Membrane Unit Research Articles

Modelling the required membrane selectivity for NO3⁻ recovery from effluent also containing Cl⁻, while saving water

We present a general outline for the selective recovery of NO3⁻ from a (waste) water stream also containing Cl⁻. The key element of the technology introduced and simulated here is a membrane unit demonstrating NO3⁻ over Cl⁻ permeation selectivity. The membrane is hypothesized to be hydrophobic and with that exploiting the difference in dehydration energy between NO3⁻ and Cl⁻. Apart from NO3⁻ recovery, the process also aims to reduce water consumption. Based on a generic outline of the process, the key parameters are defined, being the NO3⁻/Cl⁻ concentration ratio in the (waste) stream, the fraction of NO3⁻ and water recovered, and the selectivity of the membrane. The sensitivity of the separation process to these four parameters is evaluated. In the second part of the paper, the same principles are applied to a real-life process, i.e., NO3⁻ recovery from the effluent (waste) water of a fertilizer production plant. The aim was to calculate the membrane NO3⁻/Cl⁻ permeation selectivity required to recover 90% of NO3⁻, given a threshold value for the Cl⁻ concentration in the permeate stream and recycle 30% of the water, starting from two different NO3⁻/Cl⁻ concentration ratios in the effluent (waste) water. With 51 mM Cl⁻ in the effluent (waste) water and a Cl⁻ threshold of 9.9 mM, a membrane selectivity of 3 suffices. The required selectivity increases to 30 when the Cl⁻ in the effluent (waste) water is 200 mM and the Cl⁻ threshold is 4.2 mM. Reported NO3⁻/Cl⁻ membrane selectivities are still modest, with a maximal selectivity found in literature of 3. Strategies to develop membranes of significant higher selectivity are briefly discussed.

Copolyimide asymmetric hollow fiber membranes for high‐pressure natural gas purification

AbstractThe current process to purify contaminated natural gas reserves employs a highly energy‐intensive amine scrubbing technology. To satisfy the growing demand for natural gas coupled with the tight regulations on CO2 emissions, researchers worldwide are investigating the use of polymeric membranes for acid gas removal from natural gas streams, to reduce the energy consumption and carbon emission of the nowadays used technology. Placing a polymeric membrane unit at the upstream of the amine scrubbing column reduces the energy consumption during the regeneration process of saturated amines. Hence, the preparation of polymeric membranes in form of hollow fibers is a key step towards their industrial implementation for natural gas processing. The following study demonstrates the potential separation performance of 6FDA‐Durene/6FDA‐CARDO (5000:5000) in an integrally skinned defect‐free asymmetric hollow fiber geometry. The initial screening studies of the membrane shows good pure‐gas performance as it exhibits CO2/CH4 selectivity coefficients around 28 and CO2 permeance between 310 and 350 GPU. Feed pressures of up to 900 psig and stage cuts ranging from 5% to 20% were tested for a quaternary sweet mixed‐gas feed to assess the membrane performance under operating conditions that mimic those in industrial settings. Mixed‐gas permeance of all gases, and CO2/CH4 selectivity remain somewhat constant as the feed pressure increases up to 900 psig. Both mixed‐gas CO2 permeance and CO2/CH4 selectivity decline as the stage cut increases. As expected, as CO2 recovery is maximized, CO2 purity is minimized and CH4 loss increases with increasing stage cut. As a result of the trade‐off between recovery and purity, the data and analyses reported herein can provide insights into the limitations that certain operating parameters can pose on CO2 separation performance with similar polymeric hollow fiber membranes.

Strong degradation of polycarbonate and polystyrene by the CO2 capture solvent diethyl sebacate

AbstractWe report on observations of strong degradation of a polycarbonate vessel by a solvent being considered for a CO2 capture process, diethyl sebacate. This degradation led to failure of a polymeric hollow fiber membrane unit. Additional tests showed rapid degradation of polycarbonate safety glasses and polystyrene‐based petri dishes by exposure to diethyl sebacate at ambient conditions. We also report on safe operations with diethyl sebacate in extensive experiments studying the corrosion of steel in CO2‐pressurized reactors lined with PTFE and using PTFE gaskets. Used diethyl sebacate was also stored for long time periods in bottles made from low‐density polyethylene bottles without physical deterioration. These observations indicate that care must be taken in development of new contactors and processes for CO2 capture with diethyl sebacate and related solvents and in the choice of material for storage.

