Amino Acid Ionic Liquids Research Articles

Efficient Selective CO2 Composite Sorbent from Amino Acid Ionic Liquids and Silica Gel: 2H NMR Spectroscopy Provides Insight on the CO2-Binding Mechanism and in-Pore Microscopic Viscosity.

A promising CO2 sorbent based on the [Emim][Gly] (1-ethyl-3-methylimidazolium glycinate)/silica gel composite has been studied. CO2 sorption experiments have shown that the optimum loading of [Emim][Gly] ionic liquid in silica gel is 40 wt.%. The 2-step process CO2 binding mechanism in [Emim][Gly] has been proposed based on the results of sorption experiments, 2H NMR spectroscopy and ab-initio calculations. The impact of CO2 on the microscopic viscosity and the dynamical melting of ionic liquid has been thoroughly investigated. 2H NMR spectroscopy has revealed that CO2 strongly binds cation and anion in [Emim][Gly], forcing them to move in a correlated fashion.

Immobilized Tetrabutylammonium Amino Acid Ionic Liquids as Heterogeneous Catalyst in Biodiesel Production from Chlorella vulgaris

Ionic liquids (ILs) are molten salts below 100 °C with the ability to be used as a catalyst for biodiesel production. However, to this date, the implementation of ILs as catalysts remains an enigma due to their practicability. Immobilizing ILs onto waste biomass solid support may improve the sustainability of its implementation. This study is focused on synthesizing immobilized tetrabutylammonium amino acid ionic liquids (TBA AAILs) onto bamboo activated carbon (BAC) as catalysts in transesterification of fatty acids extracted from Chlorella vulgaris. Three AAILs, consisting of tetrabutylammonium paired with arginine, histidine, and lysine, were synthesized via neutralization reaction and immobilized onto BAC through wet impregnation method. Thereafter, microwave-assisted transesterification was performed with C. vulgaris as a feedstock. Impregnation of TBA AAILs caused modifications on morphology, chemical composition, and surface area of the BAC. [TBA][His]/BAC had greater impact compared to [TBA][Arg]/BAC and [TBA][Lys]/BAC, where it reduced the surface area up to 35 m2/g and pore volume to 0.020 cm3/g, initially BAC's surface area are 842 m2/g and pore volume of 0.387 cm3/g. Optimization with the Box-Behnken method achieved the highest yield 81.9% FAME using 20% [TBA][His]/BAC with 3% of catalyst dosage and 21 grams of methanol at 80°C for 48 mins with three times reusability. The immobilized TBA AAILs/BAC reduced IL consumption by 10 times and obtained comparatively higher yield than TBA AAILs, providing a sustainable alternative to conventional ILs catalyst.

Improvement of tetracycline removal using amino acid ionic liquid modified magnetic biochar based on theoretical design

In current research, biochar is widely used to remove antibiotic contamination from the environment. However, original biochar produced through direct pyrolysis has significant limitations in removing antibiotics. In this paper, response surface methodology provided the laudable choice for magnetic poplar biochar (MPBC) considering the synergistic effect of multi-factors as well as the restrictions abundance experiments during the preparation of MPBC. Amino acid ionic liquids (AAILs) are a class of ionic liquids in which amino acids act as the anionic component, combining the tunable properties of ionic liquids with the biocompatibility and functionality of amino acids. To ameliorate adsorption capacity of MPBC, tetra-ethylammonium glycinate ([TEA][Gly]) with the best affinity for tetracycline (TC) were screened from 600 AAILs based on theoretical predictions using the conductor-like screening model for real solvents (COSMO-RS) without extensive experimental. Furthermore, AAILs-modified magnetic biochar (MPBC-AAIL) was synthesized chemically for the first time. Adsorption kinetics, isotherms, and thermodynamic analyses revealed that TC adsorption by both MPBC and MPBC-AAIL is a monolayer, spontaneous, and exothermic chemical process. Moreover, MPBC-AAIL exhibited a maximum adsorption capacity of 305.9 mg·g−1. Meanwhile, MPBC-AAIL maintains superior adsorption performance for TC in different impurity solutions as well as in real water samples. The excellent reusability and selective adsorption capacity of the material demonstrate the superiority of the theoretical based design. The characterization reveals that the adsorption mechanisms include pore filling, π-π interactions, surface complexation, hydrogen bonding, and electrostatic interactions. In addition, theoretical calculations showed that ionic liquid modification altered the adsorption sites between TC and MPBC-AAIL, leading to enhanced adsorption. This comprehensive study introduces an innovative modification of biochar, providing a novel approach to designing biochar composites and promoting their application in the remediation of complex environmental pollution.

