查找使用阿拉丁产品的科研文献

Potential application of graphene oxide membranes for removal of Cs(I) and Sr(II) from high level-liquid waste

Fuyin Ma,Zheng Li,Haogui Zhao,Yiyun Geng,Wei Zhou,Qingnuan Li,Lan Zhang

As a new carbon-based membrane material used for ionic and molecular sieving, the graphene oxide (GO) membrane also has potential application in radiochemical separation. In this work, the permeation performances of some typical metallic elements in high level-liquid waste (HLLW) through the ionic sieving 5-μm-thick GO membranes were investigated. It was found that the permeation rates of ions through GO membranes markedly decreased with the increase of hydrated ionic radii. Cs(I) and Sr(II) permeated through GO membranes quickly, whereas lanthanide ions and actinide ions infiltrated much more slowly, thus providing the feasibility of separation according to the difference of hydrated ionic radii. Moreover, the concentrations of initial metal ions and acidity in feed solutions also had influences on the permeation of ions through GO membranes, and higher initial metal ions and feed solution acidity were favorable to the removal of Cs(I) and Sr(II). The barrier separation test indicated that GO membranes had promising ability for the separation of Cs(I) and Sr(II) from lanthanide and actinide ions due to the difference of hydrated ion radius, and the separation factor of Cs(I)/U(VI) and Sr(II)/U(VI) would reach about 10 and 3 in single penetration. The presented results demonstrated that the membrane separation based on GO membrane would be a promising candidate for the removal of Cs(I) and Sr(II) from HLLW.

Selective adsorption and separation of Cs(I) from salt lake brine by a novel surface magnetic ion-imprinted polymer

Lin Yang,Shengfang Li,Chunyan Sun

A new Cs(I) magnetic ion-imprinted polymer (Cs(I)-MIIP) aimed at the selective adsorption and separation of Cs(I) from salt lake brine was prepared. The Fe3O4@SiO2 was used as supporter, Cs(I) as template ion, and carboxymethyl chitosan as functional monomer. The product was characterized by Fourier transform infrared spectra, XRD, energy-dispersive spectrometry, scanning electron microcopy, thermogravimetric analysis, and vibrating sample magnetometer. The adsorption of the Cs(I)-MIIP in solution was investigated, which indicated the maximum adsorption capacity was 36.15 mg·g−1 under the optimum conditions. The pseudo-first-order kinetic model and the Freundlich isotherm model were applied to predict the adsorption process of Cs(I) onto Cs(I)-MIIP. Selectivity experiments showed that the relative selectivity coefficient (k′) were 24.995, 1.73, 1.43, 4.83, and 1.63 to Cs(I)/Li(I), Cs(I)/Na(I), Cs(I)/K(I), Cs(I)/Rb(I), and Cs(I)/Sr(II) binary solutions, higher than those of NIP, respectively. Furthermore, the Cs(I)-MIIP was successfully applied to the enrichment and separation of Cs(I) from the salt lake brine of Qinghai, with satisfactory Cs(I) recovery rates.

Highly doped and exposed Cu(I)–N active sites within graphene towards efficient oxygen reduction for zinc–air batteries

Haihua Wu,Haobo Li,Xinfei Zhao,Qingfei Liu,Jing Wang,Jianping Xiao,Songhai Xie,Rui Si,Fan Yang,Shu Miao,Xiaoguang Guo,Guoxiong Wang,Xinhe Bao

A coordinatively unsaturated copper–nitrogen architecture in copper metalloenzymes is essential for its capability to catalyze the oxygen reduction reaction (ORR). However, the stabilization of analogous active sites in realistic catalysts remains a key challenge. Herein, we report a facile route to synthesize highly doped and exposed copper(I)–nitrogen (Cu(I)–N) active sites within graphene (Cu–N©C) by pyrolysis of coordinatively saturated copper phthalocyanine, which is inert for the ORR, together with dicyandiamide. Cu(I)–N is identified as the active site for catalyzing the ORR by combining physicochemical and electrochemical studies, as well as density function theory calculations. The graphene matrix could stabilize the high density of Cu(I)–N active sites with a copper loading higher than 8.5 wt%, while acting as the electron-conducting path. The ORR activity increases with the specific surface area of the Cu–N©C catalysts due to more exposed Cu(I)–N active sites. The optimum Cu–N©C catalyst demonstrates a high ORR activity and stability, as well as an excellent performance and stability in zinc–air batteries with ultralow catalyst loading.