Long-Term Performance of Ultrafiltration Membranes: Corrosion Fouling Aspect

The past decade has seen a rise in the importance of the ultrafiltration (UF) technique in the separation of various complex solutions. However, the fouling phenomenon is the main limitation to faster process development. To the best of the authors' knowledge, the present paper is the first to aim to identify the role of corrosion fouling in long-term UF. For this purpose, polyvinylidene fluoride (PVDF) and polyethersulfone (PES) membranes were used. The investigations were carried out with the use of both pilot-scale and laboratory-scale units. Results obtained in the present study have clearly demonstrated that the oil concentration has a significant impact on the process performance. Indeed, it has been noted that a reduction in oil concentration from 160 to 100 mg/L resulted in an increase in the PVDF membrane flux from 57 to 77 L/m2h. In addition, it has been shown that the feed temperature has a significant influence on the UF performance. Importantly, it has been shown that corrosion fouling is of vital importance in UF membranes. Indeed, corrosion products such as iron oxides contaminated the membrane surface leading to an irreversible decrease in the UF process performance. In addition, it has been found that repeating the chemical cleaning of the membrane units significantly reduced the intensity of the fouling phenomenon. However, the complete elimination of its effects was not achieved. Therefore, it has been indicated that cleaning agents recommended by membrane manufacturers do not remove corrosion products deposited on the membrane surface. Undoubtedly, the obtained results can be used in the design of UF units leading to the extension of membrane installation lifetime.

Experimental study of a standalone membrane water desalination unit fully powered by solar energy

In this study, a fully solar-driven water desalination system is designed, fabricated, and tested. The proposed system is designed for remote, isolated areas with limited electricity and freshwater access. For commercial PVDF membranes, the performance of the MD unit is evaluated at various feed temperatures, flow rates, and salt concentrations. In addition, the effect of MD cell design was examined to determine the effect of the obstacles on the feed channel. Increasing the temperature by 20 degrees from 55 to 75 °C enhances productivity by 165 % from 6.2 to 16.4 kg/m2.h. At different operating conditions, the new design of the MD cell with cylindrical obstacles attained higher flux productivity compared to the conventional MD cell design. The maximum attained freshwater output flux was around 15 kg/m2.h at a feed inlet temperature of 65 °C and feed mass flowrate of 66 kg/h for the MD cell with cylindrical obstacles. In the presence of obstacles, a reduction in the specific energy consumption (SEC) by 35–15 % is associated with an increase in the gain output ratio (GOR) by 50–20 % compared to the case of no obstacles. Observations indicate that a small PV module with an area of 0.377 m2 is sufficient to operate the membrane unit for contentious 15 h. Collectively, using solar MD units collectively has the potential to be used for decentralized desalination of water.

Characterization of human AQP5 mutations found in patients suffering from palmoplantar keratosis (Bothnian type).

Aquaporins are structurally well conserved within all kingdoms of life and can be divided into two main groups: (i) orthodox aquaporins conducting only water molecules, and (ii) aquaglyceroporins channeling water and other small uncharged solutes. Water transport through these integral membrane channels takes place in a single-file fashion through the pores of each of the protomers that form tetrameric units in cell membranes.[PP1] Here we focus on the functional consequences of mutations in the orthodox aquaporin-5 (Aqp5), commonly expressed in salivary glands, digestive and respiratory systems, kidneys, the CNS, and sweat glands. These mutations cause hereditary palmoplantar keratoma (Bothnia type; PPKB), marked by hyperkeratotic lesions on the surface of palms and soles. They differ in the positions of the substituted amino acids as well as backbone interactions. We overexpressed some of the mutations in S. cerevisiae as YFP-fusion proteins, purified and reconstituted the water channels into lipid vesicles, and monitored osmotic vesicle deflation under stopped-flow conditions. Additionally assessing the number of reconstituted channels by fluorescence correlation spectroscopy allowed calculation of unitary water channel conductances. The significance of the alterations in water channeling capabilities is discussed with respect to disease genesis.

