Frontiers in Microbiology
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2022
·
IF 6.064
Zheng Fengzhen,Basit Abdul,Zhuang Huan,Chen Jun,Zhang Jianfen,Chen Weiqing
Acidophilic β-xylanases have attracted considerable attention due to their excellent activity under extreme acidic environments and potential industrial utilizations. In this study, a novel β-xylanase gene (Xyl11) of glycoside hydrolase family 11, was cloned from Trichoderma asperellum ND-1 and efficiently expressed in Pichia pastoris (a 2.0-fold increase). Xyl11 displayed a maximum activity of 121.99 U/ml at pH 3.0 and 50°C, and exhibited strict substrate specificity toward beechwood xylan (Km = 9.06 mg/ml, Vmax = 608.65 μmol/min/mg). The Xyl11 retained over 80% activity at pH 2.0–5.0 after pretreatment at 4°C for 1 h. Analysis of the hydrolytic pattern revealed that Xyl11 could rapidly convert xylan to xylobiose via hydrolysis activity as well as transglycosylation. Moreover, the results of site-directed mutagenesis suggested that the Xyl11 residues, Glu127, Glu164, and Glu216, are essential catalytic sites, with Asp138 having an auxiliary function. Additionally, a high degree of synergy (15.02) was observed when Xyl11 was used in association with commercial β-xylosidase. This study provided a novel acidophilic β-xylanase that exhibits excellent characteristics and can, therefore, be considered a suitable candidate for extensive applications, especially in food and animal feed industries.
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MINERALS ENGINEERING
·
2022
·
IF 5.479
Lu Xing,Xifei Ma,Kaibo Hu,Hanmeng Yuan,Jia Wei,Hongshuai Gao,Yi Nie
Since neodymium (Nd) has similar physicochemical properties to lanthanum (La), cerium (Ce) and praseodymium (Pr), their efficient separation and purification is very difficult. Three new phosphate-based ionic liquids (ILs): N,N-dimethyloctylamine bis(2-ethylhexyl)phosphate ([N 1,1,8,H ][DEHP]), N,N-dimethyldecylamine bis(2-ethylhexyl)phosphate ([N 1,1,10,H ][DEHP]), N,N-dimethyldodecylamine bis(2-ethylhexyl)phosphate ([N 1,1,12,H ][DEHP]) were synthesized and evaluated for selective separation of Nd(III) from aqueous solution. The influences concentration of Nd(III), phase volume ratio (O/A), cation chain length of ILs, extraction time, extraction temperature, salt concentration, solution acidity have on the performance of ILs for extraction separation of Nd(III) from aqueous solution were systematically investigated. It was found that the extraction efficiency ( E ) of Nd(III) using [N 1,1,8,H ][DEHP] was close to 100% at pH of 4, and that it only required 10 min to reach extraction equilibrium at 303 K. Meanwhile, the separation factors ( β ) values of β Nd/La , β Nd/Ce , β Nd/pr using [N 1,1,8,H ][DEHP] were all higher than 3. The density functional theory (DFT) results indicated that the interaction between [N 1,1,8,H ][DEHP] and Nd were stronger than that between La , Ce and Pr . In addition, almost 100% of Nd(III) could be recycled from the loaded [N 1,1,8,H ][DEHP] phase using 0.16 mol·L −1 hydrochloric acid via one step, and the E of Nd(III) by regenerated [N 1,1,8,H ][DEHP] remained about 97% after eight cycles. Moreover, the extraction mechanism of Nd(III) using [N 1,1,8,H ][DEHP] was complexation mechanism based on infrared spectroscopy and slope analysis. This work furnishes a strategy for selective separation of Nd(III) using phosphate-based ILs without diluent.
