Monodisperse ZrO2 ceramic beads with size larger than 1 mm have been prepared by an improved micro-droplet spray forming process, through which a compressor and a dispenser were employed to produce droplets continuously. Furthermore, the slurry recipe and drying temperature have been optimized to enhance the sphericity and smoothness of the beads. The sintered ZrO2 ceramic beads present promising mechanical performance, including a relative density of 84.6%, a crush strength of 256.2 +/- 36.6 N as well as a Vickers hardness of 1344.4 +/- 58.3 HV. Such procedure reveals great potential in mass production of ceramic beads.

Zirconia microspheres with high sphericity and hardness were successfully massively produced through a cost-effective spray granulation method by using an optimized slurry with high solid content and low viscosity which was formulated with a mixed dispersant. The influence of slurry solid content, binder addition as well as drying temperature on the shape and size of the sintered microspheres were studied. Furthermore, the formation mechanism of different granulated particles was analyzed based on the illustrated migration processes in the ZrO2 droplets with different contents of water and additives. Under the optimized conditions, the sintered ZrO2 spheres with tetragonal phase exhibit high sphericity with highest nano-hardness of 9.5 GPa, indicating it is possible to be used in the engineering fields. Such spray granulation method could directly serve for the industrial production of zirconia and other ceramic materials since it is a stable process with high yield, good granulating quality and strong controllability. (C) 2021 Elsevier B.V. All rights reserved.

Novel amino-modified rice bran biochar/MgFeAlO4 (RB@MgFeAlO4-NH2) magnetic composites were synthesized via a simple one-step solvothermal approach and applied for removing toxic Ni(II) from wastewater. The elimination process and sorption performance of Ni(II) on RB@MgFeAlO4-NH2 were analyzed by combining batch experiments and spectral techniques. The sorption isotherms and kinetic data indicated that Ni(II) sorption on RB@MgFeAlO4-NH2 was monolayer and rapid. The experimental results confirmed that the obtained RB@MgFeAlO4-NH2 magnetic composite had high sorption capacity for Ni(II). The maximum sorption capacity of Ni(II) on RB@MgFeAlO4-NH2 was 201.62 mg g-1. The researches based on the sorption mechanism showed that the ion exchange mechanism accounted for 76.51% of Ni(II) sorption. In addition, the amino, carboxyl and hydroxyl functional groups were also involved in the complexation with Ni(II). In view of its multiple advantages of environmental friendliness, low cost, easy magnetic separation and high sorption capacity, RB@MgFeAlO4-NH2 will be an excellent adsorbent for low-cost and efficient elimination of Ni(II) from aqueous solutions.

The successfully prepared 3D-birdnest-shaped MnO2had a hollow structure and a large amount of free space among nanotubes, which was more favorable for other substances to attach on it. Due to its special structure, we prepared the LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]AlxO2([Formula: see text], 0.01, 0.03, 0.05, 0.08) in a simple way by employing 3D-birdnest-shaped MnO2, and revealed the influence of Al[Formula: see text]-doped in LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2. And the sample of LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]O2had outstanding electrochemical properties; when a small amount of Al[Formula: see text] ([Formula: see text]) was doped into the material, the cyclic performance of the material was improved significantly (90.9% capacity retention after 100 cycle), and the capacity of the LiNi[Formula: see text]Co[Formula: see text]Mn[Formula: see text]AlxO2reached 186.2[Formula: see text]mAh[Formula: see text]g[Formula: see text]. Our results provided the underlying insights needed to guide the design of cathode materials.

Hollow TiO2 microspheres are designed from an Ostwald ripening process, then as-synthesized hollow TiO2 spheres are used as a template to synthesize Li4Ti5O12 via a simple hydrothermal synthesis method. Such microspheres display good electrochemical performance, including high capacity, excellent cyclic stability and remarkable rate capability. The hollow Li4Ti5O12 microspheres calcined at 700 degrees C display extremely good electrochemical performance, including high capacity (174.6 mAh/g at 1C rate), excellent cyclic stability (97.7% capacity retention after 50 cycles at 1C rate) and remarkable rate capability (140.3 mAh/g at 15 C-rate).