Pervaporation Membrane-Catalytic Reactors for Isoamyl Acetate Production

This study reports the analysis and design of a liquid phase esterification process to convert acetic acid with isoamyl alcohol into isoamyl acetate via reactive pervaporation, in the presence of an Amberlite IR-120 ion exchange resin catalyst. To accomplish this, a catalytic reactor is coupled with a separation membrane unit (Pervaporation Membrane Reactor (PVMR)). In the proposed unit, the chemical reaction equilibrium is favorably shifted towards isoamyl acetate formation by removing water with the help of a separation membrane. The study is developed by using relevant thermodynamics, kinetics, and membrane transport models, and by considering different catalytic reactor-pervaporator membrane configurations such as: (a) a two-step continuous fixed bed-pervaporator process (FBR+PVMU), (b) a two-step continuous slurry reactor-pervaporator process (SR+PVMU), (c) a single-step integrated fixed bed-pervaporator reactor (IFBPVMR), and d) a single step integrated slurry-pervaporator reactor (ISPVMR). The performance of the PVMRs is evaluated by using a R recycle ratio, a Ω membrane area to reactor volume ratio, and Da Damköhler dimensionless parameters. From the various proposed configurations, it is shown that the integrated plug flow reactor-pervaporation reactor (IFBPVMR) provides the best performance. On the basis of various simulations and design charts developed in the present study, operational conditions leading to optimum ester yields as high as 0.94 are predicted. These results provide a valuable prospect for the industrial scale-up and implementation of isoamyl acetate production units.

Configuration screening of ceramic membrane heat exchanger for an energy-efficient carbon capture process

A CO2 regeneration test rig integrated with rich solvent-split mechanism was built in this study to recover the waste heat from the hot stripped gas by using different heat exchanger configurations in carbon capture process. Five ceramic membrane heat exchangers (CMHEs) and two stainless-steel heat exchangers (SSHEs) were experimentally investigated in terms of the reboiler duty saving. The experimental results of the key parameters showed that the CMHEs have overall higher reboiler duty reduction than the SSHEs, and the Config-B (two multi-channel CMHEs in series), the Config-C (three multi-channel ceramic membrane tubes assembled in parallel), and the Config-E (seven mono-channel ceramic membrane tubes assembled in parallel) could reduce the reboiler duty by around 22%. Accordingly, the economic analysis of the different modified versions of rich-split carbon capture process was conducted. The maximum CO2 capture cost saving reached $ 4.41/t-CO2 by using the Config-D (three mono-channel ceramic membrane tubes assembled in parallel). The sensitivity analysis predicted that the development of membrane technology is expected to further promote savings in capture cost by reducing membrane unit price and prolonging membrane life. In addition, the modified rich-split system could be more suitable for the situation of rising fossil energy prices in the future.

Integrated process for zero discharge of coking wastewater: A hierarchical cycle-based innnovation

The wastewater from coke making is characterized by high toxicity, high concentration of pollutants and complex composition. Therefore, it is difficult to treat using conventional methods such as advanced oxidation and ion exchange processes. In this study, a zero-discharge integrated process (ZDIP) composed of pre-physicochemical – oxic – hydrolytic & denitrification – oxic – post-physicochemical (A/O/H/O/A) biological, pre-processing, membrane and end-processing units was created to treat coking wastewater. The results showed that most of the chemical oxygen demand, sulfide, cyanide and NH4+-N in the coking wastewater were removed in A/O/H/O/A biochemical unit. Hardness, F− and turbidity were further eliminated in the pre-processing unit, while more than 98 % of the effluent was reused in the membrane unit. Finally, zero discharge treatment of residual liquid and sludge was realized in the end-processing unit. The operating cost was about 2.49 USD/m3 and the carbon emissions 9.17 kg CO2-eq/m3 of influent for the entire ZDIP. Theoretically, the ZDIP based on hierarchical cycle drive, which is applicable to handling complex wastewaters, cutting carbon emissions and recycling water, can be taken as an effective wastewater treatment process in the next decade.

