Ionic liquid assisted dissolution of dissolved organic matter and PAHs from soil below the critical micelle concentration

Assessing the Persistence and Mobility of Organic Substances to Protect Freshwater Resources

Persistent and mobile organic substances are those with the highest propensity to be widely distributed in groundwater and thereby, when emitted at low-levels, to contaminate drinking water extraction points and freshwater environments. To prevent such contamination, the European Commission is in the process of introducing new hazard classes for persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances within its key chemical regulations CLP and REACH. The assessment of persistence in these regulations will likely be based on simulated half-life, t _1/2, thresholds; the assessment of mobility will likely be based on organic carbon-water distribution coefficient, K _OC, thresholds. This study reviews the use of t _1/2 and K _OC to describe persistence and mobility, considering the theory, history, suitability, data limitations, estimation methods, and alternative parameters. For this purpose, t _1/2, K _OC, and alternative parameters were compiled for substances registered under REACH, known transformation products, and substances detected in wastewater treatment plant effluent, surface water, bank filtrate, groundwater, raw water, and drinking water. Experimental t _1/2 values were rare and only available for 2.2% of the 14 203 unique chemicals identified. K _OC data were only available for a fifth of the substances. Therefore, the usage of alternative screening parameters was investigated to predict t _1/2 and K _OC values, to assist weight-of-evidence based PMT/vPvM hazard assessments. Even when considering screening parameters, for 41% of substances, PMT/vPvM assessments could not be made due to data gaps; for 23% of substances, PMT/vPvM assessments were ambiguous. Further effort is needed to close these substantial data gaps. However, when data is available, the use of t _1/2 and K _OC is considered fit-for-purpose for defining PMT/vPvM thresholds. Using currently discussed threshold values, between 1.9 and 2.6% of REACH registered substances were identified as PMT/vPvM. Among the REACH registered substances detected in drinking water sources, 24-30% were PMT/vPvM substances.

[Bmim]FeCl4 mediated inhibition and toxicity during anaerobic digestion: Dose-response kinetics, biochar-dependent detoxification and microbial resistance

[Bmim]FeCl₄, or 1‑butyl‑3-methylimidazolium tetrachloroferrate, is a typical ionic liquid (IL). Its recyclable, magnetic, multicomponent, and solvent-free nature makes it a particularly attractive ionic liquid for use in industrial processes. Despite its widespread use, the potential hazards that [Bmim]FeCl₄ might pose to the environment, including productive microorganisms, have not been explored. In this study, the dose-response of [Bmim]FeCl₄ in anaerobic digestion (AD) was investigated to assess the potential toxification and biochar-dependent detoxification in microbial communities, including enzymatic activity and molecule docking dynamics. Our results showed that methane production (31.52 mL_max/gVS) was sharply inhibited following [Bmim]FeCl₄ treatment. Moreover, increasing the dosage of [Bmim]FeCl₄ caused more dissolved organic matter (DOM) to be generated. Interestingly, 0.4 g/L of [Bmim]FeCl₄ could stimulate the high activity of microbial hydrolase and ATPase. However, a higher concentration of 2.65 g/L prevented these enzymatic processes from continuing. At the cellular level, higher concentration of [Bmim]FeCl₄ (>0.4 g/L) increased malondialdehyde (MDA) levels, leading to a higher cell lethal rate and weakening of the secondary structures of protein (especially, the amide I region). At the molecular level, the competitive H-bonding in the active sites caused low activity and consummated more energy. At the community level, structural equation modeling (SEM) revealed that [Bmim]FeCl₄ and biochar were the main drivers for microbial community succession. For instance, high [Bmim]FeCl₄ (8 g/L) benefited the growth of Clostridium sensu_stricto (from ≤1% to 27%). It is worth mentioning that biochar reversed the inhibition with high α-diversity, which caused a resurgence in the activity of previously inhibited ATPase and hydrolase. H₂-trophic methanogens (Methanolinea and Methaofastidisoum) were sensitive to [Bmim]FeCl₄ and decreased linearly while acetoclastic methanogens (Methanosaeta) were unchanged. These findings were consistent with the short-term activity tests and further verified by functional analysis.

