Hybrid Separation Research Articles

Inorganic-Shell Reinforcement: TiO2-Coated Polyimide Nanofibers Membrane as Advanced Separator for Lithium-Ion Batteries

Herein, we report a series of titania (TiO2)-coated polymeric nanofibers membranes with superb strength, excellent thermal stability, and admirable wettability via in situ coating TiO2 nano-shells on the surface of polyimide (PI) nanofibers. TiO2 nano-shells are able to weld the PI nanofibers and serve as a reinforcement layer, endowing the TiO2-coated PI separator with high tensile strength of 43.94 MPa. Specifically, the in situ coating technique is a simple and controllable method to fabricate high-performance hybrid separator and meet the demand of low-cost industrial production. Moreover, TiO2-coated PI separator displays preferable wettability, thermal stability, and ion conductivity than the Celgard separator. Importantly, the unique thermal dimensional stability of TiO2-nanoshells and PI materials also improves the safety of lithium ion battery (LIB). Notably, TiO2-coated PI separator exhibit superior LIB capability of 140.1 mAh g−1 at 5 C compared to the commercial Celgard separator (95.4 mAh g−1, 5 C). Besides, the present battery with TiO2-coated PI separator can operate stably after being tested at 1 C for 100 cycles. Thus, we believe that this work provides a significant contribution for realizing industrial production preparation of high-performance hybrid separators for LIBs.

An ion-conductive separator for high safety Li metal batteries

Li metal anode is promising materials for high-energy-density Li metal batteries (LMBs) due to its large theoretical specific capacity and negative reduction potential. However, the poor safety and insufficient cyclability caused by the dendritic Li growth hinder the commercialization of LMBs. To alleviate the formation of Li dendrites and further improve the cycling stability of LMBs, an ion-conductive polyacrylonitrile (PAN)-based hybrid separator is proposed. The hybrid separator is composed of flexible PAN and high ionic conductive W-doped Li6·3La3Zr1·65W0·35O12 (LLZWO) as the function of physical blocking to realize the Li dendrite-free. As a result, the hybrid separator with 20 wt% LLZWO (PLL-20) shows high ionic conductivity (6.89 × 10−5 S cm−1) and high Li-ion transference number (0.58). The Li|PLL-20|Li symmetric cells exhibit long-term stability without Li dendrite growth at 0.2 mA cm−2 for over 350 h. Furthermore, the Li|PLL-20|LiFePO4 battery delivers a high discharge specific capacity of 138.2 mAh g−1 at 0.2C under ambient conditions. This work highlights the ability of hybrid functional separators to protect Li metal anode in high-energy-density LMBs.

Separation of isobutanol/water mixtures by hybrid distillation-pervaporation process: Modeling, simulation and economic comparison

Hybrid separation processes based on the membrane processes are becoming more important in practice to overcome the thermodynamic limitations of the conventional separation processes as well as to develop more sustainable and economic processes. This study focuses on the use of the hybrid distillation-pervaporation process for the separation of isobutanol/water mixtures. For engineering design of the hybrid processes, reliable modeling and simulation of the process is indispensable. For the simulation of different configurations of the hybrid processes with Aspen Plus software (Aspen Tech), a mathematical model was developed for the pervaporation process based on the solution-diffusion mechanism using the Flory-Huggins and UNIFAC thermodynamic models and Lee’s equation. The simulation was performed for the separation of isobutanol/water mixtures with various isobutanol feed concentrations (5, 7, and 15 %wt.). It was found that for both single-phase and two-phase feed solutions, the hybrid hydrophobic-hydrophilic pervaporation process was the most economical configuration to reach the desired product purity. For the hybrid hydrophobic-hydrophilic pervaporation process with feed concentrations of 5, 7 and 15 %wt., the total annual cost was 62.9 %, 58.7 %, and 58.4 %, respectively, lower than the distillation process. Furthermore, by increasing the feed concentration, the membrane area required for the pervaporation-based hybrid process enhanced.

