查找使用阿拉丁产品的科研文献

Effect of the Zr promoter on precipitated iron-based catalysts for high-temperature Fischer–Tropsch synthesis of light olefins

Yi Yang,Weixin Qian,Haitao Zhang,Zhonghao Han,Hongfang Ma,Qiwen Sun,Weiyong Ying

FeMnxZr and FeMnxZr2Na catalysts prepared by coprecipitation and impregnation methods were applied to investigate the promoting effects of Zr on iron-based catalysts for high-temperature Fischer–Tropsch synthesis (HTFT). Ar physisorption and TEM demonstrated that Zr-promoted catalysts have a larger BET surface area and larger pore volume, which are more conducive to the distribution of active phases. Zr promoted the dispersity of iron particles and reduced the grain size of iron particles, resulting in the improvement of the FTS activity. The CO-TPD and MES results revealed that the introduction of Zr promoted the dissociative adsorption of CO, thereby promoting the formation of the active phase χ-Fe5C2 while suppressing the formation of ε′-Fe2.2C and further improving the FTS activity and the selectivity to C2=–C4= in the hydrocarbon distribution. However, the addition of an excessive amount of Zr caused the excess ZrO2 to cover the surface of the active site, inhibiting the CO dissociative adsorption and the formation of χ-Fe5C2, resulting in a decrease in the CO conversion and the selectivity to C2=–C4=. The XPS and H2-TPR results proved the interaction between Fe2O3 and ZrO2. And the Fe–ZrO2 interaction inhibited the coke deposition and aggregation of the Fe species, as confirmed by XRD and TEM, respectively. The FeMn5Zr2Na catalyst exhibited the highest C2=–C4= selectivity of 34.4% at a CO conversion of 96.3%. And FeMn5Zr2Na displayed the highest production of light olefins (441.6 g h−1 kgCat−1), which was significantly higher than FeMn2Na (162.2 g h−1 kgCat−1).

Zr-MOF-Induced Smart Accumulation Enables Surface-Enhanced Raman Spectroscopic Detection of Dioxin at ppt Level in Food Samples

Jie Cheng,Bo-en Li,Jinghui He,Peilong Wang

The fast and economical detection of trace polychlorinated dibenzo-p-dioxins (PCDDs) in food samples by current mass spectrum-based methods is hindered by tedious sample preparation and bulky & expensive analytical instruments. Surface-enhanced Raman spectroscopy (SERS) successfully detects many organic pollutants in foods but not dioxins because the employed metal nanoparticles weakly adsorb hydrophobic PCDDs. Herein, we report the detection of PCDDs in milk with SERS for the first time using a bifunctional substrate consisting of Au nanoparticles embedded in a zirconium-based metal–organic framework shell (AuNP/Zr-MOF). 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), as the most toxic PCDD, is detected as low as 1.2 parts per trillion (ppt) in real milk samples with massive interfering substances in 30 min, which is the lowest among all reported methods. The aromatic rings of Zr-MOF promote the smart accumulation of TCDD through π–π interactions, and Au–Cl interactions drive TCDD onto Au surfaces. Zr-MOF shells with pore sizes of 12.7 and 20 Å block the accessibility of larger interfering molecules. A one-step apparatus and protocol are established to be superior to traditional methods in terms of time and cost. This work provides new insight into a rational screening method for the detection of persistent organic pollutants in a real sample matrix.

