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Converting green coconut waste into value-added products can be a way to increase the profit margin of coconut exploration companies. Due to its high lignin content in green coconut fiber (GCF), alkaline pretreatments have been prioritized so that investigations with ionic liquids, potential delignifying agents, are still scarce. In this sense, the present study evaluated pretreatments of GCF with choline chloride ([Ch][Cl]] to obtain pretreated biomass enriched in cellulose and high lignin content in the liquid phase. Adding sulfuric acid boosted lignin solubility in [Ch][Cl]-rich liquid phase. The increase in [Ch][Cl] concentration and the increase in incubation time favored the rise of crystallinity and cellulose content in the pretreated GCF. The condition with 75% (w/v) [Ch][Cl], 1% (w/w) sulfuric acid, and a time of 50 min promoted high GCF disorganization, leading to the best enzymatic digestibility result (22.61 g/L), and 71.21% of GCF lignin was accumulated in the liquid phase from pretreatment. The isolated lignin successfully treated oil-contaminated water, achieving 99% oil removal using 0.2 g/L of lignin. Pretreatment with [Ch][Cl] effectively fractionates GCF and appears to be an attractive 2G ethanol technology option for other lignin-rich biomasses. [ABSTRACT FROM AUTHOR]

Hydrolyzed polyacrylamide (HPAM) in polymer flooding leads to stable oil-in-water emulsions, making the oil removal from polymer-flooding produced water (PFPW) more difficult. To elucidate HPAM's effects on the oil separation performance of conventional physical separation process for PFPW, the stability, and diameter of oil droplets of simulated PFPW were accurately determined using the Turbiscan LAB expert. The results demonstrated that an increase in HPAM's molecular weight and concentration led to a significant decrease in the diameter of oil droplets in simulated PFPW. When the molecular weight of HPAM increased from 6 to 18 MDa, there was a decrease in the Turbidity Scanning Index (TSI) values from 22.5 to 8.7, along with a significant decline in the diameter of oil droplets from 72.7 to 32.6 µm after a settling period of 40 min. Furthermore, a rise in HPAM concentration inhibited the enlargement of oil droplets. As HPAM concentration increased from 0 to 500 mg/L, the diameter of the oil droplets reduced by 42.1 µm after a 40 min settling period. HPAM's effect on restricting the growth of oil droplets remained relatively constant across oil concentrations ranging from 500 to 2500 mg/L. Moreover, increasing the molecular weight of HPAM from 6 to 18 MDa led to a 41.6% increase in PFPW's viscosity and a 38.9% decrease in oil-water interfacial tension, thereby inhibiting oil droplet coalescence. Our findings provide valuable fundamental guidance for the design of innovative separation methods for PFPW treatment. [ABSTRACT FROM AUTHOR]

The management of oil-contaminated water and wastewater in the oil industry remains a critical challenge due to its environmental and economic implications. This manuscript provides a comprehensive review of separation and removal techniques for oil from water and wastewater. It gives an overview of the origins and compositions of oil in wastewater, including natural and anthropogenic sources, as well as variations in physical states such as free, emulsified, and dissolved oil. The review delves into various separation methods, ranging from traditional gravity-based techniques to advanced technologies like membranes and recent developments in wastewater treatment systems. Furthermore, it discusses the application of new technologies specifically designed for the unique challenges faced in Middle East oil fields. The manuscript explores factors influencing oil-water separation efficiency, including operating conditions, chemical additives, equipment design, and environmental considerations. Additionally, it highlights current aspects and future directions in oily wastewater treatment, emphasizing the need for sustainable and effective solutions in the oil industry. [ABSTRACT FROM AUTHOR]

Many adsorbent materials are being studied for dye and oil removal from the environment. Bio-based materials such as silk are promising candidates due to their enhanced affinity for dyes and intrinsic hydrophobicity. This work extensively studies various silk textiles as dye and oil adsorbents. For comparison, we use electrospun fiber mats and hollow silk microparticle-treated silk fabrics. Our work is motivated by two factors: (i) massive amounts of silk waste is being discarded annually from textile factories, and (ii) the limited studies on the adsorption phenomena of pristine silk textiles. Based on our findings, 12 mg of silk filament yarn has a 90% methylene blue (MB) removal efficiency within 10 min of exposure for concentrations up to 100 ppm and exhibits adsorption capacities of 145 mg/g for 800 ppm concentrations. The adsorption kinetics obey a pseudo-second order, where the rate-controlling step is chemisorption, and isotherms follow the Langmuir model with homogenous monolayer adsorption. Furthermore, noil woven fabrics with contact angles of 1400 have oil adsorbent capacities that are double the fabric weight. Our work confirms that silk waste textiles are efficient and reusable bio-adsorbents for MB dye and oil removal, outperforming materials made with additional and energy-intensive techniques such as silk dissolution and electrospinning. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a novel electrode for electrocatalytic adsorption by fabricating ACF‐TiO2 via the sol‐gel method and binding it with IrO2‐TaO2. The electrode's effectiveness in treating oilfield produced water (OPW) was evaluated using batch techniques. Comprehensive characterization, including scanning electron microscopy (SEM), energy‐dispersive spectrometry (EDS), Brunauer‐Emmett‐Teller (BET) analysis, and Fourier‐transform infrared (FTIR) spectroscopy, confirmed uniform TiO2 loading onto the ACF surface, preserving structural integrity. BET analysis indicated increased mesopore volume and enhanced organic adsorption capacity without compromising microporous structure. Additionally, FTIR analysis revealed the emergence of functional groups conducive to adsorption and catalytic reactions. Freundlich isotherms and pseudo‐first‐order kinetics best fit the adsorption data. Remarkably, even after five cycles, the electrode maintained high removal efficiencies for chemical oxygen demand (COD) and oil content at 91.35 % and 91.12 %, respectively. We further investigated the complex phenomena of material adsorption, electrochemical oxidation, and desorption during electrocatalytic adsorption, highlighting the importance of solid‐phase adsorption and liquid‐phase electrocatalytic oxidative decomposition in OPW treatment. Comparison with similar electrodes and DSA electrodes demonstrated the superior performance and practicality of the IrO2‐TaO2‐ACF(TiO2) electrode. Its cost‐effectiveness and regeneration method further enhance its applicability in real‐world scenarios, emphasizing its potential in water treatment. [ABSTRACT FROM AUTHOR]