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JOURNAL OF CHEMICAL SCIENCES
·
2022
·Vol. 134
·期 3
·1-11
·
IF 2.15
LIU XIAOJUAN,LI MINGMING,YANG SHUMING,YANG YAYA,NIE JIANG,XUE YUBING,OUYANG YINGGEN,XIAO SONGTAO
The increasing demand for neodymium (III) and samarium (III) due to their extensive high-tech applications has drawn much attention to their recovery. In this work, the copper-based metal-organic framework HKUST-1 was prepared and used for the adsorption of neodymium (III) and samarium (III) in the media of an aqueous solution. The maximum adsorption capacity of the material for neodymium (III) and samarium (III) was 284.11 and 503.45 mg g −1 at a pH of 5.5, respectively. The adsorption removal rate could achieve nearly 100% at the solid-to-liquid ratio of 1.0 g L −1 , which is relatively excellent among such adsorbents used for rare earth elements uptake. The mechanism and reversibility of neodymium (III) and samarium (III) adsorption were systematically investigated by X-ray diffraction, Fourier transforms infrared spectroscopy, Raman spectra, and X-ray photoelectron spectroscopy, suggesting that the mechanism for the adsorption was ion exchange and complexation between trivalent rare-earth ions and the oxygen atom in the hydroxyl group. The reason behind the material displaying a more robust affinity for samarium (III) may be caused by the energy difference between f n and f n+1 states of samarium (III) was larger than that of neodymium (III), thus forming stronger covalent bonding. Graphical abstract HKUST-1 exhibited high adsorption capacity towards Nd (III) and Sm (III). The reason behind the material displaying a more robust affinity for Sm(III) was caused by that the energy difference between f n and f n+1 states of Sm(III) was larger than that of Nd(III), thus forming stronger covalent bonding.
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PHILOSOPHICAL MAGAZINE
·
2022
·
IF 1.948
Ailian Zhu,Yupeng Xie,Keyou Shi,Min Chen,Jiawei Li,Yimin Zhou,Gaiyuan Chen,Yong Liu
Coal fly ash (hereinafter CFA) was employed to rapidly immobilise Nd-contaminated soil with the addition of TiO2 via microwave sintering technology. The effect of TiO2 doping on the phase composition, microstructure, elemental distribution, density, and chemical durability of the solidified samples was systemically investigated. The results indicated that the Nd element can be incorporated in the matrix with oxyapatite and pyrochlore as TiO2 content increased at 1200°C. Moreover, the sintered sample with the high bulk density and low open porosity was fabricated at a TiO2-doping amount of 7 wt.%. Meanwhile, the as-prepared samples doping with TiO2 exhibited excellent chemical durability. Especially, the sintered sample doping with 3 wt.% TiO2 had the lowest leaching rate (7.97×10−6 g·m−2·d−1 at 28 d). Our investigation reflects that CFA is suitable for Nd-contaminated soil immobilisation via microwave sintering technology and the introduction of TiO2 is conducive to the improvement of densification and chemical durability.
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JOURNAL OF RARE EARTHS
·
2021
·
IF 3.712
Xianghua He,Ben Dai,Yafang Zhang,Dan Zhao,Dihui Zhang,Ruping Liang,Chao Chen
Efficient and applicable catalysts are highly desirable for advanced biomass transformation industry, here, we fabricated a series of Nd-Co-P catalysts for hydrogenation of furfural (FAL) to furfuryl alcohol (FOH). By comprehensive characterizations, it is demonstrated that the prepared Nd-Co-P samples are structured as (NdPO 4 ) m /Co 2 P nanocomposites with molar ratio ( m ) in range of 0.24–1.1; by manipulating m , the outstanding catalytic efficiency comparable with the performance of precious metal catalysts , such as turnover frequency (TOF) up to 0.50 s −1 (being ten-fold higher than Co 2 P) and FOH yield up to 97%, is achieved on the reusable (NdPO 4 ) m /Co 2 P composites. Temperature programmed desorption (TPD), in-situ infrared spectroscopy (IR) and kinetic-mechanism studies further disclose that Co 2 P is decisive for activating FAL, instead, NdPO 4 possesses unique capability of activating hydrogen which readily facilitate the selective hydrogenation of FAL to FOH through a rapid Langmuir–Hinshelwood process over (NdPO 4 ) m /Co 2 P catalyst. These results indicate that rare-earth phosphates like NdPO 4 can act as the promising and reliable catalytic component to activate hydrogen, which can be of interest not only for innovating novel and applicable non-metallic catalysts for sustainable biomass transformation analogous to hydrogenation of FAL, but also for expanding material base for other green mass transformation techniques involving hydrogen.
