Foam is essential in the flotation process. However, the gas–liquid–solid three-phase froth produced in the flotation process has very strong stability and is difficult to burst spontaneously. The existence of these froths will reduce the transport capacity of the pulp and affect the working efficiency of subsequent processes, such as filtration of the flotation concentrate. In this study, a new defoaming device is designed by combining mechanical impact with depressurized defoaming and its defoaming mechanism is analyzed theoretically. In addition, the liquid level height and pulp overflow method are applied to characterize the defoaming efficiency of the new defoaming device. The effects of impeller structure, pressure drop, impeller rotation frequency, and aeration rate on defoaming efficiency were studied. The results show that when increasing the pressure drop, the defoaming increases, but it will also enhance the generation of bubbles. The efficiency of combined mechanical–vacuum defoaming technology is superior under low-pressure drop using an SC impeller. Under −1 kpa vacuum condition, it only takes 168 s to eliminate 20 cm flotation froth height with combined mechanical impact, while it takes 453 s under ambient pressure, indicating that under vacuum conditions, the mechanical-defoaming method can significantly improve the defoaming efficiency, and the two have a certain synergistic effect.

We prepared Ag2NCN/Ti3C2Tx by an electrostatically driven self-assembly process with excellent performance of Rh B degradation. The superior visible light absorption and Schottky junction, are responsible for the improved photocatalytic performance.

MXenes (Ti3C2Tx) have gotten a lot of interest since their discovery in 2011 because of their distinctive two-dimensional layered structure, high conductivity, and rich surface functional groups. According to the findings, MXenes (Ti3C2Tx) may block photogenerated electron-hole recombination in the photocatalytic system and offer many activation reaction sites, enhancing the photocatalytic performance and demonstrating tremendous promise in the field of photocatalysis. This review discusses current Ti3C2Tx-based photocatalyst preparation techniques, such as ultrasonic mixing, electrostatic self-assembly, hydrothermal preparation, and calcination techniques. We also summarised the advancements in photocatalytic CO2 reduction, photocatalytic nitrogen fixation, photocatalytic hydrogen evolution, and Ti3C2Tx-based photocatalysts in photocatalytic degradation of pollutants. Lastly, the challenges and prospects of Ti3C2Tx in photocatalysis are discussed based on the practical application of Ti3C2Tx.

In this work, graphene oxide@Fe3O4 (GO@Fe3O4) two-dimensional magnetically oriented nanocomposites were prepared through the co-precipitation approach using graphene oxide as the carrier and FeCl3·6H2O and FeSO4·7H2O as iron sources. The samples were characterized and tested by X-ray diffraction, a transmission electron microscope, Fourier-transform infrared spectroscopy, a vibrating-specimen magnetometer, a polarized optical microscope, an optical microscope, etc. The effects of material ratios and reaction conditions on the coating effects of Fe3O4 on the GO surface were investigated. The stable GO@Fe3O4 sol system was studied and constructed, and the optical properties of the GO@Fe3O4 sol were revealed. The results demonstrated the GO@Fe3O4 two-dimensional nanocomposites uniformly coated with Fe3O4 nanoparticles were successfully prepared. The GO@Fe3O4 two-dimensional nanocomposites exhibited superparamagnetic properties at room temperature, whose coercive force was 0. The stable GO@Fe3O4 sol system could be obtained by maintaining 1 < pH < 1.5. The GO@Fe3O4 sol showed magneto-orientation properties, liquid crystalline properties, and photonic crystal properties under the influence of the external magnetic field. The strength and direction of the magnetic field and the solid content of the GO@ Fe3O4 sol could regulate the aforementioned properties. The results suggest that GO@Fe3O4 two-dimensional magnetically oriented nanocomposites have potential applications in photonic switches, gas barriers, and display devices.