Search

In pursuit of sustainable solutions for water pollution mitigation, we have successfully employed electrospinning technology to fabricate a multilayered sodium alginate (SA)/polyethyleneimine (PEI)/polyvinyl alcohol (PVA) nanocomposite fiber membrane, with a focus on enhancing its adsorption capacity for Cu2+ ions in wastewater. Our research underscores the potential of this novel membrane, characterized by its small diameter, high uniformity, and expansive surface area, in effectively filtering heavy metal ions. By optimizing critical electrospinning parameters such as a voltage of 19.5 KV, a collector distance of 8 cm, a specific mass ratio of SA:PEI: PVA (1:2:6), and an injection rate of 8 μL/min, we achieved a nanofiber membrane with an average diameter of 112.5 nm, exhibiting exceptional morphological characteristics and high efficiency. Notably, the membrane exhibited an adsorption capacity of over 85% for Cu2+ during initial testing, maintaining over 80% efficiency throughout four consecutive filtration cycles. This work not only advances the field of nanocomposite membranes for water purification but also contributes significantly to the broader goal of achieving environmental sustainability by mitigating the impact of heavy metal contamination in water bodies. [ABSTRACT FROM AUTHOR]

This study examines the investment behaviour of Hong Kong-based real estate firms in Mainland China. Using a sample of individual land transactions, we find that firms with higher value of growth options, as perceived in the capital market, are more likely to invest actively and further away from their home base. However, over time, Hong Kong developers tend to decrease their level of activity in Mainland China, indicating that the 'liability of foreignness' becomes a significant challenge. Our findings highlight the importance of balancing strategic expansion with the inherent risks of operating in distant emerging markets. [ABSTRACT FROM AUTHOR]

Zn-BTC (H3BTC refers to 1, 3, 5-benzoic acid) MOF was used as a self-template and a zinc source to prepare ZnS/NiS2 with a layered heterogeneous structure as a promising electrode material using cation exchange and solid-phase vulcanization processes. The synergistic effect of the two metal sulfides enhances the application of ZnS/NiS2. And the high specific surface area and abundant active sites further promote the mass/charge transfer and redox reaction kinetics. In the three-electrode system, the specific capacitance was as high as 1547 F/g at a current density of 1 A/g, along with satisfactory rate capability (1214 F/g at 6 A/g) and cycling performance. Coupled with activated carbon (AC), the prepared hybrid device (ZnS/NiS2 as the positive electrode and AC as the negative electrode) (ZnS/NiS2/AC) can be operated under a potential window of 1.6 V and provides a high energy density of 26.3 Wh/kg at a power density of 794 W/kg. Notably, the assembled ZnS/NiS2//AC showed little capacity degradation after 5000 charge/discharge cycles. [ABSTRACT FROM AUTHOR]

This study considers a market comprising two suppliers and one e‐commerce platform. The two competitive suppliers sell products to consumers through the platform. The platform can choose three selling modes: reseller, market, and mixed. Additionally, we consider two referral strategies—namely, exclusive and nonexclusive recommendations—and build a three‐party Stackelberg game model. Per the findings, the difference in the players' decision‐making results exhibits an essential relationship with the recommendation market's initial size. A counterintuitive result is that the product price is not affected by the commission rate in the market mode. This provides referential insights for platforms and suppliers. [ABSTRACT FROM AUTHOR]

To assess the alterations in soil properties resulting from the interplanting of broad-leaved tree species within coniferous forests, we conducted an investigation into soil quality in a mixed Chinese fir and broad-leaved forest, as well as in a Chinese fir pure forest (used as a control) in subtropical China. A total of 15 soil physicochemical properties were assessed across three soil depths—0–15 cm, 15–30 cm, and 30–45 cm—for the two forest types in the experimental study. Principal component analysis in conjunction with the Norm value was employed to create a minimal data set (MDS) for assessing six indicators, including bulk density (BD), total nitrogen (TN), total phosphate (TP), available potassium (AK), soil pH, and catalase (CAT). The soil quality index (SQI) was calculated for both forest types. The results demonstrated that following the interplanting of broad-leaved tree species in the Chinese fir forest, all soil physicochemical indicators were significantly improved compared to the control, and significant differences were also observed in the 0–15 cm and 15–30 cm soil layers (p < 0.05). The overall average of the SQI of the mixed forest (0.8523, 0.6636) was significantly higher than that of the control (0.4477, 0.3823) (p < 0.05) in the 0–15 cm and 15–30 cm soil layers, respectively. However, there was no significant difference in the SQI in the 30–45 cm soil layer (p > 0.05) between the two forest types. The results indicated that the SQI based on the minimal dataset (MDS) can reflect the SQI of the total dataset (TDS) when assessing soil quality in forests. Our research provides valuable scientific insights into soil science and an understanding of the relationships between soil properties, forest structure, and species composition in sustainable forest management. [ABSTRACT FROM AUTHOR]

Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) composite nanofiber membranes were prepared by electrostatic spinning, using CMC and PVA as raw materials and glutaraldehyde as a cross-linking agent. The structure, morphology, thermal stability, and filtration performance of CMC/PVA nanofiber membranes were characterized by advanced instrumental analysis methods such as scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet analysis, and energy spectrum analysis. The results show that the average fiber diameter decreases from 381 nm to 183 nm when the spinning voltage is 23 KV and the jet speed is 2 µL/min. The obtained fiber has the smallest particle size and the most uniform distribution. Infrared spectroscopy analysis confirms that the adsorption behavior of nanofiber membranes on Cu2+ and Cr6+ is chemical adsorption. The retention rates of CMC/PVA nanofiber membranes for Cu2+ and Cr6+ reached 97.2% and 98.8%, respectively. The adsorption capacities of Cu2+ and Cr6+ were 26.34 and 28.93 mg·g−1, respectively. The adsorption of heavy metal ions by nanofiber membranes can be explained by the pseudo-second-order kinetic mechanism of the chemisorption process and the Langmuir isotherm model. [ABSTRACT FROM AUTHOR]

Flexible wearable sensors show great potential for applications in wearable devices, remote health monitoring, artificial intelligence, soft robotics, and artificial skin due to their stretchability, bendability, thinness and portability, and excellent electrical properties. Hydrogels have tunable mechanical properties, excellent biocompatibility, and flexibility, making them attractive candidates for wearable flexible sensors. Among them, tremendous efforts have focused on the advancement of chitosan-based hydrogels (CS-Gels) to realize multifunctional wearable sensing by modifying hydrogel networks with additives/nanofillers/functional groups. Recently, remarkable progress has been made in flexible wearable sensors. Herein, this review summarizes recent advances in CS-Gels wearable sensors for applications such as human motion monitoring, health monitoring, human-machine interface and soft robotics. Representative synthesis methods and strategies for CS-Gels are briefly described, the problems and deficiencies of CS-Gels for wearable sensors are discussed. Finally, the possible opportunities and challenges for the future development of CS-Gels flexible wearable devices are proposed. [ABSTRACT FROM AUTHOR]

Manganese dioxide (MnO2) is a very promising catalyst material due to its unique physicochemical properties and synergistic effects with other metals or metal oxides. Especially, MnO2 was widely used to remove organic pollutants. In this paper, we summarize the phase and morphology structures of MnO2. The effects of doping and composite on the structures and catalytic properties of MnO2 materials are also compared and described. The catalytic properties of MnO2-based materials on organic pollutants (phenolic compounds, antibiotics, dyes, and pesticides) are also analyzed. In addition, we summarize the degradation mechanisms, degradation pathways, and degradation efficiency of different MnO2-based materials on organic pollutants. The development status and shortcomings of MnO2 are discussed. Its development trend of catalytic degradation of organic pollutants by manganese oxides is provided. [ABSTRACT FROM AUTHOR]

Conversion of biomass into high value-added chemicals was an effective way to solve the current problems of fossil energy depletion and global warming. 5-Hydroxymethylfurfural (HMF) was considered as one of the most important platform compounds, which could be used to prepare many high value organic compounds through oxidation, hydrogenation, and ringopening reactions. Among its derivatives, 2, 5-furandicarboxylic acid (FDCA) could be regarded as the most promising chemical, which could replace the widely used petroleum-based polyester terephthalic acid(PTA) to synthesize biodegradable polyester polyethylene furanoate(PEF). This article systematically reviewed the new processes for preparing FDCA from HMF through electrocatalytic oxidation, photocatalytic oxidation, and biocatalysis. These catalytic methods were different from traditional pyrolysis catalytic methods, which did not requiring high temperature and pressure as well as harmful solvents and expensive catalysts, and had the characteristics of high efficiency, greenness, and sustainability. However, there were still some problems, such as electrocatalysis needed special and stable electrolytes and high requirements for instruments and equipment; photocatalysis had the problems of high cost and low energy conversion rate; biocatalysis had long preparation cycles and the inhibited intermediates. By analyzing the results obtained by these methods and the existing problems, it provided feasible ideas for the efficient catalytic conversion of FDCA in the future. [ABSTRACT FROM AUTHOR]

The linkage between political turnover and policy change has attracted considerable attention, but little empirical evidence and its impacts on regional development have been provided directly. In this study, we develop a set of indicators to directly quantify the within‐city place‐based policy changes in China between 2007 and 2017, based on the spatial distribution of city governments' industrial land supply. The results show city‐chief turnovers lead to significant changes in place‐based policies. A successor city chief typically gives up some previous place‐based policies immediately after taking office and implements new policies about 1 year later. In particular, successor chiefs with stronger promotion incentives make larger policy changes, to win more points in the competition with their predecessors. We also provide evidence that the place‐based policy discontinuity caused by political turnovers generates negative economic‐development impacts. [ABSTRACT FROM AUTHOR]