High Separation Capacity Research Articles

Copper hydroxyphosphate nanosheets-covered robust membranes with superhydrophilicity and underwater ultralow adhesive superoleophobicity for oil/water separation and visible light photodegradation

With the rapid increase of oil pollution accidents, the purification of oily water has become a serious global problem to be solved. Herein, the Cu2(OH)PO4 nanosheets-covered robust mesh membranes are fabricated by a facile green wet-chemical method at different pH conditions. By the combination of the superwetting ability with photocatalytic performance of Cu2(OH)PO4, the nanosheets-covered mesh membrane fabricated at pH 9.7 exhibits a superhydrophilicity and underwater ultralow oil adhesive superoleophobicity for efficient removal of various oils from water with an oil sliding angle about 1.4°. Simultaneously, the membrane presents a high photocatalytic activity for methylene blue under visible light irradiation. After 15 cycles of separation, the test demonstrates a superior separation stability of the membrane with high permeating flux of ∼94,801 Lm−2 h-1 and separation efficiency above 99.5%. In consideration of the excellent mechanical property, chemical stability, thermal resistance and high separation capacity, the as-prepared mesh membrane is promisingly applied in purifying oily wastewater.

Superhydrophobic and Superoleophilic Fiber from Waste Bamboo Processing Residues for Oil/water Selective Separation

Biomass materials have attracted increasing attention as oil absorbents for oil/water separation duo to their renewability, biocompatibility and biodegradability. However, many separation materials preparations are either rather time consuming or have suffered from the need of harsh conditions. In the present study, bamboo fiber was successfully modified to acquire simultaneously super-hydrophobic and super-oleophilic properties by just two steps: delignification and chemical vapor deposition (CVD). The morphology and properties of MTMS-bamboo fiber were characterized by SEM, FT-IR, XPS and the oil/water contact angles. Moreover, the durability, recyclability and the practical application of selective separation were studied. The analysis results disclosed that the special surface wetting properties of MTMS-bamboo fiber resulted from the silanization of the bamboo fiber surface, notably, from its water contact angle being 153° and oil contact angle 0°. The fiber so prepared exhibited excellent durability in several kinds of chemical solutions. The absorbed oil can be recovered by simple mechanical squeezing and the bamboo fiber maintained a high oil absorption capacity after multiple squeezing-absorption cycles. The modified fiber acted as an absorbent for hot water oil/water separation and demonstrated also a high oil separation capacity. The continuous separation efficiency of the MTMS-bamboo fiber was investigated.

Investigation of Solute Diffusion through Polyvinyl Alcohol/ Polyallylamine Ultrafiltration Membrane

Ultrafiltration membrane has been widely used for several applications due to their high separation capacity, high selectivity, and low operating pressure. In this work, solutes diffusion through polyvinyl alcohol/polyallylamine ultrafiltration membrane was investigated. The membrane was prepared by phase inversion method with glutaraldehyde as crosslinking agent. Meanwhile, NaCl and CaCl2 were used as solutes, either as a single or double solute. The results showed that the increase of polyallylamine concentration led to the increase of membrane swelling degree. For both single and double solutes, diffusion of Na+ and Ca2+ were slightly decreased with the increase of swelling degree. However in double solute diffusion, there was interaction between Na+, Ca2+, and membrane that made Na+ ions moved faster and Ca2+ ions moved slower compared to single solute diffusion. In addition, the increase of solute concentration led to the increase of Na+ diffusion coefficient and the decrease of Ca2+ diffusion coefficient.

Capillary Zone Electrophoresis-Tandem Mass Spectrometry with Activated Ion Electron Transfer Dissociation for Large-scale Top-down Proteomics.