A Prospective Study on Fetomaternal Outcomes in Asymptomatic Chronic Hepatitis B Pregnant Women in a Tertiary Level Hospital

Introduction: Hepatitis B surface Antigen (HBsAGg) prevalence among pregnant women in India is between 0.9-3.1%. The most important factor in determining the prevalence is transmission from asymptomatic chronic Hepatitis B Virus (HBV) mother to newborn. This study was done to observe antiviral treatment and fetomaternal outcome in asymptomatic HBV mothers. Aim: To study fetomaternal outcomes in asymptomatic chronic hepatitis B pregnant women. Materials and Methods: This prospective cohort study enrolled 125 HBsAg seropositive singleton pregnancy over a period of 18 months from October 2020 to March 2022 at Department of Obstetrics and Gynaecology, VMMC and Safdarjung Hospital, New Delhi, India. Chronic Hepatitis B (CHB) was diagnosed when HBsAg, HBeAg or HBV DNA was present and IgM antiHBc was absent. Tenofovir was started in consultation with the Gastroenterologist in women with HBeAg positivity or with high HBV DNA titre ≥200,000 IU/mL or Alanine Transaminase (ALT)> two times the Upper Normal Limit (UNL). All women were followed with Liver Function Test (LFT) till delivery and six weeks postpartum and their fetomaternal outcome were noted. The p-value <0.05 was taken as significant. Descriptive statistics was analysed with Statistical Package for the Social Sciences (SPSS) version 17.0 software. Results: Tenofovir was started in 26 (20.8%) women. LFT flare was seen in 15.15% (15/99) women who were not on treatment and 0% in women on treatment. In women without treatment, log HBV DNA level was significantly increased while it was reduced in the women who received tenofovir and the reduction was significant (p-value <0.05). HBeAg was positive in 61.5% women on treatment and 0% in untreated women. No significant association was found in maternal outcomes i.e., Gestational Diabetes Mellitus (GDM), Antepartum Haemorrhage (APH), Preeclampsia, Premature Rupture Of Membrane (PROM), Preterm labour, Postpartum Haemorrhage (PPH) and High Dependency Unit (HDU) stay, in treated and untreated women. Foetal outcomes such as birth weight, APGAR score, Neonatal Intensive Care Unit (NICU) admission, prematurity, Foetal Growth Restriction (FGR) and neonatal jaundice also showed no significant association between antiviral treated and untreated women. Conclusion: There was no significant association of antiviral treatment with maternal and foetal outcome. Tenofovir is safe and reduces the LFT flare in CHB mothers. HBV DNA levels were reduced in treated women which may have reduced the incidence of Mother To Child Transmission (MTCT), which was not studied in the present study. HBeAg seropositivity and ALT >2 times the ULN can replace the need of HBV DNA titres for initiation of antiviral therapy in India.

Geometry-structure models for liquid crystal interfaces, drops and membranes: wrinkling, shape selection and dissipative shape evolution.