Recyclable Cu(I)/ZrSBA-15 prepared via a mild vapor-reduction method for efficient thiophene removal from modeled oil

Ce Gao,Qingda An,Zuoyi Xiao,Shangru Zhai

Nowadays, processing of ultra-low sulfur fuel oil has been a hot topic of research all over the world; hence, an efficient adsorption process to tackle this issue is eliciting increasing attention. However, the preparation of high-performance adsorbents is still a challenge. Herein, zirconium-substituted mesoporous SBA-15 with highly dispersed active Cu(I) species has been successfully synthesized by our group at 493 K via a mild vapor-reduction method. The as-prepared material was characterized by powder X-ray diffraction (XRD), nitrogen adsorption and desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis diffuse reflectance (DRUV) spectroscopy. All characterization methods demonstrated that the Cu(I) species were highly dispersed in an ordered mesoporous framework with short channels rather than piled on the surface. The as-prepared materials also exhibited an excellent adsorption capacity for thiophene (up to 29.86 mg g−1 at 323 K). Pseudo-second-order kinetics model and Freundlich isotherm can well describe the adsorption kinetics and isotherm data, respectively. More remarkably, an ultrasound-assisted treatment can be effectively employed to regenerate adsorbent, with only a slight reduction in the adsorption capacity after five cycles.

DNA fragments assembled on polyamidoamine-grafted core-shell magnetic silica nanoparticles for removal of mercury(II) and methylmercury(I)

Xiao Liang,Ying Ge,Zhenglong Wu,Weidong Qin

BACKGROUND Hg(II) and MeHg(I) are toxic pollutants causing wide concerns. Polyamidoamine-grafted magnetic silica nanoparticles (Fe 3 O 4 -SiO 2 -PAMAMs) were synthesized as beads, on which herring sperm DNA fragments were immobilized as reacting moieties for removal of Hg(II) and MeHg(I) from water matrices. The factors influencing the removal, such as DNA fragments, generation of the polyamidoamine spacers and pH, were studied. Further, the adsorption mechanisms were explored by means of adsorption kinetics and isotherms. RESULTS Assembling DNA fragments on the polyamidoamine-grafted beads promoted sharply the removal of both Hg(II) and MeHg(I). Adsorptions of Hg(II) and MeHg(I) followed pseudo-second-order kinetics; but their adsorption isotherms obeyed Langmuir and Freundlich models, respectively. Under the optimum conditions, the adsorption equilibrium time was approximately 5 min for Hg(II) and 5 s for MeHg(I) with maximum percentage removals of ∼95% and ∼90%, respectively. The adsorbent could be regenerated easily without significant decrease in removal efficiencies. CONCLUSION The Fe 3 O 4 -SiO 2 -PAMAM beads could bind DNA steadily, and the DNA fragments interacted strongly with mercury species. The strategy enabled the water-soluble DNAs to work as efficient removing reagents for rapid and cost-effective removal of Hg(II) and MeHg(I). © 2016 Society of Chemical Industry

Effective BiOBr(I)-BP nanocomposite for synergistic photothermal and radiodynamic therapy against hypoxic tumor to complement low dose radiotherapy

Jiayun Cheng,Shufen Ren,Hanping Fu,Qing Zhang,Yan Xie,Qingshuang Liang,Xiufeng Xiao

Improving radiation effect and reducing radiation resistance is the key issue to boost the effectiveness of radiotherapy. Herein, we have developed a novel BiOBr 0.5 I 0.5 -BP heterojunction nanosheets (BOBI-BP NSs) for synergistic radiodynamic and photothermal therapy to enhance the efficacy of low-dose radiotherapy under hypoxic conditions. On one hand, this BOBI-BP heterojunction is rich in high-Z elements (Bi, I) and able to deposit high radiation doses into cancer cells, enhancing the radiotherapy effect. On the other hand, due to the heterojunction structure, a large number of electron-hole pairs can be generated and separated under X-ray trigger, which significantly improves the catalytic activity of catalyzing the overexpressed H 2 O 2 in cancer cells into highly toxic •OH, overcoming the oxygen dependence. 1 O 2 could be generated because of the unique sub-band structures of BP NSs and the synergistic effect between BOBI and BP, thereby improving the therapeutic utility of low-dose X-ray irradiation. The synergistic utility of BOBI-BP NSs as a combination of radiodynamic therapy, photothermal therapy agent and radiosensitizer was demonstrated both in vitro and in vivo. This work provides the idea to develop rational designed heterostructures as efficient therapeutic nanoplatform for cancer treatment.