Hierarchically fibrillated spunlaced nonwovens from waste wool supported ionic liquid as solid amine adsorbents for CO2 capture

The environmental crisis caused by excessive emissions of carbon dioxide-based greenhouse gases has garnered widespread public concern. Solid amine is considered to be one of the most effective carbon dioxide (CO2) adsorbents. However, traditional solid amine carriers have problems such as structural collapse, low efficiency and poor regeneration. In this study, waste wool having hierarchical fibrous structure was spunlaced, fibrillated and later compounded with amino acid ionic liquids (AAIL) leading to the formation of the AAIL@feather-like wool nonwoven absorbents. A synergistic co-amine effect was observed after primary and secondary fibrillation without any sacrifice in the mechanical property of wool nonwovens. Also, the fibrillated nonwovens had high specific area which provided high loading rate (13.53 %) on AAIL. Compared with untreated wool nonwovens, the CO2 adsorption capacity of feather-like wool nonwovens was higher by 65 % (11.75 mmol/g) after loading AAIL. Furthermore, the CO2 adsorption capacity was retained (95.2 %) even after 12 cycles at 80 ℃, indicating that the AAIL@ feather-like wool nonwovens possess good long-term stability. This work paves the way for large scale manufacturing of biobased solid adsorbents with a hierarchical nonwoven structure for efficient CO2 capture.

Unravelling molecular origins of improved tribological properties of amino acid ionic liquid water-based lubricants

In the quest for sustainable lubrication, this study explores the potential of water-based lubricants (WBLs) with amino acid ionic liquid (AAIL) additives. The research combines experimental and reactive molecular dynamics (MD) simulations to assess the tribological and rheological enhancements provided by AAILs. Specifically, tetrabutylphosphonium (P4444) cations paired with Serine (Ser) and Tryptophan (Trp) anions were mixed into water to create AAIL WBLs. The introduction of AAILs significantly improved the lubricants’ rheological properties and reduced the coefficient of friction by up to 34 %. This reduction is attributed to the formation of hydration shells around the amino acid anions, which create a chemically adsorbed tribofilm on iron oxide surfaces, and P4444 cations that establish a load-bearing layer in the middle regions of the lubricant. This dual-layer structure, supported by hydration lubrication, effectively maintains lubricant fluidity while bearing substantial loads. Among the AAIL WBLs tested, those with a thicker, more stable, hydrated amino acid tribofilm demonstrated more significant friction reduction. These insights into the molecular mechanisms behind AAIL WBLs’ tribological behaviour underscore their promise as eco-friendly lubricants, contributing to advancing a circular economy in industries reliant on lubrication.

