REACTIVE & FUNCTIONAL POLYMERS
·
2021
·
IF 3.975
Zhitao Hu,Xiaohui Cao,Huahua Huang,Yongming Chen
Poly( ε -caprolactone) (PCL) has been one of the most important biomaterials, but its instinct hydrophobicity and slow biodegradation limit its broad applications. Herein, copolymerization of CL and a hydrophilic macrolactone, 2-oxo-15-crown-5 ether (O15C), was achieved through ring opening polymerization catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) using benzyl alcohol as the initiator at room temperature . A series of poly(CL- co -O15C) copolymers with different O15C contents were prepared by simply tuning the feeding ratio of [CL]/[O15C]. They showed molecular weights ranging from 11.0 to 20.6 kg mol −1 , and polydispersity index between 1.4 and 1.6, characterized by SEC (Size Exclusion Chromatography). Analysis of 1 H NMR indicated that the copolymers belong to a random copolymer structure. The introduction of O15C had a significant influence on thermal stability, hydrophilicity and degradability of the copolymers. With increasing the O15C content, the crystalline ability of PCL segment among the copolymers reduced, while the hydrophilic property was improved obviously. Through hydrolysis experiment, the poly(CL- co -O15C) with O15C content of 38 mol% exhibited a much faster degradable rate than that of the copolymer with O15C content of 10 mol%. Therefore, copolymerization of CL with a crown ether monomer via organic catalyst mediated ROP will be a feasible strategy for modification of polyester materials.
研究领域:
材料科学
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生物医学工程
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产品关联
DOI
高影响因子
ANALYST
·
2022
·Vol. 148
·期 2
·344-353
·
IF 5.227
Yufeng Sun,Shengwen Wang,Fangfang Wang,Hao Zhang,Weiya Huang,Aiguo Wu,Yujie Zhang
Urinary potassium is an important parameter in clinical health diagnosis. Rapid and convenient detection of potassium ions (K+) in urine is essential for personal healthcare and health management. Here, crown ether (4-aminodibenzo-18-crown-6, ADC) modified silver nanoparticles (ADC-Ag NPs) were successfully prepared for one-step rapid colorimetric detection of urinary potassium. The detection mechanism is as follows: due to the matching sizes of the diameter of K+ and the cavity in crown ether 6, K+ is encapsulated between the cavities of two crown ethers, resulting in the clumping of ADC-Ag NPs and the color of the solution being altered. The colorimetric detection method has a fast response and is completed within 20 minutes. It also shows good selectivity and interference immunity. The lowest detectable concentration is 20 μM with the naked eye and 2.16 μM for UV-vis absorption spectroscopy. A good linear relationship (R2 = 0.9931) between the absorption intensity ratio and K+ concentration (0–100 μM) indicates that this colorimetric probe can be used to detect K+. The method was also applied for quantitative analysis of K+ in real urine samples with recovery between 116 and 120%.
研究领域:
医学诊断
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纳米材料科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
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2015
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IF 5.636
Juan Wei,Zheng Guo,Xing Chen,Dong-Dong Han,Xiang-Ke Wang,Xing-Jiu Huang
Detection of Cr(VI) by electrochemical methods generally focuses on noble-metal-modified electrodes in strong acid solution using voltammetric techniques. In this work, we report a new strategy to detect Cr(VI) as HCrO4– at pH 5.0 in drinking water using electrochemical impedance spectroscopy. The strategy is based on the high-affinity and specific binding of crown ethers (i.e., azacrown) to HCrO4–, which forms sandwich complexes between them via hydrogen bonds and moiety interactions with K+ captured by azacrown on its self-assembled Au electrode surface. This then blocks the access of redox probes (Fe(CN)63–/4–) to the self-assembled Au electrode, further resulting in an increase in the electron transfer resistance. This method offers a detection limit of 0.0014 ppb Cr(VI) with a sensitivity of 4575.28 kΩ [log c (ppb)]−1 over the linear range of 1–100 ppb (R2 = 0.994) at pH 5.0. In addition, the azacrown self-assembled Au electrode has good selectivity for Cr(VI) with good stability and low interferences. This approach can be performed on spiked Cr(VI) as well as real samples. To the best of our knowledge, this is the first example of electrochemical impedimetric sensing that allows ultrasensitive and ultraselective detection of Cr(VI).
