Ionic liquids: environmentally sustainable materials for energy conversion and storage applications

Ionic liquids (ILs), often known as green designer solvents, have demonstrated immense application potential in numerous scientific and technological domains. ILs possess high boiling point and low volatility that make them suitable environmentally benign candidates for many potential applications. The more important aspect associated with ILs is that their physicochemical properties can be effectively changed for desired applications just by tuning the structure of the cationic and/or anionic part of ILs. Furthermore, these eco-friendly designer materials can function as electrolytes or solvents depending on the application. Owing to the distinctive properties such as low volatility, high thermal and electrochemical stability, and better ionic conductivity, ILs are nowadays immensely used in a variety of energy applications, particularly in the development of green and sustainable energy storage and conversion devices. Suitable ILs are designed for specific purposes to be used as electrolytes and/or solvents for fuel cells, lithium-ion batteries, supercapacitors (SCs), and solar cells. Herein, we have highlighted the utilization of ILs as unique green designer materials in Li-batteries, fuel cells, SCs, and solar cells. This review will enlighten the promising prospects of these unique, environmentally sustainable materials for next-generation green energy conversion and storage devices. Ionic liquids have much to offer in the field of energy sciences regarding fixing some of the world's most serious issues. However, most of the discoveries discussed in this review article are still at the laboratory research scale for further development. This review article will inspire researchers and readers about how ILs can be effectively applied in energy sectors for various applications as mentioned above.

Ionic Liquids: Environmentally Sustainable Materials for Energy Conversion and Storage Applications.. [DOI: 10.21203/rs.3.rs-2212222/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Ionic liquids (ILs), known as green designer solvents, have shown tremendous application potential in various fields of science and technology. Their unusual and unique physicochemical properties have attracted researchers worldwide from interdisciplinary research areas. ILs possess high boiling point and low volatility, that makes them suitable environmentally benign candidates for many potential applications. The more important aspect associated with ILs is their physicochemical properties can be effectively changed for desired applications just by tuning the structure of the cationic and/or anionic part of ILs. Furthermore, these environmentally benign designer materials can be used as both electrolytes as well as solvents depending on the requirement. Owing to thedistinctive properties such as low volatility, high thermal and electrochemical stability, better ionic conductivity, ILs are nowadays immensely used in variety of energy applications, particularly in the development of green and sustainable energy storage and conversion devices. Suitable ILs are designed for specific purposesto be used as electrolytes and/or solvents for fuel cells, lithium-ion batteries, supercapacitors(SCs) and solar cells. Herein, we have highlighted the utilization of ILs as unique green designer materials in Li-batteries, fuel cells,SCs and solar cells. This review will enlighten the promising prospects of these unique environmentally sustainable materials for next-generation green energy conversion and storage devices.

276 Safety of Maintaining Elective and Emergency Surgery During the COVID-19 Pandemic with the Introduction of an Innovative Protected Elective Surgical Unit (PESU): A Cross-Specialty Evaluation of 30-Day Outcomes in 9925 Patients Undergoing Surgery in a University Health Board

Aim

High quality mobile health applications (mhealth apps) have the potential to enhance the prevention, diagnosis, and treatment of burns. The primary aim of this study was to evaluate whether the quality of mhealth apps for burns care is being adequately assessed. The secondary aim was to determine whether these apps meet UK regulatory standards.

Method

We searched AMED, BNI, CINAHL, Cochrane library, Embase, Emcare, Medline and PsychInfo to identify studies assessing mhealth app quality for burns. The PRISMA reporting guideline was adhered to. Two independent reviewers screened s to identify relevant studies. We analysed whether seven established domains of mhealth app quality were assessed: design, information/content, usability, functionality, ethical issues, security/privacy, and user-perceived value.

Results

Of the 28 included studies, none assessed all seven domains of quality. Design was assessed in 4/28 studies; information/content in 26/28 studies; usability in 12/28 studies; functionality in 10/28 studies; ethical issues were never assessed in any studies; security/privacy was not assessed; subjective assessment was made in 9/28 studies. 17/28 studies included apps that met the definition of ‘medical device’ according to MHRA guidance, yet only one app was appropriately certified with the UK Conformity Assessed (UKCA) mark.