In this study, degummed and undegummed silkworm cocoon wastes were used to investigate their oil sorption capabilities for three kinds of oils, namely motor oil, vegetable oil, and crude oil. The laboratory-scale oil sorption results reveal that degummed silkworm cocoon waste has sorption capacities of 16.7, 15.8, and 14.2 g/g for motor oil, vegetable oil, and crude oil, respectively. It exhibits higher sorption capacities for these three oils compared with raw cocoons and cocoon scrap. These sorbents also exhibited excellent oil/water selectivity, retention capacity, and reusability. According to the large-scale experiment, the crude oil can be removed completely by degummed silkworm cocoon waste in 20 min, which shows that degummed silkworm cocoon waste could be considered a good alternative to synthetic sorbent materials applied to oil removal and recycling. [ABSTRACT FROM AUTHOR]

The immobilization of lipase producing alkali tolerant Staphylococcus argenteus MG2 bacterial cell and its lipase enzyme was found to have potential applications in industrial field. The immobilization of bacterial cells was done by using sodium alginate. These cells were used for lipase production. The specific activity of lipase enzyme produced by free cells in fermentation was 18.18µM/min/mg. A quite similar activity of lipase (19.55µM/min/mg) was obtained when bacterial cells were immobilized in 3% sodium alginate beads. It was concluded from the study that immobilized cells are effective as free living bacteria for the lipase production. The immobilized crude enzyme solution with diatomite degraded 0.48mg/L (48%) of oil while immobilized cells degraded 0.44 mg/L (44%) of oil which indicates that both immobilized enzymes and immobilized cells were degrading oil efficiently and can be reused easily. It was observed during the study that lipase produced from Staphylococcus argenteus MG2 was found to be effective in the formulations of laundary detergent. During the compatibility of lipase enzyme among various commercial detergent tested, intensified activity of lipase was detected with Rin (106.25%) followed by Nirma (103.12%). The stability of lipase was observed towards anionic as well as non ionic surfactants. 50U of lipase in 0.5% Rin improved the removal of oil from oiled cotton fabric. In summary, this novel and potent lipase producing strain isolated from oil contaminated soil, Staphylococcus argenteus MG2, holds immense potential for applications in the detergent industry. [ABSTRACT FROM AUTHOR]

Gravity settling is a widely employed technology that removes oil from produced water in oilfields. However, with the transition of reservoir development to low-permeability reservoirs, conventional produced water settling tanks face limitations in the treatment efficiency and coagulant dosage. This study presents an innovative approach that optimizes sedimentation tank structures and integrates micro-vortex flow technology to enhance coagulation and flocculation. Through chemical dosage experiments, comparative experiments, and long-term observation, the micro-vortex flow reactor demonstrates a 9.4% increase in oil removal efficiency while reducing the coagulant dosage by 30.0%. The MOR equipment achieved a 20.5% higher oil removal efficiency than conventional methods while maintaining effluent oil and suspended solids below 20 mg/L. The long-term observation experiment of MOR equipment further highlights oil removal efficiency of 94.2% and the micro-vortex reactor's excellent anti-pollution performance. The MOR equipment significantly reduces the land occupancy area by over 50% compared to conventional methods, thanks to the implementation of micro-vortex flow technology that effectively addresses the limitations associated with traditional settling tanks. This study contributes to advancing efficient and sustainable practices in waterflooding reservoirs, particularly for meeting stringent standards of water injection in low-permeability oilfields. [ABSTRACT FROM AUTHOR]

Due to the rapid advancement of technologies, there has been a significant increase in the discharge of industrial wastewater, and freshwater is becoming a scarce resource. Currently, research on solar evaporators is mainly focused on the efficient production of clean water, with less emphasis on the removal of residual pollutants remaining in the original solutions. Through this study, problems, including the difficult recovery of catalyst powder and the difficult removal of floating organic matter are solved by co-depositing low-surface-tension zirconia particles and bismuth tungstate onto the floating layer. Hydrogels and melamine sponges were combined to solve the problem that traditional hydrogels lack mechanical strength. An excellent water-repellent effect can be seen from the contact angle between the liquid globule and canvas/felt, which is greater than 155°. The steam generation rate of the assembled evaporation system is 1.78 kg m−2 h−1, and its purification efficiency for methyl orange and rhodamine B exceeds 99%. This study presents a novel strategy for treating wastewater contaminated with organic dyes, aiming to solve problems including environmental damage, water pollution, and water scarcity. [ABSTRACT FROM AUTHOR]

The surfactant-based microemulsion technique enhances oil-contaminated soil remediation with high removal performance. With the presence of soil in the surfactant–oil–water (SOW) system, surfactants are the key success for this technology due to their activity. This study aimed to investigate the oil removal efficiency of different surfactant mixtures and determine surfactants' and oil's material balances in the soil flushing process. The mixed surfactant systems of SDHS-C12-14Ej (j = ethylene oxide group; 1, 5, 9) and SDHS-C16-18E6P4 mixtures were formulated, and a commercial diesel was selected as a model oil. The soil flushing experiment was conducted through the sand pack column with a 0.5 ml/min flow rate at room temperature. It was found that the SDHS-C12-14E1 system (9:1 ratio, 8%wt/v NaCl, Winsor Type III) showed the highest removal efficiency. The intermediate structure (i.e., ethylene oxide: EO) in the SDHS and C12-14Ej is an influent parameter in the surfactant selection for soil remediation. The less EO group in the surfactants, the better sand was decontaminated. The microemulsion types (i.e., I, II, and III) also affected the soil washing/flushing performance. Winsor Type III had the highest oil removal efficiency, followed by Winsor Type I, and II microemulsions. For mass balance in mixed surfactant systems, > 50% of SDHS, an anionic surfactant, remained in the aqueous effluent, while most of C12-14Ej and C16-18E6P4, a nonionic surfactant, solubilized in the oil phase and significantly adsorbed onto the sand. [ABSTRACT FROM AUTHOR]

