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Search results for: residual solvents
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Effects of CO2 and Nd:YAG Laser Remelting of the Ti6Al4V Alloy on the Surface Quality and Residual Stresses
PublicationThe titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks . The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level...
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Electrical safety in low-voltage DC microgrids with B-type residual current devices
PublicationResidual current devices (RCDs) are most popular devices used in low-voltage installations for protection against electric shock and fire. In cases of high risk of electric shock the application of RCDs is mandatory. Currently, the spread of local direct current (DC) microgrids is widely considered. This creates new challenges for protective systems, in particular those based on RCDs. The main purpose of the research is to test...
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Tripping of F-type RCDs for sinusoidal residual current with superimposed smooth DC component
PublicationRecent trends in green energy development make that photovoltaics and electric vehicles are applied on an increasing scale. In both photovoltaic and electric vehicle charging installations, a significant value of DC component of the earth fault current may appear, which is a challenge, in particular, for commonly used residual current devices (RCDs). This paper presents results of the laboratory test on the operation of F-type...
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Complementary studies of residual stress distribution of repaired power plant steam turbine casing
PublicationRozkład i poziom naprężeń własnych w korpusach turbin badano za pomocą efektu Barkhausena oraz metodą nawiercania otworów. Badano również twardość. Korpusy były reperowane metodą zaspawania. Wykazano, iż zastosowana technologia nie wprowadza naprężeń o poziomie zagrażającym dalszej ekploatacji korpusu.
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Purification of model biogas from toluene using deep eutectic solvents
PublicationBiogas from landfills and wastewater treatment facilities typically contain a wide range of volatile organic compounds (VOCs), that can cause severe operational problems when biogas is used as fuel. Among the contaminants commonly occur aromatic compounds, i.e. benzene, ethylbenzene, toluene and xylenes (BTEX). In order to remove BTEX from biogas, different processes can be used. A promising process for VOCs removal is their absorption...
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Pre-selection and assessment of green organic solvents by clustering chemometric tools
PublicationThe study presents the result of the application of chemometric tools for selection of physicochemical parameters of solvents for predicting missing variables – bioconcentration factors, water-octanol and octanol-air partitioning constants. EPI Suite software was successfully applied to predict missing values for solvents commonly considered as “green”. Values for logBCF, logKOW and logKOA were modelled for 43 rather nonpolar solvents...
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SORPTION OF SELECTED CHLORINATED SOLVENTS ON PLANT DEBRIS COLLECTED IN A CITY PARK
PublicationDebris from deciduous trees in the form of park green waste was investigated as a potential biosorbent for the removal of chlorinated solvents from water. The sorption properties of beech leaves and cupules, oak leaves and acorns, birch leaves and lime leaves (all tree species common for a moderate climate) in a non-modified form were investigated with regard to the removal of perchloroethylene, 1,1,2-trichloroethane and 1,1,1,2-tetrachlorothane....
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Nano-adsorbent Modification by Deep Eutectic Solvents for Wastewater Treatment Applications
PublicationThe Greek “εύ” and “τήξις” term is the root of the “eutectic” word that refers to the low melting of mixture. Generally, an eutectic solvent depicts a mixture of components (at least one is in solid phase) that under particular ratios weak molecular interactions allow to obtain a mixture having melting point at a much lower temperature than that of each component (García-Álvarez 2019). Although A. P. Abbott et al. discovered the...
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Deep eutectic solvents – Ideal solution for clean air or hidden danger?
PublicationThe industrial sector is one of the fastest-growing sources of greenhouse gases, due to its excessive energy consumption to meet the rapidly growing demand for energy-intensive products. The use of deep eutectic solvents (DESs) has been studied extensively in order to cope with these harmful gases, but their usage can be an issue in respect to ecological reasons. Do deep eutectic solvents harm the atmosphere? Yes, these solvents...
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Lignocellulosic waste biosorbents infused with deep eutectic solvents for biogas desulfurization
PublicationThis paper introduces an innovative method for treating biogas streams, employing lignocellulosic biosorbents infused with environmentally friendly solvents known as deep eutectic solvents (DES). The primary focus of this study was the elimination of volatile organosulfur compounds (VSCs) from model biogas. Biosorbents, including energetic poplar wood, antipka tree, corncobs, and beech wood, were used, each with varying levels...
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublicationIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1: 4, 1: 6 and 1: 8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Usefulness of the Free Length Theory for assessment of the self-association of the pure solvents
PublicationWykonano pomiary szybkości rozchodzenia się dźwięku i gęstości metanolu, acetonitrylu, N,N-dimetyloformamidu, N,N-dimetyloacetamidu, dimetylosulfotlenku i fosforanu trietylu w zakresie temperatur 294 - 333 K . W oparciu o wyznaczone ściśliwości adiabatyczne zastosowano teorię FLT do oceny wzajemnej asocjacji cząsteczek. Uzyskane wyniki przedyskutowano na tle innych sposobów klasyfikacji rozpuszczalników.