Capillary zone electrophoresis (CZE)-tandem mass spectrometry (MS/MS) has been recognized as an efficient approach for top-down proteomics recently for its high-capacity separation and highly sensitive detection of proteoforms. However, the commonly used collision-based dissociation methods often cannot provide extensive fragmentation of proteoforms for thorough characterization. Activated ion electron transfer dissociation (AI-ETD), that combines infrared photoactivation concurrent with ETD, has shown better performance for proteoform fragmentation than higher energy-collisional dissociation (HCD) and standard ETD. Here, we present the first application of CZE-AI-ETD on an Orbitrap Fusion Lumos mass spectrometer for large-scale top-down proteomics of Escherichia coli (E. coli) cells. CZE-AI-ETD outperformed CZE-ETD regarding proteoform and protein identifications (IDs). CZE-AI-ETD reached comparable proteoform and protein IDs with CZE-HCD. CZE-AI-ETD tended to generate better expectation values (E values) of proteoforms than CZE-HCD and CZE-ETD, indicating a higher quality of MS/MS spectra from AI-ETD respecting the number of sequence-informative fragment ions generated. CZE-AI-ETD showed great reproducibility regarding the proteoform and protein IDs with relative standard deviations less than 4% and 2% (n = 3). Coupling size exclusion chromatography (SEC) to CZE-AI-ETD identified 3028 proteoforms and 387 proteins from E. coli cells with 1% spectrum level and 5% proteoform-level false discovery rates. The data represents the largest top-down proteomics dataset using the AI-ETD method so far. Single-shot CZE-AI-ETD of one SEC fraction identified 957 proteoforms and 253 proteins. N-terminal truncations, signal peptide cleavage, N-terminal methionine removal, and various post-translational modifications including protein N-terminal acetylation, methylation, S-thiolation, disulfide bonds, and lysine succinylation were detected.

A renewable and biodegradable all-biomass material for the separation of oil from water surface

In this work, superhydrophobic and superoleophilic loofah sponge (LS) was prepared by a facile, inexpensive, eco-friendly and sustainable dip-coating method. This method uses LS as the porous skeleton, carnauba wax (CW) and rice bran wax (RW) as the coating material and ethyl acetate as the solvent. The wax layer forms particle/film composite micro-structures, which makes the superhydrophobic coating have excellent stability against soaking of water and various oils, and high resistance to corrosive mediums. The superhydrophobic and superoleophilic LS can selectively separate oil from water surface with desirable properties, such as high separation capacity (>9.5 g/g), efficiency (>91%), and reusability (>10 cycles). In addition, the used SLS can be reused for the recovery of waxes and LS substrate. Furthermore, the LS substrate can be biodegraded in the natural ecological cycle. The present work provides a new idea and solution for developing sustainable, renewable and biodegradable all-biomass oil/water separation materials.

Highly Selective, High-Capacity Separation of o-Xylene from C8 Aromatics by a Switching Adsorbent Layered Material.

Purification of the C8 aromatics (xylenes and ethylbenzene) is particularly challenging because of their similar physical properties. It is also relevant because of their industrial utility. Physisorptive separation of C8 aromatics has long been suggested as an energy efficient solution but no physisorbent has yet combined high selectivity (>5) with high adsorption capacity (>50 wt %). Now a counterintuitive approach to the adsorptive separation of o-xylene from other C8 aromatics involves the study of a known nonporous layered material, [Co(bipy)2 (NCS)2 ]n (sql-1-Co-NCS), which can reversibly switch to C8 aromatics loaded phases with different switching pressures and kinetics, manifesting benchmark o-xylene selectivity (SOX/EB ≈60) and high saturation capacity (>80 wt %). Structural insight into the observed selectivity and capacity is gained by analysis of the crystal structures of C8 aromatics loaded phases.

A Free Tetrazolyl Decorated Metal-Organic Framework Exhibiting High and Selective CO2 Adsorption.

In this work, we employed a new tetrazolyl-functionalized ligand, 5-(1H-tetrazole-5-yl)-1,3-bis(3,5-dicarboxylphenyl)-benzene (H5TBDPB), and successfully obtained an example of incorporating free tetrazolyl groups in transition-metal-based MOFs based upon an ideal MOF platform. With a BET surface area of 2070 m2 g-1, this new tetrazolyl-decorated MOF [Cu6(TBDPB)3(H2O)6]·9DMF·15H2O (HHU-5, HHU for Hohai University) exhibits a high CO2 adsorption capacity of 37.1 wt % at 1 bar and 273 K and high CO2 separation capacity toward N2 and CH4 as well.

A novel Z-scheme Bi2MoO6/BiOBr photocatalyst for enhanced photocatalytic activity under visible light irradiation

In this work, BiOBr was firstly prepared by using a facile solvothermal approach at 393 K for 24 h, and then Bi2MoO6 well dispersed on the surface of BiOBr at 433 K for 3 h. The shape, chemical composition, crystal structure, optical property and surface area of Bi2MoO6/BiOBr were investigated by field emission electron microscope (FESEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherms and UV–Vis diffuse reflectance spectroscopy (DRS). The Bi2MoO6/BiOBr heterojunctions exhibited substantially improved performance for removal of methylene blue (MB), compared with BiOBr and Bi2MoO6 samples under 410 nm light excitation. The constant Kapp of 20%Bi2MoO6/BiOBr is 0.0539 min−1, which is 4.4 and 6.9 times higher than that of Bi2MoO6 (0.0121 min−1) and BiOBr (0.0078 min−1). The prominent enhancement of activity is due to the high charge separation capacity, which resulted from the matched band alignment of two components. Finally, the Z-scheme photocatalytic mechanism was confirmed by radical trapping experiment.