Development of an efficient membrane from waste resources has been receiving growing interest. The utilization of industrial waste coal fly ash (CFA) for the preparation of SiC based tubular membrane has reduced the raw material cost and sintering temperature, and hence beneficial in both economic and environmental points. In the present work, tubular membrane was prepared by extrusion of ceramic paste formulated using SiC powder, CFA, suitable dispersant, plasticizer and additives. The extruded green body was dried and then sintered at 850°C. The membrane was characterized by measuring porosity, morphology by scanning electron microscopy, linear shrinkage, mechanical strength. The membrane performance was evaluated using synthetically prepared oil-water emulsion, turbid water, kitchen wastewater and industrial wastewater. The membrane was found to remove 93-95% of oil depending on the oil concentration in the feed water. The oil rejection potential of the membrane was compared with other membranes reported in the literature and the results indicated that the membrane prepared in this study had a strong potential applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

Many adsorbent materials are being studied for dye and oil removal from the environment. Bio-based materials such as silk are promising candidates due to their enhanced affinity for dyes and intrinsic hydrophobicity. This work extensively studies various silk textiles as dye and oil adsorbents. For comparison, we use electrospun fiber mats and hollow silk microparticle-treated silk fabrics. Our work is motivated by two factors: (i) massive amounts of silk waste is being discarded annually from textile factories, and (ii) the limited studies on the adsorption phenomena of pristine silk textiles. Based on our findings, 12 mg of silk filament yarn has a 90% methylene blue (MB) removal efficiency within 10 min of exposure for concentrations up to 100 ppm and exhibits adsorption capacities of 145 mg/g for 800 ppm concentrations. The adsorption kinetics obey a pseudo-second order, where the rate-controlling step is chemisorption, and isotherms follow the Langmuir model with homogenous monolayer adsorption. Furthermore, noil woven fabrics with contact angles of 1400 have oil adsorbent capacities that are double the fabric weight. Our work confirms that silk waste textiles are efficient and reusable bio-adsorbents for MB dye and oil removal, outperforming materials made with additional and energy-intensive techniques such as silk dissolution and electrospinning.

Egypt is facing water shortage due to limitation in the freshwater resources and the increased population growth. Thus, there is a need for developing new water resources such as the expansion in building large-scale reverse osmosis (RO) seawater desalination plants. Oil spill in the marine environment can cause severe fouling problems and make damage to the RO membranes, which increases the operating cost. The current study focuses on oil removal from water using agricultural-based adsorbents to reduce the membrane fouling in the RO systems. Three adsorbents namely: rice husk (RH), sawdust (SD) and sugarcane bagasse (SCB) were tested to remove used motor oil (UMO) and crude oil (CO) from distilled and raw seawater. Activated carbon (AC) was included in the measurements to be used as a reference case to compare with. The oil sorption removal and adsorption capacity were determined experimentally for the four tested adsorbents. The experimental parameters included: initial oil concentration (2-40 g/L), adsorbent dose (2-30 g/L), contact time (5-120 min), agitation time (0-60 min), chemical modification (acid vs. base treatment), water salinity (up to 35 g/L). The effect of the presence of other heavy metals on oil sorption removal and adsorption capacity was also investigated. The characteristics of the adsorbents surface were studied using the Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunauer-Emmett-Teller analysis. The results demonstrated that the adsorption removal of UMO with higher viscosity is higher than CO and always the RH exhibited the highest adsorption capacity compared to SD and SCB but about 30% less than AC. Precaution should be taken when distilled water is used rather than raw seawater because the difference could reach about 50% but it depends on the type of oil and adsorbing material. Additionally, the oil sorption removal in seawater is about 20% higher in raw seawater compared to distilled water. The oil sorption removal increased with an increase in contact time, adsorbent dosage, agitation time, and salinity, and decrease in initial oil concentration. The effect of presence of metals ions concentration in raw seawater can be neglected with the adsorbent used in the current study. The adsorption isotherm models by Langmuir described the experimental data very well while the pseudo-second-order described the kinetics data very well. The small difference in performance between RH and AC indicates that RH is very promising low-cost adsorbents for oil removal in RO desalination systems. The Gibbs free energy (ΔG) was calculated and the values were negative, indicating that the sorption process was spontaneous. [ABSTRACT FROM AUTHOR]

Oil films on water are an increasingly major contamination problem worldwide. In 2020, we published a novel adsorption and transportation technology for oil–water separation based on biological role models like the floating fern Salvinia. This application provides an unexpected ability for the fast and efficient removal of oil films, particularly in ecologically important freshwater biota. A single small Bionic Oil Adsorber (BOA) with 1 m2 functional textile can collect up to 4 L of oil per hour, which equals about 100 m2 of oil film from a water surface into a collecting vessel. This is a safe, fast, and sustainable solution for the ubiquitous contaminations of, e.g., fuel oil in freshwater environments. Here, we present updated, new experimental data, and a review of the literature published since. [ABSTRACT FROM AUTHOR]

Because switchable water is difficult to apply directly for oil removal, an enhanced approach to improve oil removal is proposed using a surfactant-free microemulsion (SFME) containing switchable water. The SFME is formed using switchable water (aqueous N, N-dimethylethanolamine (DMEA) or N,N-dimethylbutylamine (BDEA)) and a hydrophobic amine (N-butyldiethanolamine (DMBA)). The single-phase region for preparing the SFME is determined using a ternary phase diagram, and the microstructure types are distinguished using the conductivity method. The pH changes and dynamic laser scattering test results demonstrate that the SFME exhibits irreversible transformation behavior regulated by CO2. Moreover, the recovered SFME containing BDEA has a microstructure with a smaller particle size after removing the CO2 by bubbling N2 at 65 °C, which is attributed to the higher proportion of DMEA than that of BDEA. In addition, dodecane and diesel oil are shown to dissolve in the SFME, and the oil solubility of the SFME increases with increasing oil phase (DMBA) content. The interface free energy theory reveals that the oil is more easily detached with the addition of SFME than with switchable water only owing to the reduced interface free energy of oil on the solid surface. Thus, an enhanced approach for removing oil is proposed to wash oil sands, where the oil removal efficiency of switchable water can be improved by using SFMEs containing switchable water.

