Showing papers by "Jian Jin published in 2018"

Nanoparticle-templated nanofiltration membranes for ultrahigh performance desalination

Abstract: Nanofiltration (NF) membranes with ultrahigh permeance and high rejection are highly beneficial for efficient desalination and wastewater treatment. Improving water permeance while maintaining the high rejection of state-of-the-art thin film composite (TFC) NF membranes remains a great challenge. Herein, we report the fabrication of a TFC NF membrane with a crumpled polyamide (PA) layer via interfacial polymerization on a single-walled carbon nanotubes/polyether sulfone composite support loaded with nanoparticles as a sacrificial templating material, using metal-organic framework nanoparticles (ZIF-8) as an example. The nanoparticles, which can be removed by water dissolution after interfacial polymerization, facilitate the formation of a rough PA active layer with crumpled nanostructure. The NF membrane obtained thereby exhibits high permeance up to 53.5 l m−2h−1 bar−1 with a rejection above 95% for Na2SO4, yielding an overall desalination performance superior to state-of-the-art NF membranes reported so far. Our work provides a simple avenue to fabricate advanced PA NF membranes with outstanding performance. Nanofiltration membranes are important for water desalination technologies, but designing membranes that achieve both high permeance and high salt rejection remains challenging. Here, the authors use sacrificial nanoparticles in the membrane fabrication process, leading to crumpled structures with ultrahigh permeance.

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

Abstract: 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 st...

Hydrogel-embedded tight ultrafiltration membrane with superior anti-dye-fouling property for low-pressure driven molecule separation

Abstract: A hydrogel-embedded tight ultrafiltration membrane composed of sodium polyacrylate-modified polyacrylonitrile (PAAS-m-PAN) is fabricated by a modified phase inversion process. The as-prepared membrane with excellent anti-dye-fouling property can effectively separate dyes from salts with permeance as high as >140 L m−2 h−1 bar−1, which is several times that of traditional polymeric filtration membranes with a similar rejection performance.

In situ growth of single-layered α-Ni(OH)2 nanosheets on a carbon cloth for highly efficient electrocatalytic oxidation of urea

Abstract: The electrochemical urea oxidation reaction (UOR) is useful for the simultaneous elimination of urea-rich wastewater and generation of hydrogen. In theory, nickel-based catalysts, as non-precious metal catalysts, show great advantages in this regard. However, poor conductivity and insufficient active sites on common nickel-based nanomaterials hinder their catalytic performance. Herein, we report methanol-directed one-step growth of single-layered (SL) α-Ni(OH)2 nanosheets on a conductive carbon cloth (CC) (SL α-Ni(OH)2 NS/CC) for highly efficient electrocatalytic urea oxidation. Without the use of any other pretreatment and modification methodology, it is found that huge SL α-Ni(OH)2 NS with a thickness of ∼0.8 nm densely and fully covers every CC fiber in the form of nanowalls. Taking advantage of the good conductivity of CC and the sufficiently exposed active surface of SL α-Ni(OH)2 NS, the resulting SL α-Ni(OH)2 NS/CC-integrated electrode displays superior UOR performance. A current density as high as 436.4 mA cm−2 at 0.5 V vs. Ag/AgCl is achieved, which represents the best UOR performance among those of the reported nickel-based electrocatalysts. This convenient approach opens a new way to obtain ultrafine heterogeneous catalysts and their integrated electrodes with the assistance of methanol solvent instead of water.

Porous superstructures constructed from ultrafine FeP nanoparticles for highly active and exceptionally stable hydrogen evolution reaction

Abstract: Aiming at providing an efficient strategy to design non-precious metal electrocatalysts with high electrocatalytic activity and simultaneously long-term stability for the hydrogen evolution reaction (HER), we report in this work the fabrication of porous FeP microsphere superstructures (SSs) made up of ultrafine FeP NPs through a self-templating gas–solid phosphorization reaction of urchin-like FeOOH microspheres. Since the ultrafine FeP NPs are arranged in a loose and isolated manner instead of being densely packed like in the resulting FeP microspheres, the FeP SS with high porosity exhibits highly active and exceptionally stable HER performance even at a low mass loading of the electrocatalyst. At a mass loading of 0.566 mg cm−2, an overpotential of 66 mV is achieved. At a mass loading as low as 0.142 mg cm−2, the highest mass activity of up to 70.4 mA mg−1 with a η10 of 102 mV is achieved, which is superior to that of all other non-precious metal electrocatalysts. The chronopotentiometry (CP) test at a current density of 10 mA cm−2 for 24 h shows that the overpotential increases slightly from 66 mV to 80 mV, indicating a fairly stable HER process.