Conclusions

The quality of mHealth apps for burns are not being adequately assessed. The majority of apps should be considered medical devices according to UK standards, but only one was appropriately certified. Regulatory bodies should support mhealth app developers, so as to improve quality control whilst simultaneously fostering innovation.

Mixed Oxime-Functionalized IL/16-s-16 Gemini Surfactants System: Physicochemical Study and Structural Transitions in the Presence of Promethazine as a Potential Chiral Pollutant

The increasing concern about chiral pharmaceutical pollutants is connected to environmental contamination causing both chronic and acute harmful effects on living organisms. The design and application of sustainable surfactants in the remediation of polluted sites require knowledge of partitioning between surfactants and potential pollutants. The interfacial and thermodynamic properties of two gemini surfactants, namely, alkanediyi-α,ω-bis(dimethylhexadecyl ammonium bromide) (16-s-16, where s = 10, 12), were studied in the presence of the inherently biodegradable oxime-functionalized ionic liquid (IL) 4-((hydroxyimino)methyl)-1-(2-(octylamino)-2-oxoethyl)pyridin-1-ium bromide (4-PyC8) in an aqueous solution using surface tension, conductivity, fluorescence, FTIR and 1H NMR spectroscopic techniques. The conductivity, surface tension and fluorescence measurements indicated that the presence of the IL 4-PyC8 resulted in decreasing CMC and facilitated the aggregation process. The various thermodynamic parameters, interfacial properties, aggregation number and Stern–Volmer constant were also evaluated. The IL 4-PyC8-gemini interactions were studied using DLS, FTIR and NMR spectroscopic techniques. The hydrodynamic diameter of the gemini aggregates in the presence of promethazine (PMZ) as a potential chiral pollutant and the IL 4-PyC8 underwent a transition when the drug was added, from large aggregates (270 nm) to small micelles, which supported the gemini:IL 4-PyC8:promethazine interaction. The structural transitions in the presence of promethazine may be used for designing systems that are responsive to changes in size and shape of the aggregates as an analytical signal for selective detection and binding pollutants.

Formation of water-in-oil microemulsions within a hydrophobic deep eutectic solvent

Hydrophobic deep eutectic solvents (DESs) as neoteric, non-toxic, and inexpensive media have the potential to replace organic solvents in various aggregation processes. Conventional water-in-oil microemulsions are formed using mostly environmentally unfavorable toxic organic solvents as the bulk oil phase. Evidence of formation of water-in-DES microemulsions is presented. These novel assemblies are formed using a hydrophobic DES constituted of n-decanoic acid (DA) and tetra-n-butylammonium chloride (TBAC) in 2 : 1 mole ratio, termed TBAC-DA, as the bulk oil phase. It is observed that in the presence of a common and popular non-ionic surfactant Triton X-100 (TX-100), water pools are formed within TBAC-DA under ambient conditions with maximum water loading (w0 = [water]/[TX-100]) of 60 ± 3 for [TX-100] = 300 mM. The formation of the microemulsions is established by using fluorescence probe pyranine, which exhibited the appearance of a band characterizing the un-protonated form of the probe clearly implying onset of water-in-TBAC-DA microemulsion formation. The UV-vis absorbance of CoII further corroborates TX-100-assisted water pool formation within TBAC-DA via the appearance of the band that is assigned to the response of the probe in water. Dynamic light scattering (DLS) measurement suggests average aggregate sizes to be in the range of 72(±4) to 122(±7) nm. These unprecedented water-in-DES microemulsions may have far reaching implications due to their benign nature.

Micellization Behavior of Conventional Cationic Surfactants within Glycerol-Based Deep Eutectic Solvent