This study deals with the efficient, low-cost, and scalable treatment of oily polluted waters including colloidal emulsions, oil-in-water mixtures, and free oil removal using melamine foams (MFs) modified by ferric chloride (FeCl3). Modified foams have superhydrophobic character due to the coordination of Fe3+ with free electron pairs on nitrogen and oxygen atoms within the melamine structure. The water contact angles (WCA) were 146° ± 2°, 148° ± 4°, 153° ± 2°, and 150° ± 4° for foams modified by the solutions with concentrations of 0.001 M, 0.005 M, 0.01 M, and 0.02 M, respectively. This modification enables the efficient treatment of various oil/water systems, including oil/water colloidal emulsions (99 vol% of the droplets have dimensions below 500 nm), oil-in-water mixtures up to 40 weight % of the oil component, and "free" oil removal as it was demonstrated in this study for the first time. The emulsions containing 100 ppm diesel oil (DO) were separated with 91.4% efficiency, and the mixtures containing 20 and 40 weight % DO were separated with 99.9% efficiency. Modified foams also quickly remove free DO from the water surface, absorbing 95 g/g DO, whereas water sorption was negligible. The separation of colloidal oil in water emulsions represents the key finding of this study as it indicates the applicability of the treated MFs for the treatment of emulsified industrial wastewater. The demulsification mechanism is based on multiple diffusion processes running at different time scales, including diffusion of the emulsion into the foam and diffusion of oil droplets within the foam, combined with parallel adsorption of oil droplets onto the solid skeleton of the foam. A multiplied usage of these foams for all these niche operations was also proven. The application of our current study with previous studies on modified MFs and polyurethane for water oil separation utilization is summarized in Table S1 ESI. [ABSTRACT FROM AUTHOR]

Literature data of domestic and foreign research works concerning the use of aluminum-containing sludge obtained in the course of drinking-water treatment as a sorption material for the removal of pollutants (ions of various metals, dyes, oil and the products of its processing) from aqueous media are systematized. Literature information on the composition of water-treatment wastes is given. Information is briefly presented concerning the studies on aluminum-containing water-treatment wastes as a sorption material for As(III) and As(V), Cd2+, Cr(VI), Co2+, Cu2+, Hg2+, Mo(VI), Pb2+, Sb(V), Se (IV), Se(VI), and Zn2+. It is shown that the water-treatment sludge containing aluminum compounds therein is an efficient sorption material for phosphorus compounds, including phosphate ions, which can be used to reduce the eutrophication of natural aquatic reservoirs. Information is also presented concerning the potentialities of petroleum products from water-treatment sludge taken from aquatic environments. It is shown that it is quite possible to provide an increase in the sorption characteristics for different pollutants through the treatment with the use of various chemical reagents. [ABSTRACT FROM AUTHOR]

Literature data of domestic and foreign research works concerning the use of iron-containing sediment obtained after drinking-water treatment as a sorption material for the removal of pollutants (various metal ions, dyes, and oil and the products of its processing) from aqueous media are summarized. Brief literature information on the composition of water-treatment wastes is given. Information is briefly presented concerning the studies on iron-containing water-treatment waste as a sorption material for As(III) and As(V), B(III), Cd2+, Cr(VI), Co2+, Cu2+, Hg2+, Mo(VI), Ni2+, Pb2+, Sb(V), Se(VI), and Zn2+ ions. It is shown that the water-treatment sludge containing iron compounds therein is an efficient sorption material for phosphorus compounds, including phosphate ions, which can be used to reduce eutrophication of natural aquatic reservoirs. Information is also presented concerning the potentialities of removing oil products from water treatment sludge taken from aquatic environments. It is shown that to provide an increase in the sorption characteristics for different pollutants through the treatment with the use of various chemical reagents is quite possible. [ABSTRACT FROM AUTHOR]

Detergency determination for single polymeric fibers is of significant importance to screening effective detergents for laundry, but remains challenging. Herein, we demonstrate a novel and effective method to quantify the detergency for single polymeric fibers using a confocal laser scanning microscope (CLSM). It was applied to visualize the oil-removing process of single polymeric fibers and thus assess the detergency of various detergents. Four typical surfactants were selected for comparison, and a compounded detergent containing multiple components (e.g., anionic and nonionic surfactants, enzymes) was demonstrated to be the most effective and powerful soil-removing detergent because more than 50% of oil on the cotton fiber could be easily removed. Moreover, the oil removal process of three kinds of fibers (i.e., cotton, viscose, and polyester) was imaged and monitored by confocal microscopy. It was found that the percentage of the detergency of a single polyester fiber exceeded 70%, which is much higher than that of cotton and viscose fibers (~50%), which may be due to its relatively smooth surface. Compared to traditional methods, the CLSM imaging method is more feasible and effective to determine the detergency of detergents for single polymeric fibers. [ABSTRACT FROM AUTHOR]

Because switchable water is difficult to apply directly for oil removal, an enhanced approach to improve oil removal is proposed using a surfactant-free microemulsion (SFME) containing switchable water. The SFME is formed using switchable water (aqueous N, N-dimethylethanolamine (DMEA) or N,N-dimethylbutylamine (BDEA)) and a hydrophobic amine (N - butyldiethanolamine (DMBA)). The single-phase region for preparing the SFME is determined using a ternary phase diagram, and the microstructure types are distinguished using the conductivity method. The pH changes and dynamic laser scattering test results demonstrate that the SFME exhibits irreversible transformation behavior regulated by CO2. Moreover, the recovered SFME containing BDEA has a microstructure with a smaller particle size after removing the CO2 by bubbling N 2 at 65 °C, which is attributed to the higher proportion of DMEA than that of BDEA. In addition, dodecane and diesel oil are shown to dissolve in the SFME, and the oil solubility of the SFME increases with increasing oil phase (DMBA) content. The interface free energy theory reveals that the oil is more easily detached with the addition of SFME than with switchable water only owing to the reduced interface free energy of oil on the solid surface. Thus, an enhanced approach for removing oil is proposed to wash oil sands, where the oil removal efficiency of switchable water can be improved by using SFMEs containing switchable water. [ABSTRACT FROM AUTHOR]