Selective adsorption of trace CO2 by immobilized amino acid ionic liquids with ultra-micropores based on amino MOFs

Great attention has been paid to effectively capture trace CO2 in air or a confined space for ensuring human safety, but it remains challenging to enhance CO2 capacity and selectivity concurrently. In this study, metal–organic frameworks (MOFs) were combined with amino groups (NH2-MIL-125(Ti) and NH2-UIO-66(Zr)) and amino acid anion-functionalized ionic liquids (ILs), namely 1-Butyl-3-methylimidazolium glycinate ([BMIm]Gly) and 1-Butyl-3-methylimidazolium arginine ([BMIm]Arg) to prepare various ionic liquid (IL) composites containing various IL contents. Relative to pristine supports, incorporating ILs significantly enhanced CO2 capacity together with CO2/N2 selectivity, in particular in the confined spaces (<5000 ppm) or in air (415 ppm). At a 50 wt% IL loading, new ultra-micropores (<0.65 nm) could be obtained in IL-NH2-UIO-66(Zr) composite, but they did not occur within pristine supports or the rest IL-NH2-UIO-66(Zr) (10 wt%, 30 wt% and 70 wt%). Among them, CO2 uptake of 50 wt% [BMIm]Arg-NH2-UIO-66(Zr) peak at 0.0005 and 0.005 bar (2.93 and 3.87 mmolCO2/g-adsorbent, respectively) at 313 K; besides, recyclability significantly increased compared with the latest values reported. Additionally, the excellent optimal CO2/N2 selectivity was determined to be 8916 at 0.005 bar and 288 K, which increased by 254.7 folds relative to NH2-UIO-66(Zr). In the meantime, as revealed by mixed gas breakthrough experimental results, 50 wt% [BMIm]Arg-NH2-UIO-66(Zr) showed superb CO2 separation effect in air and simulated confined spaces. Such ultra-high CO2 separation efficacy is associated with the synergistic effect of chemical interaction of IL anion with amino groups in MOFs and CO2 and the novel ultra-micropore effect. Findings in the present work shed more lights on designing hierarchically porous IL composites that possess ultra-micropores to efficiently remove trace CO2.

Introduction of amino acid ionic liquid into the gelatin matrix enhances the performance of immobilized laccase in degrading 2,4-dichlorophenol

The utilization of immobilized laccase to degrade and remove phenolic pollutants in water has promising application prospects. However, maintaining the activity and stability of the immobilized laccase remains a significant challenge. In this work, an amino acid-based ionic liquid (IL) modified magnetic composite material (IL-Magnetic gelatin) was prepared as a support for laccase immobilization. We conducted a detailed characterization of the nanocomposite and it exhibited excellent magnetic responses and dispersion. The catalytic performance of the immobilized enzyme was also investigated. Compared to free laccase, the immobilized laccase (Lac-IL-Magnetic gelatin) exhibited higher catalytic activity and better thermal stability. The various interactions (hydrogen bonds, ionic interaction) between enzyme molecule and ionic liquid can cause conformational rearrangement of laccase. Lac-IL-Magnetic could degrade 98.6 % of 2,4-dichlorophenol (2,4-DCP) within 20 h and maintained 55.2 % activity after 10 cycles. Moreover, the biocatalyst is easy to recycle using magnet. The results indicated that Lac-IL-Magnetic gelatin holds significant potential for the degradation of phenolic substances in environmental wastewater.

Acid-base neutralization strategy for immobilization amino acid ionic liquid within sulfonic acid-based COF as a switch for selective conversion of epoxides

Covalent organic frameworks (COFs) and ionic liquids (ILs) as raw materials exhibit effective catalytic performance and adsorption capabilities in the reaction of epoxides and atmospheric CO2, respectively. Nonetheless, bonding modes between ILs and COFs have restricted their utility, thereby constraining the in-depth study of synergistic catalytic mechanisms over these composite catalysts. Herein, a heterogeneous composite ([DBUH]2Cys@COF-X) were successfully prepared by the facile acid-base neutralization method, incorporating varying amounts of amino acid ILs ([DBUH]2Cys) into the pore channels of sulfonic acid-based COF (TpPa-SO3H). [DBUH]2Cys@COF-3 efficiently catalyzed epichlorohydrin with a yield of 96.38 % without any solvent or co-catalyst under atmospheric CO2. Notably, larger sterically hindered epoxides were selectively blocked on the surface of [DBUH]2Cys@COF-3, enabling [DBUH]2Cys@COF-3 to act as a gatekeeper for selectively catalyzing small sterically hindered epoxides due to [DBUH]2Cys was distributed within the pore channels of [DBUH]2Cys@COF-3. Through DFT calculations, comprehensive understanding of the synergistic activation conferred of -COO- and [DBUH]+ towards CO2 and epoxides in [DBUH]2Cys@COF-3 and the ring-opening mechanism was clarified. This work presents a fresh outlook on the catalyst design by the facile acid-base neutralization method for efficiently catalyzing small-hindered epoxides under atmospheric CO2.

