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26,704 result(s) for "Organic solvents"
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Utilization of green organic solvents in solvent extraction and liquid membrane for sustainable wastewater treatment and resource recovery—a review
Water pollution and depletion of natural resources have motivated the utilization of green organic solvents in solvent extraction (SX) and liquid membrane (LM) for sustainable wastewater treatment and resource recovery. SX is an old and established separation method, while LM, which combines both the solute removal and recovery processes of SX in a single unit, is a revolutionary separation technology. The organic solvents used for solute removal in SX and LM can be categorized into sole conventional, mixed conventional-green, and sole green organic solvents, whereas the stripping agents used for solute recovery include acids, bases, metal salts, and water. This review revealed that the performance of greener organic solvents (mixed conventional-green and sole green organic solvents) was on par with the sole conventional organic solvents. However, some green organic solvents may threaten food security, while others could be pricey. The distinctive extraction theories of various sole green organic solvents (free fatty acid-rich oils, triglyceride-rich oils, and deep eutectic solvents) affect their application suitability for a specific type of wastewater. Organic liquid wastes are among the optimal green organic solvents for SX and LM in consideration of their triple environmental, economic, and performance benefits.
Monolayer graphene membranes for molecular separation in high-temperature harsh organic solvents
The excellent thermal and chemical stability of monolayer graphene makes it an ideal material for separations at high temperatures and in harsh organic solvents. Here, based on understanding of solvent permeation through nanoporous graphene via molecular dynamics simulation, a resistance model was established to guide the design of a defect-tolerant graphene composite membrane consisting of monolayer graphene on a porous supporting substrate. Guided by the model, we experimentally engineered polyimide (PI) supporting substrates with appropriate pore size, permeance, and excellent solvent resistance and investigated transport across the resulting graphene-covered membranes. The cross-linked PI substrate could effectively mitigate the impacts of leakage through defects across graphene to allow selective transport without defect sealing. The graphene-covered membrane showed pure solvent permeance of 24.1 L m−2 h−1 bar−1 and stable rejection (∼90%) of Allura Red AC (496.42 g mol−1) in a harsh polar solvent, dimethylformamide (DMF), at 100 °C for 10 d.
Bamboo charcoal fused with polyurethane foam for efficiently removing organic solvents from wastewater: experimental and simulation
The development of a multifunctional oil adsorbing material which could effectively and quickly separate oily wastewater is one of the focuses in water environment restoration. In this study, bamboo charcoal (BC) was used as an improver to modify polyurethane (PU) foam. The results of scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) revealed that the addition of BC could effectively improve the mechanical properties of PU. The adsorption data exhibited that the BC-loaded PU (BC/PU) foam composites effectively removed seven organic solvents (OSs, including octane, petroleum ether, soybean oil, chlorobenzene, 1,2-dichloroethane, n-hexane, cyclohexane), and the maximum adsorption capacity of BC/PU was 23.6 g g−1 when BC content was 5%. The order of pseudo-second-order kinetic constants and maximum adsorption capacity of seven OSs was octane < petroleum ether < soybean oil < chlorobenzene < 1, 2-dichloroethane < cyclohexane < n-hexane. Based on the experimental data and density functional theory (DFT) simulation, the adsorption mechanism of OSs on BC/PU-5 was discussed. The EHOMO and μ of OSs calculated by DFT were highly correlated with absorption affinity (K2, Qe and Qmax). Hence, the contribution of OSs to the adsorption efficiency of BC/PU-5 may be mainly due to electron donor–acceptor (EDA) interaction and non-hydrophobic interaction. In addition, the adsorption capacity did not change significantly after repeated recycling 5 times. Overall, the prepared BC/PU foam composites could be used as a potential candidate for separating OSs in engineering applications.Graphical AbstractThe adsorption performance of BC/PU-5 for n-hexane reached the maximum of 23.6 g g−1.Based on the kinetic calculation and DFT simulation, the adsorption mechanism of OSs on BC/PU-5 was discussed.The quantitative correlation between the structural parameters of OSs and the adsorption properties of BC/PU-5 was established.