Boosting Antibacterial Photodynamic Therapy in a Nanosized Zr MOF by the Combination of Ag NP Encapsulation and Porphyrin Doping

Bao-Xuan Xie,Hai-Shuang Wang,Hui-Qian Zheng,Jin Xu,Li Chen,Fang-Zhong Zhang,Yu-Lin Wang,Zu-Jin Lin,Rong-Guang Lin

Antibacterial photodynamic therapy (aPDT) is regarded as one of the most promising antibacterial therapies due to its nonresistance, noninvasion, and rapid sterilization. However, the development of antibacterial materials with high aPDT efficacy is still a long-standing challenge. Herein, we develop an effective antibacterial photodynamic composite UiO-66-(SH)2@TCPP@AgNPs by Ag encapsulation and 4,4′,4″,4‴-(porphine-5,10,15,20-tetrayl)tetrakis(benzoic acid) (TCPP) dopant. Through a mix-and-match strategy in the self-assembly process, 2,5-dimercaptoterephthalic acid containing –SH groups and TCPP were uniformly decorated into the UiO-66-type framework to form UiO-66-(SH)2@TCPP. After Ag(I) impregnation and in situ UV light reduction, Ag NPs were formed and encapsulated into UiO-66-(SH)2@TCPP to get UiO-66-(SH)2@TCPP@AgNPs. In the resulting composite, both Ag NPs and TCPP can effectively enhance the visible light absorption, largely boosting the generation efficiency of reactive oxygen species. Notably, the nanoscale size enables it to effectively contact and be endocytosed into bacteria. Consequently, UiO-66-(SH)2@TCPP@AgNPs show a very high aPDT efficacy against Gram-negative and Gram-positive bacteria as well as drug-resistant bacteria (MRSA). Furthermore, the Ag NPs were firmly anchored at the framework by the high density of –SH moieties, avoiding the cytotoxicity caused by the leakage of Ag NPs. By in vitro experiments, UiO-66-(SH)2@TCPP@AgNPs show a very high antibacterial activity and good biocompatibility as well as the potentiality to promote cell proliferation.

Mixed matrix membrane for enhanced Ethanol/Water pervaporation separation by incorporation of hydrophilic Zr-MOF NU-906 in chitosan

Huayan Fu,Ruiwen Luo,Panpan Liu,Shuning Yu,Qinglei Xing,Peng Bai,Xianghai Guo,Jiafei Lyu

Conquering the trade-off between selectivity and permeability is crucial for efficient ethanol dehydration. The sophisticated metal–organic frameworks (MOFs) have proven their potential as membrane fillers despite of the limited research on few frameworks. Herein, in order to achieve enhanced water permselectivity, hydrophilic zirconium-based NU-906 nanoparticles were incorporated into chitosan (CS) to fabricate NU-906/CS mixed matrix membranes (MMMs) for alcohol dehydration. The introduction of NU-906 brought excellent water affinity and structural stability to the hybrid membranes confirmed by the water contact angle and swelling resistance tests. Benefiting from the hydrophilicity and the ordered porosity of the incorporated NU-906, simultaneously enhanced water selectivity and permeability have been achieved on the hybrid membranes. The optimum membrane with 5.0 wt% NU-906 exhibited a high flux of 1086 g/(m 2 ·h) and an excellent separation factor of 2651 for 90 wt% ethanol dehydration at 76   ℃. This research has expanded the range of MOFs available for the fabrication of MMMs and provided new options for organic solvent pervaporation dehydration.

Simultaneous Electrochemical Detection of Co-Existing Dihydroxybenzene Isomers Using Porphyrin Zr Metal-Organic Frameworks/β-cyclodextrin/Pencil Graphite Electrode

Siyi Yang,Shangming Wu,Juan Liu,Huanbao Fa,Mei Yang,Changjun Hou

Oxygenated groups enriched polyolefin-Zr(IV) complexes catalyzing low-temperature transfer hydrogenation of biomass-derived furfural with 2-propanol

