Reactive membranes for groundwater remediation of chlorinated aliphatic hydrocarbons: competitive dechlorination and cost aspects.

A nanocomposite membrane incorporating reactive Pd-Fe nanoparticles (NPs) was developed to remediate chlorinated aliphatic hydrocarbons (CAHs) from groundwater. Other than recapturing the produced Fen+ for in-situ regeneration, the functionalized polyanions prevented NPs agglomeration and resulting in a spherical Fe0 core (55 nm, O/Fe = 0.05) and an oxidized shell (4 nm, O/Fe = 1.38). The reactive membranes degraded 92% of target CAHs with a residence time of 1.7 seconds. After long-term treatment and regeneration, reusability was confirmed through recovered reactivity, recurrence of Fe0 in X-ray photoelectron spectroscopy, and >96% remaining of Fe and Pd. The total cost (adjusted present value for 20 years) was estimated to be 13.9% lower than the granular activated carbon system, following an EPA work breakdown structure-based cost model. However, non-target CAHs from groundwater can compete for active sites, leading to decreased surface-area normalized dechlorination rate (ksa) by 28.2-79.9%. A hybrid nanofiltration (NF)/reactive membrane was proposed to selectively intercept larger competitors, leading to 54% increased dechlorination efficiency and 1.3 to 1.9-fold enlarged ksa. Overall, the practical viability of the developed reactive membranes was demonstrated by the stability, reusability, and cost advantages, while the optional NF strategy could alleviate competitive degradation towards complex water chemistry.

Multivalence-State Tungsten Species Facilitated Iridium Loading for Robust Acidic Water Oxidation.

The development of the proton exchange membrane water electrolyzer (PEMWE) is still limited by the prohibitive cost and scarcity of iridium (Ir)-based oxygen evolution reaction (OER) catalyst. This work presents a novel catalyst synthesized by precursor-atomization and rapid joule-heating method, successfully doping iridium atoms into polyvalent tungsten blends (W0 , W5+ , W6+ ) based on titanium substrate. The vacancy engineering of unsaturated tungsten oxide (W5+ , W6+ ) reconstructs the electronic structure of the catalyst surface, which resulting in the low-valence state iridium species, avoiding excessive oxidation of iridium and accelerating the catalytic kinetics. Meanwhile, metallic tungsten (W0 ) improves the conductivity of catalyst and guarantees the stable existence of oxygen vacancy. The TiIrWOx possesses excellent performance in acidic OER catalysis, requiring overpotential of only 181 mV to drive 10.0 mA cm-2 , and exhibiting a high mass activity of 753 A gIr -1 at an overpotential of 300 mV. The membrane electrode assembly (MEA) with TiIrWOx as anode electrocatalyst can reduce the Ir consumption amount by >60% compared to commercial IrO2 , and it can operated over 120 h at a current density of 1.0 A cm-2 .

High-Valence-Manganese Driven Strong Anchoring of Iridium Species for Robust Acidic Water Oxidation.

Designing an efficient and durable electrocatalyst for the sluggish anodic oxygen evolution reaction (OER) has been the primary goal of using proton exchange membrane electrolyzer owing to the highly acidic and oxidative environment at the anode. In this work, it is reported that high-valence manganese drives the strong anchoring of the Ir species on the manganese dioxide (MnO2 ) matrix via the formation of an Mn-O-Ir coordination structure through a hydrothermal-redox reaction. The iridium (Ir)-atom-array array is firmly anchored on the Mn-O-Ir coordination structure, endowing the catalyst with excellent OER activity and stability in an acidic environment. Ir-MnO2 (160)-CC shows an ultralow overpotential of 181 mV at j = 10 mA cm-2 and maintains long-term stability of 180 h in acidic media with negligible decay, superior to most reported electrocatalysts. In contrast, when reacting with low-valence MnO2 , Ir species tend to aggregate into IrOx nanoparticles, leading to poor OER stability. Density functional theory (DFT) calculations further reveal that the formation of the Mn-O-Ir coordination structure can optimize the adsorption strength of *OOH intermediates, thus boosting the acidic OER activity and stability.

Anchoring Ni/NiO heterojunction on freestanding carbon nanofibers for efficient electrochemical water oxidation.