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Oil removal from water has become more important for environment sustainability since there are many cases of oil leakage accidents. Oil spills, whether caused by accidents or other factors, can have devastating effects on aquatic ecosystems and wildlife. To clean up by utilizing green materials, it can mitigate the environmental impact of oil spills and align with the principles of conservation science. Therefore, in this work, an attempt was made to clean oil contamination using rubber foam attached with cotton fabric. The enhancement of hydrophobicity would increase the efficiency of oil removal. The cotton fabric was coated by natural rubber (NR) foam and subsequently treated with hexadecyltrimethoxysilane (HDTMS) as hydrophobic agent. The results show the treated NR-coated fabric exhibited excellent oil absorption, oil selectivity and completely removed the oily layer from water. It is because hydrophobic enhancement of cotton fabric and rubber foam surfaces were achieved at 157° and 140°, respectively. The formation of hydrophobic agent with rough surface was revealed by SEM micrographs. From the results, the prepared NR-coated fabric presented an attractive hydrophobic property with simple preparation and high efficiency of oil removal. It could be said that NR-coated fabric is a green material potentially used as a perfect oil-separator to relieve the pollution from oil contamination. Conservationists and researchers can work together to raise awareness about the benefits of using green materials for oil spill cleanup, fostering a sense of environmental stewardship. [ABSTRACT FROM AUTHOR]

Spent residuum hydroprocessing (RHDP) catalysts are hazardous waste bearing high-content vanadium and large amounts of oily pollutants. In this paper, a process featuring a Fenton-like reaction and alkaline leaching was proposed to recover vanadium from spent RHDP catalysts. In the first step, a Fenton-like reaction using peroxide was conducted to degrade the oily pollutants and make the surface of the spent catalyst becomes hydrophilic. In the second step, the vanadium-containing deposit on the catalyst was leached with 0.5 M Na2S2O8 at 70 °C for transforming vanadium sulfide to oxide in 5 h. In the last step, alkaline leaching was employed to dissolve vanadium from the oxidizing residue at 80 °C for 1 h. It was found that the accumulated leaching efficiency of vanadium can reach up to 90.92%, and only a small part of aluminum and sulfur was dissolved. These results indicated that this combined process can extract vanadium selectively from spent residuum hydroprocessing catalysts under a relatively mild condition. [ABSTRACT FROM AUTHOR]

In this study, our aim was to estimate the adsorption potential of three families of aerogels: nanocellulose (NC), chitosan (CS), and graphene (G) oxide-based aerogels. The emphasized efficiency to seek here concerns oil and organic contaminant removal. In order to achieve this goal, principal component analysis (PCA) was used as a data mining tool. PCA showed hidden patterns that were not possible to seek by the bi-dimensional conventional perspective. In fact, higher total variance was scored in this study compared with previous findings (an increase of nearly 15%). Different approaches and data pre-treatments have provided different findings for PCA. When the whole dataset was taken into consideration, PCA was able to reveal the discrepancy between nanocellulose-based aerogel from one part and chitosan-based and graphene-based aerogels from another part. In order to overcome the bias yielded by the outliers and to probably increase the degree of representativeness, a separation of individuals was adopted. This approach allowed an increase in the total variance of the PCA approach from 64.02% (for the whole dataset) to 69.42% (outliers excluded dataset) and 79.82% (outliers only dataset). This reveals the effectiveness of the followed approach and the high bias yielded from the outliers. [ABSTRACT FROM AUTHOR]

The petroleum industry generates a massive amount of oily water discharge from oil–water separators.Oily water will cause a major environmental risk if not treated before discharge. The challenge is to propose a suitable low maintenance cheap treatment method.This study represents a second phase of testing polyester fibers as deep bed filtration media to treat the produced oily water. The previous, first phase, study investigated the efficiency of the polyester fiber by conducting short duration filtration tests using 40 cm polyester fiber filters.From the first phase study, two suggestions can be deduced to optimize the oil removal efficiency of polyester fiber filters in long duration field processes and to use either large number of short filters with low flow capacity or less number of long filters with high flow capacity. The two methods were employed and tested separately in this study.The results of both methods clearly showed the ability of the polyester fiber deep bed filters to produce high-quality brine of less than 5 ppm oil concentration. The polyester fibers filter was proven to be a competitor with the existing materials used in the industry.

The high processing cost is the key challenge for the economic industrial use of SiC membrane The aim of this research was to fabricate mullite bonded porous SiC ceramic membrane at low temperature from novel combinations of fly ash and alumina (FA) in weight ratio 44.5:55.5 as sintering additives. The influences of FA and pore former content on the porosity, morphology, crystalline phase composition, mechanical performance, permeability properties were investigated. The membrane prepared at 1300°C using 20 wt% FA showed pure water permeability 3690 Lm−2h−1bar−1 and exhibited high oil removal efficiency of ∼ 98% from the synthetic oil‐water emulsion having oil concentration of 1000 mg/L. The corrosion behaviour of silicon carbide membrane in the strong acid and alkali solution and its mechanism were investigated. The utilization of fly ash successfully reduced the raw material cost and sintering temperature and the use of alumina reduced the amount of oxidation of SiC as well as increased the amount of mullite bond phase which resulted excellent mechanical strength to the final ceramics. [ABSTRACT FROM AUTHOR]

