CELLULOSE
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2019
·Vol. 26
·期 17
·9149-9161
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IF 3.917
Zhu Hongxiang,Guo Wei,Wang Jian,He Hui,Hou Xudong,Zhou Shile,Wang Shuangfei
Abstract A novel biomass pulp fibre (PF)-based colorimetric sensor was prepared by grafting l -lysine ( l -lys) onto the surface of PFs via a Schiff base reaction. The grafted l -lys contained two specific synergistic recognition groups (–COOH and –NH 2 ), which only recognize Ag + . The as-prepared sensor (DAPF- l -lys) showed excellent selective recognition of Ag + and an obvious visual colour change from light-yellow to brown in aqueous solutions containing other ions (Cu 2+ , Pb 2+ , Mn 2+ , Mg 2+ , Cd 2+ , Ca 2+ , H 2 O, Al 3+ , Hg 2+ , Cr 6+ , K + , Na + and Zn 2+ ). The visual limit of detection for Ag + was 10 –7 mol/L. Furthermore, DAPF- l -lys responded to Ag + within 30 s based on the dynamic conditions of the detection method. The biomass PF matrix possessed the excellent properties, including a large external surface area, a short transit distance and good flexibility. When specific synergistic recognition groups were grafted onto the PF of the prepared PF-based colorimetric sensor, Ag + could be rapidly absorbed and enriched on the surface of DAPF- l -lys through only bi-dentate ligand chelation between Ag + and the synergistic recognition groups (–COOH and –NH 2 ) of DAPF- l -lys. Thus, the DAPF- l -lys colorimetric sensor exhibited promising prospects for on-site identification of Ag + (the level of ppb ) due to its high selectivity and sensitivity. Graphic abstract
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RSC Advances
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2018
·Vol. 8
·期 25
·14056-14063
·
IF 2.936
Juanjuan Ma,Chaocun Zhou,Jinlin Long,Zhengxin Ding,Rusheng Yuan,Chao Xu
Graphene-based cocatalysts can improve the photocatalytic properties of semiconductors, but sometimes, they also function as barrier-like materials, influencing the photoactivity of composites. However, in a multi-cocatalyst system, less attention is paid to these negative effects of graphene on the performance of other cocatalysts. In this study, by adjusting the loading sequence of graphene and Ag cocatalyst on the surface of TiO2 spheres, the barrier effect of graphene sheets on Ag nanoparticles could be controlled effectively. As a result, these ternary composites with almost no Ag nanoparticles wrapped by graphene possessed improved properties for the photocatalytic reduction of nitro-aromatics as compared to those with some Ag nanoparticles covered by graphene. Furthermore, this phenomenon of barrier effect caused by graphene could be found in the control reaction with metal silver as the main catalyst; this indicated that by avoiding the possible negative influence of graphene on other cocatalysts, the properties of composites with graphene-containing multi cocatalysts could be further improved.
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ANALYTICAL CHEMISTRY
·
2018
·
IF 6.042
Zhongju Ye,Rui Weng,Yanhong Ma,Fuyan Wang,Hua Liu,Lin Wei,Lehui Xiao
Rapid quantification of permanganate (MnO4–) in aqueous solution with a convenient and sensitive single-particle-detection (SPD) method is demonstrated by dark-field optical microscopy. The design is based on the selective etching of the Ag shell of a glucose-protected GNPs@Ag nanoparticle by MnO4–. In the presence of MnO4–, a noticeable red-shift of localized surface-plasmon resonance (LSPR, from blue to green) together with a tremendous decrease in the extinction coefficient from individual GNPs@Ag nanoparticles is observed. MnO4– can then be quantified by calculating the ratio between the number of green and blue particles on the cover glass surface after the etching process. A linear dynamic range of 0–6 μM and a limit of detection (LOD) as low as 46 nM were readily achieved, which are much lower than those of spectroscopic measurements in bulk solution. In tap water, a comparable LOD (50 nM) and satisfactory recovery efficiency are demonstrated. As a consequence of these merits, the method demonstrated herein will find promising applications for the ultrasensitive detection of MnO4– under complex milieu in the future.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 23
·15895-15906
·
IF 2.993
Sun Li,Lv Pengcheng,Li Haonan,Wang Fa,Su Wenxian,Zhang Lixin