Carbon Molecular Sieve Membranes Derived from Tröger's Base-Based Microporous Polyimide for Gas Separation.

Abstract: Carbon molecular sieve (CMS)-based membranes have attracted great attention because of their outstanding gas-separation performance. The polymer precursor is a key point for the preparation of high-performance CMS membranes. In this work, a microporous polyimide precursor containing a Troger's base unit was used for the first time to prepare CMS membranes. By optimizing the pyrolysis procedure and the soaking temperature, three TB-CMS membranes were obtained. Gas-permeation tests revealed that the comprehensive gas-separation performance of the TB-CMS membranes was greatly enhanced relative to that of most state-of-the-art CMS membranes derived from polyimides reported so far.

Microsphere-Fiber Interpenetrated Superhydrophobic PVDF Microporous Membranes with Improved Waterproof and Breathable Performance.

Abstract: Superhydrophobic membranes with extreme liquid water repellency property are good candidates for waterproof and breathable application. Different from the mostly used strategies through either mixi...

Boosting Alkaline Hydrogen Evolution Activity with Ni-Doped MoS2 /Reduced Graphene Oxide Hybrid Aerogel.

Abstract: Highly active, durable, and cost-effective non-precious-metal-based electrocatalysts are urgently needed to improve the sluggish hydrogen evolution reaction (HER) in an alkaline environment. Herein, a lyophilization/thermolysis method is successfully applied to prepare Ni-doped MoS2 (Ni-MoS2 )/reduced graphene oxide (RGO) hybrid aerogels. The MoS2 aerogel possesses a higher density of exposed active sites than its corresponding bulk material. Inheriting from GO its abundant functional groups during pyrolysis, the RGO aerogel can uniformly disperse MoS2 and simultaneously maintain excellent conductivity. The incorporation of Ni atoms can accelerate the cleavage of the HO-H bond and enhance the adsorption and desorption of intermediate OH- . Owing to the synergistic effect of the compositional and structural advantages of aerogels, the Ni-MoS2 /RGO hybrid aerogel delivers highly promoted HER kinetics in alkaline media. As a result, an optimal η10 (overpotential at 10 mA cm-2 ) of 168 mV in 1 m KOH is obtained, which is superior to the non-doped MoS2 /RGO hybrid aerogel (225 mV) and MoS2 aerogel (263 mV), letting alone bulk MoS2 (448 mV). Moreover, the η60 (overpotential at 60 mA cm-2 ) is maintained at 262 mV after chronopotentiometry tests at a constant current density of 10 mA cm-2 for 24 h, indicating an exceptionally stability of the HER catalyst.

A Novel Architecture for Carbon Nanotube Membranes towards Fast and Efficient Oil/water Separation

Abstract: Carbon nanotubes (CNT) are robust and proven as promising building blocks for oil/water separating membranes. However, according to classic fluid dynamic theory, achieving high permeation flux without sacrificing other membrane properties is a formidable challenge for CNT membranes, because of the trade-off nature among key membrane parameters. Herein, to relieve the trade-off between permeation fluxes, oil rejection rate, and membrane thickness, we present a new concept to engineer CNT membranes with a three-dimensional (3D) architecture. Apart from achieving high oil separation efficiency (>99.9%), these new oil/water separating membranes can achieve water flux as high as 5,500 L/m2.h.bar, which is one order of magnitude higher than pristine CNT membranes. Most importantly, these outstanding properties can be achieved without drastically slashing membrane thickness down to nanoscale. The present study sheds a new light for the adoption of CNT-based membranes in oil/water separation industry.