Theoretical study on the energy storage performance of Electrical double layer supercapacitors with choline amino acid ionic liquids electrolyte

Choline amino acid ionic liquids have attracted much attention in recent years due to their simple extraction process, rich sources, and easy degradation. Due to the high viscosity of such ionic liquids, the addition of organic solvents can adjust the transport performance of ionic liquids. Here, we explore the effects of different solvents (methanol, ethanol) and different temperatures on the diffusion properties and conductivity of ionic liquids through molecular dynamics simulations. The results showed that with the increase of temperature, the conductivity linearly increased. The addition of organic solvents can improve the conductivity of ionic liquids, and the addition of methanol solvent has a higher compatibility with choline amino acid ionic liquids. The conductivity after mixing methanol and choline glycine in a certain proportion is 5 times higher than before. In addition, this article investigated the performance of choline glycine ionic liquid electrolytes in Electrical Double Layers (EDLs) near planar graphene electrodes. The results indicate that similar double layer structures and double layer capacitors can be observed regardless of whether solvents are added.

Strategic design of magnetic ionic covalent organic frameworks incorporating amino acid ionic liquids for enhanced selectivity adsorption of benzimidazoles

Advancing the frontier of material design, our innovative magnetic ionic covalent organic framework (MiCOF) masterfully overcomes traditional barriers in selective adsorption, pioneering new functionalities and surface engineering techniques to effectively target and mitigate the impacts of benzimidazoles (BZDs). In previous studies, the idea of designing magnetic nanomaterials through theoretical screening of ionic liquids has been successfully proposed. This work proposed a theoretical and practical design for MiCOFs, aimed at providing a sensitive, selective, rapid, and straightforward method for analyzing trace substances in complex biological matrices. In a gentle one-pot process, the surface of Fe3O4 was coated with covalent organic frameworks (COFs) layer, followed by the modification with amino acid ionic liquid (AAIL) through covalent radical polymerization, facilitated by the abundant unsaturated vinyl groups present. This resulted in MiCOFs (Fe3O4@COF-AAIL) with a stable structure. Compared to unmodified Fe3O4@COF, Fe3O4@COF-AAIL exhibited excellent adsorption selectivity for BZDs. This enhanced selectivity is primarily due to the strong hydrogen bonds and π-π interactions between AAIL and BZDs, aligning well with COSMO-RS theoretical screening predictions. The development of magnetic dispersive solid-phase extraction (MDSPE) enabled rapid processing of BZDs in plasma with low matrix effects (0.9–1.3). This study not only validates a robust framework for the selective separation of trace contaminants in complex biological matrices but also advances the design and application of MiCOFs, setting a new paradigm in material science that could transform the design of novel materials for specific tasks.

