Ionic Liquid Materials Research Articles

Application of Ionic Liquids in Environmental and Food Fields

Abstract: As a new type of green solvent, ionic liquids have made rapid progress in the fields of organic synthesis, separation, and electrochemistry due to their unique physical and chemical properties. At the same time, the new fluorescence characteristics and good separation and adsorption functions of ionic liquids have gradually developed in the field of environment and food, showing a good application prospect. Based on the work of our research group and the progress and development of research technology, this article reviews the research results of ionic liquids in environmental monitoring and food detection and extraction in recent years. In the environmental field, ionic liquids have the ability of detection and remediation and they show the advantages of fast, efficient, green and recyclable in the detection of environmental pollutants. In the field of food, ionic liquids provide a new idea for the detection and extraction technology of food components. While ensuring green, safe and pollution-free, they show superior selectivity, repeatability and stability, and simplify the operation steps and costs to a certain extent, showing the capture vitality with life characteristics. As a potential smart material, the mechanism of ionic liquids as fluorescent probes and separation extractants was discussed. Finally, the future development and research directions of ionic liquids are prospected, and it is expected to realize the intelligentization of ionic liquid materials and the general integration of development.

Screen-Printable Iontronic Pressure Sensor with Thermal Expansion Microspheres for Pulse Monitoring.

Constructing microstructures to improve the sensitivity of flexible pressure sensors is an effective approach. However, the preparation of microstructures usually involves inverted molds or subtractive manufacturing methods, which are difficult in large-scale (e.g., in screen printing) preparation. To solve this problem, we introduced thermally expandable microspheres for screen printing to fabricate flexible sensors. Thermally expandable microspheres can be constructed into microstructures by simple heating after printing, which simplifies the microstructure fabrication step. In addition, the added microspheres can also be used as ionic liquid reservoir materials to further increase the capacitance change and improve the sensitivity. The prepared sensors exhibited superior performance, including ultrahigh sensitivity (Smax = 49999.5 kPa-1) and wide detection range (0-350 kPa). Even after 30,000 cycles at a high pressure of 300 kPa and a low pressure of 30 kPa, the sensor showed minimal signal degradation, demonstrating long-term cycling stability. In order to verify the practical potential of the sensors, we performed human radial artery beat detection experiments using these sensors. The variations in the intensity of the 3D radial artery pulse wave can be observed very clearly, which is important for human health monitoring. The above demonstrates that our strategy can provide an effective approach for the large-scale preparation of high-performance flexible pressure sensors.

Mesoporous silica supported ionic liquid materials with high efficacy for CO2 adsorption studies

CO2 capture from industrial processes and power plants, contribute to curbing global warming and advancing sustainability efforts. This study involves the design and synthesis of novel mesoporous silica supported ionic liquid based adsorbents for carbon dioxide capture. Utilization of MSILs delves into the efficiency and mechanisms of CO2 adsorption, offering insights for sustainable carbon capture technologies in combating greenhouse gas emissions. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate and 1-ethyl-3-methylimidazolium methylsulfate ionic liquids were anchored on the surface of mesoporous silica which then led to highly efficient adsorbent material. Simple, efficient and cost saving methodology was performed to synthesize such highly efficient CO2 adsorbent materials. In addition, we theoretically predicted the favorable interaction mechanism of chosen molecular entities for CO2 adsorption using density functional theory (DFT) analysis. Theoretical results depict the strong interaction of molecular entities with CO2 gas molecules which is clearly evident from the experimental findings.

Temperature-Controlled Divergent Synthesis of Pyrazoles and 1-Tosyl-1H-pyrazoles under Transition-Metal-Catalyst- and Oxidant-Free Conditions.

Herein, a general and practical temperature-controlled approach for the divergent synthesis of pyrazoles and 1-tosyl-1H-pyrazoles via electrophilic cyclization in the absence of transition-metal catalysts and oxidants was developed. The desired products were obtained in moderate to excellent yields from common starting materials in both ionic liquids and ethanol by simply tuning the reaction temperature. This strategy employs easily synthesized substrates, mild reaction conditions, and excellent functional-group tolerance.

Grafting of Poly(ionic liquid) Brushes through Fe0-Mediated Surface-Initiated Atom Transfer Radical Polymerization for Marine Antifouling.