Soybean yield and yield component distribution across the main axis in response to light enrichment and shading under different densities

Abstract: A 2-year field experiment was conducted under light enrichment and shading conditions to examine the responses of seed yield and yield components distribution across main axis in soybean. The results showed that the maximum increase in seed yield per plant by light enrichment occurred at 27 plants/m 2 , while the most significant reduction in seed yield per plant by shading occurred at 54 plants/m 2 . Light enrichment beginning at early flowering stage decreased seed size on average by 7% while shading increased seed size on average by 9% over densities and cultivars, resulting in a fewer extent compensation in seed yield decrement. Responses to light enrichment and shading occurred proportionately across the main axis node positions despite the differences in the time (15–20 days) of development of yield components between the high and low node positions. Variation intensity of seed size of three soybeans was dissimilar as a result of changes in the environment during the reproductive period. The small-seed cultivar had the greatest stability in single seed size across the main axis, followed by moderate-seed cultivar, while large-seed cultivar was the least stable. Although maximum seed size may be determined by genetic potential in soybean plants, our results suggested that seed size can still be modified by environmental conditions, and the im pact can be expressed through some internal control moderating the final size of most seeds in main stem and in all pods. It indicates that, through redistributing the available resources across main stem to components, soybean plants showed the mechanism, in an attempt to maintain or improve yield in a constantly changing environment.

Impact of Elevated CO2 on Seed Quality of Soybean at the Fresh Edible and Mature Stages

Abstract: Although the effect of elevated CO2 (eCO2) on soybean yield has been well documented, few studies have addressed seed quality, particularly at the fresh edible (R6) and mature stages (R8). Under the current global scenario of increasing CO2 levels, this potentially threatens the nutritional content and quality of food crops. Using four soybean cultivars, we assessed the effects of eCO2 on the concentrations of crude protein, crude oil, and isoflavones and analyzed the changes in free amino acids, fatty acids, and mineral elements in seeds. At R6, eCO2 had no influence on soybean seed protein and oil concentrations. At R8, eCO2 significantly decreased seed protein concentration but increased seed oil concentration; it also significantly decreased total free amino acid concentration. However, at the same stage, the proportion of oleic acid (18:1) among fatty acids increased in response to eCO2 in the cultivars of Zhongke-maodou 2 (ZK-2) and Zhongke-maodou 3 (ZK-3), and a similar trend was found for linoleic acid (18:2) in Zhongke-maodou 1 (ZK-1) and Hei-maodou (HD). Total isoflavone concentrations increased significantly at both the R6 and R8 stages in response to eCO2. Compared with ambient CO2, the concentrations of K, Ca, Mg, P, and S increased significantly under eCO2 at R6, while the Fe concentration decreased significantly. The response of Zn and Mn concentrations to eCO2 varied among cultivars. At R8 and under eCO2, Mg, S, and Ca concentrations increased significantly, while Zn and Fe concentrations decreased significantly. These findings suggest that eCO2 is likely to benefit from the accumulation of seed fat and isoflavone but not from that of protein. In this study, the response of seed mineral nutrients to eCO2 varied between cultivars.

Ultralarge Single-Layer Porous Protein Nanosheet for Precise Nanosize Separation.

Abstract: Highly permeable and precisely size-selective membranes are the subject of continuous pursuit for energy-efficient separation of fine chemicals. However, challenges remain in the fabrication of an ultrathin selective layer with homogeneous pores, in particular, with the pore sizes in the 1–10 nm range. We report the design of a free-standing porous nanosheet assembled with a single layer of proteins. Tobacco mosaic virus mutant (TMVm), a cylinder-shaped protein containing an inner pore of 4 nm in diameter, was cross-linked via a Cu2+-catalyzed disulfide-bond-forming reaction along the 2D orientation. By such a design, ultralarge single-layer TMVm nanosheets extending over tens of micrometers in width and with well-defined nanopores were successfully developed. A ∼40 nm thick ultrafiltration membrane laminated by the single-layer TMVm nanosheets through simple vacuum filtration accomplished the precise separation of ∼4 nm sized substances. Meanwhile, the membrane exhibited water permeance up to ∼7000 L m–2...

