Petroleum-based Solvents Research Articles

Application of green solvents for arsenic removal from petroleum produced water: Statistical, DFT and McCabe-Thiele determination

This work presents the novel application of green oils to extract arsenic ions from petroleum produced water via liquid-liquid extraction (LLE). In the experiment, the removal of arsenic ions from synthetic petroleum produced water is investigated, using five green oils: canola oil, corn oil, linseed oil, rice bran oil, and sunflower oil, in place of petroleum-based solvents: toluene and kerosene. Both extraction and stripping optimizations are examined. For extractants, Aliquat 336 and Cyanex 921 are implemented. The initial arsenic concentration (3.984 mg L−1) of petroleum produced water is examined. Results demonstrate that Aliquat 336 in corn oil proved to be most effective for arsenic removal. At optimal conditions via response surface methodology (RSM), the highest extraction and stripping percentages reached 99.95 % and 100.00 %, respectively. In accordance with the World Health Organization (WHO) levels of ≤0.01 mg L−1, arsenic concentration remaining in the extracted water (0.002 mg L−1), is seen to fulfill the requirement needed. The extraction and stripping kinetics are of first and second-order. Mechanisms of arsenic removal are evaluated via density functional theory (DFT). Further, selectivity, recycling of the organic phase, and the number of stages via McCabe-Thiele theory are determined under optimal conditions.

Occupational exposure to organic solvents and the risk of developing testicular germ cell tumors (TESTIS study): Effect of combined exposure assessment on risk estimation.

Etiological factors of testicular germ cell tumors (TGCT) remain largely unknown, but a causal role of occupational exposures to solvents has been suggested. Previous studies analyzing these exposures reported discordant results, potentially related to exposure assessment methods. The aim of this study was to investigate the role of occupational exposure to solvents on the risk of developing TGCT among young men. This study examined occupational exposures to solvents and TGCT risk based on the lifetime work histories of 454 cases and 670 controls, aged 18-45 years, of the French national TESTIS case-control study. Solvent exposure was estimated using: (i) exposure assignment by job-exposure matrix (JEM) and (ii) JEM combined with self-reported exposure data from specific questionnaires (SQ) and expert assessment (EA). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression models. Both approaches (JEM and JEM+SQ+EA) showed a consistent association between TGCT and trichloroethylene exposure (exposed versus not exposed; JEM=OR 1.80 [95% confidence interval (CI) 1.12-2.90] and JEM+SQ+EA= OR 2.59 (95% CI 1.42-4.72). Both approaches also observed positive associations with ketone esters and fuels & petroleum-based solvents. The results suggest that some organic solvents might be involved in the pathogenesis of TGCT among occupationally exposed men. The combined use of JEM+SQ+EA seemed to limit misclassification by considering individual exposure variability and is, therefore, an appealing approach to assess occupational exposures in epidemiological studies.

Lipidomic Profiling and Pharmacological Activities of Ficus drupacea Oil: Comparative Study Between Conventional vs. Green Solvent.

Ficus drupacea is a medicinal tree found in temperate regions. Various parts of this plant had been used traditionally for the treatment of various ailments such as root powder applied externally for skin infections. Analysis was carried out on the bioactive lipids extracted from Ficus drupacea fruit using both petroleum-based solvent (Hexane) and an environmentally friendly solvent Dimethyl carbonate (DMC). The results showed that DMC extraction yielded a high oil content in Ficus drupacea fruit (6.51 %). When examining the fatty acid composition using GC-FID analysis, Ficus drupacea oil extracted with DMC contained significant proportions of essential fatty acids such as linoleic acid (32.317 %), oleic acid (20.946 %), palmitic acid (25.841 %), etc. Additionally, DMC extraction resulted in higher levels of total phenolics in Ficus drupacea fruit oil compared to hexane. Moreover, DMC extracted oil exhibited stronger antioxidant properties, such as radical scavenging, anti- arthritic, photoprotective activity while displayed similar anti-inflammatory and anti-microbial activity as hexane-extracted oil. In summary, these findings demonstrate that DMC is an efficient and safer alternative to conventional solvent hexane for extracting oils from Ficus drupacea fruit. It is rich in bioactive compounds essential for human nutrition, including polyunsaturated fatty acids, flavonoids, and phenolic compounds, with enhanced biological activities.

