SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Lijun Guo,Liming Zhao,Yuling Tang,Jianfei Zhou,Bi Shi
Efficient degradation of organic contaminants by oxidative radicals remains a challenge due to invalid consumption of radicals and easy generation of secondary halogenated pollutants. In this work, an efficient and recyclable bimetallic biochar (Cr-Ti/BC) was developed through peroxydisulfate (PDS) activation via nonradical pathway for sulfamethoxazole (SMX) degradation. The Cr-Ti/BC exhibited excellent catalytic activity for 99.9 % of SMX removal with a high k obs of 0.13 min −1 , and negligible inhibitory effects were observed under various pH condition. The activation mechanisms were (i) metastable reactive intermediates (Cr-Ti/BC-PDS) formation via an interaction between Cr-Ti/BC and PDS on the active defective sites (e.g., OH/C O C, COOH, C O, nitric oxides, graphitic N, and pyridinic N), and (ii) 1 O 2 generation through electron transfer between Cr-Ti/BC-PDS intermediates and dissolved oxygen. The high reusability and strong stability of Cr-Ti/BC also verified the outstanding advantage of the Cr-Ti/BC during practical application. This study not only is the first study the catalytic performance of Cr and Ti co-doped biochar for PDS activation, but also successfully provides a promising strategy to induce a nonradical pathway for PDS activation, which is of great significance for the subsequent method design, and thus paving the path for exploiting advanced oxidation systems in practical application for organic contaminant removal toward polluted site remediation.
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JOURNAL OF CATALYSIS
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2023
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IF 7.3
Zijun Yang,Qiang Yu,Hua Wang,Qingfeng Ge,Xinli Zhu
Ketonization of propionic acid has been investigated on Lewis acidic TS-1 and Ti-Beta zeolites to understand the reaction mechanism and effects of pore topology and hydrophobicity. Characterizations showed that TS-1 and Ti-Beta (Si/Ti = 40) exhibited a similar acidity whereas TS-1 was more hydrophobic than the silanol-rich Ti-Beta. TS-1 showed higher activity, selectivity, stability and was more resistance to H 2 O than Ti-Beta. A combination of infrared spectroscopic, isotopic and kinetic studies showed that the molecularly adsorbed monodentate propionic acid is the most abundant reactive intermediate, and C-C coupling is the rate-determining step. The mechanism of ketonization of propionic acid at isolated tetrahedral Ti centers can be described by a Langmuir-Hinshelwood model. The turnover rate on TS-1-40 is ∼ 1.3 times higher than that on Ti-Beta-40, which is consistent with the lower fitted free activation energy, i.e., the energy difference between C-C coupling transition state and two co-adsorbed propionic acids at a Ti center. The slightly lower activation enthalpy on Ti-Beta-40 than TS-1-40 is over-compensated by much larger entropy penalty, due to more silanol groups and hydrogen bonded propionic acids in close proximity to the Ti center for Ti-Beta-40, which impose additional steric hindrance to bulkier C-C coupling complex at transition state and outweigh the difference of steric hindrance of pore confinement between MFI and BEA frameworks. This work provides insight into the ketonization mechanism on Lewis acidic zeolites, and indicates that moderate pore size with hydrophobic property promotes ketonization of carboxylic acid at isolated tetrahedral Ti centers confined in zeolites.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2023
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IF 9.9
Jing Li,Guo Lin,Fangguan Tan,Likang Fu,Biao Zeng,Shixing Wang,Tu Hu,Libo Zhang
In the context of industrialization and severe wastewater pollution, mercury ions pose a major threat due to their high toxicity. However, traditional adsorbents and common metal-organic framework (MOF) materials have limited effectiveness. This study focuses on combining magnetic materials with functionalized titanium-based MOF composite (SNN-MIL-125(Ti)@Fe 3 O 4 ) to improve mercury ion adsorption. Through comprehensive characterization and analysis, the adsorption performance and mechanism of the material were studied. The optimal adsorption of the material was achieved at pH 5, exhibiting a pseudo-second-order adsorption model and the Hill theoretical capacity of 668.98 mg/g. Hill and Tempkin models confirmed the presence of chemical and physical adsorption sites on the material surface. Thermodynamic experiments showed a spontaneous endothermic process. Despite the presence of interfering ions, the material exhibited high selectivity for mercury ions . After four cycles, adsorption performance decreased by only 8%, indicating excellent reusability. Nitrogen- and sulfur-containing functional groups played a key role in mercury ion adsorption. In conclusion, SNN-MIL-125(Ti)@Fe 3 O 4 , as a magnetic MOF adsorption material, showed potential for effective remediation of mercury-contaminated wastewater. This study contributes to the development of efficient adsorption materials and enhances the understanding of their mechanism.