Shuangshuang Cen,Lijun Wang,Cong Wan,Xinyan Chai,Lei Li,Wensheng Linghu

Zr 4+ −O 2− pairs in MOFs and macromolecule − Zr(IV) complexes have proved one of the ideal catalytic components for catalytic transfer hydrogenation of biomass-derived furfural. However, restricted by limited adjustability of Zr 4+ −O 2− coordination environment and the complex design and creation of ligand defects, currently, there are only a few efficient low-temperature (<100 °C) catalytic systems. In this work, oxygenated groups enriched polyolefin − Zr(IV) complexes were prepared and fixed on/in mesoporous silica aerogel support. The complexes possessed a stable structure with C C bonds as the connecting skeleton of each oxygenated group, and the types and densities of oxygenated groups ( COOH, SO 3 H, and OH) could be easily adjusted by using different monomers. In the catalytic transfer hydrogenation reaction of furfural and 2-propanol, the catalyst synthesized using dicarboxylic maleic acid as a monomer of polyolefin exhibited the best catalytic performance in low temperatures, the main product furfuryl alcohol with a high yield of 96.0 % and a high selectivity of 98.2 % was obtained at 85 °C for 8 h. In 6 cycles of reactions at 85 °C, the furfuryl alcohol yield decreased gradually from 96 % in the 1st cycle to 84.0 % in the 4th cycle and further restored to 90.9 % and 89.3 % in the 5th and 6th cycles, respectively, by refreshing the used catalyst with methanol washing, and there was almost no leaching of Zr 4+ species in the reaction medium. The catalyst poisoning experiment with acidic and basic sites shielded by pyridine and boric acid, respectively, showed that the catalytic activity was more sensitive to the shielding of basic sites, and the isotope experiments revealed that two H of the product furfuryl alcohol are transferred from 2-propanol. Hereby, the oxygenated group-bearing polyolefin − Zr(IV) complexes with stable structure, variable functional groups and the corresponding various Zr 4+ −O 2– coordination pairs, are ideal catalyst candidates for the selective transfer hydrogenation of furfural to furfuryl alcohol.

Removal Effectiveness for Washing Ce(IV), U(VI), and Zr(IV) Ions from Contaminated Purex Solvent by Hydrazine Carbonate

Guanghui Wang,Hui He,Yaorui Li,Meng Zhang,Yang Gao,Caishan Jiao

The contaminated solvent from the Purex process is washed with alkaline detergents such as sodium carbonate, which generates a large amount of secondary wastes. Therefore, hydrazine carbonate as a salt-free reagent deserves to be studied in depth. In this study, the Ce(IV), U(VI), and Zr(IV) metal ions in organic phases containing dibutyl phosphate (HDBP) of 30% tributyl phosphate (TBP)–dodecane were washed with hydrazine carbonate. The effects of the oscillation time (1 to 15 min); temperature (25°C to 85°C); cumulative number of washes (one to four times); mass fraction of hydrazine carbonate (0.1% to 20%); volume ratio of the aqueous phase to the organic phase (0.2 to 5); HDBP concentration (0 to 0.4 M); HNO3 concentration (0.05 to 8 M); and concentration of Ce(IV), U(VI), and Zr(IV) metal ions on the removal percentages of Ce(IV), U(VI), and Zr(IV) metal ions in polluted solvents were studied. The results showed that when the organic phase containing 0.02 M HDBP was washed three times with 5% hydrazine carbonate at 25°C, the removal percentages of the Ce(IV), U(VI), and Zr(IV) ions were 96%, 98%, and 94%, respectively. Meanwhile, the retention concentrations of the three in the organic phase were 35, 28, and 78 mg/L, respectively. The increase of the mass fraction of hydrazine carbonate enhances the removal of the metal ions from the organic phase into the aqueous phase. High acid is not conducive to alkaline washing of metal ions. The increase of HDBP concentration not only promotes extraction but also increases the retention capacity of the organic phase and has the most significant effect on Zr(IV). U(VI) promotes the preferential washing of Zr(IV) while Ce(IV) increases the metal retention concentration of Zr(IV) in the organic phase.