Highly stretchable, soft and sticky PDMS elastomer by solvothermal polymerization process
Siloxane rubber shows attractive properties of high stability, elasticity and transparency. Besides, the regulation of its properties renders it widely used in many application fields. However, most of the reported performance improvement methods of siloxane rubber focus on the change of chemical composition of siloxane rubber, including the design of molecular chain and the introduction of other compounds, etc. Such a strategy is still faced with many limitations in practical application. In this work, on the premise of not changing the chemical composition of siloxane rubber, we propose a facile solvothermal polymerization process to change the structure of cross-linking networks, so as to obtain the siloxane rubber with controllable mechanical properties. Compared to the normal curing method, we realized polydimethylsiloxane elastomer (PDMS) with maximum elongation of more than 3,000% (> 10 times of normally cured one) and tensile modulus lower than 0.15 MPa (< 1/10 of normally cured one). In addition to superior stretchability, it gains extra high softness, stickiness and sensitive response to organic solvents. Based on our solvothermal cured PDMS, its applications in oil collection and organic solvent sensor have been demonstrated. It is expected that this method can be readily utilized widely and shows great application potentials.
Total Anthocyanin Content of Strawberry and the Profile Changes by Extraction Methods and Sample Processing
Anthocyanins are the primarily pigments in many flowers, vegetables, and fruits and play a critical role in human and plant health. They are polyphenolic pigments that are soluble in water and usually quantified by spectrophotometric methods. The two main methods that quantify anthocyanins are pH differential and organic solvent-based methods. Our hypothesis was that these methods extract different anthocyanin profiles. Therefore, this experiment was designed to identify anthocyanin profiles that are extracted by pH differential and organic solvent-based methods and observe their total anthocyanin content from strawberries. Six methods were tested in this experiment to quantify and profile anthocyanins in strawberry fruits by spectrophotometry and Ultra High Performance Liquid Chromatography (UHPLC) respectively. Four methods used organic solvents (methanol, and chloroform-methanol) in different combinations. The next two methods were pH differential and a combination of organic solvent and the pH differential method. The results suggest that acidified chloroform-methanol extracted the highest anthocyanin content compared to water-based solvents. Methanol-water based solvents also performed better than methanol alone, because both methanol and water may extract different profiles of anthocyanins. Water-based extracts had the greatest absorbance at a lower wavelength (498 nm), followed by methanol (508 nm), and chloroform (530 nm). Chloroform-methanol solvent with higher pH (3.0) extracted pelargonidin as the main anthocyanin, while methanol and water-based solvents (with lower pH 1.0–2.0) extracted delphinidin as their main anthocyanin as identified by UHPLC. Therefore, chloroform-methanol and methanol-water solvents were the best solvents for extracting anthocyanins from strawberries. Also, freeze-dried strawberries had higher anthocyanin contents compared to fresh or frozen samples.
Organic solvent nanofiltration membranes for separation in non-polar solvent system
Membrane technology holds significant potential for augmenting or partially substituting conventional separation techniques, such as heat-driven distillation, thereby reducing energy consumption. Organic solvent nanofiltration represents an advanced membrane separation technology capable of discerning molecules within a molecular weight range of approximately 100–1000 Da in organic solvents, offering low energy requirements and minimal carbon footprints. Molecular separation in non-polar solvent system, such as toluene, n-hexane, and n-heptane, has gained paramount importance due to their extensive use in the pharmaceutical, biochemical, and petrochemical industries. In this review, we presented recent advancements in membrane materials, membrane fabrication techniques and their promising applications for separation in non-polar solvent system, encompassing hydrocarbon separation, bioactive molecule purification and organic solvent recovery. Furthermore, this review highlighted the challenges and opportunities associated with membrane scale-up strategies and the direct translation of this promising technology into industrial applications. This review comprehensively summarizes various types of organic solvent nanofiltration membranes and preparation strategies suitable for non-polar systems. Additionally, it provides detailed large-scale membrane fabrication techniques and the applications of organic solvent nanofiltration membranes in chemical, petrochemical and pharmaceutical industry. [Display omitted] •Three typical OSN membranes, including polymeric membranes, inorganic membranes, and nanocomposites membranes, are discussed.•The latest advancements and strategies in membrane fabrication processes that designed for non-polar OSN are reviewed.•The important applications for membrane separation in non-polar organic solvent system are summarized.•The challenges of membrane scale-up are revealed and promising transformation into industrial applications are prospected.