A Comparative Study and Characterization of Green Solvent and Hexane Extracted Bioactive lipids from Heterospathe elata Fruit

Our study aims to investigate the extraction of fixed oil from the fruit of Heterospathe elata, using traditional petroleum-based solvent hexane and green solvent dimethyl carbonate (DMC), evaluation of physicochemical parameters, chemical composition, and biological activities of extracted oil. The resulting oil components were subjected to GC-FID analysis. The evaluation of different biological activities like antioxidant, anti-inflammatory, and photoprotective activities has been done by the spectrophotometric method. The results obtained from GC-FID analysis proved the presence of fatty acids, of which myristic acid was the most prevalent component in the DMC and hexane fractions, respectively. Additionally, DMC-extracted oil possess stronger antioxidant, anti-inflammatory, and photoprotective activities than hexane-extracted oil. The findings showed that DMC is effective in replacing potentially hazardous solvents to extract oil from the Heterospathe elata fruit, rich in components relevant to the human diet, including vital polyunsaturated fatty acids and phenolic compounds, with better biological activity.

Liquid-liquid equilibria of Aliquat 336 + green solvents + water for replacement of petroleum-based solvents: Intramolecular analysis and thermodynamic behavior

The investigations of Aliquat 336 dissolved in green solvents: corn oil, rice bran oil, and sunflower oil, compared with toluene and kerosene to replace the petroleum-based solvents. Liquid-liquid equilibria of adjusted pH water + Aliquat 336 + solvents were evaluated at 303.2 K, 313.2 K, and 323.2 K and 0.1 MPa. The mass fraction of Aliquat 336 was carried out in the range 25–75 wt%. The performance of solvents was explored through the distribution coefficient (D) and selectivity factor (S). The Van’t Hoff, Jouybran – Acree model, modified Jouybran - Acree - Van’t Hoff, and nonrandom two liquid (NRTL) models were investigated. The mixed Gibbs free energy topology (GM(L)) analysis was applied to verify the accuracy of binary interaction parameters from the model. It is seen that corn oil at 303.2 K proved to be the most efficient solvent to dilute Aliquat 336. As verified by the good, correlated root mean square deviations and the GM(L) analysis, the NRTL model fits in well with the tie-line experimental data. The density functional theory reveals the stronger molecular interaction between Aliquat 336 and green oils than petroleum-based solvents. In line with the properties effect, the dielectric constants and viscosity are seen to further support the experimental results.

Investigation of alternative two-phase solvent systems for purification of natural products by centrifugal partition chromatography.

Centrifugal partition chromatography (CPC) is a liquid-liquid chromatography characterised by its solvent flexibility. The compounds undergoing separation are subjected to a continuous partition process between two immiscible phases in a column space free of solid support. In the context of green chemistry, it is important to substitute halogenated and petroleum-based solvents commonly used in purification processes. The main goal of the current study was to replace classical solvents used in CPC (e.g., hexane and methanol) by green and renewable alternatives. Solvents were first selected based on literature. Their commercial availability, price, recyclability, toxicity and ability to form two phases were particularly sought after. The new two-phase solvent systems were evaluated for the purification of two compounds of interest: piperine and cannabidiol. Using these alternative two-phase solvent systems allows us to isolate natural products with a high purity level (> 95%). Substituting petroleum-based solvents with bio-sourced, renewable alternatives reduces the environmental impact of CPC. Herein, new biphasic solvent systems were built using hexamethyldisiloxane, ethyl isobutyrate and 2-methyl tetrahydrofuran in combination with ethanol and water. Furthermore, this research provides a scientific basis for developing new and sustainable solvent systems in CPC.

Investigating bio-based solvents as a sustainable alternative in the formulation and fabrication of superhydrophobic surfaces

Organic solvents can be highly toxic to humans, causing damage to the tissues and toxin metabolizing systems. Petroleum-based solvents (such as n-hexane) are likely to trigger endocrine disruption in humans regularly exposed to them. Given this, there is still a high demand for petroleum-based solvents, as they can be used to fabricate materials for various high-performance products. In addition, extensive environmental damage is also caused by petroleum-based solvents. This biological and environmental harm has been the main cause of the demand for sustainable and cost-effective development of environmentally non-hazardous solvent systems. An area targeted to achieve this is bio-based solvent alternatives. In this report, 2-methyltetrahydrofuran (2-MeTHF), a bio-based solvent, is explored as an alternative solvent in the development of superhydrophobic surfaces, replacing n-hexane. This model system explores the factors considered when exploring the implementation of bio-based solvents in the development of highly advanced materials. In this research, both 2-MeTHF/n-hexane are used in the formulation/deposition of superhydrophobic polymer–nanoparticle composites (SPNCs). SPNCs developed using 2-MeTHF have water repelling functionality like those developed using n-hexane, while also demonstrating performance enhancements. Overall, this solvent exchange is aimed to serve as an example of what can be achieved in similar systems to enhance the sustainability of chemical processes that require organic solvents.