High performance liquid chromatography - Quantitative nuclear magnetic resonance - High performance liquid chromatography for purity measurement of human insulin

ABSTRACTQuantitative Nuclear Magnetic Resonance (qNMR) is a reliable quantitative spectroscopic technique, wherein the intensity of a resonance line is directly proportional to the number of resonant nucleus, and the absolute content of the compound can be determined, this means the inorganic stabilizer in the sample would not affect the result of qNMR. High performance liquid chromatography (HPLC) is a common analytical method with a high separation capacity. This study combined HPLC and qNMR, to measure the purity of Human Insulin (HI). It started from an original HI. The first step is purifying the original HI by HPLC to get a purified HI, with organic purity of 99.78%. The second step is assessing the absolute content of the purified HI by qNMR, and got 40.25%. The third step is measuring the purity of original HI by HPLC again, using the purified HI as the reference material. This method, called HPLC-qNMR-HPLC, is more accurate (84.12% ± 1.14%) than the traditional IDMS (isotope dilution mass spectrometry) method (86.6% ± 3.4%). This study expanded the application of qNMR to proteins with molecular weight of about 5800, and showed that this method can be widely used in measuring the purity of macromolecular proteins.

Construction of carbon dots modified MoO3/g-C3N4 Z-scheme photocatalyst with enhanced visible-light photocatalytic activity for the degradation of tetracycline

Carbon quantum dots (CDs) have been frequently used for broadening spectrum light response due to their superior up-conversion photoluminescence (UPPL) property and effective charge separation capacity. In this study, a novel CDs modified Z-scheme photocatalyst (CDs/g-C3N4/MoO3) was successfully constructed. The morphologies, chemical compositions, and optical properties of the prepared catalysts were investigated via a series of characterization techniques. Systematic studies indicated that the CDs/g-C3N4/MoO3 photocatalyst exhibited remarkably enhanced visible-light photocatalytic activity for the degradation of tetracycline (TC) compared to pristine g-C3N4 and MoO3/g-C3N4 composite. Doping 0.5% CDs resulted in the highest TC degradation rate, which was 3.5 and 46.2 times higher than that of MoO3/g-C3N4 and g-C3N4, respectively. The enhanced photocatalytic performance of CDs/g-C3N4/MoO3 can be attributed to the synergistic effects of CD properties (i.e., excellent UPPL activity and high charge separation capacity and the Z-scheme heterojunction structure). Reactive species scavenging experiments revealed that photogenerated holes are the main active species during the photocatalytic process. Possible photocatalytic degradation pathways of TC were proposed through the identification of intermediates using HPLC-MS and the frontier electron density calculation. Experimental results showed that the newly fabricated Z-scheme CDs/g-C3N4/MoO3 is a promising photocatalyst for the removal of TC from the environment.

Cupric Phosphate Nanosheets-Wrapped Inorganic Membranes with Superhydrophilic and Outstanding Anticrude Oil-Fouling Property for Oil/Water Separation.

Developing an effective and sustainable solution for cleaning up or separating oily water is highly desired. In this work, we report a completely inorganic mesh membrane made up of cupric phosphate (Cu3(PO4)2) in a special intersected nanosheets-constructed structure. Combing the hierarchical structure with strong hydration ability of Cu3(PO4)2, the nanosheets-wrapped membrane exhibits a superior superhydrophilic and underwater anti-oil-fouling and antibio-fouling property for efficient oil/water separation to various viscous oils such as heavy diesel oil, light crude oil, and even heavy crude oil with underwater oil contact angles (CAs) all above 158° and nearly zero underwater oil adhesive force even when a large preload force of up to 400 μN was applied on the oil droplet. Simultaneously, the membrane exhibits a high chemical and thermal stability and outstanding salt tolerance. Continuous separation operated on a cross-flow filtration apparatus demonstrates a large separation capacity and long-term stability of the membrane during treating a 2000 L crude oil/water mixture with constantly stable permeating flux of ∼4000 L/m2 h and oil content in the filtrate below 2 ppm. The excellent anti-oil-fouling property, high separation capacity, and easily scaled-up preparation process of the membrane show great potential for practical application in treating oily wastewater.