Evolution of liquid chromatography: Technologies and applications

Liquid chromatographic offers efficient analyte separation employing high pressure pumps. The reversed phase high performance liquid chromatography (RP-HPLC) is widely utilized in the purity testing and quantitative determination of pharmaceuticals and neutraceuticals. The limitations of traditional liquid chromatography such as particle size, resolution and selectivity demanded for the developments and Waters Corporation developed ultraperformance liquid chromatography (UPLC). Ultrafast liquid chromatography (UFLC) is another milestone, which offers faster and efficient separation. Multidimensional UHPLC provides separation of complex molecules. The particle size decrease enhances the resolution of LC separation. Ethylene bridged hybrid (BEH), Charged surface hybrid (CSH) and Peptide separation technology (PST) offer better performance in. The amalgamation of chromatographic and spectroscopic detectors namely fluorescence detector (FD) and mass spectrometry (MS) provides efficient separation. Liquid chromatography (LC) offers the analysis of pharmaceuticals, biological, food materials, and natural products. This review covers technologies and recent pharmaceutical and biomedical applications of liquid chromatography technologies

Hybrid separator containing reactive, nanostructured alumina promoting in-situ gel electrolyte formation for lithium-ion batteries with good cycling stability and enhanced safety

The thermal instability of conventional polyolefin separators and the high flammability of organic electrolytes are the primary safety-related concerns of high-energy-density lithium-ion batteries. To address these issues, reactive Al2O3 nanostructured materials are coated onto a polyethylene (PE) separator to promote the formation of gel electrolyte and enhance the thermal stability of the separator. The Al2O3 nanostructured materials are surface-treated by 3-methacryloxypropyl trimethoxysilane to induce radical polymerization with tetra(ethylene glycol) diacrylate (TEGDA) in liquid electrolyte. The three-dimensional network formed by cross-linking reactive alumina nanostructured materials and TEGDA reduces the electrolyte leakage from the cell and enhances the interfacial adhesion between separator and electrodes. Thermal shrinkage of the reactive alumina-coated separator is also significantly reduced at 140 °C, providing enhanced thermal stability. In addition to improved thermal safety, lithium-ion cells employing a reactive alumina-coated PE separator exhibit stable cycling at both ambient and high temperatures.

Selection based on meiotic behavior in <i>Urochloa decumbens</i> hybrids from non-shattered seed

This study aimed to evaluate the end-products of meiosis in sexual and apomictic hybrids of Urochloa decumbens, so as to identify genotypes with good production of viable pollen for use in breeding programs to increase yields of pure viable seed and reduce degree of seed shattering. From 457 intraspecific hybrids of U. decumbens arising from crosses between 3 artificially tetraploidized sexual plants and the apomictic cultivar Basilisk, 27 hybrids from non-shattered seed were selected. Slides were prepared by smearing anthers and staining to determine the presence of abnormalities. The abnormalities found were micronuclei, microcytes and polyads. The data were compared by the Scott-Knott test at P<0.05. Data obtained enabled separation of hybrids into 4 groups depending on the presence of micronuclei and formation of polyads and into 6 groups based on the presence of microcytes in the tetrads. Among the analyzed apomictic hybrids, R179 has the attributes for viable seed production to proceed to cultivar development. Among the sexual hybrids, R161, R181, R193 and S47 are recommended as female parents for use in crossing programs.

Interface Engineering of MXene Composite Separator for High‐Performance Li–Se and Na–Se Batteries