Polymerization-induced self-assembly amino acid ionic liquid/poly(ethylene oxide) thin-film composite membranes for CO2 separation

It is well known that crosslinking poly(ethylene oxide) (PEO) membranes exhibit high CO2/N2 solubility selectivity, and are suitable for separating CO2 from flue gas. However, the high CO2/N2 selectivity is temperature sensitive and decreases rapidly with increasing temperature. To overcome this deficiency, imidazolium-based amino acid ionic liquids (AAILs) are introduced into the PEO membranes. A series of (AAILs-PEO)/PAN thin-film composite (TFC) membranes were prepared by a polymerization-induced self-assembly process. Due to the hydrogen and Coulomb interactions between the imidazolium ring of AAILs and the ether groups of PEO monomers, the morphology of the selective layer changed from micellar to granular upon the introduction of the AAILs into the PEO membranes, while the chain-segment flexibility and interspacing of the PEO are also changed. Compared with the original PEO/PAN TFC membrane, the (AAILs-PEO)/PAN TFC membranes show much higher CO2/N2 selectivity, which increases from ∼41 to ∼ 74. In addition, the AAILs show strong hydrophilicity, which leads to a significant increase in CO2/N2 selectivity under the wet-gas feed, reaching ∼105. Compared with the original PEO/PAN TFC membranes with CO2/N2 selectivity of ∼10 at 70 °C, the (AAILs-PEO)/PAN TFC membranes show the selectivity of ∼30, coupled with CO2 permeance of ∼1300 GPU at 70 °C. Under the 40: 60 mixtures of CO2: N2, which is a common lime kiln exhaust gas, by using the (AAILs-PEO)/PAN TFC membrane, the CO2 concentration on the downstream side can reach over 90 % at 20 °C and over 70 % at 70 °C, respectively, under a pressure ratio of 5.

Alkyl chain length affecting the structure and interactions of choline-based amino acid ionic liquids: Insights from a computational study

The influences of the alkyl chain length of amino acid anions on the structure and interactions of choline-based amino acid ([Cho][AA]) ionic liquids were investigated based on density functional theory (DFT) and molecular dynamics (MD) simulations. The most stable configuration of the individual [Cho][AA] ion pair was determined, revealing negligible variations in the binding energy between choline cation ([Cho]+) and different amino acid anions ([AA]−). To further characterize the intermolecular interactions between charged entities, the atoms in molecules theory (AIM) and independent gradient model based on Hirshfeld partition (IGMH) were employed, which highlight the presence of robust hydrogen bonds between [Cho]+ and [AA] −, underscoring their significance in shaping the structure of [Cho][AA] ion pairs. The MD studies exhibited the aggregation of anions in [Cho][AA] ILs, which was attributed to side chain interactions of anions. This aggregation effect becomes more pronounced with the elongation of anionic alkyl chain. Simultaneously, radial distribution functions (RDF) analysis revealed a higher probability of hydrogen bonds occurring between [Cho]+ and [AA]− as the alkyl chain in [AA]− lengthened. Additionally, the hydrogen bond lifetimes roughly display an increasing trend as the alkyl chain of the [AA]− increases, which may be due to the reduced diffusion coefficients of ions. Hopefully, our results would contribute fundamental knowledge regarding the impact of alkyl chain length of anions on the structure and interactions in the choline-based amino acid ionic liquids.

Dynamic breakthrough performance of low concentration CO2 adsorption in fixed-bed column with porous amino acid ionic liquid composites

Low concentration carbon dioxide (CO2) capture from air or confined spaces currently faces significant challenges, such as relatively poor dynamic adsorption breakthrough performance and cyclic stability. In our previous work, functionalized ionic liquid (IL) tetraethylammonium glycine ([N2222][Gly]) and porous molecular sieve (SBA-15) were combined to synthesize porous amino acid IL composite 60 wt% [N2222][Gly]@SBA-15 with microporous and ultra-microporous structures, which provide a new pathway for low concentration CO2 capture. In order to further obtain the dynamic CO2 adsorption breakthrough performance of this material under simulated actual working conditions, the effects of temperatures, relative humidity (RH) and CO2 concentrations on CO2 adsorption and desorption breakthrough performance of 60 wt% [N2222][Gly]@SBA-15 in a fixed-bed column were systematically studied in this work. The results indicated that CO2 adsorption capacity is up to 1.81 mmolCO2/g-adsorbent at 298.15 K, 1 bar and 0 % RH under 1 vol% CO2-containing gas mixture balanced with N2 and reaches 2.44 mmolCO2/g-adsorbent at 15 % RH due to the mechanism change of CO2 reaction with primary amine from 2: 1 under dry gas to 1: 1 stoichiometry in the presence of moisture. Moreover, the adsorbent maintains good cyclic adsorption-desorption performance. Further, CO2 adsorption breakthrough behaviors were well fitted by Avrami kinetic model, and the CO2 adsorption rate of 60 wt% [N2222][Gly]@SBA-15 was controlled by intra-particle diffusion. This work implied that IL-modified adsorbents have great potentials for low concentration CO2 capture applications.