It has been reported that the addition of microbubbles in a water flow enhances a cleaning efficiency of oil adhering to a channel wall. However, the enhancement mechanism of the cleaning effect has not been sufficiently understood yet. Experiments on the removal effects of water flows in a horizontal channel with and without microbubbles were therefore conducted to investigate the removal process by microbubbles. Silicone oil adhering to the bottom wall of the channel was used as dirt. The local thickness of the oil was measured during cleaning from micrographs of fluorescence intensity. The amount of oil removed by the water flow increased with increasing the Reynolds number. Adding microbubbles to the water flow increased the amount of removed oil. Microbubbles attached to the oil interface under turbulent conditions, and the bubbles grew by mass transfer through the gas-liquid interface and bubble coalescence. The detachment of bubbles grown on the oil interface led to oil peel-off, resulting in an improvement of cleaning effect. [Display omitted] • The thickness of adhesion oil was measured using laser-induced fluorescence. • The presence of microbubbles was confirmed to enhance oil removal. • The removal rate was modeled as a superposition of shear and bubble effect terms. • Microbubbles adhering to oil can be grown by mass transfer and induce oil peeling. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to treat waste metalworking fluids (MWFs) originating from the metalworking industry. To achieve this goal, a series of treatment methods were employed in sequence, and various parameters were analyzed, including chemical oxygen demand (COD), pH, total suspended solids (TSS), turbidity, oil/grease, total organic carbon (TOC), and biochemical oxygen demand (BOD). In the initial stage of wastewater pre-treatment, cross-flow microfiltration (MF) and chemical coagulation using FeCl2•4H2O as the coagulant were implemented. The results revealed that the MF membrane (TM10) exhibited removal efficiencies of 67.2% for COD, 93.2% for suspended solids (SS), 99.3% for turbidity, and 98.6% for oil/grease. On the other hand, coagulation with ferric chloride achieved removal rates of 24.9% for COD, 66.8% for SS, 50.2% for turbidity, and 91.6% for oil/grease. Clearly, the TM10 MF membrane was more effective in the pre-treatment stage. Following the pre-treatment, the wastewater underwent further treatment using three different ultrafiltration (UF) membranes with molecular weight cut-offs (MWCO) ranging from 1 to 10 kDa in a cross-flow system. The GE (1 kDa) membrane demonstrated the highest removal efficiency, which was comparable to the GH (2 kDa) membrane. However, both the GH and GE membranes achieved fluxes of 25.58 and 20.43 L/m²/h at 6 bar pressure, respectively. For the final stage of treatment, the most efficient nanofiltration (NF) membrane (TS80) achieved removal efficiencies of 96.2%, 99.9%, 100%, and 70.7% for COD, SS, oil/grease, and electrical conductivity (EC), respectively. It was concluded that the NF filtrate could be reused as process water. This study successfully implemented a series of treatment methods for waste metalworking fluids (MWFs), effectively removing various pollutants and providing potential options for reusing the treated wastewater in the metalworking industry. [ABSTRACT FROM AUTHOR]

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Starch microspherical aerogel (SMA) prepared by enzymatic hydrolysis of starch with α-amylase was demonstrated to be higher adsorption capacity for methylene blue. Proper cleavage of α-1,4 glycosidic bonds could enhance the adsorption capacity of SMA, while the cleavage of α-1,6 glycosidic bonds showed an opposite effect. Compared with tapioca starch (TS), α-amylase hydrolyzed starch exhibited a 9.46 % decrease in amylose content, a 25.40 % increase in adsorbability, and significant decreases in weight-average molecular weight (Mw) of different amylases. When the Mw of enzymolysis starch was 6.39 × 106 g/mol, it was suitable for the preparation of SMA, and could significantly increase its adsorption capacity. The adsorbability of the crosslinked starch microspherical aerogel (CSMA) was 1.816 ± 0.026 mg/g, which was increased by 100.60 % relative to that of native starch microspherical aerogel (NSMA). CSMA had the best adsorption effect on oil and could be applied to the adsorption and removal of vegetable oil. • Μolecular weight of starch affected adsorption of starch microspherical aerogel (SMA). • Proportion of amylose/amylopectin, crosslinking influenced adsorption of SMA. • Properties of SMA (molecular structure, porosity, morphology) were analyzed. • SMA was applied to the removal of vegetable oil to explore its application potential. [ABSTRACT FROM AUTHOR]

Petrochemical wastewater (PWW) is a huge industrial contaminant that generates a wide range of resistive and poisonous organic pollutants that harm animals and plants in natural water bodies when discharged untreated or partially treated. Therefore, it is vital to develop technologies that are simple, efficient, and profitable for the treatment of oily wastewater. Although much study has been undertaken on the treatment of PWW, there has not been any recent work on bibliometric analysis of global research trends on this issue. A bibliometric analysis will help current and future researchers figure out where the gaps are and how to fill them. The present study's focus is to examine the characteristics and trends of research on oily wastewater treatment with an emphasis on the treatment of PWW. This research was performed on five important aspects, including characterization of research publications, countries' performances and collaborations, an analysis of the best papers with the most citations, keyword analysis (including frequency distribution of the keyword analysis, the transformation of the keyword combination across time, and exploration of changes in rank over time), and journal analysis, according to the 2457 papers in the Science Citation Index Expanded using the Web of Science (WoS) database from 2000 to 2021. For further analysis, the contingency matrix, bump diagram, and inter-temporal network stream were employed. [ABSTRACT FROM AUTHOR]

Oil leakage incidentally occurs and leads to environmental disasters. Because of their porous and hydrophobic characteristics, graphene sponges are often studied as an oil adsorbent to repair oil spills at sea. Graphene materials are very expensive, and their biological toxicity has been given serious concerns; however, the easier preparation and eco-friendly, biomass-derived porous carbon materials can be used as an alternative to graphene materials. In this study, we prepared a porous carbon sponge (PCS) for oil and organic solvent removal by carbonizing white-rot fungus Phanerochaete chrysosporium, a fast-growing microorganism for the production of lignin-degrading enzymes and the environmental remediation. P. chrysosporium fungus balls were converted into black PCS by carbonization at high temperatures, where PCS was light (density of 56 g/L), hydrophobic (contact angle of 115°) and porous. According to the results of BET and XPS analysis, the surface area of PCS was 14.43 m2/g, and the carbon in PCS is mainly sp2 carbon. PCS could adsorb pure oils and organic solvents within seconds. The adsorption capacities of PCS were 20.7 g/g for gasoline, 30.1 g/g for peanut oil, 27.7 g/g for toluene, 18.5 g/g for dodecane, 32.5 g/g for chloroform, 27.1 g/g for tetrahydrofuran, 23.7 g/g for acetone and 13.7 g/g for ethanol. According to the reusability study, there was no obvious capacity loss after recycling up to 10 cycles. Our results indicated that white-rot fungi could be adopted as a cheap carbon resource for oil and organic solvent removal. [ABSTRACT FROM AUTHOR]