Comparing pH differential and methanol‐based methods for anthocyanin assessments of strawberries
Anthocyanins are a group of water‐soluble polyphenolic pigments found primarily in flowers, vegetables, and fruits. These pigments play critical roles in plant and human health. Spectrophotometric methods are a simple and inexpensive way to quantify anthocyanins in plant tissues. Two main spectrophotometric methods have been developed, organic solvent‐based, and pH differential methods. Both of these methods are subject to interference from light‐absorbing impurities and need to be optimized for different matrixes of different plant materials. Eight methods have been tested in this experiment to quantify anthocyanins in strawberry fruits. Six organic solvent‐based methods tested methanol, chloroform‐methanol, and MgO in different ratios. The other two methods were pH differential method and a combination of organic solvent‐based and pH differential method. Two methods used organic solvents (methanol and chloroform‐methanol) were the best in extracting anthocyanin from strawberry fruits. Adding MgO increased the pH of the extract and was less efficient in anthocyanin extraction. All other methods had lower anthocyanin yield compared with methanol and chloroform‐methanol methods and are not recommended for strawberry fruit anthocyanin extraction. Two organic solvents, methanol and chloroform‐methanol, were the best in extracting anthocyanin from strawberry fruits. MgO decreased anthocyanin yield. All other methods had lower anthocyanin yield compared with methanol and chloroform‐methanol methods.
Successful prevention of organic solvent induced disorders
In this discussion paper, we describe the history of the science and societal action resulting in the mitigation of neurotoxic disorders from exposure to organic solvents at the workplaces in Sweden. When alkyd paints were introduced in large scale in construction painting in the 1960s and 1970s, Scandinavian unions voiced increasing concern as members reported symptoms like headache and vertigo, supported by participatory studies and case studies. Although acute and chronic neurotoxic effects were established for some specific solvents such as carbon disulphide, this was not the case for those used in the new paints. Union advocacy promoted formal epidemiological studies, providing increasing evidence for chronic neurotoxicity at levels far below current occupational exposure levels. The results were widely disseminated and accepted and led to concerted action with preventive measures, most importantly substitution of the organic solvents in paints for indoor use, but also drastic reductions in occupational exposure limits. The findings also resulted in funding of further research on solvent toxicity and the establishment of expert groups to advice authorities on occupational standards for exposure to chemicals. The substitution strategy was subsequently adopted in many other countries and occupational exposure limits were lowered, although several years or even decades later. While the societal context in Sweden was unique in many ways, we conclude that there are lessons to be learned from this preventive success when addressing current challenges.
Improving the Separation Properties of Polybenzimidazole Membranes by Adding Acetonitrile for Organic Solvent Nanofiltration
In research on membranes, the addition of co-solvents to the polymer dope solution is a common method for tuning the morphology and separation performance. For organic solvent nanofiltration (OSN) applications, we synthesized polybenzimidazole (PBI) membranes with high separation properties and stability by adding acetonitrile (MeCN) to the dope solution, followed by crosslinking with dibromo-p-xylene. Accordingly, changes in the membrane structure and separation properties were investigated when MeCN was added. PBI/MeCN membranes with a dense and thick active layer and narrow finger-like macrovoids exhibited superior rejection properties in the ethanol solution compared with the pristine PBI membrane. After crosslinking, they displayed superior rejection properties (96.56% rejection of 366-g/mol polypropylene glycol). In addition, the membranes demonstrated stable permeances for various organic solvents, including acetone, methanol, ethanol, toluene, and isopropyl alcohol. Furthermore, to evaluate the feasibility of the modified PBI OSN membranes, ecamsule, a chemical product in the fine chemical industry, was recovered. Correspondingly, the efficient recovery of ecamsule from a toluene/methanol solution using the OSN process with PBI/MeCN membranes demonstrated their applicability in many fine chemical industries.
Occupational exposure to organic solvents and the risk of developing testicular germ cell tumors (TESTIS study)
OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.