Catalytic Valorisation of Biomass-Derived Levulinic Acid to Biofuel Additive γ-Valerolactone: Influence of Copper Loading on Silica Support

γ-valerolactone (GVL) is a crucial chemical feedstock used in the production of fuel additives, renewable fuels, and fine chemicals alternative to petroleum-based solvents and chemicals, supporting the transition to sustainable energy solutions. It is promptly acquired by hydrogenating levulinic acid (LA) in a gaseous or liquid phase with a homogeneous or heterogeneous catalyst using a variety of recognized catalytic processes. Herein, this work focuses on the use of silica-supported copper (Cu/SiO2) catalysts for the gas-phase hydrogenation of LA to GVL under mild reaction conditions. The study analyzes how copper loading can affect the catalytic activity of the Cu/SiO2, while the flow rate of LA, time-on-stream, reaction temperature, and LA concentration affect the catalytic efficiency. The SiO2 support’s various Cu loadings are crucial for adjusting the catalytic hydrogenation activity. One of the studied catalysts, a 5 wt% Cu/SiO2 catalyst, demonstrated ~81% GVL selectivity with ~78% LA conversion and demonstrated stability for ~8 h while operating at atmospheric pressure and temperature (265 °C) and 0.5 mL/h of LA flow rate. The ability to activate hydrogen, high amount of acidic sites, and surface area were all discovered to be advantageous for increased GVL selectivity.

Parental occupational exposure to solvents and risk of developing testicular germ cell tumors among sons: a French nationwide case-control study (TESTIS study).

The etiology of testicular germ cell tumors (TGCT) is suspected to be related to prenatal environmental risk factors. Some solvents have potential endocrine disrupting or carcinogenic properties and may disrupt male genital development in utero. The aim of this study was to examine the association between parental occupational exposure to solvents and TGCT risk among their offspring. A French nationwide case-control study, TESTIS included 454 TGCT cases and 670 controls frequency-matched on region and 5-year age strata. Participants were interviewed via telephone and provided information on parental occupations at birth. Job-exposure matrices (JEM) developed in the French Matgéné program were used to assign exposure to five petroleum-based solvents, five solvents or groups of oxygenated solvents, and five chlorinated solvents. Odds ratios (OR) for TGCT and 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for TGCT risk factors. Occupational exposure to at least one solvent during the year of their son's birth was 41% among fathers and 21% among mothers. Paternal exposure to at least one solvent showed OR 0.89 (95% CI 0.68-1.15). Exposure to perchloroethylene (OR 1.41, 95% CI 0.55-3.61), methylene chloride (OR 1.13, 95% CI 0.54-2.34) and diesel/kerosene/fuel oil (OR 1.17, 95% CI 0.80-1.73) disclosed OR >1 but with low precision. Our results suggest a possible modest increase in non-seminoma risk for sons whose fathers were highly exposed to trichloroethylene (OR 1.44, 95% CI 0.79-2.63). Maternal exposure to at least one solvent showed OR 0.90 (95% CI 0.65-1.24). When stratifying by birth year, men born in the 1970s experienced an increased TGCT risk following maternal exposure to fuels and petroleum-based solvents (OR 2.74, 95% CI 1.11-6.76). Overall, no solid association was found between parental occupational exposure to solvents and TGCT risk. The association found with maternal occupational exposure to fuels and petroleum solvents among older men needs further investigation.