Emerging impacts of ionic liquids on eco-environmental safety and human health

Owing to their unique physicochemical properties, ionic liquids (ILs) have been rapidly applied in diverse areas, such as organic synthesis, electrochemistry, analytical chemistry, functional materials, pharmaceutics, and biomedicine. The increase in the production and application of ILs has resulted in their release into aquatic and terrestrial environments. Because of their low vapor pressure, ILs cause very little pollution in the atmosphere compared to organic solvents. However, ILs are highly persistent in aquatic and terrestrial environments due to their stability, and therefore, potentially threaten the safety of eco-environments and human health. Specifically, the environmental translocation and retention of ILs, or their accumulation in organisms, are all related to their physiochemical properties, such as hydrophobicity. Based on results of ecotoxicity, cytotoxicity, and toxicity in mammalian models, the mechanisms involved in IL-induced toxicity include damage of cell membranes and induction of oxidative stress. Recently, artificial intelligence and machine learning techniques have been used in mining and modeling toxicity data to make meaningful predictions. Major future challenges are also discussed. This review will accelerate our understanding of the safety issues of ILs and serve as a guideline for the design of the next generation of ILs.

A review on the recycling of spent lithium-ion batteries (LIBs) by the bioleaching approach

This review discusses the latest trend in recovering valuable metals from spent lithium-ion batteries (LIBs) to meet the technological world's critical metal demands. Spent LIBs are a secondary source of valuable metals such as Li (5%-7%), Ni (5%-10%), Co (5%-25%), Mn (5-11%), and non-metal graphite. Recycling is essential for the battery industry to extract valuable critical metals from secondary sources to develop new and novel high-tech LIBs for various applications such as eco-friendly technologies, renewable energy, emission-free electric vehicles, and energy-saving lightings. LIB waste is currently undergoing high-temperature pyrometallurgical or hydrometallurgical processes to recover valuable metals, and these processes have proven to be successful and feasible. These methods, however, are not preferable due to the difficulties in controlling the process, secondary waste produced, high operational cost, and high risk of scaling up. Biotechnological approaches can be promising alternatives to pyrometallurgical and hydrometallurgical technologies in metal recovery from LIB waste. Microbiological metal dissolution or bioleaching has gained popularity for metal extraction from ores, concentrates, and recycled or residual materials in recent years. This technology is eco-friendly, safe to handle, and reduces operating costs and energy demands. The pre-treatment process (material preparation), microorganisms used in the bioleaching of LIBs, factors influencing the bioleaching process, methods of enhancing the leaching efficiency, regeneration of electrode materials, and future aspects have been discussed in detail.

Different submicellar solubilization mechanisms revealed by 1H NMR and 2D diffusion ordered spectroscopy (DOSY)