Fe-Ni alloy modified Zr-based MOF derivatives as bioelectrocatalyst for regulating multipath EET efficiency and biofilm electrogenic activity

Xu Pan,Junhong Wang,Ye Chen,Qing Wen,Cunguo Lin,Haiping Gao,Zhenghui Qiu,Liuqingying Yang

As a green conversion device, the electricity performance of microbial fuel cell (MFC) was mainly affected by the extracellular electron transfer (EET) process of the biofilm. This paper presented the fabrication and characterization of carbonized derivatives composed with alloy nanoparticles (NPs) derived from Zr-based metal organic frameworks, which exhibited biocompatibility and high electrocatalytic activity. As the results of bioanodes, the charge transfer resistance decreased from 5.60 Ω (Zr-C) to 0.61 Ω (Fe/Ni-Zr-C), and the exchange current density increased from 0.56 mA/cm 2 (Zr-C) to 1.40 mA/cm 2 (Fe/Ni-Zr-C). Electrochemical tests and density functional theory (DFT) confirmed that Fe-Ni alloy NPs promoted the rapid transfer of electrons within the electrode and improved the EET efficiency mediated with the flavin compounds. High throughput sequencing and PICRUSt verified the specific screening function of Fe-Ni alloy for electrogenic bacteria (mainly Geoalkalibacter) and the promoting effect on the expression of flavin-related proteins in biofilm. The maximum power density of Fe/Ni-Zr-C MFC (5.09 W/m 2 ) was higher than that of Ni-Zr-C (4.19 W/m 2 ), Fe-Zr-C (3.58 W/m 2 ) and Zr-C (3.09 W/m 2 ) MFCs. Fe/Ni-Zr-C material can act as an economical and high-performance bioelectrocatalyst to improve the power generation capability of MFC by improving EET rate and energy conversion efficiency of biofilm.

Ni-based catalysts derived from Ni-Zr-Al ternary hydrotalcites show outstanding catalytic properties for low-temperature CO2 methanation

Feng He,Jiahao Zhuang,Bin Lu,Xianglin Liu,Jianling Zhang,Fangna Gu,Minghui Zhu,Jing Xu,Ziyi Zhong,Guangwen Xu,Fabing Su

Developing Ni-based catalysts with high activity and stability in low-temperature methanation is necessary due to their sintering and coking at high temperatures. Here, we report our developed novel Ni-Zr-Al catalysts derived from Ni-Zr-Al ternary hydrotalcites synthesized by a hydrothermal process, followed by a reduction in hydrogen. Comparing with the Ni-Al catalyst derived from Ni-Al hydrotalcite and the commercial Ni-based catalyst, the Ni-Zr-Al catalysts show a remarkably higher low-temperature activity (210−270 °C) in CO 2 methanation. Both the experimental and theoretical calculations confirmed the introduction of Zr into the Ni-Al binary hydrotalcite could generate synergetic effects between Ni and ZrO 2 , resulting in more surface oxygen vacancies, basic sites, and abundant mesopores . In-situ DRIFTS analysis showed the CO 2 methanation to CH 4 follows the intermediate formate route. This work provides a new theoretical understanding of CO 2 activation and methanation, and a practical way to address the existing problem for Ni-based catalysts.

Three-dimensional macroporous Carbon/Zr-2,5-dimercaptoterephthalic acid metal-organic frameworks nanocomposites for removal and detection of Hg(II)