研究领域:
分析化学
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环境科学
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DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2024
·
IF 4.9
Yiping Tan,Shuangke Li,Xiaoping Xu,Pan Chen,Zhiyong Gao,Wei Sun,Belinda McFadzean,Jian Cao
Quartz and feldspar are the primary impurities in the mineral processing of pollucite. Due to the highly similar surface properties of these three minerals in terms of physicochemical characteristics, achieving efficient flotation enrichment of pollucite has been a challenging problem. To address this issue, the development of flotation collectors with high selectivity towards pollucite is crucial. In this study, different-sized crown ethers acted as selective collectors for the direct flotation to detach pollucite from feldspar and quartz were investigated, leveraging the selective bonding of crown ethers to alkali metal active site on the surface of pollucite. The properties of 21-crown-7 ether (21C7), benzo-21-crown-7 (B21C7) and dibenzo-21-crown-7 (DB21C7) (with three different cavity sizes) were investigated as collectors for pollucite flotation. The experimental results indicated that DB21C7 exhibited the best collecting performance. The mechanism was studied through various experimental measurements and computational simulations, and the results revealed that the selective adsorption mechanism of crown ethers onto the surface of pollucite was achieved through a combination of chelation interaction involving “spatial effect” and hydrogen bonding interaction. This work has disclosed that crown ether compounds may hold significant potential as collectors for flotation of pollucite.
研究领域:
矿物加工工程
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表面化学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2018
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IF 4.513
Bing Liu,Su Wang,Yongzhong Jia,Wenbo Zhu,Quanyou Zhang,Xingquan Wang,Ying Yao,Yan Jing
A green and efficient ionic liquid-anisole extraction system was employed for the separation of lithium isotopes by comparing 4‑aminobenzo‑15‑crown‑5 (4‑NH 2 ‑B15C5), 4‑nitrobenzo‑15‑crown‑5 (4‑NO 2 ‑B15C5) and benzo‑15‑crown‑5 (B15C5) extraction agents. The results of the effects of crown ether substituents, crown ether concentration and lithium salt anion on solvent extraction indicated that the molar ratio of crown ether and lithium ion complex is 2:1 and the order of the extraction efficiency in three extraction agents was 4‑NH 2 ‑B15C5 > B15C5 > 4‑NO 2 ‑B15C5. Furthermore, the single-stage separation factor α for 6 Li/ 7 Li obtained in present work was 1.032 and maximum abundance of 6 Li in organic phase was reached 7.762% in the extraction system of LiI/4‑NO 2 ‑B15C5‑ILs.
研究领域:
化学
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材料科学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Chaochi Huang,Jinhe Sun,Ciming Wang,Qian Zhang,Mingyong Wang,Pengrui Zhang,Zixuan Xue,Yan Jing,Yongzhong Jia,Fei Shao
Lithium isotopes (6Li and 7Li) play an important role in the nuclear industry. The development of green and efficient separation methods is a top priority for the lithium isotope industry. In this work, an “aqueous solution|ionic liquid–crown ether organic solution|aqueous solution” system was constructed and used for lithium isotope electromigration separation. The influence and synergy of Li+ diffusion, electromigration, and chelation of crown ether on Li+ migration and isotope separation were investigated, discussed, and verified carefully. The separating laws were summarized. The process and mechanisms of lithium isotope separation were explored preliminarily. The presence of crown ether in organic solution and the introduction of electric field can change the migration ratio and lithium isotope enrichment effect of different parts in the system. The synergy of Li+ diffusion, electromigration, and chelation of crown ether can change the behaviors of Li+ migration and isotope separation significantly. What’s more important, the driving forces are not constant but dynamic. The diffusion increased with the increasing concentration gradient among different parts. The chelation decreased with the increasing Li+ concentration in organic solution. The electromigration also changed with the varied chemical speciation of Li+. The results helped in understanding the roles of driving forces more clearly and provided a foundation for developing green and efficient methods for lithium isotope separation.