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CRYSTAL GROWTH & DESIGN
·
2025
·
IF 3.4
Yun Lv,Yanhong Wang,Yaling Dou,Ang Li,Jinkui Tang,Olga S. Volkova,Alexander N. Vasiliev,Hongcheng Lu
We report the synthesis and magnetic properties of three rare-earth magnetic compounds RE2O2CN2 (RE = Nd, Dy, Gd) with a frustrated triangular spin–lattice, as well as their thermal stability and Fourier transform infrared (FTIR) spectroscopy. The magnetic susceptibility results show paramagnetic behavior with no long-range order (LRO) down to 2 K in Nd2O2CN2 and Dy2O2CN2 due to spin frustration, which are further confirmed by the specific heat measurements, despite the large Curie–Weiss temperature for strong intralayer interaction through the RE–O–RE pathway (RE = Nd, Dy). While Gd2O2CN2 with a large spin exhibits LRO at 2.7 K, which should be caused by the non-negligible interlayer interactions. The field-dependent magnetization curves show a linear increase up to 7 T for Nd2O2CN2 and Gd2O2CN2, which are far from their saturation. While the magnetization of Dy2O2CN2 increases linearly below 3 T, then slowly increases to saturation, and the magnetization value is 6.62 μB at 7 T. Our work provides promising magnetic triangular lattice systems to further investigate frustration and quantum magnetism in rare-earth magnetic systems.
研究领域:
凝聚态物理
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材料化学
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磁性与磁性材料
·
量子材料
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Yaozu Guo,Junhua You,Wenli Pei,Yingdong Qu,Dong Zhao,Zhengwen Yang
This paper reports a novel chemical method to synthesize Nd-Fe-B magnetic nanoparticles . The fabrication mechanism of the particles have been studied through understanding formation of the corresponding intermediate phases as well as their microstructures after annealing and reduction-diffusion processes as function of the (C 2 H 5 ) 3 NBH 3 content. Nd-Fe-B intermediate phases were composed of small Fe 3 O 4 particles and Nd and Fe microcrystals encapsulated with nitriles . Fe 3 O 4 was reduced by BH 3 − into α-Fe as the (C 2 H 5 ) 3 NBH 3 content increased. After annealing, Nd-Fe-B oxide particles gradually agglomerated as the (C 2 H 5 ) 3 NBH 3 content increased, which affected the particle sizes after the reduction-diffusion step. Mixture of Nd 2 Fe 14 B and H 5 Nd 2 was obtained from precursors synthesized with 1.5 and 2.5 mmol of (C 2 H 5 ) 3 NBH 3 . Magnetic properties of these mixtures demonstrated soft magnetic phase characteristics. Relatively pure Nd 2 Fe 14 B nanoparticles with a coercivity of 5.09 kOe and magnetic energy product (BH max ) of 2.862 MGOe were obtained when (C 2 H 5 ) 3 NBH 3 initial content was 3.5 mmol. Exchange coupling nanoparticles of Nd 2 Fe 14 B, Fe 3 B and Fe 2 B were obtained with the coercivity of 3.787 kOe and (BH) max equal to 4.871 MGOe at (C 2 H 5 ) 3 NBH 3 content of 4.5 mmol.
