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Efficient and facile generation of tiny droplets is critical to many cutting-edge applications, such as flexible electronic skin, customized circuits, and micro-electro-mechanical systems. However, conventional piezoelectric inkjet printing techniques show more prominent problems of high driving voltage and relatively low printing frequency. Here, a novel principle for high-throughput droplet dispensing was proposed based on the resonance of the liquid column within the glass capillary. The mechanisms of this high-throughput piezoelectric droplet dispensing technique were studied both experimentally and theoretically. It is demonstrated experimentally that the resonance frequencies of different orders of the liquid column in the capillary fit perfectly with the theoretical value. It is further demonstrated that when the working frequency is close to the resonant frequency of piezoelectric ceramic, droplets can be ejected out by a driving voltage as low as 1 V. This ultra-low driving voltage and power consumption make this dispenser compatible with various digital transistor–transistor logic or complementary metal–oxide–semiconductor drive circuits without any power amplifier. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are novel pollutants, which can carry toxic contaminants and are released in biota and accumulate. The adsorption behavior of MPs and aged MPs has attracted extensive attention. In this paper, the aging process of polystyrene (PS) and poly (butyleneadipate-co-terephthalate) (PBAT) plastics under ultraviolet (UV) irradiation at a high temperature and their adsorption properties for the contaminant diclofenac sodium (DCF) before and after aging was investigated. There are many factors affecting the adsorption capacity of MPs. In this experiment, three aspects of MPs, organic pollutants, and environmental factors are explored. The Freundlich model as well as the pseudosecondary kinetic model is more applicable to the process of DCF adsorption by MPs. The main effects of adsorption of organic pollutants by MPs are electrostatic interactions, hydrogen-halogen bonds, and hydrophobic interactions. The adsorption capacity of the UV-aged MPs on DCF is significantly enhanced, and the order of adsorption capacity is Q(A-PBAT) (27.65 mg/g) > Q (A-PS) (23.91 mg/g) > Q (PBAT) (9.30 mg/g) > Q (PS) (9.21 mg/g). The results show that more active sites are generated on the surface of MPs after aging, which can enhance their adsorption capacity for organic pollutants. This adsorption mechanism will increase their role as contaminant carriers in the aquatic food chain. [ABSTRACT FROM AUTHOR]

A Cu-based catalyst has been widely used in ethynylation of formaldehyde for synthesis of 1,4-butynediol. Herein, bismuth, magnesium, and manganese species were separately doped into Cu-based catalysts by a co-precipitation method and applied in ethynylation reaction. All catalysts were characterized through X-ray diffraction (XRD), Transmission electron microscope (TEM), H2 temperature-programmed reduction (H2-TPR), scanning electron microscopy (SEM) and elements mapping, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results show that Mn-doped Cu-based catalysts exhibit the best yield of 1,4-butynediol (65%). It is mainly due to CuO in CuO/MnOx catalysts with smaller particle size, better dispersibility and the electronic synergy between copper and manganese species. Moreover, CuO/MnOx-15 catalysts prepared by optimized conditions can further improve the yield and selectivity of 1,4-butynediol to 76% and 96% and remain selectivity of 1,4-butynediol unchanged in about 50 h, which is higher than that of the commercial catalyst (yield of 62%, selectivity of 90%). [ABSTRACT FROM AUTHOR]