Mesoporous Chitosan–SiO2 Nanoparticles: Synthesis, Characterization, and CO2 Adsorption Capacity

Mesoporous chitosan–SiO2 nanoparticles (NPs) were successfully synthesized. The prepared nanoparticles were characterized using TEM, FTIR, XRD, TGA, EDX, and (CHN) elemental analysis. From TEM micrograph, chitosan–SiO2 NPs were sphere-like, pretty uniformly distributed with coarse surface. The average size of chitosan–SiO2 NPs was determined as 211 nm with DLS, which was confirmed by TEM. The mesoporous structure of chitosan–SiO2 NPs was characterized with N2 adsorption/desorption measurements. BET surface area was 621 m2 g–1 and the total pore volume was 0.71 m3 g–1. CO2 adsorption was evaluated by a volumetric method. Chitosan–SiO2 NPs showed a maximum CO2 adsorption capacity of 4.39 mmol g–1 at 25 °C and a high selective separation capacity for CO2 over N2 (SCO2/N2 = 15.46). The influence of amines on carbon dioxide adsorption was discussed. Stable CO2 adsorption/desorption was confirmed after six cycles of experiments. Therefore, chitosan–SiO2 NPs exhibit great potential for CO2 capture.

Surface Design of Separators for Oil/Water Separation with High Separation Capacity and Mechanical Stability.

A convection heat treatment that can replace existing chemical oxidation methods was developed for the preparation of hierarchically oxidized Cu meshes with various surface morphologies, representing a very simple and green route that does not involve toxic chemicals. Three types of Cu meshes [bumpy-like (BL) and short and long needle-like (NL) structures] exhibited similar separation efficiencies of 95-99% over 20 separation cycles, as indicated by their similar water contact angles (WCAs; 147-150°). However, these Cu meshes exhibited different flux behaviors. Excessively rough and excessively smooth surfaces of the Cu mesh resulted in increased resistance to flow and to a decrease of the penetration of oil. A surface with intermediate smoothness, such as the BL-Cu mesh, was necessary for high flux over a broad range of oil viscosities. Furthermore, a less rough surface was more suitable for the separation of highly viscous oil. Computational fluid dynamics (CFD) simulations were carried out to support our experimental results. The BL-Cu meshes also showed outstanding mechanical stability because of their low resistance to the flow of fluids.

Recent progress of fillers in mixed matrix membranes for CO 2 separation: A review

Abstract Among various CO2-mitigation technologies, membrane-based technology has offered a more energy efficient and eco-friendly process for CO2 separation from large emission sources, in order to reduce CO2 emission level into atmosphere. In general, polymeric and inorganic membranes have been used in gas separation processes, but each has its own pros and cons. Currently, membrane research has addressed the trade-off limitations of membranes in different ways through fabrication of new type of mixed matrix membranes (MMMs) by incorporation of inorganic particles as fillers into polymer matrices. The performance of MMMs depends on textural properties of fillers, molecular sieving effect and membrane–penetrant interactions. The main challenges in the fabrication of MMMs is selection of fillers, which controls the gas separation characteristics of membranes. In this review, the influences of fillers like zeolite, carbon, and metal organic framework in MMMs fabrication and their CO2 permeability and CO2/CH4 and CO2/N2 selectivity were compiled from recent reports. Further, a new protocol is introduced for screening of fillers, which will helps to development of new fillers as well as for fabrication of new MMMs with high CO2 separation capacity.

Cellulose-Supported Ionic Liquids for Low-Cost Pressure Swing CO2 Capture

Reducing the cost of capturing CO2 from point source emitters is a major challenge facing Carbon Capture, Utilisation and Storage. While Solid Ionic Liquids (SoILs) have been shown to allow selective and rapid CO2 capture by pressure swing separation of flue gases, expectations of their high cost hinders their potential application. Cellulose is found to be a reliable, cheap and sustainable support for a range of SoILs, reducing the total sorbent cost by improving the efficiency of the ionic liquid through increased ionic surface area that results from coating. It was also found that cellulose support imparts surface characteristics, which increased total sorbent uptake. Combined, these effects allowed a 4 to 8-fold improvement in uptake per gram of ionic liquid for SoILs that have previously shown high uptake and a 9 to 39-fold improvement for those with previously poor uptake, offering the potential to drastically reduce the amount of ionic liquid required to separate a given gas volume. Furthermore, the fast kinetics are retained which means het rapid cycling can be achieved which results in high separation capacity relative to conventional temperature swing process. The projected reduction in plant size and operational costs represents a potentially ground-breaking step forward is carbon dioxide capture technologies.