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CRYSTENGCOMM
·
2022
·Vol. 25
·期 1
·95-107
·
IF 3.756
Lei Wang,Xudong Liu,Jinsheng Li,Mu Zhang,Xiaoguo Bi,Zhixin Ma,Jialin Chen,Xudong Sun
High-performance dielectric materials are essential components of electronic devices. In this work, RE-doped SrTiO3 (RE = La, Nd, Yb) single crystals with excellent dielectric properties were prepared by the Verneuil method. For La-STO and Nd-STO, the RE ions are substituted for Sr2+ only, and the excellent dielectric properties are mainly caused by defect dipoles associated with oxygen vacancies including and defect dipole clusters. For Yb-STO, Yb3+ partially replaces Ti4+, forming an additional defect dipole , resulting in the best dielectric properties (ε′ = 3.6 × 104, tan δ = 0.0036 under 1 kHz). In addition, N2 atmosphere treatment promotes the production of oxygen vacancies and Ti3+ and the formation of more defect dipoles, thus further optimizing the dielectric properties of Yb-STO (ε′ = 4.9 × 104, tan δ = 0.004 under 1 kHz). This work suggests that the dielectric properties of RE-doped SrTiO3 materials are closely related to oxygen vacancies, and the simultaneous substitution of Sr2+ and Ti4+ should enable obtaining dielectric properties superior to those of the substitution of Sr2+ only. The present work provides a clearer understanding of the origin of SrTiO3 dielectric properties, which is of great significance to the development of SrTiO3-based dielectric materials.
研究领域:
材料科学
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凝聚态物理
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电子器件
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PROGRESS IN ORGANIC COATINGS
·
2026
·
IF 7.9
Han Yu,Ying Wang,Zhen Shi,Chenxi Fang,Hang Zeng,Junting Sun,Vilko Mandić,Xuefeng Zhang
Although superhydrophobic coatings have been widely employed for corrosion protection due to their low surface energy, their low surface energy characteristic also results in weak interfacial adhesion and the influence of interfacial adhesion on the overall anti-corrosion performance remains poorly understood. Herein, we explored the corrosion resistance of superhydrophobic coatings on sintered Nd-Fe-B magnets from the perspective of work of adhesion (Wₐ), which represented the interfacial stability and bonding strength. By precisely controlling the PDA shell thickness and the degree of hydrophobization, the work of adhesion can be regulated correspondingly. The results revealed that the overall anti-corrosion performance of superhydrophobic coatings was directly proportional to the work of adhesion. At an optimized Wₐ of 49.44 mN·m -1 , the coated magnet exhibited a low corrosion current density of 1.09 × 10 −8 A/cm 2 , which was three orders of magnitude lower than that of 3.27 × 10 −5 A/cm 2 for bare Nd-Fe-B magnet. Moreover, outstanding protection durability was also demonstrated in both acidic and alkaline environments with robust interfacial contact. In contrast, weak adhesion induced the formation of interfacial gaps, which served as preferred penetration pathways for the corrosive medium. This study evidenced the importance of interfacial structural integrity, revealing the critical role of adhesion layer design in enabling robust and durable anti-corrosion performance of superhydrophobic coatings.
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ELECTROCHIMICA ACTA
·
2026
·
IF 5.8
Kaung Khant Kyaw,Tao Jiang,Heng Cao,Zhaoyang Leng,Hajra Baig,Waris Ghani,Youqi Zhu,Chuanbao Cao,Meishuai Zou
Lattice contraction increases defect oxygen species and modifies surface transition-metal redox states. • HEP-Nd-0.3 achieves a bifunctional potential gap ΔE = 0.77 V with OER overpotential of 290 mV and ORR half-wave potential of 0.75 V. • Zn-air battery delivers 115 mW cm⁻² peak power density and stable operation for over 340 h. • A-site lattice modulation alone enhances intrinsic OER/ORR activity without aliovalent doping. Rechargeable zinc–air batteries require bifunctional air-cathode catalysts capable of efficiently catalyzing both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, La 1-x Nd x (Cr 0.2 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 ) O 3 (x = 0, 0.1, 0.2, and 0.3) high-entropy perovskites (HEP) were synthesized to examine the influence of isovalent Nd³⁺ substitution at the A site on bifunctional oxygen electrocatalysis. Replacement of La³⁺ with smaller Nd³⁺ preserves the nominal A-site charge while inducing lattice contraction and modifying the surface chemical environment of the multication perovskite. Among the investigated compositions, HEP-Nd-0.3 exhibits the best bifunctional activity, delivering an OER overpotential of 290 mV at 10 mA cm −2 , an ORR half-wave potential of 0.75 V versus RHE, and a bifunctional potential gap of 0.77 V. When used as the air-cathode catalyst in a rechargeable zinc–air battery, HEP-Nd-0.3 achieves a peak power density of 115 mW cm −2 and stable charge–discharge operation for >340 h. The enhanced performance is associated with Nd-content-dependent variations in lattice structure, surface oxygen chemistry, electrochemically accessible surface area, and charge-transfer characteristics. These results identify isovalent rare-earth A-site substitution as a practical strategy for tuning high-entropy perovskite oxygen electrocatalysts. Download: Download high-res image (313KB) Download: Download full-size image