Long-term manure addition reduces diversity and changes community structure of diazotrophs in a neutral black soil of northeast China

Abstract: Although biological nitrogen fixation is an important nitrogen source for agroecosystem, the knowledge of their response to long-term fertilization under neutral soil is limited. The aims of this study were to explore the effects of different fertilization treatments on diversity and compositions of diazotrophic community in a neutral black soil in northeast China. The long-term fertilization experiment under monoculture maize was established in a neutral black soil since 1979. Soil samples from four treatments were collected in September 2014: non-fertilization (NoF), chemical fertilization (CF), manure fertilization (M), and chemical fertilization plus manure (CFM). qPCR and Illumina MiSeq sequencing were used to assess the abundance and compositions of diazotrophic community targeting nifH gene. M treatment significantly increased the nifH gene abundance, but inverse trends were found in the CF and CFM treatments when compared with NoF. The diazotrophic community was overwhelmingly dominated by Alphaproteobacteria with relative higher abundance in manure-added treatments. Principal coordinate analysis (PCoA) indicated that the total diazotrophic community was separated into two groups with and without manure addition, and soil available P was the most influential factor on the changes of diazotrophic community. Our results suggested that soil nutrients rather than soil pH were the main influential factors on the changes of diazotrophic communities and manure addition had a greater effect than chemical fertilization on diazotrophic community structure in neutral black soil.

Ammonia-Oxidizing Archaea Show More Distinct Biogeographic Distribution Patterns than Ammonia-Oxidizing Bacteria across the Black Soil Zone of Northeast China.

Abstract: Black soils (Mollisols) of northeast China are highly productive and agriculturally important for food production. Ammonia-oxidizing microbes play an important role in N cycling in the black soils. However, the information related to the composition and distribution of ammonia-oxidizing microbes in the black soils has not yet been addressed. In this study, we used the amoA gene to quantify the abundance and community composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) across the black soil zone. The amoA abundance of AOA was remarkably larger than that of AOB, with ratios of AOA/AOB in the range from 3.1 to 91.0 across all soil samples. The abundance of AOA amoA was positively correlated with total soil C content (p 0.05). In contrast, the abundance of AOB amoA positively correlated with soil pH (p = 0.009) but not with total soil C. Alpha diversity of AOA did not correlate with any soil parameter, however, alpha diversity of AOB was affected by multiple soil factors, such as soil pH, total P, N, and C, available K content, and soil water content. Canonical correspondence analysis indicated that the AOA community was mainly affected by the sampling latitude, followed by soil pH, total P and C; while the AOB community was mainly determined by soil pH, as well as total P, C and N, water content, and sampling latitude, which highlighted that the AOA community was more geographically distributed in the black soil zone of northeast China than AOB community. In addition, the pairwise analyses showed that the potential nitrification rate (PNR) was not correlated with alpha diversity but weakly positively with the abundance of the AOA community (p = 0.048), whereas PNR significantly correlated positively with the richness (p = 0.003), diversity (p = 0.001) and abundance (p < 0.001) of the AOB community, which suggested that AOB community might make a greater contribution to nitrification than AOA community in the black soils when ammonium is readily available.

Biomass and catabolic diversity of microbial communities with long-term restoration, bare fallow and cropping history in Chinese Mollisols

