CEL), 109.6% for materials comprising poplar seed hair fibers (PSH), 92.9% for materials comprising pomace (POM) and 127.7% for materials comprising Asclepias syriaca fibers (ASF), compared with a reference sample. The addition of lignin to all the formulations conferred good antimicrobial properties against different microorganisms, S. aureus and especially E. coli. The good mechanical properties, water resistance and antimicrobial activity against pathogens recommend these composites to be used in the manufacture of packaging materials.