Hydrogen assisted magnesiothermic reduction (HAMR) of TiO 2 is a promising new process developed recently to produce Ti metal with low cost and less energy consumption. This work focuses on the understanding and optimization of the reduction process to control the quality of the reduced product. TiO 2 precursor particles with different relative densities were prepared, and the effects of the relative densities on reduction by Mg in H 2 were studied. The changes of oxygen contents vs. reduction time at various temperatures were investigated. The phase transformations during the reduction were analyzed both theoretically and experimentally. The relationship between the morphology of the reduced products and the relative densities of the TiO 2 precursors was analyzed by SEM characterization and the likely reason for the morphology evolution was discussed.
Hamidreza Abadikhah,Ehsan Naderi Kalali,Shabnam Behzadi,Sayed Ali Khan,Xin Xu,Marjan E. Shabestari,Simeon Agathopoulos
In this paper, graphene oxide based nanohybrids decorated with TiO 2 nanoparticles (TiO 2 @rGO) were synthesized and incorporated into the thin film nanocomposite (TFN) membrane for efficient organic solvent nanofiltration (OSN) with antifouling properties. In order to improve the compatibility of TiO 2 @rGO in the polyamide active layer, the nanohybrids were amino-functionalized before their incorporation in the interfacial polymerization process. TiO 2 @rGO incorporated TFN membranes showed intense permeability increment and antifouling characteristics in comparison with the controlled composite membrane and graphene oxide (GO) incorporated TFN membrane. The GO nanosheets structure favors solvent channeling and TiO 2 provides super hydrophilic characteristics, both resulted in a super permeable-hydrophilic OSN membrane with high structural stability and premium antifouling properties.
Gang Chen,Si Ouyang,Yiqing Deng,Mengxiao Chen,Yanqing Zhao,Wangcai Zou,Qiang Zhao
UV curable waterborne polyurethane acrylate (WPUA) with surfactant-modified TiO2/reduced graphene oxide (TiO2/rGO) nanocomposites were prepared and analyzed to improve their mechanical performance and self-cleaning ability. TiO2/rGO nanocomposites were prepared by a simple hydrothermal method with nano-TiO2 and graphene oxide, and modified with cationic surfactant (CTAB) to obtain a cationic TiO2/rGO (C-TiO2/rGO). Then, the obtained C-TiO2/rGO was incorporated into anionic waterborne polyurethane acrylate by in situ fabrication to obtain a composite emulsion (C-TiO2/rGO-WPUA). The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) showed that CTAB was successfully intercalated into TiO2/rGO, and TiO2 nanoparticles were evenly distributed on graphene sheets with good dispersibility. Compared to UV-cured neat WPUA and C-TiO2/rGO-WPUA, the mechanical properties and thermal stability of the composites were significantly improved. When the content of C-TiO2/rGO was 0.5%, the UV-cured composites had overall excellent performance. In particular, the WPUA composites exhibited good self-cleaning ability in photocatalysis. The photocatalytic degradation rate of methyl orange in 0.5% C-TiO2/rGO-WPUA reached 88.3% under 6 h visible light irradiation.
Yonghui Yang,Hengwei Yan,Zhanwei Liu,Shenghui Guo,Wenhui Ma,Mingyi Hu,Rui Xia,Wenrong Wang
This study explores a CaO-regulated thermal–electrochemical synergistic reduction approach for TiO 2 in fluoride-based molten salts, aiming to enhance deoxygenation efficiency and particle densification. At elevated temperatures, CaO reacts with TiO 2 and the NaF–K 2 TiF 6 molten salt to form CaF 2 and reactive intermediate phases, which facilitate the in situ generation of metallic Ca and alter the local redox environment. These transformations promote the complete electrochemical reduction of TiO 2 into metallic titanium through the formation and subsequent reduction of titanium oxyfluoride complexes such as K 2 NaTiOF 5 and TiOF 2 . Cyclic voltammetry reveals that CaO addition induces a negative shift in the Ti(IV)/Ti(III) redox potential, suggesting a modified reduction pathway and increased activation energy. The titanium powders synthesized at 890 °C with current densities ranging from 2.0 to 3.5 A/cm 2 exhibit reduced oxygen content down to 2900 ppm and a dense, near-spherical morphology. Microstructural analyses using FIB–SEM and EDS confirm that CaO incorporation suppresses surface oxidation and promotes particle uniformity. These findings provide mechanistic insight into the synergistic role of CaO in titanium deoxygenation and demonstrate its potential in reducing the oxygen content of titanium powders and improving their compositional uniformity.
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