Amino Acid Ionic Liquid Coated Magnetic Core Fe&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;@SiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; Nanoparticles Coupled with UV Spectrophotometry for the Separation /Analysis Congo Red

Congo red has strong tinting strength, low price that it was used in meat dyeing. Amino acid ionic liquids (AAILs) containing amino acid cations or anions are synthesized from natural amino acids, which has the characteristics of low toxicity. Nowadays, Fe&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;@SiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;@AAIL composites has seemly not been reported for the separation/analysis of congo red. In this work, Fe&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;4&amp;lt;/sub&amp;gt;@SiO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;@AAIL nanoparticles were used as magnetic solid phase adsorbents in combination with UV spectrophotometry for separation of congo red.

Effect of Amino Acid Ionic Liquids on the Interfacial Structure and Degradation Behavior of PLA/PBAT Blends

Effect of Amino Acid Ionic Liquids on the Interfacial Structure and Degradation Behavior of PLA/PBAT Blends

Research progress of small molecule carbon dioxide capture agent

At present, the excessive emission of carbon dioxide has threatened people 's living environment and future development. More and more countries have begun to pay attention to carbon emission reduction. China has set the dual-carbon strategic goal of “carbon dioxide content reaches its peak” and “carbon neutrality”. According to the research on carbon dioxide capture technology by many scholars at home and abroad, it is found that the use of chemical absorbents to capture carbon dioxide is a relatively low cost, less technical difficulty, and can be widely put into industrial production. In this paper, several common chemical absorbents such as hot potassium alkali method, organic amine absorption method, amino acid salt, ionic liquid and phase change absorbent are reviewed. Through the research of various kinds of absorbents by researchers from various countries, their reaction principle, performance advantages and disadvantages, research status are introduced, and the future development direction of carbon dioxide negative emission technology is analyzed.

Role of [N2222][Arg] amino acid ionic liquids in the enhancement of biomass in Haematococcus pluvialis via the regulation of reactive oxygen species signals

The slow growth of Haematococcus pluvialis restricts its use for large-scale production of astaxanthin. In this study, [N2222][Arg] amino acid ionic liquids (AAILs) were applied to increase the biomass of H. pluvialis. The maximum biomass concentration and cell count reached 0.98 g L−1 and 165.3 × 104 cells mL−1, respectively. An increase of 38.03% in biomass and 34.31% in cell number was observed following supplementation with [N2222][Arg]. Treatment with [N2222][Arg] resulted in increases in carbohydrate, protein and chlorophyll contents, Fv/Fm and the expression levels of genes associated with cell growth. Notably, [N2222][Arg] application triggered reactive oxidative species (ROS) and lateral membrane diffusion and changed the fatty acid composition, which is potentially involved in cell division and growth. Further data indicated that exogenous H2O2 could enhance alga biomass production in the presence of the [N2222][Arg] ionic liquid. Moreover, the accumulation of astaxanthin also increased in H. pluvialis treated with [N2222][Arg]. This study presents a potential method for enhancing the biomass production of H. pluvialis using amino acid ionic liquids and elucidates the role of ROS signalling in the regulation of cell growth.