研究领域:
化学
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核工业
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材料科学
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 47
·期 6
·3134-3139
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IF 3.925
Yuhong Huang,Xiaowei Li,Linlin Chen,Guiling Luo,Duanjian Tao,Jing Sun,Zhenjiang Qiu,Yanhong Chao,Wenshuai Zhu
To meet the requirements of the strong future market for lithium resources, it is crucial to retrieve lithium from high Mg/Li ratio brines. Herein, a novel magnetic crown ether Li+-imprinting polymer was designed by combining surface ion imprinting and magnetic separation techniques. Through the specific recognition of Li+ by the crown ether modified with a hydroxyl functional group, an excellent lithium ion separation performance was achieved. The separation selectivity factors for Li+ using OS@FeSi@CE-OH for Na+, K+ and Mg2+ were 7.74, 2.75 and 2.98, respectively. In addition, the use of an external magnetic field avoids filtration and centrifugation to achieve efficient recovery of adsorbed materials, which can shorten the analysis time and simplify the separation process. Therefore, these remarkable features address the problems encountered with traditional powder adsorbents, making OS@FeSi@CE-OH a potential candidate for lithium recovery.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 10
·6346-6355
·
IF 3.9
Lina Wu,Huiping Wang,Xiangqian Kong,Haibo Wei,Sheng Chen,Lisheng Chi
Effective removal of strontium isotopes in radioactive waste streams has important implications for the environment and the sustainable development of nuclear energy. In this work, a zirconium phosphate/18-crown-ether-6 (ZrP/18C6) composite was prepared using the intercalation method by loading crown ether into zirconium phosphate. The composite was structurally and morphologically characterized by XRD, FT-IR, XPS, and SEM. The adsorption experiments of Sr2+ onto the ZrP/18C6 composite were conducted as a function of temperature, pH, Sr2+ concentration and competing ions. The results indicate ZrP/18C6 can adsorb 98.6% of Sr2+ within 30 minutes at an Sr2+ concentration of 100 mg L−1 and maintain a high removal rate with a distribution coefficient of 7 × 105 mL g−1 when Sr2+ is at a low level of 4.28 mg L−1. The ZrP/18C6 composite reached a maximum adsorption capacity of 195.74 mg g−1 at an Sr2+ concentration of 380 mg L−1, which is significantly higher than the 43.03 mg g−1 of α-ZrP. The adsorption performance of Sr2+ onto ZrP/18C6 is not significantly affected by temperature, pH and competing ions. Furthermore, the adsorption kinetics and thermodynamics were analyzed based on the adsorption data obtained in the present work. It is shown that the adsorption of Sr2+ onto ZrP/18C6 follows the pseudo-second-order model and the Langmuir monolayer model, respectively. Additionally, the adsorption mechanism of Sr2+ by ZrP/18C6 is discussed.
研究领域:
环境科学
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核化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2023
·
IF 5.5
Yu Zhang,Junming Dai,Hua Lai,Yinhua Wan,Young Moo Lee,Yongbing Zhuang
The development of proton exchange membrane fuel cells (PEMFCs) that operate over a wide temperature range without additional humidification systems remains challenging. In this work, wide-temperature-range proton exchange membranes (PEMs) were constructed from novel Tröger’s base (TB)-based intrinsically microporous copolyimides (co-PIs) finely adjusted by incorporating crown ether units into chain backbones. Owing to the strong siphoning effect of existing microporosity and hydrogen bonds or the acid–base interactions of crown ether and TB units with phosphoric acid (PA) and/or H2O, the PA-doped co-PI membrane electrode assemblies (MEAs) can easily operate stably from 30 to 160 °C under H2/air conditions even without any external humidifiers. Regarding its single-cell performance, PI-TB-N30C achieved maximum power densities of 250 and 361 mW cm–2 at 80 and 160 °C, respectively, under anhydrous conditions. In addition, PA-doped co-PI MEA can accomplish long-term stable operation under low or high temperatures for 120 h. The structural architectures for PEMs based on finely adjusted microporous co-PIs extend beyond the current capabilities of existing PEMFCs.
