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Two-dimensional material membranes with fast transport channels and versatile chemical functionality are promising for molecular separation. Herein, for the first time, we reported ...design and engineering of two-dimensional Ti3C2Tx MXene (called transition metal carbides and nitrides) membranes supported on asymmetric polymeric hollow fiber substrate for water desalination. The membrane morphology, physicochemical properties and ionsexclusion performance were systematically investigated. The results demonstrated that surface hydrophilicity and electrostatic repulsion and size sieving effect of interlayer channels synergistically endowed the MXene hollow fiber membrane with fast water permeation and efficient rejection of divalent ions during nanofiltration process.
Two-dimensional (2D) materials have been demonstrated as promising building blocks of designing high-performance membranes for molecular separation. Nevertheless, it is a big challenge to apply ...2D-material membranes for water desalination. Herein, we proposed a new type of surface-charged MXene (SC-MXene) membrane for water desalination, which was facilely fabricated by laminar stacking of MXene nanosheets and subsequent surface-coating with polyelectrolyte layer. The morphology, physicochemical structure and surface property of the MXene materials and resulted membranes were observed by XPS, SEM, water contact angle test, AFM, IR and XPS. These results demonstrated that coating polyelectrolyte (PEI) successfully tuned the surface charge and enhanced the hydrophilicity without scarifying the laminar structure of MXene membrane. By utilizing the effects of electrostatic interaction and size-sieving, the resulting surface-charged MXene (SC-MXene) membrane exhibited high salt rejection and water permeance during either nanofiltration or forward osmosis process, showing great potential for water desalination.
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•Surface-charged MXene membrane was fabricated via polyelectrolyte coating.•Polyelectrolyte coating tuned surface charge and enhanced hydrophilicity.•Membrane exhibited outstanding water desalination performance in NF or FO process.
Novel design of hydrophobic membrane could improve the efficiency of membrane distillation (MD) technology. Owning to being easy to realize hydrophobic modification, fast radial heat transfer rate ...and limiting the passage of larger contaminants, hydrophobic graphene oxide (GO) membrane shows potential for MD process. In this work, we reported on a new type of nanoparticles intercalated GO membrane with hydrophobic surface for MD application fabricated by vacuum-filtration method. The introduction of nanoparticles (SiO2) by physical mixing enhanced the surface roughness of GO membrane. A subsequent grafting of long alkyl chains (hexadecyltrimethoxysilane) further increased the membrane hydrophobicity. The effects of treating temperature and nanoparticles content on the membrane nanostructures, surface hydrophobicity and desalination performance were systematically investigated. The optimized membrane annealed at 80 °C with hydrophobic surface (water contact angle: 120.8°) exhibited water flux of 13.59 kg m-2 h-1 and salt rejection of 99.99% under 60 °C for 35 g L-1 NaCl in water during vacuum MD process. Besides of the expected gradually higher water flux at elevated temperature, such excellent desalination performance remains stable by varying the salt concentration or adding model foulants such as surfactant sodium dodecyl sulfate and organic humid acid in the feed.
•Introduction of nanoparticles enhanced surface roughness of GO membrane.•Subsequent grafting of long alkyl chains further increased membrane hydrophobicity.•Hydrophobic GO membrane was used for MD water desalination.
Aims
Phytoremediation by halophytes has been widely advocated as an alternative approach to remediate salt-affected and heavy metal-contaminated soils. The present study was the first to evaluate the ...phytoremediation potential of halophyte
H. glomeratus
in heavy metal-contaminated saline soils using a field trial.
Materials and methods
H. glomeratus
seeds were sown in heavy metal-contaminated saline soil plots and plots without plants were used as the control. The effects of phytoremediation on heavy metal-contaminated saline soils were measured in the following parameters: the plant performance in heavy metal-contaminated saline soil, the exchangeable cation and heavy metal composition of salt samples, the selected chemical properties in soil after planting
H. glomeratus
, and the oil composition and content in seeds.
Results
After one growth season, the survival of plants, dry biomass, seed, and total salt yields of plants were 92.36%, 9806.30 kg ha
−1
, 619.81 kg ha
−1
, and 2105.35 kg ha
−1
, respectively. A large amount of salts and heavy metals accumulated in
H.glomeratus
plants growing on the heavy metal-contaminated saline soil plots. The salt samples extracted from
H. glomeratus
plants showed high Na levels (83.33%) and heavy metal concentrations, including Cr, Ni, Cu, Zn, As, Cd, and Hg. After sowing
H. glomeratus
seeds in heavy metal-contaminated saline soil plots, the levels of salt, Na, and heavy metals in test soils were significantly decreased compared with unsown plots. In addition, the oil content of seeds harvested from
H. glomeratus
was 19.2% and contained 91.8% unsaturated fatty acids.
