No abstract

No abstract

The design of heterojunction with superior performance of light absorption and appropriate conduction band and valence band potentials is a promising approach for the applications in efficient environmental remediation and the solar energy storage. In recent years, many studies have been devoted to the applications of graphitic carbon nitride (g-CN)-based heterojunction photoactive nanomaterials under visible light irradiation due to its excellent physical, optical, and electrical properties, which inspired us to compile this review. Although many reviews demonstrated about the syntheses and applications of g-CN composites, a targeted review on the systematic application and photocatalytic mechanisms of g-CN-based heterojunction, in which components are in intimate linkage with each other rather than a physical mixture, is still absent. In this review, the applications of g-CN-based heterojunction photoactive nanomaterials in environmental remediation and solar energy storage, such as photocatalytic treatment of persistent organic pollutants, heavy-metal-ion redox, oxidative decomposition of pathogens, water splitting for H evolution, and CO reduction, are systematically discussed. In addition, some emerging applications, such as solar cells and biosensors, are also introduced. Meanwhile, a comprehensive assessment on the basis of first-principles calculations and the thermodynamics and kinetics of surface catalytic reaction for the electronic structure and photocatalytic properties of g-CN-based heterojunction are valued by this review. In the end, a brief summary and perspectives in designing practical heterojunction photoactive nanomaterials also showed the bright future of g-CN-based heterojunction. Altogether, this review systematically complements the information that previous reviews have frequently ignored and points out the future development trends of g-CN-based heterojunction, which expected to provide important references and right directions for the development and practical applications of g-CN-based heterojunction photoactive nanomaterials.

No abstract

Temperature is an important parameter during electrospinning, and virtually, all solution electrospinning processes are conducted at ambient temperature. Nanofiber diameters presumably decrease with the elevation of working fluid temperature. The present study investigated the influence of temperature variations on the formation of polymeric nanofibers during single-fluid electrospinning. The surface tension and viscosity of the fluid decreased with increasing working temperature, which led to the formation of high-quality nanofibers. However, the increase in temperature accelerated the evaporation of the solvent and thus terminated the drawing processes prematurely. A balance can be found between the positive and negative influences of temperature elevation. With polyacrylonitrile (PAN, with N,N-dimethylacetamide as the solvent) and polyvinylpyrrolidone (PVP, with ethanol as the solvent) as the polymeric models, relationships between the working temperature (T, K) and nanofiber diameter (D, nm) were established, with D = 12598.6 − 72.9T + 0.11T 2 (R = 0.9988) for PAN fibers and D = 107003.4 − 682.4T + 1.1T 2 (R = 0.9997) for PVP nanofibers. Given the fact that numerous polymers are sensitive to temperature and numerous functional ingredients exhibit temperature-dependent solubility, the present work serves as a valuable reference for creating novel functional nanoproducts by using the elevated temperature electrospinning process.

Compost and biochar, used for the remediation of soil, are seen as attractive waste management options for the increasing volume of organic wastes being produced. This paper reviews the interaction of biochar and composting and its implication for soil amendment and pollution remediation. The interaction of biochar and composting affect each other's properties. Biochar could change the physico-chemical properties, microorganisms, degradation, humification and gas emission of composting, such as the increase of nutrients, cation exchange capacity (CEC), organic matter and microbial activities. The composting could also change the physico-chemical properties and facial functional groups of biochar, such as the improvement of nutrients, CEC, functional groups and organic matter. These changes would potentially improve the efficiency of the biochar and composting for soil amendment and pollution remediation. Based on the above review, this paper also discusses the future research required in this field.

No abstract

No abstract