Abstract: Microbial biomass and community catabolic diversities at three depths (0–10 cm, 20–30 cm, and 40–50 cm) in Chinese Mollisols as influenced by long-term managements of natural restoration, cropping and bare fallow were investigated. Microbial biomass was estimated from chloroform fumigation-extraction and substrate-induced respiration (SIR), and catabolic diversity was determined by using Biolog® EcoPlate. Experimental results showed that microbial biomass significantly declined with soil depth in the treatments of restoration and cropping, and not in the treatment of bare fallow, where the microbial biomass had a positive relationship with the total soil C content. The inspections into the catabolic capability of the microbial community at the same soil depth showed that the treatment of natural restoration had a relatively stronger metabolic ability than the cropping and bare fallow treatments. Shannon’s diversity index, substrate richness and substrate evenness calculated from the Biolog data were higher in the treatments of natural restoration and cropping than the bare fallow treatment with the same soil depth, and with the highest values in the top soil. Principal component analysis indicated that the catabolic profiles not only varied with the soil depth in each treatment, but also differed in the three treatments within the same soil depth. The catabolic profiles of the three treatments were similar to each other in the soil depth of 0–10 cm and dis tinctly different in the soil depths of 20–30 cm and 40–50 cm. These results suggest that it was microbial biomass rather than community function that was influenced by the different soil management in the topsoil (0–10 cm); in the relative depths, the soil microbial community function was more easily influenced than microbial biomass.

Elevated CO 2 alters the abundance but not the structure of diazotrophic community in the rhizosphere of soybean grown in a Mollisol

Abstract: The effect of elevated CO2 (eCO2) on rhizospheric diazotrophic community in cropland has little been studied, although eCO2 facilitates nodulation and N2 fixation in legumes. In this study, four soybean cultivars (Xiaohuangjin, Suinong 8, Suinong 14, and Heinong 45) were grown in Mollisols for 65 days under ambient CO2 (aCO2) (390 ppm) or eCO2 (550 ppm). Quantitative PCR and Illumina MiSeq sequencing targeting the nifH gene that reflects the composition of diazotrophic community were determined. Elevated CO2 significantly increased the abundance of nifH gene copies in the rhizospheres of the Suinong 8 and Heinong 45 cultivars, but not in the Suinong 14 and Xiaohuangjin cultivars. The nifH abundance correlated negatively with nodule density (p ≤ 0.01) but positively with nodule size (p ≤ 0.01). Elevated CO2 did not significantly alter the composition of diazotrophic community, nor shift dominant bacterial operational taxonomic units (OTUs). These results indicated that eCO2 stimulated the growth but did not alter the community composition of diazotrophs in the rhizosphere of soybean, which depended on cultivar and might contribute to nodulation responses to eCO2.

Rhizobacterial community structure in response to nitrogen addition varied between two Mollisols differing in soil organic carbon

Abstract: Excessive nitrogen (N) fertilizer input to agroecosystem fundamentally alters soil microbial properties and subsequent their ecofunctions such as carbon (C) sequestration and nutrient cycling in soil. However, between soils, the rhizobacterial community diversity and structure in response to N addition is not well understood, which is important to make proper N fertilization strategies to alleviate the negative impact of N addition on soil organic C and soil quality and maintain plant health in soils. Thus, a rhizo-box experiment was conducted with soybean grown in two soils, i.e. soil organic C (SOC)-poor and SOC-rich soil, supplied with three N rates in a range from 0 to 100 mg N kg−1. The rhizospheric soil was collected 50 days after sowing and MiSeq sequencing was deployed to analyze the rhizobacterial community structure. The results showed that increasing N addition significantly decreased the number of phylotype of rhizobacteria by 12.3%, and decreased Shannon index from 5.98 to 5.36 irrespective of soils. Compared to the SOC-rich soil, the increases in abundances of Aquincola affiliated to Proteobacteria, and Streptomyces affiliated to Actinobacteria were greater in the SOC-poor soil in response to N addition. An opposite trend was observed for Ramlibacter belong to Proteobacteria. These results suggest that N addition reduced the rhizobacterial diversity and its influence on rhizobacterial community structure was soil-specific.