Conclusions
Our pilot results showed
H. glomeratus
can potentially hyperaccumulate not only salts but also heavy metals, and the seed oil contained a favorable ratio of fatty acids. Therefore,
H. glomeratus
is a promising candidate for phytoremediation of salt-affected and heavy metal-contaminated soils.
The undeveloped molybdenum borides (Mo2Bx, x = 1 or 4) were investigated as the active ingredients coupled with CdS for photocatalytic hydrogen production for the first time.
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•The ...undeveloped Mo2Bx were used for photocatalytic HER for the first time.•The CdS-Mo2Bx (15 wt%) exhibit excellent photocatalytic HER activities.•Mo2Bx show strong boron dependence in electrocatalysis and photocatalysis.
Molybdenum based compounds, such as MoCx, MoSe2, MoS2 MoPx, MoOx and their derivatives, have been considered as the alternative catalysts for platinum (Pt) whether in electrocatalytic or photocatalytic hydrogen evolution reaction (HER). This means molybdenum based compounds have great application potential in solving the energy crisis and environmental pollution. Herein, for the first time, the unexplored Mo2Bx (x = 1 or 4) were investigated as the active components in a visible-light driven photocatalytic hydrogen production system. Experimental results demonstrate that they both exhibit excellent hydrogen evolution activities when combined with CdS or organic photosensitizers. Additionally, for the same kind of light-harvesting material, the photocatalytic HER activity of Mo2B4 is obviously better than that of Mo2B. This clearly indicates the photocatalytic activities of them are affected by the content of electron deficient atom boron (B) in Mo2Bx samples and exhibits a strong B dependence in photocatalytic HER. The reason for this B dependency is studied in detail by photo/electrochemical methods and optical characterizations in this work, where it is essentially caused by the difference in the electron transfer (ET) rates between light-harvesting material and Mo2Bx samples and just manifested as B dependency. Additionally, the relation between photocatalysis and electrocatalysis in HER is discussed.
SUMMARY
The Northern China Domain is located between the Central Asian Orogenic Belts to the north and the Kunlun–Qinling belt to the south, and it comprises the North China, Alxa and Tarim blocks. ...The relationships among the Northern China domain and the southern tectonic elements such as the Qaidam Basin/Terrane are debated because of the major modification by crustal deformation in the late Mesozoic–Cenozoic. To address this issue, we conducted a palaeomagnetic and high-precision radiometric dating study of Triassic volcanic rocks and Middle Jurassic strata in the Qaidam Terrane. Our objective was to determine the relationship between the Qaidam Terrane with the Tarim Block and the North China Block (NCB) during the late Palaeozoic and early Mesozoic. Four volcanic samples yielded zircon U-Pb ages of 236–243 Ma. The characteristic remanent magnetizations (Middle Triassic: D = 40.2°, I = 54.6°, α95 = 3.4°; Middle Jurassic: D = 27.4°, I = 48.0°, α95 = 7.9°) passed the fold and reversal tests, and yielded Middle Triassic and Middle Jurassic palaeopole positions at 57.6° N, 178.2° E, A95 = 4.0° and 65.8° N, 197.6° E, A95 = 7.8°, respectively. Based on these new poles, combined with other reliable data, we compared the apparent polar wander path (APWP) of the Qaidam Terrane with those of the NCB and Tarim Block. The results show that, from the Carboniferous through Early Cretaceous, the APWP of the Qaidam Terrane resembles that of the Tarim Block, but it is quite different from that of the NCB. Combined with other reported evidence, we conclude that the Qaidam Terrane was an independent dynamic unit during the late Palaeozoic until its connection with the Tarim Block, which was followed by continuous eastward motion. During this process, the connection between the Qaidam Terrane and the NCB–Alxa blocks occurred in the Middle Triassic, and subsequently the Qaidam Terrane underwent multiple tectonic responses to collisions with the Qiangtang Terrane, Lhasa Terrane and the India Plate, before the formation of its modern tectonic configuration.