We review our recent contributions to anisotropic soft matter models for liquid crystal interfaces, drops and membranes, emphasizing validations with experimental and biological data, and with related theory and simulation literature. The presentation aims to illustrate and characterize the rich output and future opportunities of using a methodology based on the liquid crystal-membrane shape equation applied to static and dynamic pattern formation phenomena. The geometry of static and kinetic shapes is usually described with dimensional curvatures that co-mingle shape and curvedness. In this review, we systematically show how the application of a novel decoupled shape-curvedness framework to practical and ubiquitous soft matter phenomena, such as the shape of drops and tactoids and bending of evolving membranes, leads to deeper quantitative insights than when using traditional dimensional mean and Gaussian curvatures. The review focuses only on (1) statics of wrinkling and shape selection in liquid crystal interfaces and membranes; (2) kinetics and dissipative dynamics of shape evolution in membranes; and (3) computational methods for shape selection and shape evolution; due to various limitations other important topics are excluded. Finally, the outlook follows a similar structure. The main results include: (1) single and multiple wavelength corrugations in liquid crystal interfaces appear naturally in the presence of surface splay and bend orientation distortions with scaling laws governed by ratios of anchoring-to-isotropic tension energy; adding membrane elasticity to liquid crystal anchoring generates multiple scales wrinkling as in tulips; drops of liquid crystals encapsulates in membranes can adopt, according to the ratios of anchoring/tension/bending, families of shapes as multilobal, tactoidal, and serrated as observed in biological cells. (2) Mapping the liquid crystal director to a membrane unit normal. The dissipative shape evolution model with irreversible thermodynamics for flows dominated by bending rates, yields new insights. The model explains the kinetic stability of cylinders, while spheres and saddles are attractors. The model also adds to the evolving understanding of outer hair cells in the inner ear. (3) Computational soft matter geometry includes solving shape equations, trajectories on energy and orientation landscapes, and shape-curvedness evolutions on entropy production landscape with efficient numerical methods and adaptive approaches.

Cigarette smoking and mitochondrial dysfunction in peripheral artery disease.

This study evaluated the association of smoking with mitochondrial function in gastrocnemius muscle of people with peripheral artery disease (PAD). Participants were enrolled from Chicago, Illinois and consented to gastrocnemius biopsy. Mitochondrial oxidative capacity was measured in muscle with respirometry. Abundance of voltage-dependent anion channel (VDAC) (mitochondrial membrane abundance), peroxisome proliferator-activated receptor-γ coactivator (PGC-1α) (mitochondrial biogenesis), and electron transport chain complexes I-V were measured with Western blot. Fourteen of 31 people with PAD (age 72.1 years, ABI 0.64) smoked cigarettes currently. Overall, there were no significant differences in mitochondrial oxidative capacity between PAD participants who currently smoked and those not currently smoking (complex I+II-mediated oxidative phosphorylation: 86.6 vs 78.3 pmolO2/s/mg, respectively [p = 0.39]). Among participants with PAD, those who currently smoked had a higher abundance of PGC-1α (p < 0.01), VDAC (p = 0.022), complex I (p = 0.021), and complex III (p = 0.021) proteins compared to those not currently smoking. People with PAD who currently smoked had lower oxidative capacity per VDAC unit (complex I+II-mediated oxidative phosphorylation [137.4 vs 231.8 arbitrary units, p = 0.030]) compared to people with PAD not currently smoking. Among people without PAD, there were no significant differences in any mitochondrial measures between currently smoking (n = 5) and those not currently smoking (n = 63). Among people with PAD, cigarette smoking may stimulate mitochondrial biogenesis to compensate for reduced oxidative capacity per unit of mitochondrial membrane, resulting in no difference in overall mitochondrial oxidative capacity according to current smoking status among people with PAD. However, these results were cross-sectional and a longitudinal study is needed.

Atmospheric Carbon Capture

Human-generated carbon emissions are the leading cause of climate change. There is a global commitment to reduce carbon emissions, in an effort to limit climate change effects. Many climate change solutions involve the mitigation of carbon emissions, mitigation alone is not enough. Carbon Dioxide (CO2) can live in the atmosphere for over 100 years. If we were to switch to 100% renewable energies, we would still damage the planet with the stagnant CO2 from the 1920’s. To combat climate change, we need a solution that can remove this carbon. One such solution is carbon capture, one of our best weapons in tackling climate change. The replacement of fossil fuel energy will not happen in the next few years, maybe not even for decades. Therefore, carbon capture is a promising ‘bridge’ technology, while we reach a sustainable level of green energy production. Carbon capture technology development has largely focused on singular processes (typically absorption, adsorption and membranes) capturing carbon from industrial exhaust systems. Recently, studies have delved into the idea of combining two or more of these technologies into one more efficient system and employing them in the industrial exhaust systems but also capturing carbon from the atmosphere. This project aims to develop a hybrid membrane and adsorption unit to capture carbon directly from the atmosphere. The aim is to provide the technology necessary to remove carbon from the atmosphere more effectively and cheaper than earlier technologies.