研究领域:
材料科学
·
能源工程
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产品关联
DOI
高影响因子
JOURNAL OF PHYSICAL CHEMISTRY B
·
2023
·
IF 3.3
Zhuanfang Jing,Yongquan Zhou,Toshio Yamaguchi,Koji Ohara,Jianming Pan,Guangguo Wang,Fayan Zhu,Hongyan Liu
The underlying recognition mechanisms of alkali metal ions by crown ethers in aqueous solutions are yet to be fully understood at the molecular level. We report direct experimental and theoretical evidence for the structure and recognition sequence of alkali metal ions (Li+, Na+, K+, Rb+, and Cs+) by 18-crown-6 in aqueous solutions by wide-angle X-ray scattering combined with an empirical potential structure refinement modeling and ab initio molecular dynamics simulation. Li+, Na+, and K+ are located in the negative potential cavity of 18-crown-6, with Li+ and Na+ deviating from the centroid of 18-crown-6 by 0.95 and 0.35 Å, respectively. Rb+ and Cs+ lie outside the 18-crown-6 ring and deviate from the centroid of 18-crown-6 by 0.05 and 1.35 Å, respectively. The formation of the 18-crown-6/alkali metal ion complexes is dominated by electrostatic attraction between the cations and the oxygen atoms (Oc) of 18-crown-6. Li+, Na+, K+, and Rb+ form the H2O···18-crown-6/cation···H2O “sandwich” hydrates, while water molecules only hydrate with Cs+ of the 18-crown-6/Cs+ complex on the same side of Cs+. Based on the local structure, the recognition sequence of 18-crown-6 for alkali metal ions in an aqueous solution follows K+ > Rb+ >Na+ >Li+, which is completely different from that (Li+ > Na+ > K+ > Rb+ > Cs+) in the gas phase, confirming that the solvation medium seriously affects the cation recognition of crown ethers. This work provides atomic insights into understanding the host–guest recognition and solvation behavior of crown ether/cation complexes.
研究领域:
化学
·
物理化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Shuting Li,Manting Li,Limin Chen,Jianying Yang,Zhao Wang,Fan Yang,Linhong He,Xinchun Li
Artificial nanochannels have seen great progress in energy storage, molecular filters, nanofluidic diodes, and biosensors. Precisely recognizing and transporting molecules or ions underpin the basis of artificial nanochannels. Here, we report highly efficient Li + responsive nanochannels by design of functionalized porous anodic aluminum oxide (AAO) membranes. The 12-crown-4 unit was tethered to the synthesized spiropyran molecule, creating a smart Li + responsive element, photochromic crowned spiropyran (CE-SP). The crown unit can specifically bind with Li + while exempting the harassment of other metallic cations; and importantly, the spiropyran moiety possesses reversible photochemistry response, adding the flexibility to regulate ion transport behaviors. Upon the ultraviolet light stimulus, hydrophobic CE-SP molecules transform to positively charged crowned merocyanine (CE-MC), which can further convert to oxygen-negative ions in weak alkaline environment, thereby forming O - -Li + interaction. Such structural evolutions enable to deftly tune the surface charge and wettability of the nanochannels, and thus ingeniously manipulate Li + recognition profiled by ionic current signal. Moreover, electrically-driven release of the captured Li + can be realized in an amiable condition, showing controllable capture-to-release ability. Finite element simulation unveils the fundamental mechanisms of ion transport pertaining to Li + recognition events in the nanoconfinement. This work thus paves a way to construct high-performance Li + -selective nanodevice, and holds promise for Li + -related electrochemistry energy research.
研究领域:
材料科学
·
纳米技术
·
电化学
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DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Qian Zhang,Yongzhong Jia,Jinhe Sun,Pengrui Zhang,Chaochi Huang,Mingyong Wang,Zixuan Xue,Ciming Wang,Fei Shao,Fengtai Tong,Yilin Xiao,Yan Jing
Azacrown ethers contain multiple coordination sites, which show specific complexation to alkali metal ions . In this research, a neoteric liquid-liquid extraction system was investigated for the selective separation of lithium isotope using N -phenylaza-15-crown-5 (Ph-N15C5) as chelating agent and [BMIm][NTf 2 ] and anisole as extraction solvent. The effects of the counter anions of lithium salt , concentrations of crown ether , temperature, extraction equilibrium time and concentrations of lithium salt solution on the separation of lithium isotope with Ph-N15C5 were studied. The maximum extraction efficiency of lithium ions was 41.54% and the maximum single-stage separation factor (α) of 6 Li/ 7 Li obtained in the present study was 1.025, indicating that the lighter isotope 6 Li was enriched in organic phase while the heavier isotope 7 Li was concentrated in the aqueous phase. The complexation ratio of the lithium crown ether complex was determined as 1:1 by the slope analysis method. The lithium ions in the aqueous phase were extracted into the organic phase to form [Li(Ph-N15C5)] + complex. The thermodynamic data obtained at different temperatures demonstrated that lithium isotope exchange was a spontaneous exothermic process , and lowering the temperature was beneficial to increase the separation factor. In addition, the system reached the extraction equilibrium after 60 min. This high efficiency and green liquid-liquid extraction system has potential application in lithium isotope separation.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）