Changes in total phenolic content and color of bottle gourd (Lagenaria siceraria) juice upon conventional and ohmic blanching.

Plant phenolics exist in a complex matrix and require a high separation capacity for analysis. Bottle gourd (BG) was blanched using conventional thermal and alternate thermal ohmic heating methods using different combinations of temperature (60-90°C) and time (1-5min), and the effect of these methods on total phenolic content (TPC) and color was examined. Complete characterization on the basis of the phenolic profile of unblanched, ohmically blanched, and conventionally blanched samples of BG was studied. Gas chromatography-mass spectrometry and Liquid chromatography-mass spectrometry were used to detect volatile and nonvolatile phenolic compounds, respectively. The color profiles of the unblanched and conventionally and ohmically blanched samples were studied via hunterLab colorimeter using L*, a*, and b* coordinates. The highest increase in TPC was observed at 80°C, 4 min and 90°C, 5min in the case of ohmic and conventional blanching, respectively. The conventionally and ohmically blanched samples both produced desirable green-color retention in comparison to the unblanched samples; however, highest retention was observed in the ohmically blanched samples. The ohmically blanched samples exhibited the maximum extraction of phenolic compounds and better color of BG juice in comparison to the other samples.

Preparation of a poly(styrene-co-DPHA-co-EDMA) monolith and its application for the separation of small molecules and biomacromolecules by HPLC

A high performance liquid chromatography (HPLC) monolithic column was prepared by redox polymerization of styrene, dipentaerythritol hexaacrylate (DPHA) and ethylene glycol dimethacrylate (EDMA) in a porogen system of n-propanol/PEG400. The monolith was characterized by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and the results indicated that the monolith had a stable and homogeneous structure. The porosity of the monolithic column was 75.86% and average pore diameter was 2.1µm. Several alkylbenzenes and anilines were used to evaluate the column performance in terms of hydrophobicity. Then the column was applied to separate small molecules including phytosterol and BSA tryptic digest. Finally, five standard proteins, egg white and plasma were separated respectively and high separation capacity of protein was obtained.

Analyzing slowly exchanging protein conformations by ion mobility mass spectrometry: study of the dynamic equilibrium of prolyl oligopeptidase.

Ion mobility mass spectrometry (IMMS) is a biophysical technique that allows the separation of isobaric species on the basis of their size and shape. The high separation capacity, sensitivity and relatively fast time scale measurements confer IMMS great potential for the study of proteins in slow (µs-ms) conformational equilibrium in solution. However, the use of this technique for examining dynamic proteins is still not generalized. One of the major limitations is the instability of protein ions in the gas phase, which raises the question as to what extent the structures detected reflect those in solution. Here, we addressed this issue by analyzing the conformational landscape of prolyl oligopeptidase (POP) - a model of a large dynamic enzyme in the µs-ms range - by native IMMS and compared the results obtained in the gas phase with those obtained in solution. In order to interpret the experimental results, we used theoretical simulations. In addition, the stability of POP gaseous ions was explored by charge reduction and collision-induced unfolding experiments. Our experiments disclosed two species of POP in the gas phase, which correlated well with the open and closed conformations in equilibrium in solution; moreover, a gas-phase collapsed form of POP was also detected. Therefore, our findings not only support the potential of IMMS for the study of multiple co-existing conformations of large proteins in slow dynamic equilibrium in solution but also stress the need for careful data analysis to avoid artifacts. Copyright © 2016 John Wiley & Sons, Ltd.

Oil‐Water Separation: Oil‐Water Separation: A Gift from the Desert (Adv. Mater. Interfaces 7/2016)

Pre-wetted sand shows approximate underwater superoleophobicity and ultralow oil-adhesion in water medium based on its strong water absorbing ability. In article number 1500650, a pre-wetted sand layer was successfully applied in the field of oil-water separation by J. Yong and co-workers and showed extremely high separation efficiency and separation capacity. This method for separating oil and water is simple, almost free of cost, green, and very efficient.

Synthesis of metal-adeninate frameworks with high separation capacity on C2/C1 hydrocarbons

By introducing isophthalic acid or 2,5-thiophenedicarboxylic acid to assemble with adenine and cadmium salt, two isostructural and anionic porous metal-organic frameworks (1 and 2) possessing the novel (4,8)-connected sqc topology are presented here. 1 shows permanent porosity with Langmuir surface area of 770.1m2/g and exhibits high separation capacity on C2/C1 hydrocarbons.