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CRYSTAL GROWTH & DESIGN
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2023
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IF 3.8
Caiyun Liu,Huihui Niu,Dexin Wang,Yanshu Liu,Amir Said,Guo Wang,Chen-Ho Tung,Yifeng Wang
Selective oxidation utilizing sunlight and O2 is a cost-effective technique for converting organic raw materials into value-added products. We present a novel Bi-doped Ti-oxide cluster (TOC), Ti19Bi2, for the selective conversion of benzyl alcohols to benzaldehydes under sunlight irradiation. It is prepared as single crystals and precisely characterized by single-crystal X-ray diffraction. A structure–activity study is performed by combining experiments and density functional theory. Bi mainly contributes to the LUMO + 1 of Ti19Bi2, with a minor effect on the band gap energy. Bi doping causes the accumulation of photogenerated electrons at Bi sites, resulting in potent reducing power and high O2 activation ability, promoting charge separation and interfacial charge transfer. The Ti19Bi2 solar system showed good activity, selectivity, substrate scope, and catalyst recyclability in the selective oxidation of benzyl alcohols. It outperforms reference TOCs free of Bi, such as Ti8O8Bz16 (Bz = benzoate) and commercial TiO2 P25. Additionally, Ti19Bi2 is effective in photocatalytic CO2/epoxide cycloaddition and dye degradation reactions.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2022
·Vol. 414
·期 27
·7885-7895
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IF 4.478
Zhang Xiaoya,Feng Quanshou,Xie Zehu,Xu Fuxing,Yan Yinghua,Ding Chuanfan
In this work, on the basis of an immobilized metal ion affinity chromatography enrichment strategy, a new kind of covalent organic framework (COF) material for enrichment of phosphorylated peptides and exosomes was successfully prepared in a facile method, and Ti 4+ and Nb 5+ were used as dual-functional ions (denoted as COF-S–S-COOH-Ti 4+ /Nb 5+ ). With the advantage of unbiased enrichment towards phosphopeptides, COF-S–S-COOH-Ti 4+ /Nb 5+ shows ultra-high selectivity (maximum molar ratio of β -casein: BSA is 1:20,000) and low limit of detection (0.2 fmol). In addition, the material has an excellent phosphopeptide loading capacity (100 μg/mg) and reusability (at least seven times). Furthermore, applying the material to the actual sample, 4 phosphopeptides were selectively extracted from the serum of renal carcinoma patients. At the same time, exosomes with an intact structure in the serum of renal carcinoma patients were successfully isolated rapidly using this strategy. All experiments have shown that COF-S–S-COOH-Ti 4+ /Nb 5+ exhibits exciting potential in practical applications. Graphical abstract
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JOURNAL OF ALLOYS AND COMPOUNDS
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2022
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IF 6.371
Zhicheng Zhang,Chao Xu,Xudong Xiong,Chen Wang,Qi Zhang,Zhao Fan,Yongqian Wang
The application of CdS in pollutant degradation was limited due to the rapid compounding of photogenerated carriers. A ternary Au@NH 2 -MIL-125(Ti)/CdS (5Au@40NMT/CdS) composite catalyst was synthesized with a two-step method and methylene blue (MB) was used as simulate contaminants to evaluate its photocatalytic performance under simulated visible light. The compounding of NH 2 -MIL-125 and the loading of Au nanoparticles significantly enhanced the photodegradation performance of the composite catalyst. Compared with pure CdS, the ternary composite catalyst exhibited higher degradation efficiency (93.3 %) and higher degradation rate (9 times that of CdS)within 30 min, which was attributed to the high specific surface area and the synergistic effect of the three components that accelerated the carrier separation and broadened the photoresponse range. In addition, superoxide radical (·O 2 - ) was identified as the main active species in the MB degradation process by the electron spin resonance (ESR) technique. This work was expected to give a strategy for the fabrication and design of CdS/MOF composite catalysts in the field of pollutant degradation.