Techno-Economic Comparison of Integration Options for an Oxygen Transport Membrane Unit into a Coal Oxy-Fired Circulating Fluidized Bed Power Plant.

The inclusion of membrane-based oxygen-fired combustion in power plants is considered an emerging technology that could reduce carbon emissions in a more efficient way than cryogenic oxygen-fired processes. In this paper, a techno-economic assessment was developed for a 863 MWel,net power plant to demonstrate whether this CCS technique results in a reduction in efficiency losses and economic demand. Four configurations based on oxygen transport membranes were considered, while the benchmark cases were the air combustion process without CO2 capture and a cryogenic oxygen-fired process. The type of driving force through the membrane (3-end or 4-end), the point of integration into the oxy-fuel combustion process, the heating system, and the pollutant control system were aspects considered in this work. In comparison, the efficiency losses for membrane-based alternatives were lower than those in the cryogenic oxygen-fired process, reaching savings of up to 14% net efficiency. Regarding the specific energy consumption for CO2 capture, the configuration based on the oxygen transport membrane unit with 4-end mode and hot filtration presented 1.01 kWel,net,·h/kgCO2 captured with 100% CO2 recovery, which is an improvement of 11% compared with the cases using cryogenic oxygen. Comparing economic aspects, the specific investment costs for cases based on the oxygen transport membrane unit varied between 2520 and 2942 $/kWel,net·h. This was between 39.6 and 48.2% above the investment for the reference case without carbon capture. However, its hypothetical implantation could suppose a savings of 10.7% in terms of investment cost compared with cryogenic oxygen-based case. In terms of the levelized cost of electricity and the cost of CO2 avoidance, the oxygen transport membrane configurations achieved more favorable results compared with the cryogenic route, reaching savings up to 14 and 38%, respectively. Although oxygen transport membrane units are currently not mature for commercial-scale applications, the results indicated that its application within carbon capture and storage technologies can be strongly competitive.

Boosting brackish water treatment via integration of mesoporous γ-Al2O3NPs with thin-film nanofiltration membranes

In this study, a simple method based on non-ionic surfactant polysorbates-80 was used to create mesoporous γ-Al2O3NPs. The properties of the prepared mesoporous alumina nanoparticles (Al2O3NPs) were verified using ATR-FTIR, XRD, SEM, TEM, DLS, and BET surface area analysis. Then, thin-film nanocomposite (TFN) nanofiltration membranes were fabricated by interfacial polymerization of embedded polyamide layers with varied contents (0.01 to 0.15 wt.%) of mesoporous γ-Al2O3NPs. The surface roughness, porosity, pore size, and contact angle parameters of all the prepared membranes were also determined. The performance of the fabricated membranes was investigated under various mesoporous γ-Al2O3NPs loads, time, and pressure conditions. Mesoporous γ-Al2O3NPs revealed an important role in raising both the membrane hydrophilicity and the surface negativity. The addition of 0.03 wt.% mesoporous γ-Al2O3NPs to the TFN membrane increased water flux threefold compared to the TF control (TFC) membrane, with maximum water flux reaching 96.5, 98, 60, and 52 L/(m2.h) for MgSO4, MgCl2, Na2SO4, and NaCl influent solutions, respectively, with the highest salt rejection of 96.5%, 92.2%, 98.4%. The TFN-Al2O3 membrane was also able to soften water and remove polyvalent cations such as Mg2+ with a highly permeable flux. The TFN-Al2O3 membrane successfully removed the hardness of the applied water samples below the WHO limit compared to using merely the TFC membrane. Furthermore, the TFN-Al2O3 nanofiltration membrane unit proved to be a promising candidate for the desalination of real brine like that collected from the Safaga area, Egypt.