Flash Points Prediction Based on GC/MS Analysis and Vapor Pressure Measurement of Petroleum-based Solvents

石油系溶剤は消防法における危険物第四類の引火性液体に該当するが，沸点が概ね140 °C以下であるナフサを主原料としていることから，多くの製品が引火点21 °C未満の第一石油類に分類される．石油系溶剤は，複数種類の成分から構成される多成分系の工業製品であることから，蒸発時には，火災危険性を表す最も重要な指標の一つである引火点が変化すると予想され，その変化を予測することは容易ではない．本研究では，5種類の石油系溶剤（石油エーテル，ホワイトガソリン，ベンジン，ラッカーシンナー，塗料用シンナー）を試料に選択して，引火点を予測する手法について検討した．石油系溶剤の蒸発変性試料を作成し，ガスクロマトグラフ質量分析法（GC/MS）により得られたTIC（トータルイオンクロマトグラム）の主要ピークの面積百分率から成分組成を計算することによって，蒸発の進行による石油系溶剤の成分組成変化を調べた．また，蒸発変性試料の飽和蒸気圧測定を行い，蒸気圧測定結果から試料の蒸気圧定数を導出し，任意の温度，蒸発率における飽和蒸気圧の計算式を示した．さらに，引火点においては，液面上の蒸気濃度がLEL（燃焼下限界）と等しいと考え，GC/MSによって得られた成分組成から計算したLELと蒸気圧計算式から，石油系溶剤の蒸発の進行による引火点を予測する手法を提唱した．本手法により予測した石油系溶剤の引火点は実測値と概ね一致した．

Targeted analysis of sea buckthorn oil extracted by accelerated solvent extraction technique using green and conventional solvents

Sea buckthorn oil (SBO) was extracted using accelerated solvent extraction with two green solvents (ethanol and 2-methyltetrahydrofuran), and two petroleum-based solvents (hexane and diethyl ether) at four different temperatures (60, 90, 120 and 150 °C), using one extraction cycle at 103.42 bar, 10 min static time, 5 min preheating and 30% flushing volume. β-carotene and α-tocopherol were quantified jointly using HPLC-UV/VIS and the fatty acid profile was analyzed using GC-MS. Extraction yield was also measured and the data was compared to a conventional extraction using Soxhlet. The extraction with ethanol achieved significantly higher concentrations of β-carotene in the final oil (1.67 mg/g oil) compared to the results of any other solvent (e.g. 1.23 mg/g oil for hexane ASE) or to the conventional extraction (1.27 mg/g oil). However, the use of green solvents led to the dragging of unwanted polar compounds (sugars), leading to lower oil yield values after purification.

Extraction of Polyphenolic Antioxidants from Red Grape Pomace and Olive Leaves: Process Optimization Using a Tailor-Made Tertiary Deep Eutectic Solvent

In the framework of introducing green strategies for food processing, the industrial orientation has shifted towards the replacement of conventional petroleum-based solvents with alternative eco-friendly ones. On this basis, the objective of this study was to synthesize a novel, tertiary, food-grade deep eutectic solvent, composed of glycerol, citric acid, and L-proline (GL-CA-Pro), and to test it as a solvent for the extraction of polyphenols from agri-food waste biomass. After an initial screening on various common residual materials (apple peels, lemon peels, orange peels, red grape pomace, olive leaves), evidence emerged that indicated GL-CA-Pro was more effective than other DESs commonly used for polyphenol extraction. Furthermore, extracts from red grape pomace (RGP) and olive leaves (OLL) were shown to contain higher level of total polyphenols and increased antioxidant activity. Process optimization for those two materials with the response surface methodology revealed that the major difference pertained to the extraction time. In addition, for both materials, GL-CA-Pro was shown to provide higher total polyphenol yields (53.25 and 42.48 mg gallic acid equivalents per g of dry mass, respectively) compared to water and 60% aqueous ethanol. However, the chromatographic analyses for OLL suggested aqueous ethanol was a more suitable solvent for some principal polyphenolic constituents. The RGP extract produced with GL-CA-Pro exhibited significantly stronger antioxidant effects compared to the aqueous and hydroethanolic extracts, but the outcome for the OLL extracts was diversified. It was concluded that GL-CA-Pro is a very efficient solvent for RGP polyphenols, but its efficiency regarding OLL was comparable to that of aqueous ethanol.

Reactive distillation for sustainable synthesis of bio-ethyl lactate: Kinetics, pilot-scale experiments and process analysis

Bio-ethyl lactate (EL), an alternative green solvent to the traditional petroleum-based solvent, has a distinct advantage in the chemical industry. However, to solve the problem of high energy consumption and low yield in the production of EL is the premise of large-scale production and application. This work proposes an economical and energy-efficient reactive distillation (RD) process through excess lactic acid (LA). As the primary data of RD process design, the kinetics of esterification reaction between LA and EL were investigated using the ion exchange resins KRD001 catalyst. Besides, the developed RD model has been validated utilizing five pilot-scale RD experimental data for process design. Furthermore, the proposed process is optimized with the objective of the minimum heat duty per kilogram product (HDP) of EL, taking into account energy consumption, reaction conversion, economic and environmental impacts. The proposed process has obvious economic and environmental advantages, which can cause a reduction of 52.25% for the total annual cost per kilogram product (TACK) of EL and 4.63% for the gas emissions compared with the excess ethanol (EtOH) process. This provides guidance and reference for the green technology development and production of EL.