AbstractSelenium (Se), due to its high electronic conductivity and high energy density, has recently attracted considerable interest as a cathode material for rechargeable Li/Na batteries. However, the poor cycling stability originating from the severe shuttle effect of polyselenides hinders their practical applications. Herein, highly stable Li/Na–Se batteries are developed using ultrathin (≈270 nm, loading of 0.09 mg cm−2) cetrimonium bromide (CTAB)/carbon nanotube (CNT)/Ti3C2Tx MXene hybrid modified polypropylene (PP) (CCNT/MXene/PP) separators. The hybrid separator can immobilize the polyselenides via enhanced Lewis acid–base interactions between CTAB/MXene and polyselenides, which is demonstrated by theoretical calculations and X‐ray photoelectron spectroscopy. The incorporation of CNT helps to improve the electrolyte infiltration and facilitate the ionic transport. In situ permeation experiments are conducted for the first time to visually study the behavior of polyselenides, revealing the prohibited shuttle effect and protected Li anode from corrosion with CCNT/MXene/PP separators. As a result, the Li–Se batteries with CCNT/MXene/PP separators deliver an outstanding cycling performance over 500 cycles at 1C with an extremely low capacity decay of 0.05% per cycle. Moreover, the hybrid separators also perform well in Na–Se batteries. This study develops a preferable separator–electrolyte interface and the concept can be applied in other conversion‐type battery systems.

Hybrid Separation Process of Refinery Off-gas toward Near-Zero Hydrogen Emission: Conceptual Design and Techno-economic Analysis

This article presents a conceptual design of hybrid separation processes of refinery off-gas on the refinery scale, aiming at the recovery of high-value-added components toward near-zero hydrogen e...

A hybrid batch distillation/membrane process for high purification part 1: Energy efficiency and separation performance study for light impurities removal

High purification processes are usually characterized by high energy demand and unavoidable losses of a purified substance during removal of trace impurities. An unsteady-state hybrid separation method based on a batch distillation with integrated membrane gas separation was studied for high purification of liquefied gases. The performance of a hybrid process versus a standalone batch distillation was analyzed through simulations and experiments for the case of light impurities removal from ammonia. A model of a middle-vessel batch distillation column was built in Aspen Plus Dynamics™ with an integrated hollow fiber membrane model implemented in Aspen Custom Modeler™. The results of batch distillation simulations are validated against the experimental data. Among the considered aspects are the hydrodynamics study, the effect of operating conditions on column separation performance, and the dynamics of the purification process. The simulations were done at a varied impurity cut withdrawal rate, membrane area, stage cut, and membrane selectivity taking into account the effective (mixed gases) selectivity data for ammonia/impurity systems available in the open literature. The possibility of both reducing the total energy input and improving the product recovery is shown for a hybrid purification process involving the separation of the withdrawn impurity cut in a membrane module with recycling of the purified component back to the distillation column.

Nanofluid Based on Carbon Dots Functionalized with Ionic Liquids for Energy Applications

The development of materials that can help overcome the current limitations in energy storage and consumption is a pressing need. Recently, we developed non-Newtonian nanofluids based on non-toxic, carbon nanoparticles (NPs), carbon dots (Cdots) functionalized with ionic liquids. Here, we wanted to prove that these new nanofluids are, not only interesting as possible electrolytes, but also as new organic/inorganic hybrid separators. As such, we developed an entrapment method using poly(vinyl alcohol) (PVA). Indeed, the highly conductive Cdots were successfully retained inside the membrane even upon the application of several wetting/drying cycles. Moreover, the morphological characteristics did not change upon wetting/drying cycles and remained constant for more than four months. These nanofluids could be an interesting approach to tackle some of the current problems in the fields of solid-state batteries, and energy storage, among others.

Design and Test of Wind Plate-type Residual Membrane Hybrid Separator

In order to realize the effective separation of the residual membrane mixture, this paper designs the wind plate-type membrane hybrid separation device, which is composed of square air box, residual film discharge, conveyor belt, wind plate, soil and orange stalks shredded final row outlet, drive shaft, residual membrane mixture inlet, drive belt wheel and driven belt wheel, through analysis to determine the drain-outlet shape, number of wind plates and wind plate materials. Experiments showed that the membrane hybrid separation rate of membrane hybrid separation device is 91.5%, which meets the requirements of agronomy and realizes the effective separation of residual membrane mixture.