Different submicellar solubilization mechanisms of two systems, Triton X-100 (TX-100)/tetradecane and sodium dodecyl sulfate (SDS)/butyl methacrylate, are revealed on the molecular scale by ¹H NMR spectroscopy and 2D diffusion ordered spectroscopy (DOSY). It is evident that the apparent solubilities of both tetradecane and butyl methacrylate are enhanced, even at much lower surfactant concentrations than the CMCs. Solubilized solutes also contribute to the early formation of surfactant micelles. In general, the molar solubilization ratios (MSRs) of both solutes linearly increase as the surfactant concentrations increase. However, variations in MSRs of the two systems are different below and above the CMC, which is probably related to the different solubilization mechanisms. For TX-100/tetradecane, as the TX-100 concentration increases, the tetradecane resonance in the independent state transforms into that of the aggregated state and the corresponding evolution of diffusions is shown in the 2D DOSY spectra. These results demonstrate that below the CMC, tetradecane is first solubilized in TX-100 solutions, and then solubilized in TX-100 micelles above the CMC. For SDS/butyl methacrylate, the appearance of oligomeric SDS resonances below the CMC indicates that butyl methacrylate is partially solubilized in SDS oligomers. Then, when the CMC is reached, the dominant, monomeric SDS molecules aggregate into oligomers, and the similar diffusivity trend of butyl methacrylate with that of SDS indicates that a proportion of butyl methacrylate molecules are solubilized in it. Finally, the fusion of SDS resonances in the two states and the tendency of co-diffusion of SDS and butyl methacrylate indicate that all the SDS molecules gradually aggregate into micelles, and almost all the butyl methacrylate molecules are solubilized in them. In conclusion, above the CMCs, the solubilization manners of these two systems are similar. However, they are different below CMCs. The solubilization of tetradecane by TX-100 is driven by the intermolecular hydrophobic interaction, i.e., molecular-pair formation. However, the polar interaction between functional groups of butyl methacrylate and the polar head of SDS contributes to the solubilization of butyl methacrylate. The different submicellar solubilization mechanisms are mainly caused by the different properties of solutes and surfactants, which also results in different MSRs and solubilization sites in the micelles.

Structural characteristics, analytical techniques and interactions with organic contaminants of dissolved organic matter derived from crop straw: a critical review

Dissolved organic matter (DOM) represents one of the most mobile and reactive organic compounds in an ecosystem and plays an important role in the fate and transport of soil organic pollutants, nutrient cycling and more importantly global climate change. Advances in environment geochemistry in the past two decades have improved our knowledge about the genesis, composition, and structure of DOM, and its effect on the environment. Application of analytical technology, for example UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR) spectroscopy, and three-dimensional fluorescence spectroscopy (3D-EEM) have resulted in these advances. At present, crop straw, as a part of energy development strategy, is mainly used for soil amendment, fodder, fertilizer and industrial materials. Moreover, the fermentation and decomposition of straw should be also promoted for ecological agriculture. However, few studies have focused on the structural properties of DOM derived from crop straw in farmland soil. In this article, DOM derived from crop straw, which is abbreviated to "CDOM", presents active physicochemical properties that can affect the migration and bioavailability of organic contaminants (OCs) in terrestrial ecosystems. The objectives of this review paper are: (i) to discuss the structural characteristics, analytical techniques and interactions between CDOM and OCs in farmland soil; (ii) to present a critical analysis of the impact of CDOM on the physicochemical transformation and transport of OCs in farmland soils; (iii) to provide the perspectives in future research. Therefore, the findings obtained from this study can be utilized to evaluate the relations of interactions between CDOM and OCs in agricultural soils, in order to support some suggestions for future development in agricultural waste recycling, buffering of organic pollution, and the effect on the global carbon cycle.

Effects of soil components and solution inorganic cations on interactions of imidazolium-based ionic liquid with soils

Effects of alkyl chain length of ionic liquid (IL), soil components and solution inorganic cations on a selected IL (1-methyl-3-octylimidazolium chloride, [OMIM]Cl) interaction with Chinese soils were investigated using batch sorption experiments. The results indicated that sorption energy was mainly controlled by chain length of [OMIM]Cl and contents of soil organic matter (SOM). [OMIM]Cl sorption on soils was mainly controlled by cation exchange process. Contributions of SOM and clay minerals (CMs) to [OMIM]Cl sorption were 7.3%-53.8% and 46.2%-92.7%, respectively. SOM possessed higher energy cation-exchange binding sites than CMs. To predict the sorption of [OMIM]Cl on soils, a model for the relationship between sorption coefficient (K_d) and cation exchange capacity (CEC) from soil components (SOM and CMs, i.e., CEC_SOM and CEC_CMs) as well as solution concentration (C_e) was established: LogK_d = Log(1.67*CEC_SOM + 3.22*CEC_CMs) - 0.58LogC_e. This model could provide a good prediction for sorption coefficients and the prediction errors were within 0.48 log unit. Competitive effects caused by inorganic cations followed the order of Ca²⁺ = Mg²⁺ > K⁺ > Na⁺. Concentrations and valence of coexisting ions both affect their competitive capability on [OMIM]Cl sorption. The finding of this study provided valuable information for evaluating the fate of [OMIM]Cl in soils.