Surface-tethered poly(ionic liquid) brushes have attracted considerable attention in widespread fields, from bioengineering to marine antifouling. However, their applications have been constrained due to the poor polymerization efficiency and sophisticated operation process. In this work, we efficiently synthesized the poly(ionic liquid) brushes with unparalleled speed (up to 98 nm h-1) through Fe0-mediated surface-initiated atom transfer radical polymerization (Fe0 SI-ATRP) while consuming only microliter of monomer solution under ambient conditions. We also demonstrated that poly(ionic liquid) brushes with gradient thickness and wettability were easily accessible by regulating the distance between the opposite plates of Fe0 SI-ATRP. Moreover, the resultant poly(ionic liquid) brushes presented excellent antibacterial activities against Escherichia coli (99.2%) and Bacillus subtilis (88.1%) after 24 h and low attachment for proteins and marine algae (≤5%) for over 2 weeks. This research provided pathways to the facile and controllable fabrication of poly(ionic liquid) materials for marine antifouling applications.

Asymmetric 1, 2-naphthoquinone cathode material with enhanced capacity for rechargeable aluminium ion batteries

Rechargeable aluminium ion batteries (RAIBs) offer higher safety and lower costs than traditional lithium-ion batteries and have therefore been seen in recent years as a very promising potential development in areas such as large-scale energy storage. However, the development of RAIBs is limited by the cathode material, with most research currently focused on inorganic materials. Organic small molecules like naphthoquinone (NQ) based derivants have the potential to be advantageous in designing high performance cathode materials due to their molecular structural diversity and tunability. Together with 1, 4-NQ, 1, 2-NQ was successfully prepared by chemical oxidation using naphthol derivatives and assembled as RAIBs. Elucidated by Gaussian calculation, the asymmetric structure of 1, 2-NQ provides reaction sites with a higher possibility of binding to AlCl2+ ions than 1, 4-NQ, to the extent that there is an expected enhancement in its electrochemical performance. It is verified by the experimental results that the chemical and electrochemical stability of NQ cathode materials in ionic liquids is improved by the asymmetric structure. The 1, 2-NQ based RAIBs exhibits an outstanding initial specific capacity of 165.9 mAh g−1 and remains at 117.2 mAh g−1 with a Coulombic efficiency of about 98 % after the cycling of 600 and longer cycle life than the 1, 4-NQ based ones. The working concept and satisfying performance of the NQ based cathode material suggest that asymmetric molecules could be a promising design strategy for developing high-performance electrode materials for RAIBs.

Microwave controlled ignition and combustion characteristics of ADN-based ionic liquid propellant with fast response and environmental friendliness

The ADN-based ionic liquid propellants have been successfully implemented in liquid rocket engines, owing to high specific impulse and thrust, low toxicity and environmental friendliness. However, the traditional catalyst ignition of ADN-based propellant suffers from the problems of catalyst deactivation problems in the heating process. Microwaves could interact with the material holistically due to excellent penetration ability. Compared with solid materials, ionic liquids are natural microwave receptors on account of great polarity. To date, the possibility of microwave ignition of ionic liquid materials has not been explored. In this work, two kinds of ionic liquids: ADN and [AMIM][DCA] were used as oxidant and fuel of liquid propellant to achieve the maximum microwave absorption effect. The microwave controlled ignition and combustion of ADN-based liquid propellant was first realized and systematically studied. Compared to single component, the heat release, gas production, conductivity and heating rate of the mixed system was greatly enhanced. The sample (ADN/[AMIM][DCA] 10%) was successfully ignited by microwaves, displaying a decreased ignition delay time at higher power inputs. The ignition was generated in the gas phase and rapidly diffused into the solution, and the extinguishment was highly consistent with the input cessation of microwaves. The ignition delay was significant reduced in repeated ignition, resulted from the faster moving speeds of ions. The successful realization of microwave controlled ignition and combustion of ADN-based IL propellant will broaden the scope of their applications in space fuel and provide a new direction for the reform of liquid engines.

