Recovery Of Ionic Liquid Research Articles

Copper leaching from waste printed circuit boards using typical acidic ionic liquids recovery of e-wastes’ surplus value

In this study, using several types of acidic ionic liquids as the leaching reagents, the leaching behaviors of the copper present in waste printed circuit boards (WPCBs) were investigated. The effects of various parameters on the copper leaching rate were studied, such as the particle size of the shredded WPCB, type of ionic liquid used, hydrogen peroxide dosage, solid-to-liquid ratio, leaching temperature, and leaching time. The experimental results showed that the copper leaching rate increases continuously when the powder particle size is increased from 0.071 to 0.500 mm. Moreover, the copper leaching rate also increases with an increase in the leaching temperature. In contrast, the leaching rate first increases and then decreases with increases in the leaching time, hydrogen peroxide dosage, and solid-to-liquid ratio. The optimal conditions that provided a 98.31% copper leaching rate were: particle size >0.500 mm, 8.5 mL 90% (v/v) ionic liquid, 1.5 mL 30% hydrogen peroxide, solid-to-liquid ratio of 1/20, leaching temperature of 80 °C, and leaching time of 2 h.

Separation and Recovery of a Hemicellulose-Derived Sugar Produced from the Hydrolysis of Biomass by an Acidic Ionic Liquid.

Biomass processing with ionic liquids (ILs) has been one of the most topical research areas in recent years. However, separation and recovery of biomass products and ILs are currently a challenge. Recovery of produced monosaccharides from an IL postreaction solution and the possibility to reuse the IL are strongly required to guarantee the sustainability of biomass processing. The present study demonstrates a novel approach that aims at separating a biomass hemicellulose-derived product, namely, xylose, and 1-ethyl-3-methylimidazolium hydrogensulfate ([emim][HSO4 ]). High polarity of a postreaction system composed of xylose, IL, and water is one of the major hindrances in the separation performance. A proposed solution is fine-tuning of the system polarity by the addition of moderately polar acetonitrile. To scrutinize the potential of xylose and IL separation, phase equilibria of a system constituted by [emim][HSO4 ], water, and acetonitrile were studied. Additionally, preparative chromatography experiments with alumina as a stationary phase were performed to determine the conditions required for efficient separation of the sugar and the IL by selective adsorption of xylose on alumina in detriment of IL. The amount and treatment of the stationary phase, eluent polarity, and amount of loaded sample were also scrutinized in this study. Treatment of alumina was considered as a necessary step to achieve recovery yields of 90.8 and 98.1 wt % for the IL and xylose, respectively, as separate fractions.

Recovery and purification of ionic liquids from solutions: a review.

With low melting point, extremely low vapor pressure and non-flammability, ionic liquids have been attracting much attention from academic and industrial fields. Great efforts have been made to facilitate their applications in catalytic processes, extraction, desulfurization, gas separation, hydrogenation, electronic manufacturing, etc. To reduce the cost and environmental effects, different technologies have been proposed to recover the ionic liquids from different solutions after their application. This review is mainly focused on the recent advances of the recovery and purification of ionic liquids from solutions. Several methods for recovery of ionic liquids including distillation, extraction, adsorption, membrane separation, aqueous two-phase extraction, crystallization and external force field separation, are introduced and discussed systematically. Some industrial applications of ionic liquid recovery and purification methods are selected for discussion. Additionally, considerations on the combined design of different methods and process optimization have also been touched on to provide potential insights for future development of ionic liquid recovery and purification.