Toward sustainable and systematic recycling of spent rechargeable batteries

A comprehensive and novel view on battery recycling is provided in terms of the science and technology, engineering, and policy.

Roles of polar groups and aromatic structures of biochar in 1-methyl-3-octylimidazolium chloride ionic liquid adsorption: pH effect and thermodynamics study

Adsorption mechanisms of 1-methyl-3-octylimidazolium chloride ([OMIM]Cl) on rice straw-derived biochars produced at 400, 500, and 700 °C (referred as RB400, RB500, and RB700, respectively) were evaluated. Adsorption affinity followed the order of RB700 > RB400 > RB500. Electrostatic attraction and hydrogen bond controlled adsorption of [OMIM]Cl on RB400, while π-π EDA interaction between [OMIM]Cl and the aromatic rings of biochar dominated adsorption of RB500 and RB700. With increasing solution pH, -COOH and -OH on biochar became deprotonated. Consequently, [OMIM]Cl binding to these sites changed from hydrogen bond to electrostatic attraction. Adsorption capacity of [OMIM]Cl increased with increasing pH during the adsorption process. Solid concentration induced by -OH of [OMIM]Cl was higher than that of -COOH. Thermodynamics study indicated that adsorption process was spontaneous and endothermic. ∆H ⁰ values indicated that [OMIM]Cl adsorption on biochars was a physisorption.

Interaction between Dissolved Organic Matter and Long-Chain Ionic Liquids: A Microstructural and Spectroscopic Correlation Study

The production and use of ionic liquids (ILs) increase the potential risk after their emission into the environment. After entering the environment, ILs will readily interact with dissolved organic matter (DOM), and their environmental behavior will be impacted by DOM, which is abundant in the environment and has various functional groups. However, to date, the interaction between DOM and ILs, especially long-chain ILs, remains unclear. In this work, the interaction between long-chain ILs and humic acid (HA), a representative DOM, was investigated using synchronous fluorescence, Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential techniques, which were integrated with two-dimensional correlation spectroscopy (2DCOS), hetero-2DCOS, and perturbation-correlation moving-window analyses. The results show that cation exchange by the carboxylic groups in humic-like fractions was primarily responsible for interaction at low IL concentrations. As a result, the decrease in electrostatic repulsion and the increase in hydrophobicity facilitated the loose aggregation of HA. With an increase in IL concentration, the aromatic and carbonyl groups were involved in the interaction via the π-π interaction and dipole-dipole interaction, respectively, which resulted in the disruption of the intramolecular hydrogen bond and promoted the compaction of HA under the hydrophobic effect. The intensity transition sequence of various groups in HA was elucidated more specifically by 2DCOS. With these results, a comprehensive view of the structural changes of DOM in its IL-binding process was obtained, and the fate and environmental impact of ILs could be better understood. Furthermore, the superior potential of such an integrated approach in investigating the complex interactions in the environment was also demonstrated.