Bulk single crystal growth and optoelectronic properties of the quasi-two-dimensional perovskites (CH3NH3)3Bi2X9 (X-=Br- and I-)

Zhiyuan Li,Xiangjun Wang,Peng Zhao,Jingquan Liu,Xiangxin Tian

Two-dimensional perovskites have demonstrated superior application prospects in optoelectronic fields, such as X-ray detection, light emitting diodes, and photovoltaics, as their tunability of band structures, improved stability, fast responses, and suppressed noise signal. In this work, bulk single crystals of MA3Bi2Br9 (MA+=CH3NH3+) and its two mixed crystal MA3Bi2(Br0.74I0.26)9, MA3Bi2(Br0.62I0.38)9 were successfully grown using the bottom-seeded solution growth method. MA3Bi2I9 crystals were also prepared and characterized for comparisons. X-ray diffraction analysis revealed that all the crystals had quasi-two-dimensional (2D) structures and the partial substitution of I- for Br- did not alter the space group symmetry. However, with the increase of I- concentrations, the incongruently melting temperature gradually decreased from 342 oC for MA3Bi2Br9 to 328 oC for MA3Bi2(Br0.62I0.38)9, respectively. For optoelectronic properties, the MA3Bi2Br9 was measured to have a direct bandgap of 2.60 eV, while the values decreased to 2.15 eV for MA3Bi2(Br0.74I0.26)9, 2.04 eV for MA3Bi2(Br0.62I0.38)9, and 1.97 eV for MA3Bi2I9, respectively. Similarly, the photoluminescence peaks blue-shifted from 550 nm for MA3Bi2Br9, to 453 nm for MA3Bi2(Br0.74I0.26)9, 445 nm for MA3Bi2(Br0.62I0.38)9, and 444 nm for MA3Bi2I9, respectively. Due to the strong dielectric confinement effects and anisotropic exciton transportation characteristics of the 2D structures, the targeted crystals studied all exhibited ultrafast fluorescence decay characteristics, where decay time as short as 0.65 ns the sub-nanosecond, for MA3Bi2Br9, 1.06 ns for MA3Bi2(Br0.74I0.26)9, 3.00 ns for MA3Bi2(Br0.62I0.38)9, and 3.12 ns for MA3Bi2I9, respectively, were observed. Besides, the low dimensional structures also brought the crystals superior environmental stability as the suppressed ion migrations. This work provides simple, straightforward method for the large-sized crystal growth of low dimensional MA3Bi2X9 (X-=Br-, I-), and reveals their promising application prospects in novel optoelectronic fields.

Flash synthesis of high-performance and color-tunable copper(I)-based cluster scintillators for efficient dynamic X-ray imaging

Zhao Wenjing,Wang Yanze,Li Ruizi,Liu Xiaowang,Huang Wei

Exploration of novel dual-emission NL-CDs/Cu–Cy–I ratio fluorescent probe for the sensitive detection of amoxicillin

Bowen Shi,Zirui Yin,Xiaodan Tang,Hongmei Yu,Shuanping Cui,Wei Chen

A dual-emission ratio fluorescence probe (NL-CDs/Cu–Cy–I) was fabricated via an electrostatic self-assembly method. NL-CDs served as the reference signal (Em = 433 nm), remaining insensitive to amoxicillin, while Cu–Cy–I acted as the response signal (Em = 601 nm), exhibiting varying degrees of fluorescence quenching with amoxicillin concentration changes. This established a fluorescence sensing platform leveraging internal filtration and static quenching synergistically, ensuring high specificity. Compared to the single-signal Cu–Cy–I fluorescence probe, the detection range expanded from 0.5–15 μmol L−1 to 0.2–30 μmol L−1, with the detection limit decreasing from 0.12 μmol L−1 to 0.073 μmol L−1, demonstrating significant enhancements in both range and limit. The developed ratiometric fluorescent probe was effectively employed for amoxicillin monitoring in environmental water samples, urine samples, and amoxicillin capsules, achieving recovery rates of 96.5–102.9%. This underscores the accuracy and practical applicability of the NL-CDs/Cu–Cy–I ratio fluorescence probe-based fluorescence analysis method for amoxicillin detection.