The aggregation behavior of two cationic surfactants, i.e., cetyldimethylethanolammonium bromide (CDMEAB) and cetyltributylphosphonium bromide (CTBPB), within an aqueous deep eutectic solvent (DES) is studied. The synthesized DES is composed of 1:2 mole ratio of choline chloride and glycerol and is further characterized by Fourier transform infrared (FTIR) and 1H NMR spectroscopy techniques. The critical micellar concentration (CMC), micellar size, and intermolecular interaction in surfactants within Gly-based DES solutions are investigated by various techniques including surface tension, conductivity, fluorescence, dynamic light scattering (DLS), FTIR, 1H NMR, and two-dimensional (2D) nuclear Overhauser effect spectroscopy (NOESY). The various interfacial properties and thermodynamic parameters are determined in the presence of 5 wt % glyceline (Gly)-based DES in an aqueous solution. The CMC, aggregation number (N agg), and Stern-Volmer constant (K sv) have also been determined by a steady-state fluorescence method. DLS is used to obtain information regarding the size of the aggregates formed by the cationic surfactants in DES solutions. FTIR spectroscopy is used to study the surfactant-DES interactions that tune the micellar structure of the surfactants within the Gly-based DES solution. The functional groups involved in the interactions (H-bonding and electrostatic) are the head groups (HO-CH2-CH2-N+ ion for CDMEAB and quaternary phosphonium (P+) ion for CTBPB) of the surfactants with the -OH-containing Gly DES. The hydrophobic moieties are involved in the hydrophobic interactions. The 1H NMR data show that differences in chemical shifts can provide significant information about the interactions taking place within the system. 1H NMR and NOESY techniques are further employed to strengthen our claim on the feasible structural arrangements within the aqueous surfactant-DES self-assembled structures. It is observed that both the cationic surfactants, i.e., CDMEAB and CTBPB, form self-assembled nanostructures in the Gly-based DES solutions. The present results are expected to be useful for colloidal solutions of DES and their mixtures with water.

Self-aggregation of bio-surfactants within ionic liquid 1-ethyl-3-methylimidazolium bromide: A comparative study and potential application in antidepressants drug aggregation

Aggregation behavior of bio-surfactants (BS) sodium cholate (NaC) and sodium deoxycholate (NaDC) within aqueous solution of ionic liquid (IL) 1-ethyl-3-methylimidazolium bromide [Emim][Br] has been investigated using surface tension, conductivity, steady state fluorescence, FT-IR and dynamic light scattering (DLS) techniques. Various interfacial and thermodynamic parameters are determined in the presence of different wt% of IL [Emim][Br]. Information regarding the local microenvironment and size of the aggregates is obtained from fluorescence and DLS, respectively. FT-IR spectral response is used to reveal the interactions taking place within aqueous NaC/NaDC micellar solutions. It is noteworthy to mention that increasing wt% of [Emim][Br] results in an increase in the spontaneity of micelle formation and the hydrophilic IL shows more affinity for NaC as compared to NaDC. Further, the micellar solutions of BS-[Emim][Br] are utilized for studying the aggregation of antidepressants drug promazine hydrochloride (pH). UV-vis spectroscopic investigation reveals interesting outcomes and the results show changes in spectral absorbance of PH drug on the addition of micellar solution (BS-[Emim][Br]). Highest binding affinity and most promising activity are shown for NaC as compared to NaDC.

Self-assembly of a short-chain ionic liquid within deep eutectic solvents

Ionic liquids (ILs) and deep eutectic solvents (DESs) are receiving increased attention from both academic and industrial research due to their immense application potential. These designer solvents are environmentally friendly in nature with tunable physicochemical properties. In the present investigation, we have studied the aggregation behavior of a short-chain IL 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] within aqueous DESs using fluorescence, UV-vis, dynamic light scattering (DLS) and FT-IR spectroscopic techniques. We have prepared two DESs, ChCl–urea and ChCl–Gly, which are obtained by heating a mixture of an ammonium salt choline chloride with hydrogen bond donor urea or glycerol, respectively, in 1 : 2 molar ratios. The local microenvironment and size of the aggregates are obtained from steady state fluorescence (using pyrene and pyrene-1-carboxaldehyde as polarity probes) and DLS measurements, respectively. DLS results shows that IL [Bmim][OS] forms relatively larger micelles within the aqueous solution of DES ChCl–urea (avg. hydrodynamic radii = 209 nm) than compared to ChCl–Gly (avg. hydrodynamic radii = 135 nm). A significant decrease in the critical micelle concentration and increase in the aggregation number (N_agg) are observed within DES solutions as compared to that in water, thus indicating that the micellization process of the IL [Bmim][OS] is much favored in the DES solutions. Molecular interactions of [Bmim][OS] in DESs are revealed from FT-IR spectroscopic investigation. Furthermore, these systems were applied to study the IL-drug binding of the antidepressant drug promazine hydrochloride (PH).