Homogenous esterification of cellulose pulp in [DBNH][OAc

Cellulose acetate is widely used in films, filters, textiles, lacquer and cosmetic products. Herein we demonstrate the production of cellulose esters under homogeneous conditions using 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) as solvent. The reagents have been chosen such that the system is recyclable, i.e. by-products are low boiling and easy to remove. It is demonstrated that cellulose acetate can be synthesized with different degree of substitution (DS) values, and that some commonly used acylation regents, like vinyl carboxylates react well without additional base catalyst. Low to high DS values are possible with good recovery of high purity ionic liquid (IL). A linear correlation method of two separate methods, IR and 31P NMR, is proposed to reliably assess the DS of the products. The recyclability of the solvent is demonstrated by acetylating cellulose with isopropenyl acetate to high degree and regeneration into water. After regeneration of cellulose acetate from the IL with addition of water, the residual water was entrained using n-butanol to minimize hydrolysis of [DBNH][OAc], to allow for high recovery and high purity of the ionic liquid. Thus, an overall scheme for batch cellulose acetylation and recovery of [DBNH][OAc] from aqueous solutions is proposed.

COSMO-based/Aspen Plus process simulation of the aromatic extraction from pyrolysis gasoline using the {[4empy][NTf 2 ] + [emim][DCA]} ionic liquid mixture

Abstract The ionic liquids (ILs) have been widely studied as potential replacements of conventional solvents in the extraction of aromatic hydrocarbons from alkanes. However, most of the literature is focused in obtaining liquid-liquid equilibria experimental data without studying the complete extraction and IL regeneration process. In this paper, a computer-aided methodology combining COSMO-based molecular simulations and Aspen Plus process simulations has been used to study the extraction process of aromatic hydrocarbons from pyrolysis gasoline employing a binary mixture of 1-ethyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4empy][NTf 2 ]) and the 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]) ILs as solvent. An extensive comparison (more than 600 points) between experimental data and the predictions obtained by the COSMO-based thermodynamic model of liquid–liquid and vapor–liquid equilibria and ILs physical properties was made for validation purposes. Process simulations were performed in three system configurations: with one, two, or three flash distillations in the IL recovery section. The potential advantage of using binary IL-IL mixture as extracting solvent was studied in the whole range of composition. The configuration with three flash distillations and the binary IL-IL mixture with a 75% of [4empy][NTf 2 ] were selected as the optimal conditions to increase aromatic recovery and purity, improving the separation performance respect to the neat ILs.

Research on the quick and efficient recovery of 1-allyl-3-methylimidazolium chloride after biomass pretreatment with ionic liquid-aqueous alcohol system

Membrane-based methodology electrodialysis (ED) was employed for the quick and efficient recovery of ionic liquid AmimCl from the aqueous solutions after biomass pretreatment with AmimCl-aqueous methanol/ethanol systems. IL recovery performance was relatively stable as the variation of IL-alcohol systems employed in the pretreatment process. IL recovery ratio (R) of 66%–71%, IL recovery performance of specific energy consumption (Sp) of 429–467g/kwh and IL transport rate (Tr) of 5.3–8.2g/(m2min) were obtained by single ED treatment. Enhanced IL recovery performance was resulted with the semi-continuous ED-assisted process with R reached 93% and Sp reached 482g/kwh. Based on the characteristics of IL solutions, influence of different AmimCl-based solvents pretreatment on IL recovery was discussed and feasibility of electrodialysis treatment for such IL recovery task was also analyzed. Potential gained from this study suggests a feasible methodology for the quick and efficient recovery of ionic liquid after biomass pretreatment.

Surface Charge-Induced Efficient Recovery of Ionic Liquids from Aqueous Phase.

Ionic liquids (ILs), which consist of pure cations and anions, are widely used in diverse applications and regarded as one of the best choices of "green solvents." However, the lack of effective green methods for recovering ILs and the safety issues caused by entering environment severely hinder the application of ILs in the green chemistry. Here, we show that rationally tuning the surface charge of a poly(tert-butyl acrylate) (PtBA)-coated porous mesh can selectively let ILs pass through, thus providing an efficient and convenient strategy to recover ILs. The surface charge of the porous mesh can be precisely controlled by regulating the hydrolysis degree of the chemically grafted PtBA coating. PtBA-coated porous mesh with a proper surface charge can be tuned to be IL-philic for a specific IL but hydrophobic, and thus can be applied to recover various kinds of ILs from the aqueous phase. This study offers a new platform for the development of functional membranes for efficient recovery of ILs.