Eco-friendly xonotlite nanowires/wood pulp fibers ceramic hybrid separators through a simple papermaking process for lithium ion battery

In this study, we successfully fabricate lithium-ion battery hybrid separator of Xonotlite Nanowires/Wood Pulp Fibers through a simple papermaking process, which has not only strong heat resistance properties, but also outstanding electrochemical performance. To be specific, it doesn't show any signs of shrinkage at 600 oC and it can quickly suppress combustion even in the center of flame, which greatly improves the safety of lithium-ion battery at high temperature compared to commercial separator. In addition, it is worth mentioning that the battery still maintains 91% of initial capacity after 100 cycles of charge-discharge tests at static current of 0.2C. Meanwhile, the study finds that the half-cell with the separator exhibits excellent reversibility at different charge-discharge currents, so the cell has better cycling performance and C-rate performance than commercial battery. Last but not least, the separator does not use any contaminating solvent in the preparation process, the raw materials are easy to obtain and the cost is relatively low as well. Therefore, it can be expected to be a candidate for a high-performance separator for a lithium ion battery.

Coupling Rhodium-Catalyzed Hydroformylation of 10-Undecenitrile with Organic Solvent Nanofiltration: Toluene Solution versus Solvent-Free Processes.

Intensification of the rhodium-catalyzed hydroformylation process to produce 12-oxo-dodecanenitrile from biosourced 10-undecenitrile was performed by coupling the reaction with organic solvent nanofiltration (OSN) for the recycling of the expensive Rh catalyst and the ligands. Four phosphorus-based ligands were compared with respect to their catalytic performance and rejection in OSN. Biphephos showed the best compromise and up to 3 reaction-OSN cycles were performed in toluene. A good recycling of the catalytic system was evidenced arising from the OSN (up to 88 % rejection). In order to develop a greener process, a similar approach was achieved in bulk (i. e. solvent-free medium), thus proving the catalyst recycling feasibility but also that the optimal OSN conditions are not the same as for toluene. Finally, integration of OSN in the overall production process is discussed, aiming at the proposal of a hybrid separation process involving a combination of OSN and distillation for an energy-efficient separation step.

Molecularly Engineered Nanoporous Membranes for Safety Enhanced Battery Separators

A battery separator physically and electronically separates the anode and cathode but permits Li+ transport between them. Battery separators play a critical role in battery safety by providing, e.g., thermal shutdown functionality in abusive events, or, by preventing lithium metal dendrites or other defects in the cell from penetrating the membrane which can cause internal short circuit leading to uncontrolled thermal runaway, as in the case of the Boeing 787 battery fire incident [1]. One of the challenges with designing safe battery separators is the trade-off between mechanical robustness and porosity/transport properties. For example, high separator tortuosity is good for dendrite resistance but can lead to higher separator resistance [2]. Separator design is further complicated by additional constrains including tolerance to abuse conditions, stable at high voltages (e.g., > 4V), chemically inert to other cell materials, and low cost to meet the performance and cost targets. There is a need to tailor design battery separators that enable high energy/power density with engineered functionality for safety, without adversely affecting performance. Here we present our efforts to develop a nanoporous battery separator that is highly tunable in physical/mechanical properties (e.g., porosity, elastic modulus, toughness) and safety characteristics (e.g., thermal shutdown temperature). Our nanoporous separators are derived from functionalized block copolymers (polyolefins) with low cost precursors [3, 4, 5]. We will also present a hybrid separator concept where the rapid thermal shutdown-capable nanoporous separator developed is hybridized with a highly porous, mechanically and thermally robust separator. This approach renders a hybrid separator technology that affords high energy density, high rate capability, long cycle life and unprecedented safety characteristics for the next generation Li-ion batteries. Figure 1 shows scanning electron microscopy (SEM) images of a representative, synthesized nanoporous polyethylene (NPE) membrane samples, ~ 25 mm in thickness, revealing the desired bicontinuous cubic morphology and percolating pore architecture. Figure 2 shows separator impedance as a function of temperature, for NEP1-3 membrane samples and a commercial separator. An environment (EV) chamber was programmed to increase the temperature at a very low rate of 0.5°C/min for accurate temperature shutdown measurements. The onset of the impedance rise corresponded to ~ 120°C for the NPE separators and ~ 130°C for the commercial separator. The increase of the separator impedance is a result of the separator thermal shutdown, i.e., micropore closing due to the melting/shrinking of the separator, which impedes the ionic motion. It is interesting to note that the separator impedance increased by one to two orders of magnitude at the peak of the thermal shutdown comparing with the initial impedance value. The drastic separator impedance increase associated with the separator thermal shutdown is responsible for providing the safety feature to the otherwise normal operation of Li-ion batteries. The enhanced thermal shutdown features seen in the NPE separators will render earlier, much more rapid and effective thermal shutdown at abusive events (e.g., short circuit, overcharge, etc.), which leads to much improved safety charasteristics for batteries. Our study shows that the molecularly engineered nanoporous membranes are very promising to allow exquisite tuning of mechanical properties (e.g., porosity, elastic modulus, toughness) and safety features (e.g., thermal shutdown temperature). The NPE-based hybrid separator approach will afford an unprecedented performance and safety characteristics for the next generation batteries. Figure 1