Abstract 10883: Cigarette Smoking and Mitochondrial Function in Peripheral Artery Disease

Introduction: In humans without peripheral artery disease (PAD) and animal models, exposure to cigarette smoke is associated with reduced mitochondrial respiratory function. Many people with PAD smoke cigarettes, but the association of smoking with mitochondrial function in lower extremity skeletal muscle of people with PAD is unknown. Methods: From the Chicago, IL area, 31 people with PAD (ankle brachial index (ABI) &lt; 0.90) were enrolled and consented to gastrocnemius muscle biopsy. Mitochondrial oxidative capacity in gastrocnemius muscle was measured with respirometry. Western blots were performed to quantify mitochondrial membrane abundance via voltage-dependent anion channel (VDAC), mitochondrial biogenesis via peroxisome proliferator-activated receptor-γ coactivator (PGC-1α) , and electron transport chain complexes I-V. Results: Among 31 people with PAD (mean 72.1 years, mean ABI 0.64), 14 (45.2%) smoked cigarettes currently. Participants who currently smoked had higher abundance of PGC-1α (0.75 vs. 0.45 arbitrary units (AU), P&lt;0.01), VDAC (0.62 vs. 0.37 AU, P=0.022), electron transport chain complex I (0.46 vs. 0.21 AU, P=0.031), and complex III (0.76 vs. 0.42 AU, P=0.031), compared to those who did not currently smoke. After normalizing to VDAC, participants who currently smoked had lower mitochondrial oxidative capacity per unit of mitochondrial membrane compared to those who did not currently smoke (complex I+II-mediated oxidative phosphorylation (156.3 vs. 287.0 AU, P=0.017), complex I+II-mediated electron transport chain capacity (184.8 vs. 343.1 AU, P=0.019), complex I-mediated fatty acid oxidative phosphorylation (45.9 vs. 82.1 AU, P=0.034)). After statistical adjustment for age, sex, race, ABI, and body mass index (BMI), most associations were attenuated but remained statistically significant for the higher abundance of VDAC (0.65 vs. 0.35 AU, P=0.037) and complex I (0.50 vs. 0.18 AU, P=0.038) in participants who currently smoked compared to those who did not currently smoke. Conclusions: Results suggest that among people with PAD, current cigarette smoking may stimulate a compensatory increase in mitochondrial biogenesis that may counteract effects of reduced oxidative capacity per unit mitochondrial membrane.

Determination of polyunsaturated and omega-3 fatty acids in vegetable oils and animal fats by the double-quantum filtered correlation spectroscopy (DQF-COSY)

Polyunsaturated fatty acids in vegetable oils and animal fats were one of the most important nutrient substances in the daily intake of humans and animals. These kinds of compounds were responsible for the source of energy, the structural unit of the cell membrane and important physical function. The conventional gas chromatography method inevitably used corrosive and carcinogenic chemicals, and spent long sample preparation time and detection time. To provide a determination method, the molar concentrations of omega-3 FAs and PUFAs in vegetable oils and animal fats were directly investigated with the DQF-COSY spectrum. The method was validated with trueness, selectivity, precision, limit of quantification, and linearity. The method could be used to quantify 14 kinds of vegetable oils, 5 kinds animal fats and 3 kinds of blend oils. The technique was found suitable for the quality control, the market supervision and the nutritional evaluation of FAs.