Improving Polycyclic Aromatic Hydrocarbon Biodegradation in Contaminated Soil Through Low-Level Surfactant Addition After Conventional Bioremediation

Efficacy of bioremediation for soil contaminated with polycyclic aromatic hydrocarbons (PAHs) may be limited by the fractions of soil-bound PAHs that are less accessible to PAH-degrading microorganisms. In previous test-tube-scale work, submicellar doses of nonionic surfactants were screened for their ability to enhance the desorption and biodegradation of residual PAHs in soil after conventional bioremediation in a laboratory-scale, slurry-phase bioreactor. Polyoxyethylene sorbitol hexaoleate (POESH) was the optimum surfactant for enhancing PAH removal, especially the high-molecular weight PAHs. This work extends that concept by treating the effluent from the slurry-phase bioreactor in a second-stage batch reactor, to which POESH was added, for an additional 7 or 12 days. Surfactant amendment removed substantial amounts of the PAHs and oxy-PAHs remaining after conventional slurry-phase bioremediation, including more than 80% of residual 4-ring PAHs. Surfactant-amended treatment decreased soil cytotoxicity, but often increased the genotoxicity of the soil as measured using the DT-40 chicken lymphocyte DNA damage response assay. Potential ecotoxicity, measured using a seed germination assay, was reduced by bioreactor treatment and was reduced further after second-stage treatment with POESH. Of bacteria previously implicated as potential PAH degraders under POESH-amended conditions in a prior study, members of the Terrimonas genus were associated with differences in high-molecular weight PAH removal in the current study. Research using submicellar doses of surfactant as a second-stage treatment step is limited and these findings can inform the design of bioremediation systems at field sites treating soil contaminated with PAHs and other hydrophobic contaminants that have low bioaccessibility.

Environmental Application, Fate, Effects, and Concerns of Ionic Liquids: A Review

Ionic liquids (ILs) comprise mostly of organic salts with negligible vapor pressure and low flammability that are proposed as replacements for volatile solvents. ILs have been promoted as "green" solvents and widely investigated for their various applications. Although the utility of these chemicals is unquestionable, their toxic effects have attracted great attention. In order to manage their potential hazards and design environmentally benign ILs, understanding their environmental behavior, fate and effects is important. In this review, environmentally relevant issues of ILs, including their environmental application, environmental behavior and toxicity are addressed. In addition, also presented are the influence of ILs on the environmental fate and toxicity of other coexisting contaminants, important routes for designing nontoxic ILs and the techniques that might be adopted for the removal of ILs.

Novel surface-active ionic liquids used as solubilizers for water-insoluble pesticides

Three surface active ionic liquids (ILs) containing organic anions but no halides were used as solubilizers for water insoluble pesticides and as well as alternates for similar ILs with halide anions, which have been increasingly popular in the agricultural practice. The solubilities of five pesticides (fluazifop-P, clethodim, pyrethrin, fosthiazate, and prochloraz) in three aqueous micellar systems, each containing 1-octyl-3-methylimidazolium--tartrate ([OMIM][Tart]), 1-octyl-3-methylimidazolium-l-proline ([OMIM][Prol]), 1-octyl-3-methylimidazolium-l-lactate ([OMIM][lact]), respectively, were measured. The solubilities of all five pesticides were found to increase with the increasing concentrations of ILs solubilzers The enhancements in solubilities were related to surface activities of these SAILs, as indicated in the results of the measurements of their corresponding critical aggregation concentration (CAC), lowest surface tension (γcac), maximum surface excess concentration (Γmax) and minimum area per molecule (Amin) of aqueous solutions of ILs. When comparing with similar ILs with halides as counter anions, we found that these ILs with organic counterions are at least comparable, often more effective solubilizers for all of the five very different pesticides we tested. We conclude that these novel SAILs with organic counterions would serve as at least similarly effective and more environmentally-friendly solubilizers over the more traditional ones with halides.