Separation of Am(III) from nitric acid medium by phosphonium ionic liquid–hydroxyacetamide mixture

A strongly hydrophobic phosphonium ionic liquid, trihexyltet radecylphosphonium bis(trifluoromethanesulfonyl)imide ([P66614][NTf2]) was employed as the diluent for the extraction behavior of Am(III) using N,N-dihexyl-2-hydroxyacetamide(DHHy) as extractant. The extractibility of americium(III) in [P66614][NTf2] phase was measured as a function of various parameters such as aqueous phase acidity (0.1–8 M), extractant concentration (0.01–0.15 M), equilibration time (5–120 min) and temperature (298–333 K). The extraction performance observed in DHHy/[P66614][NTf2] was compared with those observed in N,N-dihexyloctamide (DHOA) in [P66614][NTf2] and DHHy in other diluents such as [C4mim][NTf2] and n-dodecane. The effect of temperature on D Am(III) in ionic liquid system and recovery of Am(III) from the loaded phase were ascertained in detail.

Polyelectrolyte multilayer modified nanofiltration membranes for the recovery of ionic liquid from dilute aqueous solutions

ABSTRACTThe feasibility of nanofiltration membranes fabricated by static polyelectrolyte layer‐by‐layer deposition of poly(styrene sulfonate) and poly(allylamine hydrochloride) on poly(ether sulfone) ultrafiltration and alumina microfiltration membranes for the recovery of ionic liquid from low molecular weight sugar was investigated. The surface properties of these modified membranes were correlated with their performances. The selectivity for 1‐butyl‐3‐methylimidazolium chloride over cellobiose and glucose was found to be as high as 50.5/2.3 for modified alumina and 32.3/3.5 for modified poly(ether sulfone) membranes with optimized number of bilayers. The values for membrane permeance were 4.8 and 2.5 L m−1 h2 bar−1, respectively. For low depositions, the separation mechanism was predominantly governed by size‐exclusion. For higher depositions, the enhanced negative zeta potential of the modified membranes suggested preferred dominating electrostatic interactions, resulting in high selectivity of ionic liquids over low molecular weight sugars. At very high depositions, the molecular weight cut‐off of the membrane becomes constricting for size‐exclusion effect. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45349.

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

BackgroundBiomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration.ResultsWe evaluated a commercially available PV system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that >99.9 wt% [C2C1Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses.ConclusionsThese findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.

Efficient recovery of ionic liquid by electrodialysis in the acid hydrolysis process

ABSTRACTElectrodialysis (ED) has been recently known as a highly effective technique to remove and recover ionic liquids from aqueous solution. When a conventional electrolyte solution for the ED process containing Na2SO4 was used, a recovery ratio of an acidic IL, 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim][HSO4]), was 90%. On the other hand, the value clearly increased to 96% when we employed [Bmim][HSO4] as the electrolyte solution. In an acid hydrolysis of bagasse using the IL under microwave irradiation, the recovery ratio maintains 96%, irrespective of reaction time. This demonstrates the applicability of the proposed ED system in biomass processing.

Recovery of lignin and ionic liquid by using organic solvents

Abstract Studies of lignin and ionic liquid separation by using an organic solvent were investigated. Effects of main factors including solvent type and amount, separation temperature on product yield, and purity were examined. Solvents show their different separation effectiveness, the most effective solvent for lignin–ionic liquid separation is isopropanol. An attempt to enhance efficiency of single-stage separation was also carried out by using multi-stage separation. TGA data, 1H NMR and SEM images indicate that chemical and thermal properties of recovered ionic liquid and precipitated solid from multi-stage separation are comparable with those of fresh materials.

Imidazolium-based ionic liquids for cellulose pretreatment: recent progresses and future perspectives.