Comparison on fungal molecular ecological networks of agricultural soils with different latitudes in the black soil region of Northeast China

Abstract: To investigate the differences of fungal network structures and interaction among fungal species of in black soil region of Northeast China, Illumina MiSeq sequencing was used to reveal the fungal communities in the three long-term fertilization experimental fields. Fungal molecular ecological networks were constructed based on random matrix theory (RMT). The results demonstrated that Ascomycota, Basidiomycota and Zygomycota were the dominant phyla and Hypocreales, Pleosporales and Sordariales were the dominant order, but the relative abundance of some dominant taxa significantly varied in different locations. Fungal molecular ecological network structures in three locations showed significant difference, with more complex fungal network being observed in north location with more competitive relations among species. The fungal network in south location was more easily disturbed by environmental perturbations with less stability. Only seven shared nodes were detected among three fungal molecular ecological networks. There were large differences in connectivity of shared nodes within individual fungal network. The subnetwork of Hypocreales was gradual complex from south to north location while subnetwork of Pleosporales presented reversed trend. The key species of south, middle and north locations were Chaetomiaceae, Pleosporales and Penicillium coralligerum, respectively. Soil pH and total N content were the main soil properties simultaneously influencing three fungal networks.

Complete genome sequence of a novel bacteriophage infecting Bradyrhizobium diazoefficiens USDA110.

Abstract: The nitrogen-fixing symbiotic bacteria, rhizobia are the most important beneficial bacteria in soil, as they form nodules with host legume plants to fix nitrogen to maintain soil fertility and facilitate plant growth. Although these bacteria are critically important to agriculture, bacteriophages of rhizobia (rhizobiophages) are commonly present in soils, rhizosphere, and nodules, which have major influences on the composition and population of rhizobia in soils and affect nodulation and nitrogen fixation. Despite the importance of rhizobiophages, only 23 phage full genomes have been sequenced. Among them, 7, 15, and 1 phages were isolated from Sinorhizobium sp., Rhizobium sp., and Mesorhizobium sp., respectively (Johnson et al., 2015). The full genome of Bradyrhizobium phage has not been reported. Bradyrhizobium diazoefficiens, formerly known as Bradyrhizobium japonicum, is a slow-growing rhizobium capable of nodulating and fixing nitrogen in soybean. In this study, a typical bacterial strain Bradyrhizobium diazoefficiens USDA110 was used as the trapping host for phage

Macromolecular separation film as well as preparation method and application thereof

Abstract: The invention discloses a macromolecular separation film as well as a preparation method and application thereof. The macromolecular separation film comprises a continuous phase of a polymer with a micropore structure, wherein the polymer comprises a microporous polymer and a dispersion phase containing inorganic materials; the microporous polymer comprises PIM-1 and/or PIM-1 derivatives. The preparation method comprises the following steps of uniformly mixing the microporous polymer and the inorganic materials into a solvent to obtain a blended solution; coating the blended solution onto a polymer support layer to obtain a macromolecular separation film. The composite gas separation film maintains good mechanical performance, thermal stability and processing performance of the polymer materials and good gas selection performance of inorganic materials, and has the advantages of high seepage performance and high selectivity during mixed gas separation, particularly oxygen gas and nitrogen gas separation; the preparation method is simple; the method is suitable for scaled industrial production; the potential application prospects are realized in the aspects of rich-oxygen, namely oxygen gas enriching application.

Cuprous oxide nanoparticle preparation method

Abstract: The invention belongs to the technical field of preparation of nanometer materials, and particularly relates to a cuprous oxide nanoparticle preparation method, which comprises: selecting a superhydrophobic electric-conduction substrate; preparing a deposition liquid, wherein a water-soluble copper salt and a water-soluble complexing salt are dissolved, the pH value is adjusted to a neutral pH value, and a molar ratio of the copper ions in the water-soluble copper salt to the anion in the water-soluble complexing salt is 1:5-1:30; and carrying out constant current deposition, wherein the superhydrophobic electric-conduction substrate is immersed into the deposition liquid, and constant current deposition is performed at a current density of -0.5 to -0.1 mA/cm by using the superhydrophobic electric-conduction substrate as a working electrode to obtain the cuprous oxide nanoparticles. According to the present invention, the superhydrophobic electric-conduction substrate as the workingelectrode, and the immersing characteristic of the superhydrophobic electric-conduction substrate is utilized, such that the completely-new simple environment-friendly cuprous oxide nanoparticle preparation method is provided, has characteristics of simple process and easy control, can avoid the disadvantage of electrodeposition or involving toxic substances in the strong alkali environment in the prior art, and can easily achieve the environmentally-friendly low-cost large-scale production.