Separation of Dicyclopentaidene in a C5 stream using a tetraethoxydimethyl disiloxane-derived silica composite membrane

Hybrid separation of dicyclopentadiene (DCPD) in a C5 stream was performed using a 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS)-derived silica composite membrane. High purity DCPD, the key monomer of the C5 stream can be concentrated by removing CPD through pervaporation from the CPD-DCPD mixtures obtained by conventional distillation. Silica membranes were prepared using 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS) by “spacer” and “template” techniques, which allowed for control the pore size of silica membranes using bridged alkoxides that have pendant groups. TEDMDS-derived silica membranes calcined at 450 °C showed a high total flux of 0.06–0.5 kg·m−2 h−1 with a CPD separation factor of 6–33 in a 95 wt% DCPD mixture, for feed temperature of 50–70 °C. The silica membranes prepared in this study shows relatively a high flux and acceptable separation factor. Therefore, they may find applications in commercial processes alongside the conventional distillation, by saving energy and reducing byproducts.

Data-based modeling and optimization of a hybrid column-adsorption/depth-filtration process using a combined intelligent approach

Lack of robust techniques for optimization of hybrid separation systems is obvious in the literature. A novel hybrid approach for modeling and optimization of a hybrid process consisting of fixed-bed adsorption column (FBAC) and dead-end filtration (DEF) for the removal of methylene blue from water was presented. Artificial neural network (ANN), response surface methodology (RSM) and genetic algorithm (GA) were used for this purpose. ANN was employed to successfully approximate the breakthrough curves. Central composite design was used to investigate the impact of the operating variables, i.e. feed flowrate, initial concentration, adsorption bed length, and filter type on the removal rate as the objective function. RSM variables together with the operation time were considered as input parameters and the normalized concentration was defined as output of the network. A regression model was developed using RSM to correlate the experimental data. The model was then optimized via GA to maximize the removal rate at break time. The optimal removal rate was 3.79 s−1 corresponding to OS-100 filter, 1.12 L/min flowrate, 30 cm bed length and, 40.49 mg/L initial concentration. Sobol sensitivity analysis indicated that flowrate with 43% and filter type with 41% were the most effective variables on the process performance.

Application of breakthrough curve analysis and response surface methodology for optimization of a hybrid separation system consisting of fixed-bed column adsorption and dead-end depth filtration

This work investigates the performance and optimization of a hybrid process consisting of a fixed-bed adsorption (FBA) column and a dead-end filtration (DEF) cell for the removal of methylene blue (MB) from water. Granular activated carbon and cellulose acetate depth filter sheets were used as adsorbent and filter medium, respectively. Effects of four operation parameters (initial concentration, feed flowrate, bed length, and filter type) on the MB removal rate (RR) were investigated using breakthrough data analysis and response surface methodology. This RR (mass of MB removed per second) captures the removal capacity and separation rate, simultaneously. The maximum RR was found theoretically equal to 3.875 s−1 at the optimized conditions of initial concentration =39.86 mg/L, flowrate = 1.15 L/min, bed length =29.95 cm, and filter type = OS100, and validated with the experimental data with 99% agreement. The performance of the hybrid process operating at the optimal operation conditions was found to be superior to those of the individual FBA column and DEF cell. After 100 s from the process commencement, the RR obtained with the hybrid process was about 64% higher than that obtained with the FBA column and 30% higher than that obtained with the DEF cell.