The horizontal transfer of antibiotic resistance genes is enhanced by ionic liquid with different structure of varying alkyl chain length

Antibiotic resistance genes (ARGs) have become a global health concern. In our previous study, an ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) had been proven to facilitate the dissemination of ARGs in the environment. However, enhanced alkyl group chain length or the substitution of alkyl groups with the cation ring corresponded with increased antimicrobial effects. In this study, we investigated how different structures of ILs with 4, 6, and 8 C atoms in the longer alkyl chain on the imidazolium cations facilitated the dissemination of ARGs. The promotion of plasmid RP4 transfer frequency decreased with [CnMIM][BF4] increasing the alkyl chain length from 4 carbon atoms to 8 carbon atoms on the imidazolium cations, which is observed with [BMIM][BF4] (n = 4, 5.9 fold) > HMIM][BF4] (n = 6, 2.2 fold) > [OMIM][BF4] (n = 8, 1.7 fold). This illustrates that [CnMIM][BF4] with increasing the alkyl chain length exert decreasing ability in facilitating plasmid RP4 horizontal transfer, which is possibly related to IL-structure dependent toxicity. The IL-structure dependent plasmid RP4 transfer frequency was attributable to bacterial cell membrane permeability weaken with increasing alkyl chain length of [CnMIM][PF4], which was evidenced by flow cytometry. In freshwater microcosm, [CnMIm][BF4] promoted the relative abundance of the sulI and intI genes for 4.6 folds, aphA and traF for 5.2 folds higher than the untreated groups, promoting the propagation of ARGs in the aquatic environment. This is the first report that ILs with different structure of varying alkyl chain length facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment, and thus add the adverse effects of the environmental risk of ILs.

Ionic Liquid Facilitates the Conjugative Transfer of Antibiotic Resistance Genes Mediated by Plasmid RP4

The dissemination and propagation of antibiotic resistance genes (ARGs) is an emerging global health concern. In our previous study, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) had been proven to facilitate the dissemination of ARGs via horizontal gene transfer. In this study, we further confirm that this compound facilitates the horizontal transfer of plasmid RP4 through a conjugation mechanism and not by natural transformation. The mechanisms for [BMIm][PF6] promoting conjugative transfer are attributable to enhancing the mRNA expression levels of conjugative and global regulatory genes, as well as by inhibiting the genes that are responsible for the vertical transfer of cell growth. [BMIm][PF6] significantly enhanced the expression of the outer membrane porin proteins (OMPs) OmpC and OmpA and the corresponding mRNA expression levels of ompC and ompA genes in recipient bacteria, which contributed to pore formation and increased cell membrane permeability. The increased expression of pilin and pili allowed the donor pilus to attach to and access the recipient cells, thereby assisting cell-to-cell contact to facilitate the conjugative transfer of plasmid RP4. To the best of our knowledge, this is the first insightful exploration of [BMIm][PF6] facilitating the conjugative transfer of ARGs mediated by plasmid RP4 and of several other ILs with different cations or anions that are capable of promoting plasmid transfer. It is therefore suggested that the application of some ILs in industrial processes should be carefully evaluated before their bulk emission into the environment.

Enhanced horizontal transfer of antibiotic resistance genes in freshwater microcosms induced by an ionic liquid

The spread and propagation of antibiotic resistance genes (ARGs) is a worldwide public health concern. Ionic liquids (ILs), considered as "environmentally friendly" replacements for industrial organic solvents, have been widely applied in modern industry. However, few data have been collected regarding the potential ecological and environmental risks of ILs, which are important for preparing for their potential discharge into the environment. In this paper, the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) (0.001-5.0 g/L) was tested for its effects on facilitating ARGs horizontal transfer mediated by plasmid RP4 in freshwater microcosms. In the horizontal transfer microcosms, the transfer frequency of plasmid RP4 was significantly enhanced (60-fold higher than untreated groups) by the IL [BMIm][PF6] (1.0 g/L). Meanwhile, two strains of opportunistic pathogen Acinetobacter spp. and Salmonella spp. were isolated among the transconjugants, illustrating plasmid RP4 mediated horizontal transfer of ARGs occurred in pathogen. This could increase the risk of ARGs dissemination to human pathogens and pose great threat to public health. The cause that [BMIm[PF6] enhanced the transfer frequency of plasmid RP4 was proposed by suppressed cell membrane barrier and enhanced cell membrane permeability, which was evidenced by flow cytometry (FCM). This is the first report that some ILs facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment and thus add the adverse effects of the environmental risk of ILs.