Rational design of low-cost and efficient electrocatalyst for the anodic oxygen evolution reaction (OER) to replace noble-metal-based catalysts is greatly desired for the large-scale application of water electrocatalysis. And compared with the conventional powdery catalysts, the freestanding electrode architecture is more attractive owing to the enhanced kinetics and stability. In this work, we report an electrospinning-carbonization-post oxidation strategy to develop the freestanding N-doped carbon nanofibers anchored with Ni/NiO nanoparticles (denoted as Ni/NiO-NCNFs) as efficient OER electrocatalyst. In the synthesized Ni/NiO-NCNFs, the conductive ultrathin carbon layer could promote electron transfer and thus improve the electrocatalytic activity. Meanwhile, the ratio between Ni and NiO could be regulated by tuning the oxidation duration, so as to optimize the adsorption energy of intermediates and improve the OER activity. The Ni/NiO-NCNFs prepared with the oxidation time of 3 h exhibit a promising OER activity and long-term operation durability in 0.1 M KOH solution, requiring an overpotential as small as 153 mV to achieve a current density of 10 mA cm-2. Its overpotential is far lower than that of the reported OER catalysts. This work offers an efficient pathway to develop low-cost and highly active freestanding transitional metal-based OER electrocatalyst for potential renewable electrochemical energy conversion.

Multiscale Engineering of Nonprecious Metal Electrocatalyst for Realizing Ultrastable Seawater Splitting in Weakly Alkaline Solution.

Seawater electrolysis is an attractive technique for mass production of high-purity hydrogen considering the abundance of seawater. Nevertheless, due to the complexity of seawater environment, efficient anode catalyst, that should be, cost effective, highly active for oxygen evolution reaction (OER) but negligible for Cl2 /ClO- formation, and robust toward chlorine corrosion, is urgently demanded for large-scale application. Although catalysis typically appears at surface, while the bulk properties and morphology structure also have a significant impact on the performance, thus requiring a systematic optimization. Herein, a multiscale engineering approach toward the development of cost-effective and robust OER electrocatalyst for operation in seawater is reported. Specifically, the engineering of hollow-sphere structure can facilitate the removal of gas product, while atom-level synergy between Co and Fe can promote Co sites transforming to active phase, and in situ transformation of sulfate ions layer protects catalysts from corrosion. As a result, the as-developed hollow-sphere structured CoFeSx electrocatalyst can stably operate at a high current density of 100 mA cm-2 in the alkaline simulated seawater (pH = 13) for 700 h and in a neutral seawater for 20 h without attenuation. It provides a new strategy for the development of electrocatalysts with a broader application potential.

Comparative Microbial Profiles of Colonic Digesta between Ningxiang Pig and Large White Pig.

Sixteen 35-day-old piglets, including eight Large White (LW) piglets (a lean-type pig breed) and eight Ningxiang (NX) piglets (a fatty-type Chinese Indigenous pig breed), were fed the same diet for 105 days. NX pigs had higher intramuscular fat content than LW pigs (p < 0.05). According to 16S rRNA gene sequencing, the relative abundances of the genera Ruminococcaceae_NK4A214_group, Parabacteroides, Christensenellaaceae_R-7_group and Ruminiclostridium were higher, whereas the abundances of Prevotellaceae_NK3B31_group, Prevotella, Subdoligranulum and Faecalibacterium were lower, in the colon of NX pigs compared to that of LW pigs. Nonmetric multidimensional scaling analysis revealed that the microbiota of the two pig breeds clustered separately along the principal coordinate axis. Furthermore, functional prediction of the bacterial communities suggested higher fatty acid biosynthesis in NX pigs. NX pigs also exhibited lower concentrations of total short-chain fatty acids, propionate and butyrate in the colon (p < 0.05). These findings suggest that NX pigs exhibited higher intramuscular fat content and backfat thickness than LW pigs. The bacterial communities in the colon of NX pigs were also more diverse than those in the colon of LW pigs, which might be used as a potential metabolomics mechanism to research different breeds of pigs.

Effect and safety of traditional Chinese exercises for patients with type 2 diabetes: A protocol for systematic review and network meta-analysis.

BACKGROUND: Traditional Chinese exercises are more and more popular for type 2 diabetes patients for the treatment and rehabilitation; however, the comparative effectiveness and safety remains unclear. Our study aims to compare the pros and cons of these exercise interventions for type 2 diabetes by implementing a network meta-analysis. METHODS: Eight databases will be searched for relevant systematic reviews including SinoMed, VIP, CNKI, Wanfang, PubMed, Embase, Web of Science and the Cochrane Library from inception to Oct 2021. Randomized controlled trials that meeting eligibility in published systematic reviews will be identified. Randomized controlled trial related to Traditional Chinese Exercises or Qigong therapy in the treatment of type 2 diabetes will be included. Two researchers conducted literature screening, data extraction and risk of bias assessment independently. Network meta-analysis of the data was performed by Stata 14.0. The Grades of Recommendations Assessment, Development and Evaluation system will be used to evaluate the rank of evidence. RESULTS: The findings will be reported according to the preferred reporting items for systematic reviews and meta-analyses- network meta-analysis statement. This systematic review and network meta-analysis will summarize the direct and indirect evidence for different kinds of traditional Chinese exercises therapies and to rank these interventions. The results will be submitted to a peer-reviewed journal once completed. CONCLUSION: The network meta-analysis was designed to update and expand on previous research results of clinical trials to better evaluate the effectiveness and safety of different interventions of traditional Chinese exercises for type 2 diabetes patients. OSF REGISTRATION DOI: 10.17605/OSF.IO/MNJD6.