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International Journal of Applied Ceramic Technology
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2022
·Vol. 20
·期 1
·527-533
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IF 2.328
Mengwen Zhang,Lutong Yang,Zhaosheng Li,Binyang Jiang
Al 2 O 3 –cBN has received considerable attention in the field of ceramic cutting tools due to its high hardness, high wear resistance, and low cost, but poor interfacial bonding affects the performance of the composite. In this study, a novel hot-forging process was used to prepare high-performance Al 2 O 3 –cBN composites using Ti(C,N) as a binder. The evolution of the morphology, phase, and microstructure of the hot-forged Al 2 O 3 –Ti(C,N)–cBN composites was determined, and the mechanical properties were measured. The relative density of the composites increases significantly after hot forging, and the deformation of the composites increases with the hot-forging temperature. The highest performing Al 2 O 3 –Ti(C,N)–cBN composite was prepared by hot forging at 1600°C and has a hardness of 20 GPa, a bending strength of 647 MPa and a fracture toughness of 5.37 MPa m 1/2 , which are superior to those of a directly hot-pressed sintered composite. However, at hot-forging temperatures higher than 1700°C, Al 5 O 6 N and TiB 2 are formed in the composite. In the composite hot forged at 1800°C, serrated grain boundaries promote the strength and toughness of the composite to 877 MPa and 6.76 MPa m 1/2 , respectively. Therefore, the novel hot-forging process is expected to enhance material properties.
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Journal of Central South University
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2022
·Vol. 29
·期 6
·1811-1822
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IF 2.392
Dong Zhao-wang,Xia Yang,Guo Xue-yi,Liu Han-ning,Liu Pei-dong
Ti-6Al-4V alloy powder was prepared through a two-step reduction of a mixture of TiO 2 , V 2 O 5 and Al 2 O 3 in this study. The oxide mixture was first reduced by Mg in MgCl 2 at 750 °C in argon, where oxygen was reduced to 2.47 wt% from 40.02 wt%. The oxygen content in the final powder was eventually reduced to an extremely low level (0.055 wt%) using calcium at 900 °C in argon, and the final powder had the composition of 90.12 wt% Ti, 5.57 wt% Al, and 3.87 wt% V, which meets the standard specification of Ti-6Al-4V (ASTM F1108-09). Between the two reductions, a heat treatment step was designed to help controlling the specific surface area and particle size. The effect of the heat treatment temperature on the morphology, and composition uniformity of the powder was investigated in detail. Heat treatment above 1300 °C attributed to a dense powder with a controlled specific surface area. Thermodynamic modeling and experimental results indicated that only α -Ti enriched with Al and β-Ti enriched with V exist in the final powder, and other possible phases including Al-Mg and Al-V were excluded. This study also offers a triple-step thermochemical process for producing high-purity Ti-based alloy powder.
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ACS Biomaterials Science & Engineering
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2022
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IF 5.395
Libing Wang,Fei Dai,Yusheng Yang,Zehua Zhang
Titanium (Ti)-based implants are widely utilized in artificial joints, pedicle screws, and dental implantations due to their excellent biocompatibility, near perfect mechanical capacities, and strong corrosion resistance. However, the Ti substrates are bioinert and lack desirable antibacterial abilities, severely hindering their bone regeneration applications. Herein, the titania nanotubes (TNTs) are fabricated onto the Ti surfaces through anodic oxidation. They are then modified with naringin (Nar)-loaded zeolitic imidazolate framework-8 (ZIF-8) in order to obtain a multifunctional coating (TNT-ZIF-8@Nar) via hydrothermal treatment. The TNT-ZIF-8@Nar exhibits excellent pH-responsive properties and a strong antimicrobial effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by releasing Zn2+ and Nar. TNT-ZIF-8@Nar coatings significantly enhance the proliferation and osteogenic differentiation of osteoblasts. Furthermore, in vivo studies demonstrated the efficacy of TNT-ZIF-8@Nar coatings in improving osseointegration and antibacterial capabilities. This work shows the promising therapeutic potential of TNT-ZIF-8@Nar in its ability to inhibit implant-associated infections and achieve favorable osseointegration simultaneously.