Ferricyanide-Mediated, Electrocatalytic Mechanism of Electrochemical Aptamer-Based Sensor Supports Ultrasensitive Analysis of Cardiac Troponin I in Clinical Samples

Xuewei Du,Wanxue Zhang,Suyan Yi,Shaoguang Li,Hui Li,Fan Xia

Rapid, reagent-free, and ultrasensitive analysis of cardiac troponin I (cTnI) is of significance for early diagnosis of acute myocardial infarction (AMI). The electrochemical aptamer-based (EAB) sensors are promising candidates to fill this role as they are reagentless and can be directly interrogated in complex matrices (e.g., blood). To achieve high sensitivity, EAB sensors typically require nanomaterials or other amplification strategies, which often involves a cumbersome fabrication process. To circumvent this, here we develop a simple yet effective electrocatalytic electrochemical aptamer-based (Ec-EAB) sensor that utilizes target-induced regulation of the catalytic mechanism to achieve ultrasensitive measurement of cTnI. In this assay, we employed a probe-attached redox reporter (i.e., methylene blue, MB) and a solution-diffusive redox reporter (i.e., Fe(CN)63–) to generate two signals, of which the latter is used to catalyze MB to amplify aptamer-mediated charge transfer. The recognition of target altered the diffusion of catalysts (2.2 × 10–9 mol/cm2 in the target-free state versus 1.2 × 10–9 mol/cm2 in the target-bound state) and thus electrocatalytical efficiency, enabling ultrasensitive measurement of cTnI with a 1000-fold improvement in their sensitivity (a limit of detection value: 10 pg/mL).

I-Motif DNA Based Fluorescent Ratiometric Microneedle Sensing Patch for Sensitive Response of Small pH Variations in Interstitial Fluid

Lin He,Yan Zhou,Min Zhang,Mingjian Chen,Yuchen Wu,Lanlin Qi,Lamei Liu,Bin Zhang,Xiaohai Yang,Xiaoxiao He,Kemin Wang

Detection of slight pH changes in skin interstitial fluid (ISF) is crucial yet challenging for studying pathological processes and understanding personal health conditions. In this work, we construct an i-motif DNA based fluorescent ratiometric microneedle sensing patch (IFR-pH MN patch) strategy that enables minimally invasive, high-resolution, and sensitive transdermal monitoring of small pH variations in ISF. The IFR-pH MN patch with advanced integration of both ISF sampling and pH sensing was fabricated from the cross-linking of gelatin methacryloyl and methacrylated hyaluronic acid, wrapping with pH-sensitive hairpin-containing i-motif DNA based fluorescent ratiometric probes in the matrix. Because it is mechanically robust for skin penetration and has high swelling ability, the IFR-pH MN patch could be quickly extracted as sufficient liquid from agarose gel (∼56.4 μL in 10 min). Benefiting from conformation changes of the hairpin-containing i-motif DNA under pH variation and ratiometric fluorescence signal readout, the IFR-pH MN patch could quantitate pH over a small range between pH 6.2 and 6.9 with an accuracy of 0.2 pH units in the mimic skin model. Furthermore, in vivo testing on wound and tumor mouse models indicated the ability of the biocompatible IFR-pH MN patch to penetrate the skin for obtaining transdermal pH values, demonstrating the potential applications in monitoring and intervention of pathological states.

Flexible anode materials for lithium-ion batteries derived from waste biomass-based carbon nanofibers: I. Effect of carbonization temperature

Lei Tao,Yuanbo Huang,Xiaoqin Yang,Yunwu Zheng,Can Liu,Mingwei Di,Zhifeng Zheng

Carbon nanofibers (CNFs) with excellent electrochemical performance represent a novel class of carbon nanostructures for boosting electrochemical applications, especially sustainable electrochemical energy conversion and storage applications. This work builds on an earlier study where the CNFs were prepared from a waste biomass (walnut shells) using a relatively simple procedure of liquefying the biomass, and electrospinning and carbonizing the fibrils. We further improved the mass ratio of the liquefying process and investigated the effects of the high temperature carbonization process at 1000, 1500 and 2000 °C, and comprehensively characterized the morphology, structural properties, and specific surface area of walnut shell-derived CNFs; and their electrochemical performance was also investigated as electrode materials in Li-ion batteries. Results demonstrated that the CNF anode obtained at 1000 °C exhibits a high specific capacity up to 271.7 mA h g−1 at 30 mA g−1, good rate capacity (131.3 and 102.2 mA h g−1 at 1 A g−1 and 2 A g−1, respectively), and excellent cycling performance (above 200 mA h g−1 specific capacity without any capacity decay after 200 cycles at 100 mA g−1). The present work demonstrates the great potential for converting low-cost biomass to high-value carbon materials for applications in energy storage.