As the most abundant biomass in nature, cellulose is considered to be an excellent feedstock to produce renewable fuels and fine chemicals. Due to its hydrogen-bonded supramolecular structure, cellulose is hardly soluble in water and most conventional organic solvents, limiting its further applications. The emergence of ionic liquids (ILs) provides an environmentally friendly, biodegradable solvent system to dissolve cellulose. This review summarizes recent advances concerning imidazolium-based ILs for cellulose pretreatment. The structure of cations and anions which has an influence on the solubility is emphasized. Methods to assist cellulose pretreatment with ILs are discussed. The state of art of the recovery, regeneration, and reuse aspects of ILs is also presented in this work. The current challenges and development directions of cellulose dissolution in ILs are put forward. Although further studies are still much required, commercialization of IL-based processes has made great progress in recent years.

Recovery of benzothiazolium ionic liquids from the coexisting glucose by ion-exchange resins

The recycling of ionic liquids (ILs) is an essential process to recover them from complex systems for repeated use, which is very crucial for its “green” feature. Saccharides are a kind of common coexisting constituents with ILs in many applications. The study used ion-exchange resins to recover three kinds of benzothiazolium ionic liquids from coexisting glucose. Five ion-exchange resins with different function groups and ionic form were investigated by mixing with the solution of ILs and glucose in batch. Influencing factors were also investigated in detail for adsorption of ionic liquid from glucose aqueous solution. Among them, only D001 resin showed the weak adsorption capacity for glucose. Under the optimal conditions, the maximum adsorption ratio of [HBth][CF3SO3] was 98.58%. Moreover, desorption of target ILs and reuse of resins were also investigated, and the maximum desorption ratio of [HBth][CF3SO3] was 98.6%. After the ILs were applied in the extraction of saccharides in Lycium barbarum L. and hydrolysis of pretreated bagasse cellulose, the adsorption ratio of [HBth][CF3SO3] was 91.1% and [HBth][CH3SO3] was 90.8% by the recovery method respectively.

Dissolution and fractionation of nut shells in ionic liquids

The aim of this work was to study the dissolution of raw peanut and chestnut shells in ionic liquids. Dissolution of raw biomass up to 7wt% was achieved under optimized operatory conditions. Quantification of polysaccharides dissolved through quantitative 13Cq NMR revealed extractions of the cellulosic material to ionic liquids as high as 87%. Regeneration experiments using an antisolvent mixture allowed to recover the cellulosic material and the ionic liquid. The overall mass balance presented very low loss rates (<8%), recoveries of 75% and 95% of cellulosic material from peanut and chestnut shells, respectively, and the recovery of more than 95% of the ionic liquid in both cases. These results show the high potential of using nut shells and ionic liquids for biorefining purposes. Moreover, high recovery of ionic liquids favors the process from an economical point of view.

Techno‐economic analysis of cellulose dissolving ionic liquid pretreatment of lignocellulosic biomass for fermentable sugars production

Pretreatment of biomass is essential to produce fermentable sugars, which can be further transformed into biofuels. Most of the common pretreatment methods, including sulfuric acid pretreatment, lead to low sugar yields and high microbial inhibitors formation, and require an additional detoxification step prior to fermentation. Ionic liquid (IL) pretreatment has the potential to reduce or eliminate these problems, and, thus, recently, has gained significant attention as an alternative pretreatment technology. However, before commercial deployment, IL pretreatment requires a thorough assessment of its techno-economic feasibilities and bottlenecks. Thus, the main objective of this study was to assess the techno-economic feasibility of a commercial-scale IL pretreatment for a 113 million liter/year (30 million gal/year) cellulosic biorefinery and identify operational targets for process improvement. 1-ethyl-3-methylimidazolium acetate IL was used for analyses, which is one of the mostly investigated ILs and is currently best at dissolving the lignocellulosic biomass. Corn stover, poplar, and switchgrass were used as the model feedstock. Input data were obtained from recent literatures on IL pretreatment of these feedstocks. Estimated sugar production costs ($/kg) from corn stover, switchgrass and poplar were 2.7, 3.2, and 3.0, respectively. IL recovery was identified to be the most sensitive parameter followed by IL cost and heat recovery. Furthermore, for IL pretreatment to be economically competitive with sulfuric acid pretreatment, >97% IL recovery, ≤$1/kg IL cost, and >90% waste heat recovery are necessary, all of which are very optimistic considerations at the present state of technology, thus requires further research and development efforts. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd

Recovery of ionic liquid via a hybrid methodology of electrodialysis with ultrafiltration after biomass pretreatment

Hybrid membrane-based methodology of electrodialysis (ED) with ultrafiltration (UF) was employed to recover the IL BmimBr (1-Butyl-3-methylimidazolium bromide) after biomass fractionation. Ultrafiltration was used to remove the residual lignin in IL solutions. Influence of molecular weight interception of UF treatment, initial IL concentration in dilute section, applied voltage and flow rate in each section of ED module were studied in detail. In this study, the highest overall IL recovery ratio reached 75.2% and the current efficiency of ED process approached 79.1%. Besides, the highest IL recovery performance of specific energy consumption was about 514.1g/kw·h. Insight gained from this study suggests a potential methodology for IL recovery after the pretreatment process for biomass.

Ionic liquid pretreatment at high solids loading: A clean approach for fabrication of renewable resource based particulate composites

Recently, the concept of high solids loading in ionic liquid (IL) based pretreatment of lignocellulosic biomass has gained numerous attention due to significant economic, environmental, and sustainability benefits. The objective of the present work was to investigate the impact of ILs pretreatment of lignocellulosic oil palm frond (OPF) biomass at high solids loading on the mechanical and thermal properties of the composite panels. The process combines the pretreatment of OPF particles with ILs [bmim][Cl] (1‐butyl‐3‐methylimidazolium chloride) and [emim][OAc] (1‐ethyl‐3‐methylimidazolium acetate) followed by IL recovery by rinsing with acetone‐water mixture prior to mixing of OPF particles with polymer binder to fabricate compression‐molded composite panels. Untreated and treated OPF particles were characterized by scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, and chemical composition analysis. Further, the effect of ILs pretreatment on kinetics of thermal degradation of biocomposites was evaluated by activation energy approach. Maximal flexural strength, modulus, and strain energy density (SED) of 25 MPa, 1,928 MPa, and 0.48 MJ/m3, respectively, were found for IL [emim][OAc] treated composite. Besides, thermal properties of IL treated composites were also improved. Present study could be a significant step toward practical IL pretreatment strategies for manufacturing of lignocellulosic based composite materials. POLYM. COMPOS., 39:1994–2003, 2018. © 2016 Society of Plastics Engineers

Acid-free extraction of cellulose type I nanocrystals using Brønsted acid-type ionic liquids

Extraction of cellulose type I nanocrystals from cotton fibers was straightforwardly carried out using exclusively Brønsted acid-type ionic liquids (ILs) via a two-step swelling/hydrolysis route, the switch between these two stages being induced by water addition. Since the whole process was achieved in a single reaction medium predominantly based on 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([SBMIM]HSO4), the process parameters were investigated in order to ensure a perfect compatibility and sequencing towards the two-step route proposed here. The impacts on nanoparticle morphology, crystallinity evolution, and cellulose type I to type II denaturation were observed under field-emission gun scanning electron microscopy and corroborated by X-ray diffraction characterizations. ILs recovery and reuse were also demonstrated, opening up new prospects of conception of multi-cycle, environmentally and economically sustainable processes.

Green determination of aconitum alkaloids in Aconitum carmichaeli (Fuzi) by an ionic liquid aqueous two-phase system and recovery of the ionic liquid coupled with in situ liquid–liquid microextraction

A green and effective extraction system based on the use of an ultrasound-assisted IL-ATPS was developed for the determination of aconitum alkaloids.