Highly efficient removal of diclofenac sodium with polystyrene supported ionic liquid

ABSTRACT Diclofenac sodium (DS) is now recognized as an emerging pollutant, and is one of the most commonly discovered pharmaceuticals in water due to its extensive application in the clinic. This study examined the adsorption performance of a polystyrene-supported ionic liquid material (PS-[Nim][Cl]) for the removal of diclofenac sodium (DS) from water. The data from this study showed that maximum removal of DS can be achieved even in conditions with significant pH and temperature fluctuations. The adsorption process was rapid, more than 90% of DS could be removed within the first 10 min and adsorption equilibrium could be reached in just 30 min with a high removal efficiency (>99.9%). Adsorption reached saturation with a maximum adsorption capacity of approximately 785.2 mg/g. Moreover, the presence of K+, Na+, Ca2+, Mg2+, Cl-, and H2PO4 - ions had little influence on DS adsorption, even when concentrations of these ions were 10,000 times higher than that of DS in water samples. The adsorbent also showed promising performance for the treatment of environmental water samples and groundwater containing DS.

Unusual phosphatidylcholine lipid phase behavior in the ionic liquid ethylammonium nitrate

HypothesisThe forces that govern lipid self-assembly ionic liquids are similar to water, but their different balance can result in unexpected behaviour. ExperimentsThe self-assembly behaviour and phase equilibria of two phospholipids, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), in the most common protic ionic liquid, ethylammonium nitrate (EAN) have been investigated as function of composition and temperature by small- and wide-angle X-ray scattering (SAXS/WAXS) and small-angle neutron scattering (SANS). FindingsBoth lipids form unusual self-assembly structures and show complex and unexpected phase behaviour unlike that seen in water; DSPC undergoes a gel Lβ to crystalline Lc phase transition on warming, while POPC forms worm-like micelles L1 upon dilution. This surprising phase behaviour is attributed to the large size of the EAN ions that solvate the lipid headgroup compared to water changing amphiphile packing. Weaker H-bonding between EAN and lipid headgroups also contributes. These results provide new insight for the design of lipid based nanostructured materials in ionic liquids with atypical properties.

Ultrasonic assisted magnetic solid phase extraction of ultra-trace mercury with ionic liquid functionalized materials

Due to the agglomeration between particles, the inherent adsorption characteristics of magnetic powder materials are usually difficult to fully display. Taking ionic liquid functional materials as an example, the enrichment behavior of these adsorbents for trace mercury (Hg2+) in ultrasonic (US) assisted dispersion mode was systematically studied. The dissociation of protonic ionic liquids (IL) occur in the process of dispersion and the strong electrostatic attraction can improve the diffusion and adhesion of mercury on the adsorbent surface. Spectral measurement data showed that with the help of US, the more uniform dispersion of magnetic materials accelerated the adsorption of trace Hg2+. Ultrasonic intrinsic parameters such as frequency, power and radiation duration significantly affect the dispersion and apparent adsorption properties of magnetic functional materials. In the range of experimental parameters, the dye/paper image experimental results documents that there is a positive correlation between cavitation effect and ultrasonic frequency/power. The enrichment degree of fixed adsorbate (0.1 μg L−1) under high frequency (59 kHz) or high-power input (100%) is 1–2 times higher than that under low frequency (40 kHz) or low power (60%) input. This is a valuable conclusion for the subsequent study of US dispersion of magnetic and even non-magnetic powder materials. In addition, the in-situ desorption and accurate measurement of adsorbed mercury were realized by combining slurry vapor generation atomic fluorescence spectroscopy (SVG-AFS). The constructed US assisted magnetic solid phase extraction (US-MSPE) method has the characteristics of low detection limit (0.36 ng L−1), high recovery (>90%), sustainable utilization (>3) and reasonable measurement deviation (<5%), which can meet the requirements of ultra-trace Hg2+ (0.01–1.0 μg L−1).

Research progress of CO2 separation technology by solvent absorption

The combustion of fossil fuels emits a large amount of CO2, which causes the greenhouse effect and leads to global warming and poses a serious threat to life on earth. CO2 capture technology can effectively reduce the concentration of CO2 in the atmosphere, alleviate the greenhouse effect, and improve the environment. CO2 capture technologies include absorption, membrane separation and adsorption separation, among which chemical absorption and separation have the advantages of high efficiency, low cost and easy availability of materials. In this paper, the advantages and disadvantages of three main chemical absorption and separation methods (inorganic reagents, organic amines and ionic liquids) adsorb CO2 are summarized. Among inorganic adsorbents, NH3·H2O can achieve rapid and efficient absorption of CO2, and it is relatively stable and not easy to degrade. Common types of organic amine adsorbents are monoethanolamine, methanolamine, and sterically hindered amine. However, it is difficult for a single organic amine adsorbent to meet the requirements of high absorption rate, high absorption capacity and low reaction heat at the same time. Therefore, mixing organic amine absorbents with different characteristics can improve their performance in absorbing CO2. Ionic liquids have the advantages of good thermal stability, very low saturation vapor pressure, and designable structure, and are a new type of CO2 adsorbent, but ionic liquids have high viscosity themselves. Combining ionic liquids with organic or inorganic porous materials to form loaded ionic liquid materials, which can be used as CO2 adsorbent not only to improve the separation effect, but also to avoid the problem of high viscosity caused by direct absorption of ionic liquids, thus improving CO2 adsorption efficiency.