Ammonium removal by metakaolin-based geopolymers from municipal and industrial wastewaters and its sequential recovery by stripping techniques

In this study, a technical scheme of an ammonium recovery process from diluted municipal or industrial wastewaters was developed, and the main operational parameters of adsorption/desorption and air-stripping/acid-scrubbing or membrane units were examined. The proposed approach combines the removal of ammonium nitrogen by an ion-exchange mechanism on metakaolin-based geopolymers (MKGPs) followed by adsorbent regeneration. A regeneration agent was purified by the air-stripping technique or membrane technology. A ready-to-use market-grade fertilizer or industrial-grade ammonia water could be obtained as the final product. The properties and regeneration ability of MKGP, prepared from activated kaolinite clay, were compared with new geopolymer adsorbents based on papermill sludge (FS MKGP). Adsorption fixed-bed column experiments with continuously circulated regeneration solution purified by air-stripping or the membrane approach were conducted to determine the limits of the regeneration solution’s application. Sodium and potassium salts were tested as regeneration agents, and the influence of regeneration solution composition on ammonium removal and recovery rates was investigated. Based on a breakthrough curve analysis, the removal rate of ammonium N by FS MKGP was found to be 3.2 times higher than that by MKGP for actual wastewater samples. Moreover, there were substantial differences in the regeneration regime between the two adsorbents. For the air-stripping technique, a liquid-phase temperature of 45°C was minimal and enough for efficient ammonia transfer to the gaseous phase. For the membrane technique, a feed-phase temperature of 40°C was enough for removing ammonia from the regeneration solution, while no heating of a receiving phase was required.

Multidimensional Building Blocks for Molecular Sieve Membranes.

Chemical separations aiming for high-purity commodities are critical to modern society. Compared to distillation, chemical absorption, and adsorption, membrane separation is attractive for its energy efficiency, ease of operation, and compact footprint. Molecular sieve membranes (MSMs) are broadly defined as membranes that are constructed from intrinsically and artificially porous materials. On the basis of our recent studies, this Account will first summarize the evolution of MSMs from the viewpoint of dimensionality of building blocks, which fundamentally determines the stacking architectures, intercrystalline gaps, and mass transfer channels of MSMs. Intergrowth of three-dimensional (3D) crystals as primary building blocks gives rise to classical MSMs. However, the poor connection between crystals inherent to those membranes results in intercrystalline gaps that are catastrophic for separation selectivity. We adopted a variety of strategies to close the crystal boundary gaps, including microwave synthesis, electrochemical-ionothermal synthesis, and modular integration. These efforts make us better understand the structure-performance relationship in membranes and create solutions for industrial processes. Excitingly, we first scaled-up the microwave synthesis of a Linde type A (LTA) zeolite membrane and built the world's largest ethanol dehydration membrane unit with an annual capacity of 100,000 tons. MSMs can also be made of two-dimensional (2D) nanosheets as primary building blocks. Those strike a balance between permeation rate and selectivity because the nanometer thickness ensures the minimization of the mass-transfer resistance of the membrane and the layer-by-layer stacking mode can significantly reduce the intercrystalline gaps. By publishing our first report on metal-organic framework (MOF) nanosheet membranes in Science, we committed to establishing top-down and bottom-up methods for assembly of laminae. Once the stacking, orientation, and connection between the layers are meticulously controlled, nanosheet building blocks with diversity open the door for ultrapermeable and selective MSMs. We recently proposed a supramolecule array membrane (SAM) with zero-dimensional (0D) molecules as primary building blocks, which has great potential to absolutely eliminate intercrystalline gaps in membranes. In contrast to the classical transport through nanopores of membranes, selective transport through the intermolecular spacing of supramolecules is creatively realized within the SAM, which marks a new breakthrough in ultraprecise sieving of molecules with tiny differences in size and revolutionizes MSMs in regard to stacking modes, intercrystalline gaps, and transport channels. MSMs have proven to be successful in diverse applications and have triggered wide interest. A unique perspective on the dimensionality evolution of building blocks will accelerate the progress of MSMs. The synergy of multidimensional MSMs will be a positive response to fundamental bottlenecks and industrial questions of membranes and will unlock the potential of membranes to displace the existing separation technologies in the future.

SHRINKING LUNG SYNDROME: A RARE COMPLICATION OF SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

SHRINKING LUNG SYNDROME: A RARE COMPLICATION OF SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)