In this study, a novel recyclable, hydrophobicity foam with excellent oil/water separation based on polyurethane (PU) and polypropylene glycol (PPG) grafted stearic acid (PGGA) has been developed. PGGA was simply synthesized by the esterification of stearic acid and PPG, while the PU/PGGA foam was fabricated by the reaction of PPG and methyl diphenyl diisocynate (MDI) with the addition of PGGA. The PU/PGGA foam exhibits improved oil adsorption capacity, water rejection as well as oil/water selectivity with the increase of PGGA weight loadings. The presence of PGGA at high loading (≥ 5 wt%) reduces the pore size and porosity of PU/PGGA foam due to the high viscosity of PGGA preventing the foam formation reaction. As a result, the oil adsorption capacity of PU/PGGA foam is slightly neglected, nevertheless, the oil/water selectivity is significantly enhanced compared to the original PU foam. The result in this work suggests a simple and cost-effective method with potential in oil removal at large scale application. In this study, novel hydrophobicity agent (PGGA) is developed for enhancing the oil/water separation of polyurethane (PU) foam. At lower weight loading of PGGA (≤ 3 wt%), the PU/PGGA foam exhibits improvement in oil adsorption capacity, water rejection and oil/water separation. Above 5 wt% loading of PGGA, the oil adsorption of PU/PGGA foam is decreased, however, the oil/water selectivity were drastically improved. With this result, the PU/PGGA foam is highly potential for oil removal at large scale application. [ABSTRACT FROM AUTHOR]

The hydrophobic magnetic materials of HMC-1 and HMC-2 were obtained by blending synthesized Fe3O4 nanoparticles and commercial CaCO3 powder with stearic acid solution, which is used as hydrophobic modifier. HMC-2 was loaded on the PU sponge for the further improvement of the applicability. The structural properties of the two materials were detected by X-ray powder diffractometer and infrared spectrometer. Thermal stability of HMC-2 was analysed by differential scanning calorimeter. The hydrophobic properties of the samples were determined by contact angle meter. The results show that HMC-2 has more stable hydrophobic properties than HMC-1. HMC-2 exhibits more stable hydrophobic performance. The contact angle remains nearly unchanged (about 150°) after oil removal. HMC-2 shows no release of Fe(Ⅲ) ions, which has taken place during the oil removal experiment using HMC-1. PU sponge loaded with HMC-2 can remove 98% oil in 3 s. The oil removal rate remains 95%, after 20 times of repeated oil absorption. The mass ratio of oil adsorption/adsorbent is larger than 100.

The purpose of this work was to evaluate the efficiency of oil sorption of silica particles modified by three different types of cationic polymers and a cationic surfactant. Low-molecular-weight polyethyleneimine (LPEI), high-molecular-weight polyethyleneimine (HPEI), polydiallyldimethylammonium chloride (PDM), and cetyltrimethylammonium bromide (CTAB) were used to modify the silica particles and then compared their performances for oil removal. The scanning electron microscope and zeta potential measurements were used to analyze the surface characteristics of unmodified and modified silica particles. Adsorptions of motor oil and palm oil on the modified silica particles have been investigated under various parameters such as the silica particle size, the oil concentration, the polymer/surfactant concentrations, and the pH. The results have shown that the modified silica particles enhanced the oil sorption ability by approximately 10–20 times depending on the size of silica particles, pH, and the type of polymer/surfactant used when compared with the unmodified silica particles. The highest palm oil adsorption values of LPEI-silica, HPEI-silica, PDM-silica, CTAB-silica, and unmodified silica were 2.40, 2.10, 1.95, 1.50, and 0.15 g/gsilica, respectively. Moreover, the oil sorption of the modified silica particles was increased by approximately 30–50% for the smallest-sized silica particles. HIGHLIGHTS Cationic polymers/surfactant-modified silica particles can enhance the oil sorption by approximately 10–20 times.; Polymer/surfactant-modified silica can be used to remove both fresh and used oil.; Low molecular weight of the cationic polymer performed the outstanding oil sorption performance.; Oil sorption on small particles was 30–50% higher than that of the large particles.;

The petroleum industry generates a massive amount of oily water discharge from oil–water separators. Oily water will cause a major environmental risk if not treated before discharge. The challenge is to propose a suitable low maintenance cheap treatment method. This study represents a second phase of testing polyester fibers as deep bed filtration media to treat the produced oily water. The previous, first phase, study investigated the efficiency of the polyester fiber by conducting short duration filtration tests using 40 cm polyester fiber filters. From the first phase study, two suggestions can be deduced to optimize the oil removal efficiency of polyester fiber filters in long duration field processes and to use either large number of short filters with low flow capacity or less number of long filters with high flow capacity. The two methods were employed and tested separately in this study. The results of both methods clearly showed the ability of the polyester fiber deep bed filters to produce high-quality brine of less than 5 ppm oil concentration. The polyester fibers filter was proven to be a competitor with the existing materials used in the industry. [ABSTRACT FROM AUTHOR]

Produced water (PW) generated from the petroleum industry, during the extraction of oil and gas, has harmful impacts on human health and aquatic life, due to its complex nature. Therefore, it is necessary to treat it before discharging it into the environment in order to avoid serious environmental concerns. In this research, oil adsorption from PW was investigated using clay-alginate beads loaded with ionic liquids (ILs), as the adsorbent material. The effects of several process parameters, such as the initial concentration of oil, contact time, pH, and temperature on the removal efficiency of the beads, were analyzed and optimized. Different characterization methods, such as the Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and thermal gravimetric analysis (TGA), were used to investigate the surface morphology, the chemical bond structure and functional group, and the thermal stability of the ILs-based beads. The results revealed that the clay-alginate-ILs beads indicated a removal efficiency of 71.8% at the optimum conditions (600 ppm initial oil concentration, 70 min contact time, 10 pH, and at room temperature) with an adsorption capacity of 431 mg/g. The FTIR analysis confirmed the successful chemical bond interaction of the oil with the beads. The SEM analysis verified that the beads have a porous and rough surface, which is appropriate for the adsorption of oil onto the bead's surface. The TGA analysis provides the thermal degradation profile for the clay-alginate-ILs. The beads used in the adsorption process were regenerated and used for up to four cycles. [ABSTRACT FROM AUTHOR]