Recent Developments on Bioinspired Cellulose Containing Polymer Nanocomposite Cation and Anion Exchange Membranes for Fuel Cells (PEMFC and AFC)

Hydrogen fuel cell (FC) technologies are being worked on as a possible replacement for fossil fuels because they produce a lot of energy and do not pollute the air. In FC, ion-exchange membranes (IEMs) are the vital components for ion transport between two porous electrodes. However, the high production cost of commercialized membranes limits their benefits. Various research has focused on cellulose-based membranes such as IEM with high proton conductivity, and mechanical, chemical, and thermal stabilities to replace the high cost of synthetic polymer materials. In this review, we focus on and explain the recent progress (from 2018 to 2022) of cellulose-containing hybrid membranes as cation exchange membranes (CEM) and anion exchange membranes (AEM) for proton exchange membrane fuel cells (PEMFC) and alkaline fuel cells (AFC). In this account, we focused primarily on the effect of cellulose materials in various membranes on the functional properties of various polymer membranes. The development of hybrid membranes with cellulose for PEMFC and AFC has been classified based on the combination of other polymers and materials. For PEMFC, the sections are associated with cellulose with Nafion, polyaryletherketone, various polymeric materials, ionic liquid, inorganic fillers, and natural materials. Moreover, the cellulose-containing AEM for AFC has been summarized in detail. Furthermore, this review explains the significance of cellulose and cellulose derivative-modified membranes during fuel cell performance. Notably, this review shows the vital information needed to improve the ion exchange membrane in PEMFC and AFC technologies.

Advanced Formulations Based on Poly(ionic liquid) Materials for Additive Manufacturing.

Innovation in materials specially formulated for additive manufacturing is of great interest and can generate new opportunities for designing cost-effective smart materials for next-generation devices and engineering applications. Nevertheless, advanced molecular and nanostructured systems are frequently not possible to integrate into 3D printable materials, thus limiting their technological transferability. In some cases, this challenge can be overcome using polymeric macromolecules of ionic nature, such as polymeric ionic liquids (PILs). Due to their tuneability, wide variety in molecular composition, and macromolecular architecture, they show a remarkable ability to stabilize molecular and nanostructured materials. The technology resulting from 3D-printable PIL-based formulations represents an untapped array of potential applications, including optoelectronic, antimicrobial, catalysis, photoactive, conductive, and redox applications.

Triethylammonium thiocyanate ionic liquid electrolyte-based supercapacitor fabricated using coconut shell-derived electronically conducting activated charcoal electrode material