Development and validation of an efficient approach for extracting essential oil, scutellarin, and rosmarinic acid from Perilla frutescens leaves using vacuum microwave-mediated rotary hydrodistillation and extraction in situ and a choline amino acid ionic liquid

In this study, an efficient vacuum microwave-mediated rotary hydrodistillation and extraction in situ (VMRHDE) device was used for extracting essential oil, scutellarin, and rosmarinic acid from Perilla frutescens leaves with choline amino acid ionic liquid solution. The extracted products were then analyzed through GC–MS and HPLC. The optimal parameters were determined through a Doehlert design matrix and desirability function, resulting in the use of 10 % choline glutamate ionic liquid ([Ch][Glu]), a liquid–solid ratio of 15 mL/g, a microwave irradiation time of 20 min, a microwave irradiation power of 540 W, and a rotary speed of 24 r/min. Under optimal operating conditions, the yields of essential oil, scutellarin, and rosmarinic acid were 0.41 % ± 0.02 %, 0.39 % ± 0.01 %, and 0.36 % ± 0.01 %, respectively. GC–MS analysis revealed that adding [Ch][Glu] significantly increased the content of perilla aldehyde and oxygenates in the essential oils. Methodological validation confirmed that the established method met the detection requirements, with recoveries of 99.20 % for scutellarin and 99.83 % for rosmarinic acid, demonstrating high accuracy. The linear relationship of scutellarin and rosmarinic acid was good in the concentration range, with R2 values of 0.9999 for both.

Evaluating acute toxicity of amino acid ionic liquids towards Poecilia reticulata fish for designing sustainable chemical processes

An acute toxicity study assessed the LC50 values for eight different amino acid ionic liquids (AAILs), featuring two cations, tetrabutylphosphonium [P4444] and tetrabutylammonium [N4444], coupled with four anions [PHE], [ASP], [SER], and [GLY]. According to the OECD 203 standard for acute fish toxicity tests with guppy fish (Poecilia reticulata, all the AAILs exhibited low toxicity levels, and were practically nontoxic and harmless. The LC50 values surpassed 100 mg/L and 1000 mg/L. This study provides valuable insights for industrial professionals in utilizing tetrabutylphosphonium-based amino acid ionic liquids [P4444] [AA] and tetrabutylammonium-based amino acid ionic liquids [N4444][AA] in chemical processes, indicating their safety in aquatic environments. These promising results highlight the potential of incorporating these AAILs into diverse chemical processes while ensuring minimal ecological impact.

Quantitative analysis method for absorption mechanism and energy consumption of CO2 capture by amino acid ionic liquids

Amino acid ionic liquids (AAILs) are attractive candidates for CO2 capture due to their high solubility for CO2. Quantitatively analyzing the interaction of amino groups in AAILs with CO2 and evaluating the energy consumption of CO2 capture is critical to the molecular design of ideal AAILs. In this work, a thermodynamic model based on the cubic plus association equation of state was proposed to calculate the contribution from the chemical reactions between various stoichiometric ratios of CO2 and AAIL (Nm:n,m:n is stoichiometric ratio) on CO2 solubility. The results show that the larger contribution to the CO2 solubility in [Glu], [Tyr] and [Gln]-IL with strong polar groups is derived from association scheme N1:2, while the N1:1 association interaction is the dominant contribution of [Gly], [Ala], [Val] and [Pro]-IL with hydrogen atom or short alkyl side chains, and [VBIm]-IL with multiple amino groups. The N2:1 association interaction is primary between CO2 and [Cho][His] or [Cho][Arg]. Besides, the contributions of these association effects are greater than that of dispersion and repulsion to CO2 solubility. Then, the solvent cyclic capacity and regeneration energy of AAILs in the pressure swing and temperature swing CO2 capture system were estimated. More amino groups result in higher regeneration energy consumption and do not necessarily increase solvent cyclic capacity. Among the studied AAILs, [Cho][Gly] which exhibits high cyclic capacity and low energy consumption has great potential in CO2 capture solvent.