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CHEMOSPHERE
·
2022
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IF 8.943
Hongyu Lu,Chengxun Deng,Zhimin Yu,Dianya Zhang,Weiping Li,Jun Huang,Teng Bao,Xiaowei Liu
Plasma techniques to degrade pollutants are generally more efficient than conventional methods, but exist some problems such as high energy consumption, incomplete degradation of pollutants, and secondary pollution caused by highly toxic intermediates. In this study, the dielectric barrier discharge plasma (DBDP) combined with the Ti-based metal organic frameworks (MOFs) catalysts (P25/NH 2 -MIL-125(Ti)) was used to degrade fluorene in the soil. The synergistic treatment technique used in soil remediation can realize a green and promising treatment efficiency with relatively low energy consumption. Compared with DBDP system alone, the synergetic treatment system of DBDP and P25/NH 2 -MIL-125(Ti) considerably increased the degradation efficiency of fluorene in the soil to above 90% at 10 min, even with a relatively low discharge voltage (5 kV). The synergistic treatment system achieved 88.8% of fluorene mineralization at 60 min. Optical emission spectroscopy and electron paramagnetic resonance spectroscopy both showed that •OH and •O 2 − played an important role in the synergetic treatment system. Nine main intermediates were identified using gas chromatography-mass spectrometry and Fourier transform infrared analysis. The main degradation of fluorine in soil was caused by the electronic transition of the catalytic material excited by DBDP, and finally mineralized into CO 2 and H 2 O. The fluorene and its toxic intermediates were effectively removed. This study provides an insight for achieving high efficiency and environmentally friendly application perspective in soil remediation.
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OPTICAL MATERIALS
·
2021
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IF 3.08
Yang Wang,Sheng Feng,Wei Wu,Yun Zhou,Zhiwei Ye,Xiaojun Dai,Xun Cao
In this article, we reported a method for synthesizing cluster-like NH 2 -MIL-125(Ti)/BiOBr (NMT/B) Z type heterojunction composite materials with different content by using ionic liquid as bromine source assisted solvothermal method. In visible light , the photocatalytic activity of the materials was analyzed by degradation of tetracycline. Characterize the prepared composite material by XRD , FTIR, SEM, TEM, XPS , UV–vis diffuse reflection spectra (DRS). The result proved that the NH2-MIL-125(Ti) (NMT) nanosheets were tightly loaded on the BiOBr surface. NMT/B composite materials showed higher catalytic activity than monomer materials. The removal rate of TC reached 88% in 90min, which was 3 times and 5.7 times that of the monomer NMT and BiOBr monomer materials, respectively. In the catalytic process, –O 2 - and h + are the main active substances that degrade pollutants. This is proved by free radical capture experiments. It could be inferred that the improved photocatalytic activity of NMT/B composites was contributed to the good energy band structure and the formation of Z-type heterojunctions in close contact, which greatly facilitates the photogenerated carrier and hole migration and dissociation. Cycle experiment proved that the prepared composite material has excellent stability, which indicated that it had a good prospect in practical applications.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
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IF 5.455
Mengyao Li,Yi Zhai,Xubin Zhang,Fumin Wang,Guojun Lv,Ahishakiye Rosine,Mengyue Li,Qing Zhang,Yongkui Liu
The preparation of hollow zeolite with a large cavity structure to improve the accessibility to the active sites of catalyst is of great significance. A thin-walled Ti-rich hollow Titanium silicalite-1 (TS-1) Nanobox was synthesized by dissolution-recrystallization using Silicalite-1 (S-1) as the parent zeolite and (NH 4 ) 2 SO 4 as the dual-function crystallization-mediating agent. The wall thickness of the zeolite is about 30 nm, the hollow percentage (the ratio of the cavity area in the middle of the zeolite to the overall area of the zeolite) can reach 0.57, and the Si/Ti ratio is 39.63. The formation mechanism of hollow TS-1 was studied. As the parent zeolite, S-1 is easier to dissolve than TS-1, making it easier for the hollow zeolite to get a complete cavity. When the molar ratio of (NH 4 ) 2 SO 4 /TEOS reaches 0.25, the dissolution rate matches the crystallization rate best, and a perfect hollow structure is obtained. The pH of the initial gel is the key factor for the hollow structure. The catalytic activity and stability were tested by 1-hexene epoxidation. The conversion of 1-hexene using HTS-1#S0.25 as the catalyst is much higher than that using hollow TS-1 prepared by the conventional method as the catalyst. HTS-1#S0.25 remains a high oxidation activity and high selectivity after five recycle experiments. In addition, the type of anion also has a great influence on the reactivity. This method can provide a new idea for the preparation of hollow TS-1.
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