Carbon hollow fiber membranes for a molecular sieve with precise-cutoff ultramicropores for superior hydrogen separation.

Carbon molecular sieve (CMS) membranes with rigid and uniform pore structures are ideal candidates for high temperature- and pressure-demanded separations, such as hydrogen purification from the steam methane reforming process. Here, we report a facile and scalable method for the fabrication of cellulose-based asymmetric carbon hollow fiber membranes (CHFMs) with ultramicropores of 3-4 Å for superior H2 separation. The membrane fabrication process does not require complex pretreatments to avoid pore collapse before the carbonization of cellulose precursors. A H2/CO2 selectivity of 83.9 at 130 °C (H2/N2 selectivity of >800, H2/CH4 selectivity of >5700) demonstrates that the membrane provides a precise cutoff to discriminate between small gas molecules (H2) and larger gas molecules. In addition, the membrane exhibits superior mixed gas separation performances combined with water vapor- and high pressure-resistant stability. The present approach for the fabrication of high-performance CMS membranes derived from cellulose precursors opens a new avenue for H2-related separations.

Sandstorm weather is a risk factor for mortality in ischemic heart disease patients in the Hexi Corridor, northwestern China.

Ischemic heart disease (IHD) is one of the leading causes of mortality worldwide. Moreover, the effects of air pollution have been associated with several cardiovascular diseases (CVDs). The relationship between sandstorm weather and IHD is unknown. The Hexi Corridor is located in northwestern China and is a typical desert region comprising a large area of desert with a high incidence of sandstorms. This study aimed to explore the association between sandstorm weather and IHD-related mortality in this area. We acquired meteorological data of sandstorm weather from 2006 to 2015 from the Gansu Meteorological Bureau, and data regarding deaths due to IHD in five cities within the Hexi Corridor were collected from the death registration system of the Center for Disease Control of Gansu during the same period. Two other cities with few sandstorm events were selected as control regions. The time series method of the generalized additive model (GAM) was used to assess the association between sandstorm weather and IHD-related mortality in the Hexi Corridor. The results showed that the frequency of sandstorms in the Hexi Corridor was higher than that in the control regions (5.48% vs 1.64%, P < 0.01), and IHD-related mortality was correspondingly higher than that in the control regions (56.42/100,000 vs 45.62/100,000, P < 0.01). After stratification by gender, age, and urban/rural residence, a significant difference in IHD-related mortality was also noted (P < 0.05). Significant associations were found between sandstorm weather and IHD-related mortality, and the relative risk (RR) increased with an increasing number of days of sandstorm weather. According to the monthly and annual analyses, the mortality rate corresponded to sandstorm frequency. Our data suggest a positive association between sandstorm weather and IHD-related mortality in the Hexi Corridor of Gansu Province. The underlying mechanism requires further study.

Spinning Cellulose Hollow Fibers Using 1-Ethyl-3-methylimidazolium Acetate⁻Dimethylsulfoxide Co-Solvent.

The mixture of the ionic liquid 1-ethyl-3-methylimidazolium acetate (EmimAc) and dimethylsulfoxide (DMSO) was employed to dissolve microcrystalline cellulose (MCC). A 10 wt % cellulose dope solution was prepared for spinning cellulose hollow fibers (CHFs) under a mild temperature of 50 °C by a dry⁻wet spinning method. The defect-free CHFs were obtained with an average diameter and thickness of 270 and 38 µm, respectively. Both the XRD and FTIR characterization confirmed that a crystalline structure transition from cellulose I (MCC) to cellulose II (regenerated CHFs) occurred during the cellulose dissolution in ionic liquids and spinning processes. The thermogravimetric analysis (TGA) indicated that regenerated CHFs presented a similar pyrolysis behavior with deacetylated cellulose acetate during pyrolysis process. This study provided a suitable way to directly fabricate hollow fiber carbon membranes using cellulose hollow fiber precursors spun from cellulose/(EmimAc + DMSO)/H2O ternary system.