Application of solvent pH under pressurized conditions using accelerated solvent extraction and green solvents to extract phytonutrients from wild berries

Berry fruits are known as “superfoods” due to health benefits associated with the high content of bioactive compounds or phytonutrients. Organic extraction solvents are fundamentally volatile compounds acquired from non-renewable resources, i.e petroleum-based solvents are presumed to be harmful to both human health and the environment. Owing to the new emphasis on environmental and safety protections and the development of green chemistry, finding alternative solvents to replace the organic ones has recently become a major concern. Indeed, there is a great interest in the scientific community to develop a suitable green approach to allow the extraction and recovery of the bioactive phytonutrients from berry sources for applications in improving human health and nutrition. In this study, the phytonutrient composition of three popular wild berries: blueberry (Vaccinium angustifolium), partridgeberry (Vaccinium vitis-idaea L.) and Rosehipberry (Rosa canina), were evaluated following extraction using biphasic green solvents at pH 2.5, 7.0, and 11.5 under pressurized conditions using Accelerated Solvent Extraction (ASE) system. The total phenolic content and composition, antioxidant activity, vitamin and mineral content of the berry extracts were evaluated using Folin-Ciocalteu assay, Ferric Reducing Antioxidant Power Assay (FRAP), Ultra-High-pressure Liquid Chromatography-Mass Spectrometry (UHPLC-MS) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The highest total antioxidant activity (p ≤ 0.05) and phenolic content were observed in rosehip berry followed by blueberry and partridgeberry in the hydroethanolic extracts at pH 11.5. Nevertheless, the highest extraction efficiency of total fat-soluble vitamins (FSV) and total B vitamins were also observed in the hydroethanolic extract at pH 11.5. Both in rosehipberry and partridgeberry the highest vitamin C content was observed in hydroethanolic extract at pH 11.5, whereas in blueberry it was observed in the pH 2.5 hydroethanolic extract. In the present study, results demonstrated that using the green solvent system (hydroethanolic, 70:30 v/v) at alkaline pH (11.5) as a pressurized fluid in the ASE system provided significant recovery of phytonutrients from wild berries. This green environmentally friendly system of extraction could represent a suitable alternative for the preparation of food grade or green solvent-based extracts for applications in the food and nutraceutical industry.

Stereospecific Epoxidation of Limonene Catalyzed by Peroxygenase from Oat Seeds.

Limonene is one of the most abundant naturally occurring cyclic monoterpenes and has recently emerged as a sustainable alternative to petroleum-based solvents as well as a chemical platform for the production of value-added compounds. The biocatalytic epoxidation of both enantiomers of limonene was carried out in the presence of a peroxygenase-containing preparation from oat (Avena sativa) flour. Different reaction profiles were observed depending on the starting enantiomer of limonene, but in both cases the 1,2-monoepoxide was obtained as the main product with excellent diastereoselectivity. Trans-1,2-monoepoxide and cis-1,2-monoepoxide were isolated from the reaction of (R)-limonene and (S)-limonene, respectively, and the reactions were scaled-up to 0.17 M substrate concentration. The process is valuable for operational simplicity, lack of toxic metal catalysts, and cost-effectiveness of the enzymatic source. Pure stereoisomers of 1,2-monoepoxides of limonene constitute a useful starting material for biorenewable polymers, but can be also converted into other chiral derivatives by epoxide ring opening with nucleophiles. As a proof of concept, a tandem protocol for the preparation of enantiopure (1S,2S,4R)-1,2-diol from (R)-limonene and (1R,2R,4S)-1,2-diol from (S)-limonene was developed.