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhongyan Luo,Jukka Kuva,Jan Luyten,Risto Koivula,Małgorzata Szlachta,Hongli Bao,Junhua Xu
The increasing demand for Co, Nd, and Dy, particularly in neodymium iron boron (NdFeB) magnets, has heightened concerns over their supply risks. Developing efficient, environmentally friendly methods to recover Co, Nd, and Dy from spent NdFeB magnets is therefore critical. This study presents the synthesis of two types of crystalline zirconium phosphate (ZrP) encapsulated in polyacrylonitrile (PAN) composite beads. The structure, morphology, and chemical properties were analyzed using X-ray diffraction (XRD), thermogravimetry (TG), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray computed tomography (XCT), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and 31 P nuclear magnetic resonance (NMR). The intercalation of dimethylformamide (DMF) enlarged the interlayer spacing of α-ZrP and γ-ZrP, thereby enhancing their ion exchange properties. Batch sorption experiments revealed that α-ZrP/PAN outperformed γ-ZrP/PAN in both sorption and separation efficiency. α-ZrP/PAN beads exhibited high selectivity for Nd 3 + and Dy 3 + , with minimal Co 2 + sorption (8.57 %). Stepwise elution studies on α-ZrP/PAN demonstrated the obtained metal purities to be ∼100 wt% for Co, 64.1 wt% for Nd, and 96.5 wt% for Dy. Sorbent regeneration was investigated over ten sorption–desorption cycles, which revealed that α-ZrP/PAN retained 72.72 % of its sorption capacity, demonstrating excellent reusability and stability, while γ-ZrP/PAN’s capacity declined to 68.95 % after five cycles. The ion-exchange reaction accompanied by shrinking of the interlayer space was illustrated by combining the batch sorption experiments, column operations, and analyses from XRD, FT-IR, and X-ray photoelectron spectroscopy (XPS). Overall, α-ZrP/PAN shows promise for Co, Nd, and Dy separation from NdFeB magnets, although further optimization of sorbents and elution agents is necessary.
研究领域:
材料科学
·
环境工程
·
化学工程
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Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 6
·966-978
·
IF 4.776
Pei Wang,Pan Xiong,Jing Liu,Shuang Gao,Tingfei Xi,Yan Cheng
Magnesium (Mg) alloys have been intensively investigated as potential absorbable coronary stent materials as their use avoids risks such as late inflammation and restenosis generated by permanent metallic implants. Besides that, clinical trials on coronary stents fabricated from Mg alloys have made great progress recently. However, the over-rapid corrosion rate, magnesium corrosion-induced thrombosis formation and delayed endothelium regeneration continue to be problematic for coronary artery stent therapy. In this study, silk fibroin blended with heparin and GREDVY (Gly-Arg-Glu-Asp-Val-Tyr) peptide was immobilized on a HF-pretreated MgZnYNd alloy surface via a polydopamine layer to improve its corrosion resistance, blood compatibility and endothelialization. Standard electrochemical measurements along with the long-term immersion results indicated that the functionalized MgZnYNd alloy had preferable anti-corrosion abilities compared with the bare MgZnYNd alloy. The modified surface exhibited outstanding hemocompatibility with reduced platelet adhesion, hemolysis rate and prolonged blood coagulation time. Human umbilical vein endothelial cell (HUVEC) and vascular smooth muscle cell (VSMC) co-culture results revealed more attached HUVECs on the functionalized samples than on the MgZnYNd alloy surfaces. The excellent corrosion retardation, hemocompatibility and re-endothelialization of the multi-functional coating indicate a promising method in the field of biodegradable magnesium-based implantable cardiovascular stents.
研究领域:
生物医学工程
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材料科学
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心血管疾病研究
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高影响因子
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