An underestimated technique. Does pressurized and pressure-assisted capillary electrochromatography have potential in drug and pharmacological-active compounds analysis?

Abstract Pharmaceutical analysis guarantees patient safety all over the world. Thus, continuous development of existing analytical techniques is still very important. Pressurized capillary electrochromatography and pressure-assisted capillary electrochromatography are hybrid separation techniques that combine the selectivity of liquid chromatography and the high separation efficiency of capillary electrophoresis. They use a smaller amount of reagents and samples, hence, reducing the total cost of analysis. Therefore they have found application in a number of pharmaceutical and biomedical analysis. This review article focuses on the use and importance of pressurized and pressure-assisted capillary electrochromatography in pharmaceutical and biomedical analysis, taking into account types of detectors and capillaries used. Despite the fact that pressurized capillary electrochromatography and pressure assisted capillary electrochromatography offer many possibilities and have been available for over a dozen years, they are still underdevelopment and not fully explored.

Wastewater treatment using a hybrid system combining adsorption, photocatalytic degradation and membrane filtration processes

In the present study, Chooka’s Wastewater treatment was investigated using different combinations of adsorption, photocatalytic degradation, and membrane filtration process. Polymeric membranes were fabricated using wet phase inversion method employing polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and dimethylformamide (DMF) as a polymer matrix, hydrophilic additive, and solvent, respectively. Activated carbon and TiO2 nanoparticles were selected as an adsorbent and photocatalyst, respectively. TiO2 nanoparticles were synthesized using the sol-gel method and activated carbon was purchased from Merck Company. Liquid-liquid displacement (LLDP), scanning electron microscope (SEM) and contact angle tests were implemented to characterize the fabricated membranes. FT-IR and XRD analysis were also used for TiO2 nanoparticles characterization. The wastewater of Iran pulp and paper factory (Chooka) was used as the feed in separation processes. In hybrid separation systems, 6 different configurations were considered and wastewater compositions were measured to determine the effectiveness of the utilized processes before and after treatment. Accordingly, the mean pore size of the fabricated PAN/PVP (16%/3%) membrane obtained from LLDP analysis was 9.72 nm. SEM results also indicated thicker active layer for the PAN/PVP membrane than that of the neat PAN membrane. According to the results of the contact angle tests, with the increasing of PVP content in the polymer matrix, the hydrophilicity of membranes improved. It was also found that membrane filtration had the best performance among single stage processes and the best separation performance was achieved when photocatalytic degradation, adsorption, and membrane filtration were used in series, respectively.

Novel superhydrophobic and superoleophilic sugarcane green ceramic hollow fibre membrane as hybrid oil sorbent-separator of real oil and water mixture

The frequent oil spill accidents in nowadays has aroused great attention all over the world. Superhydrophobic and superoleophilic grafted on various substrates have attracted much attention to treat oil and water mixture because of their unique performance that can effectively separate oil and water mixture. At the same time, ceramic membrane also shows potential substrates to be used in treating oil and water mixture. However, conventional ceramic membrane that made from alumina show drawbacks in term of its high cost production. Herein, we report a new ceramic membrane that derived from agricultural-sugarcane bagasse waste and modified into superhydrophobic and superoleophilic to act as hybrid oil sorbent and separator. In this study, we successfully treat three types of real oil and water mixture from palm oil mill effluent (POME), restaurant and car wash with oil rejection and flux up to 99% and 134 L/m2h, respectively. In summary, this work demonstrates a facile, economic and effective method to fabricate superhydrophobic and superoleophilic substrates for oil and water separation.