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Apparent molar volumes and compressibilities of tetrabutyl-ammonium bromide in organic solvents
PublicationW oparciu o pomiary gęstości i szybkości rozchodzenia się dźwięku w niewodnych roztworach bromku czterobutyloamoniowego obliczono pozorne objętości molowe w przedziale temperatur od 288,15 K do 323,15 K oraz pozorne ściśliwości w temperaturze 298,15 K. Graniczne wielkości pozornej objętości molowej i ściśliwości wyznaczono w oparciu o równanie Massona, jak i równanie Redlicha, Rosenfelda i Mayera oraz z wykorzystaniem teorii Pitzera....
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Determination of chlorinated solvents in industrial water and wastewater by DAI- GC-ECD
PublicationA very simple and quick analytical method, basedon direct aqueous injection, for determination of halogenatedsolvents in refinery water and wastewater, is described.There is a need to determine halogenated solvents in refinerywater streams, because they may originate from severalprocesses. There is also a need to develop methods enablingVOX to be determined in samples containing oil fractions.The method described enables simultaneous...
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Ionic Liquids and Deep Eutectic Mixtures: Sustainable Solvents for Extraction Processes
PublicationIn recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized...
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublicationIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1:4, 1:6 and 1:8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Precipitation and Transformation of Vaterite Calcium Carbonate in the Presence of Some Organic Solvents
PublicationIn this paper, the production of CaCO3 particles via the carbonation route in the reaction of CaCl2 and CO2, using NH3 as a promoter of CO2 absorption, was studied. The solvents used as the reaction media for CaCO3 precipitation were aqueous solutions of methanol, isopropanol and dimethyl sulfoxide (DMSO), in a concentration range of 0–20% (v/v). It was found that the presence of an organic additive influenced the precipitation...
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Calculating the Partition Coefficients of Organic Solvents in Octanol/Water and Octanol/Air
PublicationPartition coefficients define how a solute is distributed between two immiscible phases at equilibrium. The experimental estimation of partition coefficients in a complex system can be an expensive, difficult, and time-consuming process. Here a computational strategy to predict the distributions of a set of solutes in two relevant phase equilibria is presented. The octanol/water and octanol/air partition coefficients are predicted...
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Searching for Solvents with an Increased Carbon Dioxide Solubility Using Multivariate Statistics
PublicationIonic liquids (ILs) are used in various fields of chemistry. One of them is CO2 capture, a process that is quite well described. The solubility of CO2 in ILs can be used as a model to investigate gas absorption processes. The aim is to find the relationships between the solubility of CO2 and other variables—physicochemical properties and parameters related to greenness. In this study, 12 variables are used to describe a dataset...
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Assessment and design of greener deep eutectic solvents – A multicriteria decision analysis
PublicationDeep eutectic solvents (DES) are often considered as green solvents because of their properties, such as negligible vapor pressure, biodegradability, low toxicity or natural origin of their components. Due to the fact that DES are cheaper than ionic liquids, they have gained many applications in a short period of time. However, claims about their greenness sometimes seem to be exaggerated. Especially, bearing in mind lots of data...
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Comparison of the Antibacterial Activity of Selected Deep Eutectic Solvents (DESs) and Deep Eutectic Solvents Comprising Organic Acids (OA‐DESs) Toward Gram‐Positive and Gram‐Negative Species
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The solvent-free thermal dehydration of hexitols on zeolites
PublicationPodczas termicznej dehydratacji heksytoli w obecności zeolitów otrzymano szereg produktów zachodzących zarówno z inwersją lub retencją konfiguracji przy asymetrycznych atomach węgla. Produkty rozdzielano i identyfikowano przy pomocy chromatografii i spektroskopii NMR. 1,4:3,6-dianhydroiditol scharakteryzowano przy pomocy rentgenowskiej analizy strukturalnej.
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Antifungal activity of propolis extracts produced with deep eutectic solvents.
Open Research DataThis dataset contains results of our investigation aiming in determination of antimicrobial potential of the propolis extracts produced with deep eutectic solvents. The activity was determined against C. albicans and C. glabarat strains. On the basis of these results MIC values can be calculated. Three samples of propolis were tested.
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Pyocyanin extraction - the comparison of typical organic solvents and ionic liquids
Open Research DataPyocyanin is a pigment produced by Pseudomonas aeruginosa that recently gained importance as a valuable chemical. Most often, the method for its extraction is based on the use of chloroform, a recognized hazardous substance. Therefore, an efficient and more environment-friendly method is vital for further use. In this work, we compared different organic...