We report the synthesis of reduced graphene oxide (rGO)-α-Fe2O3 nanocomposite and its application to remove and recover dissolved oil from a high-salinity oil–water emulsion in batch and column/breakthrough setups. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and nitrogen adsorption characterized the synthesized nanocomposite's structure, morphology, and surface properties. Both batch and continuous breakthrough adsorption studies were investigated. The effect of the adsorption parameters on the adsorption capacity and removal efficiency was analyzed. The rGO-Fe2O3 nanocomposite (rGO-Fe2O3-NC) demonstrated a superior adsorption capacity, both when measured experimentally (1213 mg/g) and predicted using the Freundlich isotherm (1301 mg/g). The adsorption process followed pseudo-second-order kinetic, and the rGO-Fe2O3-NC exhibited a very rapid removal, with more than 60% of oil being removed within 10 min. Breakthrough confirmed the exceptional removal capacities with good regeneration and cycling ability under a short contact time. Moreover, the adsorption capacity was enhanced with an emulsion salinity of up to 100,000 ppm, confirming the suitability for high-salinity wastewater. [ABSTRACT FROM AUTHOR]

Magnetically functionalized attapulgite (ATP) was synthesized by loading Fe3O4 onto ATP via co-precipitation method. The surface functional groups, thermal stability, microstructure, morphology, and magnetic properties of the samples were measured by Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscope and vibrating magnetometer, respectively. The oil removal and recovery of magnetic ATP for oil-in-water emulsion was investigated. The results show that the magnetic ATP exhibits a saturation magnetization Ms of 1.5 emu/g, the coercivity Hc of 10 Oe and the residual magnetization Mr of 0.03 emu/g. In addition, the thermal stability and the dispersibility in oil-water emulsion of ATP is significantly improved by Fe3O4 modification. The adsorption capacity of ATP for emulsified oil slightly decreases from 8.14 to 7.16 mg/g after Fe3O4 modification, regardless of the effect of acid treatment or increment of loading amount. In particular, the modified ATP is easily recovered by an external magnetic field. [ABSTRACT FROM AUTHOR]

In the process of oily sludge conditioning centrifugal treatment, it is necessary to add high-effective conditioning agent for oily sludge conditioning. A new inorganic polymer coagulant, named poly-silicate aluminium magnesium zinc (PSAMZ) was prepared by using direct composite method with raw materials of sodium silicate, aluminium sulphate, magnesium sulphate and zinc sulphate. PSAMZ was applied for the effective conditioning--centrifugal treatment of oily sludge. The optimum preparation conditions of the coagulant were determined according to single factor and orthogonal experiment, in which the ratio of the number of various elements of PSAMZ was n(Zn):n(Si):n(Mg):n(Al)=3:1:0.66:0.33, and the reaction temperature was set to 30°C. The property of the prepared PSAMZ was determined by infrared spectroscopy and XRD. Results showed that metal ions and activated poly-silicate can form new silicon aluminium magnesium zinc polymer through complexation, polycondensation and coordination binding. The experimental result of conditioning--centrifugal treatment of oily sludge showed that the dosage of coagulant was 70 mg/L, pH=9 and the oil removal rate of oily sludge can reach 81.18% under optimum treatment conditions, which were the stirring temperature was 30°C, the stirring time was 30 min, the centrifugation speed was 3400 r/min and the centrifugation time was 35 min. The results indicated that PSAMZ was an effective coagulant. Scanning electron microscopy analysis results showed that after the coagulant was added into oily sludge, its adsorption bridging, electric neutralisation and netting function can be fully exerted, thereby promoting the oil phase to separate from sludge. Thermogravimetric analysis showed that some crude oil and bound water were effectively removed from oily sludge. [ABSTRACT FROM AUTHOR]

Produced water contaminated with oil has adverse effects on human health and aquatic life. Providing an efficient method for the removal of oil from produced water is a challenging task. In this study, the effects of carbon chain length and the cation nature of ionic liquids (ILs) on the removal efficiency of oil from produced water were investigated. For this purpose, seven ILs containing the bis (trifluoromethylsulfonyl) imide (NTf2) anion, and various cations such as imidazolium, pyridinium, phosphonium, and ammonium, were employed for the removal of oil from produced water via liquid–liquid extraction. The effects of process parameters such as the initial concentration of oil in produced water, contact time, pH, salinity, phase ratio, and temperature on the removal efficiency of oil were studied and optimized. 1-Decyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([C10mim][NTf2]) (IL4) was found to give the highest oil extraction efficiency of 92.8% under optimum conditions. The extraction efficiency was found to increase with increasing cation alkyl chain length from C2 to C10. The extraction efficiency of ILs based on cations follows the order imidazolium > ammonium > phosphonium > anpyridinium. Fourier Transform infrared spectroscopy (FTIR) was used to explore the ILs interaction with oil using [C10mim][NTf2] as a model. In addition, 1H and 13C NMR spectra were recorded to obtain a better understanding of the molecular structure of IL and to investigate the peak shifts in H and C atoms. Moreover, the cell viability of the most efficient IL, [C10mim][NTf2], in human cells was investigated. It has been concluded that this IL exhibited minimal cytotoxic effects at lower concentrations against human cell lines and is effective for the extraction of oil from aqueous media. [ABSTRACT FROM AUTHOR]

In this study, our aim was to estimate the adsorption potential of three families of aerogels: nanocellulose (NC), chitosan (CS), and graphene (G) oxide-based aerogels. The emphasized efficiency to seek here concerns oil and organic contaminant removal. In order to achieve this goal, principal component analysis (PCA) was used as a data mining tool. PCA showed hidden patterns that were not possible to seek by the bi-dimensional conventional perspective. In fact, higher total variance was scored in this study compared with previous findings (an increase of nearly 15%). Different approaches and data pre-treatments have provided different findings for PCA. When the whole dataset was taken into consideration, PCA was able to reveal the discrepancy between nanocellulose-based aerogel from one part and chitosan-based and graphene-based aerogels from another part. In order to overcome the bias yielded by the outliers and to probably increase the degree of representativeness, a separation of individuals was adopted. This approach allowed an increase in the total variance of the PCA approach from 64.02% (for the whole dataset) to 69.42% (outliers excluded dataset) and 79.82% (outliers only dataset). This reveals the effectiveness of the followed approach and the high bias yielded from the outliers.