Formulation of Environmentally Safe Graffiti Remover Containing Esterified Plant Oils and Sugar Surfactant

The removal of graffiti or over-painting requires special attention in order to not induce the surface destruction but to also address all of the important eco-compatibility concerns. Because of the necessity to avoid the use of volatile and toxic petroleum-based solvents that are common in cleaning formulations, much attention has recently been paid to the design of a variety of sustainable formulations that are based on biodegradable raw materials. In the present contribution we propose a new approach to graffiti cleaning formulations that are composed of newly synthesized green solvents such as esterified plant oils, i.e., rapeseed oil (RO), sunflower oil (SO), or used cooking oil (UCO), ethyl lactate (EL), and alkylpolyglucosides (APGs) as surfactants. Oil PEG-8 ester solvents were synthesized through the direct esterification/transesterification of these oils using monobutyltin(IV) tris(2-ethylhexanoate) and titanium(IV) butoxide catalysts under mild process conditions. The most efficient formulations, determined by optimization through the response surface methodology (RSM) was more effective in comparison to the reference solvents such as the so-called Nitro solvent (denoting a mixture of toluene and acetone) and petroleum ether. Additionally, the optimal product was found to be effective in removing graffiti from glass, metal, or sandstone surfaces under open-field conditions in the city of Wrocław. The performed studies could be an invaluable tool for developing future green formulations for graffiti removal.

Green Solvent to Substitute Hexane for Bioactive Lipids Extraction from Black Cumin and Basil Seeds.

A comparative study of bioactive lipids extraction from black cumin (Nigella sativa L.) and basil (Ocimum basilicum L.) seeds using conventional petroleum-based solvent and green solvent 2-methyltetrahydrofuran (MeTHF) was performed. MeTHF extraction allowed obtaining the highest oil yield in black cumin (34%). Regarding fatty acids composition, linoleic acid (61%) and α-linolenic (78%) were relevant in black cumin and basil green and conventionally extracted oils, respectively. Besides, MeTHF allowed obtaining higher tocopherols and total phenolics contents in black cumin (400 mg/kg of oil and 12 mg EGA/g oil) and basil (317 mg/kg oil and 5 mg EGA/g oil) compared to hexane-extracted ones. The content of major phenolic compounds in the two seed oils, trans-hydroxycinnamic acid, rosmarinic acid, and thymol was enhanced by MeTHF extraction. Furthermore, MeTHF-extracted oils possess stronger antioxidant activities (radical scavenging, total antioxidant, and β-carotene bleaching activities) and high and similar anti-inflammatory capacity to hexane-extracted oils. In conclusion, the results revealed that MeTHF is efficient to replace hazardous solvents to extract oil from black cumin and basil seeds rich in compounds relevant to the human diet, including essential polyunsaturated fatty acids (n-6 and n-3), tocopherols, and phenolic compounds with improved biological activities.

2-Methyloxolane (2-MeOx) as Sustainable Lipophilic Solvent to Substitute Hexane for Green Extraction of Natural Products. Properties, Applications, and Perspectives.

This review presents a complete picture of current knowledge on 2-methyloxolane (2-MeOx), a bio-based solvent for the extraction of natural products and food ingredients. It provides the necessary background about the properties of 2-MeOx, not only its solvent power and extraction efficiency, but its detailed toxicological profile and environmental impacts are discussed. We compared 2-MeOx with hexane which is the most used petroleum-based solvent for extraction of lipophilic natural products. The final part focuses on successful industrial transfer, including technologic, economic, and safety impacts. The replacement of petroleum-based solvents is a hot research topic, which affects several fields of modern plant-based chemistry. All the reported applications have shown that 2-MeOx is an environmentally and economically viable alternative to conventional petroleum-based solvents for extraction of lipophilic foodstuff and natural products.

Extraction of Methylene Blue from Aqueous Solutions by Waste Cooking Oil and its Back-Extraction

This work aimed to use waste cooking oil as a greener replacement for the petroleum-based solvents in removing methylene blue (MB) from aqueous solutions by solvent extraction. The effects of different extraction parameters such as equilibrium pH, aqueous to organic phase ratio, and initial MB concentration on the extraction of MB from aqueous solutions by waste cooking oil were investigated. The back-extraction of MB from MB-loaded waste cooking oil was also explored. The maximum extraction (∼90%) and back-extraction (>90%) of MB were attained at equilibrium pH of 8, aqueous to organic phase ratio of 1:1, initial MB concentration of 20 mg/L, and with 1 M of sodium bicarbonate as the back-extraction agent.

Maternal occupational exposure to solvents and gastroschisis in offspring - National Birth Defects Prevention Study 1997–2011

ObjectivesThe aim of this study was to assess the association between maternal occupational exposure to solvents and gastroschisis in offspring.MethodsWe used data from the National Birth Defects Prevention Study, a...