Organic solvents are commonly used as commercial electrolytes in supercapacitors, but they have several drawbacks, such as high volatility, toxicity, and environmental issues. To overcome these problems, ionic liquids are used though their high costs hamper commercial applications. In this study, a novel and low-cost ionic liquid based on triethylammonium cation and thiocyanate anion were synthesized and used as the electrolyte in a low-cost supercapacitor fabricated using electronically conducting activated carbon derived from cleaned coconut shells as electrode material. The temperature dependence of electrolyte conductivity was investigated, in the frequency range of 1 Hz-500 kHz, using AC impedance analysis, in the temperature range from 30 °C - 90 °C in ten-degree increments and found to be in the range of 4.5 to 14.4 mS cm−1. The ion transport kinetics behaves according to the Vogel-Tammann-Fulcher (VTF) model with an activation energy (Ea) and the pre-exponential factor (AσT) of 0.0158 eV and 114.9 S m−1 K1/2, respectively. The activated carbon material developed has a high porosity and high electronic conductivity. The electrode fabrication methodology was optimized by varying the polyvinylpyrrolidone (PVP) binder amount with respect to the mass of activated carbon on a titanium sheet as a function of heat treatment temperature. The supercapacitor that gives the highest specific capacitance is based on the electrode constructed using 5 % w/w PVP in 0.50 g of activated carbon deposited on a titanium sheet by heat treating at 200 °C for 20 min. At the scan rate of 5 mV s−1, two-electrode CV studies revealed a specific capacitance of 36.8 F g−1 for the optimized supercapacitor assembly. The electrolyte triethylammonium thiocyanate (TAT) demonstrated good electrochemical stability and a large operating voltage window of 1.8 V and high stability, with 94.4 % capacity retention after 1000 cycles. The AC impedance studies also gave comparable results. Prime novelty statementThe manuscript describes a method to prepare a novel and low-cost ionic liquid material triethylammoniumthiocyanate starting from triethylamine and ammonium thiocyanate, and its application as the ionic liquid electrolyte in a low-cost supercapacitor. The electrode material used in the supercapacitor was fabricated using electronically conducting activated carbon derived from cleaned coconut shells, which were deposited firmly adhering to titanium sheets using polyvinylpyrrolidone binder under optimized heat treatment conditions. As such, both the ionic liquid electrolyte and the activated carbon electrode material are novel and attractive materials for the commercial production of low-cost supercapacitors.

Separation and recovery of Th(IV) from rare earth and other cation solutions using pH-responsive ionic liquids at high acidity condition of 1 M HNO3

Thorium has received widespread attention as a potential nuclear fuel alternative, but it is still a difficult task to extract thorium from strong HNO3 media. Meanwhile, stimulus-responsive materials have received extensive attention in the field of separation due to their special properties. Herein, we designed and synthesized a new type of stimulus responsive ionic liquid (SIL) material and applied it to solve the problem of low thorium extraction efficiency in strong HNO3 media. By utilizing the pH-response performance of SIL, a SIL and thorium complex (SILTh) is found to self-assemble and precipitate out from solution upon simple adjustment of the pH. We found that the extraction efficiency of thorium can reach 99.6% under high acidity and that it can be even higher than 98.8% when the temperature changes. Under experimental conditions, SIL showed a record-breaking maximum extraction capacity for thorium (644.2 mg g−1) with an excellent selectivity for thorium over lanthanide and transition metal in 1 M HNO3 (S>1400). Studies reveal that PO is complexed with thorium, which also explains the high adsorption capacity and selectivity of SIL for thorium under high acidity. Moreover, the pH-response characteristics of SIL are reversible. The pH-responsive SIL material and the extracted thorium can be recovered, and SIL also shows an excellent recycling ability over five cycles, with extraction and recovery efficiencies for Th(IV) of 98.0% and 98.7%, respectively within five cycles, indicating that the material has a good recycling ability. This study explores the possibility of using pH-responsive materials to recover thorium in strong HNO3 media, and provides ideas for the design and synthesis of new materials for the recovery of thorium.

Physical, chemical and antibacterial properties of 1-methyl-3-(4-vinylbenzyl) imidazol-3-ium chloride ionic liquid: Experimental and ab-initio analysis

1-methyl-3-(4-vinylbenzyl)-imidazol-3-ium chloride ionic liquid material was successfully synthetized and studied using both experimental and theoretical approaches. Firstly, the chloride anion was weakly bonded to the most negative NBO charge of the organic cation of the molecule; then, the structures before and after the bonding with chloride anion were optimized using density functional theory (DFT) calculations based on B3LYP/6–311G++ (d, p). The 13C and 1H nuclear magnetic resonance peaks were all assigned and confirmed by DFT. Furthermore, the vibration modes were analyzed by FTIR and RAMAN spectroscopies, and then, they were attributed to various functional groups, thank to DFT. The frontier molecular orbitals yield a band gap of 4.63 eV and other values for the physical and chemical global quantum chemical descriptors. The mapping electrostatic potential illustrates that the chlorine brings nucleophile character comparatively to pristine organic part. The first static-hyper polarizability was calculated, illustrating a predicted non-linear optical properties. Finally, the material tested for an antimicrobial performance, depicted an excellent activity toward some bacteria strains.

