JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 12
·9352-9365
·
IF 2.22
Li Cai-Xia,Yang Bin,Zhang Shan-Tao,Hong Yue-Nan,Liu Dan-Qing,Zhang Rui,Shuo Gu,Cao Wen-Wu
Lead-free Ba 0.70 Ca 0.30 TiO 3 + x mol% MnO 2 (abbreviated as BCTM x , x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 1.0 and 1.2) piezoelectric ceramics were synthesized by the solid-state reaction method. The effects of MnO 2 additives on the phase transition, microstructure, dielectric, ferroelectric, strain behaviors and piezoelectric properties are investigated. BCTM x ceramics ( x = 0–1.2) exhibit diphasic tetragonal and orthorhombic phases. The tetragonal phase is gradually suppressed by increasing x . As x increases from 0 to 1.2, the Curie temperature ( T C ) decreases monotonically from 128 to 45 °C, while the grain size, dielectric and ferroelectric properties increase and reach the maximum near x = 0.6. On the other hand, the piezoelectric coefficient ( d 33 ) and the electromechanical coupling coefficient ( k p %) decrease simultaneously, whereas the mechanical quality factor ( Q m ), bipolar and unipolar strain increase and reach the maximum values of 684, 0.28% and 0.24%, respectively, near x = 0.6. The optimum electrical performance with \(\varepsilon_{r}\) = 1323, tan \(\delta\) = 0.08, T C = 66 °C, P max = 12.2 μC/cm 2 , P r = 6.9 μC/cm 2 , E C = 13.3 kV/cm, d 33 = 116 pC/N, k p % = 0.22%, Q m = 684 and the normalized strain \(d_{33}^{*}\) = S max / E max as high as 480 pm/V were observed for x = 0.6. The high strain and Q m suggested that the MnO 2 -modified Ba 0.70 Ca 0.30 TiO 3 ceramics are promising candidate for high power applications.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Jueyu He,Hongwei Su,Guilong Yan,Li Wang,Dong Xiang,Zhenyu Li,Yuanpeng Wu,Jingyu Chen
Economic and efficient routes to achieve clean freshwater from oil-water mixtures and seawater have gained special attention to reduce the current water crisis, but still a challenge unsolved. Herein, poly (ether ether ketone) (PEEK) membrane, modified with MnO 2 layer, has been prepared by facile hydrothermal method to address this issue aforementioned. Given the existence of PEEK and underwater superoleophobicity/underoil superhydrophilicity of MnO 2 , the composite membrane exhibits strong mechanic properties (tensile stress: 110.2 MPa) and high separation efficiencies (99.9 %) for different oil–water mixtures under gravity. Additionally, our membrane could also effectively separate immiscible oil mixtures according to the dipole–dipole interaction. Furthermore, firm chemical stability against dichloromethane, N, N-Dimethylformamide, 1 M NaOH, 1 M HCl, and 1 M NaCl has been achieved. Most importantly, our membrane displays durable evaporation efficiency (2.63 kg m -2 h −1 ), high energy efficiency (85.9 %), and super salt tolerance under 1 sun irradiation, for solar-assisted seawater desalination.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Yanyi Liu,Wenhuan Yuan,Wenli Lin,Shan Yu,Lei Zhou,Qingyi Zeng,Jin Wang,Luoheng Tao,Qunwei Dai,Juan Liu
Even though uranium (U) is considered to be an essential strategic resource with vital significance to nuclear power development and climate change mitigation , U exposure to human and ecological environment has received growing concerns due to its both highly chemically toxic and radioactively hazardous property. In this study, a composite (M-BC) based on Ficus macrocarpa (banyan tree) aerial roots biochar (BC) modified by δ-MnO 2 was designed to separate U(VI) from synthetic wastewater. The results showed that the separation capacity of M-BC was 61.53 mg/g under the solid – liquid ratio of 1 g/L, which was significantly higher than that of BC (12.39 mg/g). The separation behavior of U(VI) both by BC and M-BC fitted well with Freundlich isothermal models, indicating multilayer adsorption occurring on heterogeneous surfaces. The reaction process was consistent with the pseudo-second-order kinetic model and the main rate-limiting step was particle diffusion process. It is worthy to note that the removal of U(VI) by M-BC was maintained at 94.56% even after five cycles, indicating excellent reusability and promising application potential. Multiple characterization techniques ( e.g. Scanning Electron Microscope-Energy Dispersive Spectrometer (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET) and X-ray Photoelectron Spectroscopy (XPS)) uncovered that U(VI) complexation with oxygen-containing functional groups ( e.g. O–C O and Mn–O) and cation exchange with protonated ≡MnOH were the dominant mechanisms for U(VI) removal. Application in real uranium wastewater treatment showed that 96% removal of U was achieved by M-BC and more than 92% of co-existing (potentially) toxic metals such as Tl, Co, Pb, Cu and Zn were simultaneously removed. The work verified a feasible candidate of banyan tree aerial roots biowaste based δ-MnO 2 -modified porous BC composites for efficient separation of U(VI) from uranium wastewater, which are beneficial to help address the dilemma between sustainability of nuclear power and subsequent hazard elimination.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）