Hanlun Yang,Canwei Peng,Jiajia Han,Yonghai Song,Li Wang

Mercury ion (Hg(II)) has serious destructive effects on organisms and environments even at extremely low concentration. Therefore, effective removal and highly sensitive determination of trace Hg(II) is very important. Herein, mercaptan functionalized metal-organic frameworks (MOFs) were prepared by the coordination between Zr (IV) and 2,5-dimercaptoterephthalic acid (Zr-DMBD MOFs) and attached to three-dimensional kenaf stem-derived carbon (3D-KSC) to form a novel nanocomposite for removal and electrochemical detection of Hg(II). The sensitivity of Hg(II) detection was 324.58 μA μM −1  cm -2 , the linear range was 0.25 μM–3.5 μM and the detection limit was 0.05 μM. The good performances were because lots of Zr-DMBD MOFs were uniformly dispersed on 3D-KSC and the porous Zr-DMBD MOFs had a large number of mercaptan groups to enrich Hg(II) significantly on the electrode. The Hg(II) detection would not be interfered by other co-existing heavy metal ions, and the Zr-DMBD MOFs/3D-KSC also showed excellent stability and reproducibility. Furthermore, the Zr-DMBD MOFs/3D-KSC could effectively remove Hg(II) in real wastewater. The residues were lower than national discharge standard of industrial wastewater (GB30770-2014).

Hard-and-Soft Integration Strategy for Preparation of Exceptionally Stable Zr(Hf)-UiO-66 via Thiol–Ene Click Chemistry

Jingcheng Du,Li Chen,Xinjuan Zeng,Shuai Yu,Wei Zhou,Luxi Tan,Lichun Dong,Cailong Zhou,Jiang Cheng

UiO-66 metal–organic frameworks (MOFs) are unstable in some harsh aqueous environments, which limit their practical applications. We demonstrate a postsynthetic modification methodology to transform hydrophilic Zr(Hf)-UiO-66 into superhydrophobic Zr(Hf)-UiO-66-SH-y (SH = thiol, y = fluoroalkyl) by introducing long fluoroalkyl chains into organic linkers through a thiol–ene click reaction. Water contact angles of the four modified UiO-66 MOFs are all larger than 150°. The grafted low-surface-energy fluorine-containing groups become an effective protective shield for the MOFs, making them exhibit remarkable stability in extreme conditions such as alkaline (pH = 12), saturated HCl, and high concentration of NaCl solution (20 wt %). The Zr-UiO-66 MOFs grafted with 1H,1H,2H-perfluoro-1-hexene have high CO2 adsorption contents of 1.54 and 2.88 mmol·g–1 at 298 and 273 K, respectively. Moreover, the superhydrophobic MOFs also showed potential application in oil/water separation.

Efficient Selective Removal of Pb(II) by Using 6-Aminothiouracil-Modified Zr-Based Organic Frameworks: From Experiments to Mechanisms

Chao Xiong,Shixing Wang,Peng Hu,Liyun Huang,Can Xue,Zujin Yang,Xiantai Zhou,Yongqing Wang,Hongbing Ji

We report an efficient, reusable, and selective 6-aminothiouracil (ATA)-modified Zr(IV)-based adsorbent (defined as UiO-66-ATA(Zr)) for lead ion removal in water. The adsorption equilibrium time and the maximum sorption capacity of UiO-66-ATA(Zr) for Pb(II) are, respectively, 120 min and 386.98 mg/g at pH 4 and 298 K. The Pb(II) removal rate reaches 96% at 60 min and exceeds 99% at the equilibrium state in the pH range of 2.0–5.8. Hill and pseudo-second-order models can well describe the sorption process. Pb(II) adsorbing onto UiO-66-ATA(Zr) is an irreversible, favorable chemisorption process with multimolecule participation and film diffusion control. The calculations of density functional theory, the experimental results, and the characterization analyses suggest that the binding mechanisms are the chelation and ion-exchange/electrostatic interactions between hydroxyl/amino/sulfhydryl groups of UiO-66-ATA(Zr) and Pb(II). Besides, UiO-66-ATA(Zr) has a better affinity to Pb(II) than the coexisting ions in water and an excellent repeatability at eight cycles of adsorption. Moreover, the thermodynamic study shows that UiO-66-ATA(Zr) adsorbing Pb(II) is an endothermic reaction. Thus, UiO-66-ATA(Zr) is a prospective sorbent for Pb(II) removal under the initiative of environmental protection and water purification, and this work may also provide an idea for industrial catalysis.