Self-assembly of short-chain imidazolium-based ILs within DESs have been investigated by fluorescence, UV-Vis, DLS and FT-IR spectroscopy. Further, these micellar systems [Bmim][OS]-DESs are utilized to study the IL-drug binding of an antidepressant drug (PH).

Self-assembly of a short-chain ionic liquid within deep eutectic solvents

Self-assembly of short-chain imidazolium-based ILs within DESs have been investigated by fluorescence, UV-Vis, DLS and FT-IR spectroscopy. Further, these micellar systems [Bmim][OS]-DESs are utilized to study the IL-drug binding of an antidepressant drug (PH).

Host–guest complexation of ionic liquid with α- and β-cyclodextrins: a comparative study by 1H-NMR, 13C-NMR and COSY

The inclusion complexation of 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] with host α- and β-cyclodextrins (CDs) has been explored by ¹H NMR, ¹³C NMR and COSY methods. The insertion of a guest molecule into the cavity of CD is clearly reflected by changes in ¹H-NMR and ¹³C-NMR chemical shift values and COSY NMR suggest that both H-bonding and electrostatic interactions involved to the complexation.

Effect of partial supplementation of sun-dried Azolla as a protein source on the immunity and antioxidant status of commercial broilers

AIM

The present study was conducted to evaluate the effect of partial supplementation of sun-dried Azolla as a protein source on the immunity of commercial broilers in coastal Odisha.

MATERIALS AND METHODS

A 180 day-old broiler chicks were distributed in six dietary treatments viz. C1: Basal diet, C2: Basal diet + enzyme, T1: Basal diet +5% protein from Azolla, T2: Basal diet + 5% protein from Azolla + enzyme, T3: Basal diet +10% protein from Azolla, and T4: Basal diet + 10% protein from Azolla + enzyme. Cutaneous basophilc hypersensitivity (CBH) and humoral immunity response were determined at the 38(th) day of age. At 42(nd) day, the weight of lymphoid organs, an antioxidant enzyme, and lipid peroxidation activity were determined.

RESULTS

The CBH response did not differ significantly among the treated groups, but the sheep red blood cells response was significantly higher in T4. The weight of lymphoid organs or immune organs of all the treated groups did not differ significantly (p>0.05). The erythrocyte catalase level of T4 group was found to be significantly higher than rest of the treated groups except T3.

CONCLUSION

It may be concluded that supplementation of Azolla at 10% of dietary protein requirement along with enzyme supplementation in an isonitrogenous diet showed a better immune response in broilers.

Hybrid green nonaqueous media: tetraethylene glycol modifies the properties of a (choline chloride + urea) deep eutectic solvent

In mixture of a deep eutectic solvent Reline with tetraethylene glycol, inter-species interactions are stronger than the intra-species interactions.

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO₂) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO₂ sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

Status Epilepticus in Children

Status epilepticus (SE) is a life-threatening emergency that requires prompt treatment, including basic neuroresuscitation principles (the ABCs), antiepileptic drugs to stop the seizure and identification of etiology. It results from an inability to normally abort an isolated seizure either due to ineffective inhibition, or due to abnormally persistent excessive excitation. Symptomatic SE is more common in younger children and the likely etiology depends on the age of the child. Treating the precipitating cause may prevent ongoing neurologic injury and facilitates seizure control. Benzodiapenes, phenytoin and phenobarbital form the mainstay of treatment. A systematic treatment regimen, planned in advance, is needed, including one for refractory status epilepticus (RSE). Patient education and home management of seizures is important to reduce the morbidity and mortality associated with SE.

Ionic liquid-induced unprecedented size enhancement of aggregates within aqueous sodium dodecylbenzene sulfonate