Poly(ionic liquid) materials tailored by carboxyl groups for the gas phase-conversion of epoxide and CO2 into cyclic carbonates

Carbon dioxide (CO2) is an important C1 resource, and the preparation of cyclocarbonate by catalyzing CO2 and epoxides is a nature-friendly route to utilize. In this study, polymer ionic liquid materials (PILMs) were prepared by copolymerizing the vinylimidazole-based ionic liquids (ILs) as monomer with carbonyl-rich copolymer monomer methyl methacrylate (MMA) and crosslinking agent ethylene glycol dimethacrylate (EGDMA), to enhance the affinity of PILMs for CO2 and PO. Then, epoxides and CO2 were converted to cyclic carbonates using PILMs by the gas-liquid reaction (GLR) and the gas phase-conversion progress (GCP). Amongst those polymer ionic liquid materials, the PILM containing carboxypropyl group (PILM-VCPImBr) exhibited the performance with the propylene carbonate (PC) yield of 96.7% (at 130 °C, 3 MPa CO2, reaction time 3 h) by GLR. And the yield of PC reached 94.2% (at 130 °C, 2 MPa CO2, reaction time 3 h) by GCP, which was the same as that of GLR. The excellent catalytic activity can be attributed to the fact that the PILMs fully dispersed the active sites and were rich in pores, which could effectively catalyze propylene oxide (PO) and CO2 to generate PC. Finally, 1H NMR spectra showed that VCPImBr and PO formed strong hydrogen bonds to participate the ring-opening process of epoxides, and a possible catalytic mechanism of H-bond synergistic effect was proposed. This article provides a novel strategy for designing both stable and nature-friendly catalysts in the CO2 transformation, and proposes a new method for cyclic carbonate conversion.

Mixed-Matrix Ion Gel Membranes for Gas Separation

The potential of ionic liquid materials to improve membrane-based gas separation processes has been realized during the past few years, through the exploitation of diverse configurations, chemical functionalities, and properties. Nowadays, one of the most recent trends on this field is the development of mixed-matrix ion gels, an emerging family of ionic soft-solid materials, in which fillers are embedded into polymer/IL matrices. This review aims at presenting an overview on the latest developments and advances on ion gel membranes containing a third component, such as zeolites, metal organic frameworks, silica, graphene oxide, metal salts, and nanoparticles, for gas separation processes. We provide an analysis of this building system and highlight the diverse type of mixed-matrix ion gels hitherto reported, for which the impact of the different fillers on the ion gels’ overall properties is discussed in detail. The main challenges on their preparation, as well as their transport mechanism and how it can be influenced by the different fillers, are also addressed. Finally, technological aspects, perspectives, and opportunities to pursue this topic are discussed from a critical point of view.

Development of Robust, Ion-Selective Anion Exchange Membranes Through the Incorporation of Ionic Liquid Materials for Water Purification Via Electrodialysis

Development of Robust, Ion-Selective Anion Exchange Membranes Through the Incorporation of Ionic Liquid Materials for Water Purification Via Electrodialysis

Cost-Effective Processing of Carbon-Rich Materials in Ionic Liquids: An Expeditious Approach to Biofuels.

This work presents a cost-effective approach for processing of renewable carbon-rich biomass using pyridinium-based Lewis acidic ionic liquids (LAILs). Rice husk as carbon-rich lignocellulosic waste was pretreated with a series of neutral and Lewis acidic ionic liquids to yield valuable intermediate platform monosaccharides. Novelty in the work lies in direct conversion of lignocellulosic carbohydrates into reducing sugars without their further conversion into 5-hydroxymethylfurfural or any other platform chemicals that are fermentation inhibitors for bioethanol production. The unconverted cellulose-rich material (CRM) is regenerated as a delignified material by the simultaneous addition of antisolvents. CRM and recovered lignin obtained after pretreatment were analyzed via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The process was optimized with respect to a high yield of platform sugars and the quantity as well as quality of recovered CRM and lignin contents. Various reaction parameters involving the molecular structure of ionic liquids (ILs), Lewis acidic strength of ILs, biomass loading into IL, time, temperature, and biomass particle size were screened thoroughly. From all of the tested ILs, unsymmetrical 3-methylpyridinium IL having N-octyl substitution and chloroaluminate anion showed a greater conversion efficiency at 100 °C for 1.5 h. FTIR and SEM analyses of recovered CRM justify >90% lignin removal from rice husk. From all of the removed lignin, 60 wt % of original lignin content was recovered. The Lewis acidic system possessed recycling ability up to 3 times for subsequent treatment of rice husk without a significant loss of efficiency.