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Solvent dependency of carbon dioxide Henry's constant in aqueous solutions of choline chloride-ethylene glycol based deep eutectic solvent
PublicationThe Henry's constants of carbon dioxide absorbed in aqueous solutions of ethaline (choline chloride-ethylene glycol) were determined for temperatures ranging from 303.15 to 323.15 K based on solubility measurement at CO2 pressure ranging from 0 to 6 bar (0.6 MPa). These studies revealed that the Henry's constant increased with the increase of temperature. Data indicated the highest capacity of CO2 absorption is obtained for ethaline...
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Verification of safety in low-voltage power systems without nuisance tripping of residual current devices
PublicationLow-voltage power systems require initial and periodical verification to check the effectiveness of protection against electric shock. As a protection in case of fault, automatic disconnection of supply is most often used. To verify such a protection measure, the earth fault loop impedance or resistance is measured. This measurement is easy to perform in circuits without residual current devices. When residual current devices are...
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Effect of Linear Energy and Microstructure on the Content of Residual Hydrogen in Welded Joints made of Superduplex Steels
PublicationThe article presents tests concerning the content of retained hydrogen present in FCAW and SAW welded joints made of superduplex steel. The use of various welding technologies resulted in the obtainment of welds having different microstructures and ferrite contents. Measurements of retained hydrogen present in joints (performed using the complete combustion method) revealed various contents of hydrogen in the base material and...
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublicationThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublicationW referacie przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oszacowano wpływ tego odkształcenia na próg fibrylacji serca. Analizowano skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania zaproponowanego...
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Modification of the operating point of residual current transformers for high frequency earth fault currents detection
PublicationFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when earth fault current with high frequency components occurs. Serious hazard of electrocution exists then. One of the most important element of residual current devices is a residual current transformer with iron core. Tripping characteristic of residual current devices strictly...
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Residual current protective device for circuits of distorted earth fault currents – concept, construction and testing
PublicationThis dissertation presents behavioral and performance verification and analysis of residual current devices (RCDs), as well as a proposal for the construction of a new RCD protection. The state of the art focuses over pre-existing design of the RCD and its behavior and response to the circuits with distorted (non-sinusoidal) earth fault currents. The study highlights the loopholes of the existing design and depicts the problem...
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Performance of Vector-valued Intensity Measures for Estimating Residual Drift of Steel MRFs with Viscous Dampers
PublicationViscous Dampers (VDs) are widely used as passive energy dissipation system for improving seismic performance levels especially in retrofitting of buildings. Residual Inter-story Drift Ratio (R-IDR) is another important factor that specifies the condition of building after earthquake. The values of R-IDR illustrates the possibility of retrofitting and repairing of a building. Therefore, this study aims to explore the vector-valued...
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Advanced Scalar-valued Intensity Measures for Residual Drift Prediction of SMRFs with Fluid Viscous Dampers
PublicationMaximum Residual Inter-story Drift Ratio (RIDRmax) plays an important role to specify the state of a structure after severe earthquake and the possibility of repairing the structure. Therefore, it is necessary to predict the RIDRmax of Steel Moment-Resisting Frames (SMRFs) with high reliability by employing powerful Intensity Measures (IMs). This study investigates the efficiency and sufficiency of scalar-valued IMs for predicting...
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RCDs Tripping in the Range from DC to AC 50 kHz for Slowly Rising Residual Current
PublicationThe wide use of power electronic converters means that in many low-voltage systems earth fault currents containing components from DC to AC of various frequencies have to be taken into account. Due to the tendency to increase the modulation frequency in converters, components of higher frequencies may be in the order of several tens of kilohertz. Therefore, it is very important to verify the behavior of devices for protection against...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublicationWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Analysis of Residual Stresses and Dislocation Density of AA6082 Butt Welds Produced by Friction Sir Welding
PublicationThe Friction Stir Welding (FSW) method was employed to join AA6082 sheets. The welds were produced with different tool traverse speed (200 and 250 mm/min), rotational speed (1000 and 1250 RPM) and tool tilt angle (0 and 2 deg). Based on the analysis of XRD patterns, the total precipitation volume fractions in the nugget zones and the base material were calculated. The FSW process resulted in a reduction in the fraction of precipitates...
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Application of the Finite Element Method for Modelling of the Spatial Distribution of Residual Stresses in Hybrid Surface Layers
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Residual stresses distribution in long seam-welded offshore catenary riser of high-manganese steel
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Residual Current Devices Operational Characteristics within the Frequency Range 50 Hz to 1000 Hz.
PublicationW artykule przedstawiono charakterystyki działania powszechnie stosowanych wyłączników różnicowoprądowych przy prądach różnicowych w zakresie częstotliwości 50÷1000 Hz. Częstotliwość wyższa niż 50 Hz wpływa niekorzystnie na prąd zadziałania wyłączników, a w skrajnych przypadkach mogą one w ogóle nie reagować na wolno narastający prąd różnicowy.