Physicochemical properties of aqueous micellar solutions may change in the presence of ionic liquids (ILs). Micelles help to increase the aqueous solubility of ILs. The average size of the micellar aggregates within aqueous sodium dodecylbenzene sulfonate (SDBS) is observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM) to increase in a sudden and drastic fashion as the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) is added. Similar addition of [bmim][PF(6)] to aqueous sodium dodecyl sulfate (SDS) results in only a slow gradual increase in average aggregate size. While addition of the IL [bmim][BF(4)] also gives rise to sudden aggregate size enhancement within aqueous SDBS, the IL 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF(4)]), and inorganic salts NaPF(6) and NaBF(4), only gradually increase the assembly size upon their addition. Bulk dynamic viscosity, microviscosity, dipolarity (indicated by the fluorescent reporter pyrene), zeta potential, and electrical conductance measurements were taken to gain insight into this unusual size enhancement. It is proposed that bmim(+) cations of the IL undergo Coulombic attractive interactions with anionic headgroups at the micellar surface at all [bmim][PF(6)] concentrations in aqueous SDS; in aqueous SDBS, beyond a critical IL concentration, bmim(+) becomes involved in cation-π interaction with the phenyl moiety of SDBS within micellar aggregates with the butyl group aligned along the alkyl chain of the surfactant. This relocation of bmim(+) results in an unprecedented size increase in micellar aggregates. Aromaticity of the IL cation alongside the presence of sufficiently aliphatic (butyl or longer) alkyl chains on the IL appear to be essential for this dramatic critical expansion in self-assembly dimensions within aqueous SDBS.

Ionic liquid induced changes in the properties of aqueous zwitterionic surfactant solution

Modifying properties of aqueous surfactant solutions by addition of external additives is an important area of research. Unusual properties of ionic liquids (ILs) make them ideal candidates for this purpose. Changes in important physicochemical properties of aqueous zwitterionic N-dodecyl- N, N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) surfactant solution upon addition of hydrophilic IL 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF 4], are reported. Dynamic light scattering results indicate a dramatic reduction in the average micellar size in the presence of [bmim][BF 4]; micellar (or micelle-like) aggregation in the presence of as high as 30 wt % [bmim][BF 4] is confirmed. Responses from fluorescence probes are used to obtain critical micelle concentration (cmc), aggregation number ( N agg), and dipolarity and microfluidity of the micellar pseudophase of aqueous SB-12 in the presence of [bmim][BF 4]. In general, increasing the amount of [bmim][BF 4] to 30 wt % results in decrease in N agg and increase in cmc. Increase in the dipolarity and the microfluidity of the probe cybotactic region within the micellar pseudophase is observed on increasing [bmim][BF 4] concentration in the solution. It is attributed to increased water penetration into the micellar pseudophase as [bmim][BF 4] is added to aqueous SB-12. It is proposed that IL [bmim][BF 4] behaves similar to an electrolyte and/or a cosurfactant when present at low concentrations and as a polar cosolvent when present at high concentrations. Electrostatic attraction between cation of IL and anion of zwitterion, and anion of IL and cation of zwitterion at low concentrations of [bmim][BF 4] is evoked to explain the observed changes. Presence of IL as cosolvent appears to reduce the efficiency of micellization process by reducing the hydrophobic effect.

Modulating properties of aqueous sodium dodecyl sulfate by adding hydrophobic ionic liquid

Altering and modifying important physicochemical properties of aqueous surfactant solutions is highly desirable as far as potential applications of such systems are concerned. Changes in the properties of aqueous solutions of a common anionic surfactant sodium dodecyl sulfate (SDS) are assessed in the presence of a common and popular 'hydrophobic' ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)). Upon addition of up to approximately 0.10 wt% bmimPF(6), a dramatic decrease in critical micelle concentration (cmc) is accompanied by an increase in the degree of counterion dissociation (alpha) and micellar aggregation number (N(agg)) indicating micellar growth. However, in the range 0.10 wt% < or = bmimPF(6) 2.00 wt%, relatively gradual decrease in alpha and N(agg) is observed along with no change in cmc. Significantly decreased microfluidity of the aqueous SDS solutions on addition of bmimPF(6) is indicated by a fluorescence microviscosity probe 1,3-bis-(1-pyrenyl)propane which suggests partitioning of bmimPF(6) into the SDS micellar phase. Behavior of solvatochromic fluorescence probes, pyrene, pyrene-1-carboxaldehyde, and 2-(p-toluidino)naphthalene-6-sulfonate, confirms interaction, and possible complexation, between IL bmimPF(6) and anionic micellar surface. Increased solubility of bmimPF(6) with increasing SDS concentration further confirms SDS-bmimPF(6) interactions. Presence of strong electrostatic attraction between bmim(+) and anionic micellar surface is proposed to be the most dominant reason for these observations. All-in-all, unique role of a hydrophobic ionic liquid bmimPF(6) in modifying the properties of aqueous anionic sodium dodecyl sulfate is demonstrated.