Pseudomonas aeruginosa
(
P. aeruginosa
) is a widespread, gram-negative, pathogenic bacterium that causes serious internal and external infections in humans and other animals. The increasing ...antibiotic resistance has complicated bacterial infection treatment, and current antibiotic therapies cannot cure all infections. Owing to this, bacteriophages (phages) have regained attention as potential therapeutics for bacterial infections. In this study, the phage “PaVOA” was isolated from hospital sewage and characterized. Next, a New Zealand rabbit skin infection model was used to determine the therapeutic efficacy of PaVOA as compared to a phage cocktail or the cephalosporin antibiotic ceftriaxone. Characterization results demonstrated that phage PaVOA belongs to the
Myoviridae
family, has a double-stranded DNA genome, is resistant to low temperatures (−20°C), is most optimal at 40°C, has good acid–base tolerance, and remains stable for 30 min under 20 W ultraviolet (UV) intensity. The optimal multiplicity of infection of PaVOA was 0.1, and a one-step growth curve showed a short latency period (10 min), thus demonstrating its ability to rapidly kill bacteria. Furthermore, the addition of calcium (Ca) and magnesium (Mg) ions significantly increased the PaVOA titer. An
in vivo
phage kinetic curve showed that PaVOA was rapidly inactivated within the blood of New Zealand rabbits (undetectable after 12 h), and no animals died due to phage treatment. Wound healing studies showed that the phage cocktail induced a high healing rate and an acceleration of the skin remodeling process, and was more efficacious than ceftriaxone. Therefore, phage cocktail therapy represents a novel therapeutic approach in the treatment of traumatic skin infections caused by multi-drug resistant
P. aeruginosa
.
In this work, NaH
2
PO
2
, Na
2
S
2
O
3
and CdCl
2
were used to synthesize P-doped CdS samples for the photocatalytic decomposition of formic acid to CO reaction. The CO production rates and ...selectivity of P-doped CdS are as high as 24.5 mmol g
−1
h
−1
and 92.4%, in which the rate is 7 times higher than that of the pure CdS. Multiple characterizations show that the P-doping increases the specific surface area, widens the band gap and shifts the energy band position of CdS, resulting in enhanced photocatalytic activity.
The P-doped CdS samples was used for the photocatalytic decomposition of formic acid to CO, in which the CO production rates and selectivity are as high as 24.5 mmol g
−1
h
−1
and 92.4%.
An inexpensive catalytic system, which used a readily available Fe(acac)
3 and trace quantity of Cu(acac)
2 as the co-catalyst and air as the oxidant for the homo-coupling of terminal alkynes, has ...been developed. The catalytic system could also apply to the cross-coupling reaction of two different terminal alkynes.
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A lack of phosphorus (P) in plants can severely constrain growth and development. Barley, one of the earliest domesticated crops, is extensively planted in poor soil around the world. To date, the ...molecular mechanisms of enduring low phosphorus, at the transcriptional level, in barley are still unclear. In the present study, two different barley genotypes (GN121 and GN42)-with contrasting phosphorus efficiency-were used to reveal adaptations to low phosphorus stress, at three time points, at the morphological, physiological, biochemical, and transcriptome level. GN121 growth was less affected by phosphorus starvation and recovery than that of GN42. The biomass and inorganic phosphorus concentration of GN121 and GN42 declined under the low phosphorus-induced stress and increased after recovery with normal phosphorus. However, the range of these parameters was higher in GN42 than in GN121. Subsequently, a more complete genome annotation was obtained by correcting with the data sequenced on Illumina HiSeq X 10 and PacBio RSII SMRT platform. A total of 6,182 and 5,270 differentially expressed genes (DEGs) were identified in GN121 and GN42, respectively. The majority of these DEGs were involved in phosphorus metabolism such as phospholipid degradation, hydrolysis of phosphoric enzymes, sucrose synthesis, phosphorylation/dephosphorylation and post-transcriptional regulation; expression of these genes was significantly different between GN121 and GN42. Specifically, six and seven DEGs were annotated as phosphorus transporters in roots and leaves, respectively. Furthermore, a putative model was constructed relying on key metabolic pathways related to phosphorus to illustrate the higher phosphorus efficiency of GN121 compared to GN42 under low phosphorus conditions. Results from this study provide a multi-transcriptome database and candidate genes for further study on phosphorus use efficiency (PUE).
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