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Elimination of the negative effect of earth fault current higher frequency on tripping of residual current devices
PublicationCzęstotliwość prądu różnicowego większa niż 50/60 Hz ma niekorzystny wpływ na wyzwalanie wyłączników różnicowoprądowych. Przy zwiększonej częstotliwości prądu różnicowego rzeczywisty prąd zadziałania wyłączników zwiększa się, a niektóre z nich w ogóle nie wyzwalają. W artykule omówiono główne przyczyny zwiększenia się prądu zadziałania wyłączników różnicowoprądowych oraz przedstawiono sposób eliminacji niekorzystnego wpływu zwiększonej...
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A new method of fault loop resistance measurement in low voltage systems with residual current devices
PublicationThis paper presents a new method of fault loop resistance measurement in low voltage systems with residual current devices. The method enables measuring fault loop resistance without nuisance tripping of residual current devices, by application an unconventional waveform of measurement current. It is important for proper verification of the effectiveness of protection against electric shock.
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The effect of PWM frequency on the effectiveness of protection against electric shock using residual current devices
PublicationW artykule przedstawiono analizę widmową odkształconego prądu ziemnozwarciowego z obwodu silnika o regulowanej prędkości obrotowej za pomocą przemiennika częstotliwości. Oceniono skuteczność ochrony przeciwporażeniowej wykorzystującej wyłączniki różnicowoprądowe przy różnych wartościach częstotliwości PWM przemiennika. Przedstawiono charakterystykę działania proponowanego wyłącznika różnicowoprądowego.
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Evaluation of applicability of classic methods of a fault loop impedance measurement to circuits with residual current devices
PublicationMeasurement of fault loop impedance in low voltage grids and systems is in most cases performed to verify the effectiveness of protection against electric shock by automatic disconnection of supply. For the sake of measurement accuracy, it is advisable to perform it using large current. Unfortunately, in circuits with residual current devices which are very widely used nowadays, a large measurement current may trigger those devices...
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Expectation-Maximization Model for Substitution of Missing Values Characterizing Greenness of Organic Solvents
PublicationOrganic solvents are ubiquitous in chemical laboratories and the Green Chemistry trend forces their detailed assessments in terms of greenness. Unfortunately, some of them are not fully characterized, especially in terms of toxicological endpoints that are time consuming and expensive to be determined. Missing values in the datasets are serious obstacles, as they prevent the full greenness characterization of chemicals. A featured...
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Natural Deep Eutectic Solvents as Agents for Improving Solubility, Stability and Delivery of Curcumin
PublicationPurpose Study on curcumin dissolved in natural deep eutectic solvents (NADES) was aimed at exploiting their beneficial properties as drug carriers. Methods The concentration of dissolved curcumin in NADES was measured. Simulated gastrointestinal fluids were used to determine the concentration of curcumin and quantum chemistry computations were performed for clarifying the origin of curcumin solubility enhancement in NADES. Results NADES...
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Donor properties of water in organic solvents derived from infrared spectraof HDO
PublicationPrzedyskutowano niektóre ilościowe aspekty kooperatywności wiązań wodorowych wody. Zaproponowano skalę własności elektronodonorowych wody w środowisku aprotycznych rozpuszczalników organicznych, pochodną w stosunku do skali liczb donorowych Gutmanna.
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Application of Deep Eutectic Solvents and Ionic Liquids in the Extraction of Catechins from Tea
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Porous Deep Eutectic Solvents–Unfulfilled Dream or the Next Breakthrough in Scientific Innovation?
PublicationPorous deep eutectic solvents (PDES) are capturing the imagination of scientists, promising a revolutionary leap in material science. These innovative materials, blending the versatility of deep eutectic solvents (DES) with the intricate architectures of porous structures, offer an exciting array of applications—from green chemistry and catalysis to energy storage and environmental remediation. However, the journey from laboratory...
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Catalysts for advanced oxidation processes: Deep eutectic solvents-assisted synthesis – A review
PublicationNew catalyst synthesis techniques, including green materials, are extensively studied for heterogeneous photocatalytic advanced oxidation processes (AOPs) on spotlight of sustainable development. Deep eutectic solvents (DESs) started to be used in this field as environmentally friendly alternative to ionic liquids (ILs). During the catalyst synthesis, DESs can act as stabilizers, capping agents, structure directing agents, templates,...
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VOCs absorption from gas streams using deep eutectic solvents – A review
PublicationVolatile organic compounds (VOCs) are one of the most severe atmospheric pollutants. They are mainly emitted into the atmosphere from anthropogenic sources such as automobile exhaust, incomplete fuel combustion, and various industrial processes. VOCs not only cause hazards to human health or the environment but also adversely affect industrial installation components due to their specific properties, i.e., corrosive and reactivity....