Theoretical investigations on C60 -ionic liquid interactions and their impacts on C60 dispersion behavior

Increased use and production of carbon nanomaterials (e.g., fullerene C60 ) and ionic liquids (ILs) may result in their concomitant releases into the environment. Inevitably there will be interactions between carbon nanoparticles (CNPs) and ILs. However, experimental data on the interaction of CNPs with ILs are not readily available, and the mechanism behind the interactions is still elusive. To contribute to an understanding of the molecular interactions established between CNPs and ILs, theoretical investigations at multiple levels were performed to determine the interactions of C60 with 6 different imidazolium-based ILs. The results indicate that C60 mainly interacts with the IL molecules through the van der Waals, π-cation, and hydrophobic interactions. Mulliken population analysis suggests that charge transfer occurs from the IL to C60 during the C60 -IL interaction. The self-diffusion coefficient (D) of C60 in [C60  + IL] systems reaches the maximum in the case of moderate C60 -IL interaction (interaction energy, EINT ), implying that in this case a good dispersion of an agglomerate species of C60 is obtained. The D value of C60 in [C60  + IL +water] systems increases with an increase of the EINT , implying that the presence of ILs can play an important role in the aqueous dispersion of the C60 agglomerate.

Determination of cmc of imidazolium based surface active ionic liquids through probe-less UV-vis spectrophotometry

In the first of its kind we herein report the results of our studies undertaken on the micellization behaviour of imidazolium based surface active ionic liquids (SAILs) to prove that their critical micelle concentration (cmc) can be estimated through ultraviolet-visible (UV-vis) spectroscopy without using any external probe. Tensiometric and spectrophotometric investigations of a series of freshly prepared SAILs viz. 1-octyl-3-methylimidazolium chloride ([OMIM][Cl]), 1-octyl-3-methylimidazolium dodecylsulphate ([OMIM][DS]), 1-octyl-3-methylimidazolium benzoate ([OMIM][Bz]), 1-octyl-3-methylimidazolium salicylate ([OMIM][Sc]), 1-octyl-3-methylimidazolium acetate ([OMIM][Ac]) are presented as a case study in support of the said claim. The cmcs estimated through spectrophotometric method were found to be close to the values estimated through tensiometry for the said SAILs. The cmcs for the investigated SAILS were found to vary in order of [OMIM][Cl]>[OMIM][Ac]>[OMIM][Bz]>[OMIM][Sc]>[OMIM][DS]. To the best of our knowledge the present communication will be the first report about the synthesis, characterization and micellization behaviour of [OMIM][Bz] and [OMIM][Sc].

Innovative application of ionic liquid to separate Al and cathode materials from spent high-power lithium-ion batteries

Because of the increasing number of electric vehicles, there is an urgent need for effective recycling technologies to recapture the significant amount of valuable metals contained in spent lithium-ion batteries (LiBs). Previous studies have indicated, however, that Al and cathode materials were quite difficult to separate due to the strong binding force supplied by the polyvinylidene fluoride (PVDF), which was employed to bind cathode materials and Al foil. This research devoted to seek a new method of melting the PVDF binder with heated ionic liquid (IL) to separate Al foil and cathode materials from the spent high-power LiBs. Theoretical analysis based on Fourier's law was adopted to determine the heat transfer mechanism of cathode material and to examine the relationship between heating temperature and retention time. All the experimental and theoretic results show that peel-off rate of cathode materials from Al foil could reach 99% when major process parameters were controlled at 180°C heating temperature, 300 rpm agitator rotation, and 25 min retention time. The results further imply that the application of IL for recycling Al foil and cathode materials from spent high-power LiBs is highly efficient, regardless of the application source of the LiBs or the types of cathode material. This study endeavors to make a contribution to an environmentally sound and economically viable solution to the challenge of spent LiB recycling.