Abstract The green and controllable synthesis of Au–Ag alloy nanoparticles (NPs) in one-pot has been a challenge in nanotechnology. Here, the soluble starch was employed as a reducing and capping agent to synthesize stable Au–Ag alloy NPs without using any toxic agent. The surface plasmon resonance wavelength and the composition of Au–Ag alloy NPs could be continuously adjusted only by the synthesis time in one-pot. Au–Ag alloy NPs were characterized by means of various techniques. It could be found as-prepared NPs were quasi-spherical with a small average size and a face-centered cubic polycrystalline structure. The above green synthesis method, facile, efficient and eco-friendly, can be extended to the controllable synthesis of other bimetallic NPs. Obtained Au–Ag alloy NPs exhibited a superior photocatalytic activity and stability for the 4-nitrophenol (4-NP) degradation due to abundance hydroxyl groups of the soluble starch and the synergistic effect between Au and Ag elements. The rate constant of 4-NP degradation could be linearly tuned by the composition of Au–Ag alloy NPs and their synthesis time besides their addition amount. The above methods to control the rate constant provide promising routes for other photocatalytic reactions using bimetallic NPs as photocatalysts. Graphical Abstract
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CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Gongduan Fan,Xiaomei Zheng,Jing Luo,Huiping Peng,Hui Lin,Minchen Bao,Liang Hong,Jinjin Zhou
The presence of acetaminophen (ACT) used for painkillers has attracted great attention in the world, which have potentially adverse effects on aquatic lives and human beings. Advanced oxidation technology applied to water repair has received increasing concerns in recent years. In this study, photodegradation ACT in aqueous solution over Ag/AgCl@ZIF-8 synthesised by a simple stirring method was investigated under visible light irradiation. The prepared photocatalyst was characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectra (UV-vis). The degradation rates of ACT under different parameters were studied to get the optimal operating conditions in water. Results showed that the photodegradation process fitted pseudo-first order model well. 99% ACT degradation achieved when Ag/AgCl@ZIF-8 was delivered to the solution compared with ZIF-8 and Ag/AgCl with the maximum value of constant ( k app ). The degradation rate obviously slowed down when the initial concentration of ACT increased to 2 mg/L while it increased with the increasing of dosage of photocatalyst. In contrast, pH has little effect on the degradation of ACT over Ag/AgCl@ZIF-8. The Ag/AgCl@ZIF-8 showed high efficiency for degradation after three repeated cycles which demonstrated the prepared photocatalyst has high stability. The O 2 − turned out to be the main active group during the photodegradation process responsible for the disappearance of ACT. Intermediate products analysis results by LC-MS showed that photolysis was the first step of photocatalytic degradation for ACT followed by a ring cleavage.
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NANO
·
2018
·
IF 1.1
Zongxue Yu,Xia Min,Fei Li,Qi Chen
In the study, the Ag–SiO 2 –APTES nanocomposite was synthesized via the self-assembly method to prepare Ag–SiO 2 and subsequently used 3-aminopropyltriethoxysilane (APTES) to functionalize its surface. The as-prepared Ag–SiO 2 –APTES nanocomposite was embedded into poly(vinylidene fluoride) (PVDF) membrane by the co-blending way to fabricate the Ag–SiO 2 –APTES membrane. The Ag–SiO 2 –APTES nanocomposites were characterized by X-ray diffraction (XRD). These membrane materials were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and FT-IR spectra. The performance of membrane was investigated simultaneously for removing the organic dye methylene blue (MB), Rhodamine B, Direct Red 28 and anti-microbial ability. The experimental results demonstrated that the Ag–SiO 2 –APTES modified membrane were presented to be more hydrophilic with a contact angle 55.6 ∘ , whereas the pristine PVDF membrane was 81.8 ∘ . The dye rejection ratios were also improved after adding Ag–SiO 2 –APTES, which reached 86.8% for MB, 87% Rhodamine B, 88% for Direct Red 28, besides, the removal rate of MB was about 98.7% at pH = 11. More importantly, the Ag–SiO 2 –APTES membranes exhibited excellent antifouling properties for treating MB solution and could reach 85% of flux recovery ratio after four cyclic experiment. Finally, via inhibition zone method of antimicrobial test Ag–SiO 2 –APTES membrane exhibited the antimicrobial activity against Escherichia coli ( E. coli ) excellently. The novel antifouling and antibacterial Ag–SiO 2 –APTES membrane has a potential for dye wastewater treatment and water purity.
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ACS Omega
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2018
·
IF 0
Dan Yang,Xinxin Kong,Yufeng Ni,Yingjie Xu,Shuo Huang,Guangjie Shang,Hao Xue,Wenli Guo,Liqun Zhang
We demonstrate the synthesis of a novel core–satellite-structured BaTiO3–poly(dopamine)–silver (BT–PDA–Ag) nanoparticle for improving dielectric properties of nitrile-butadiene rubber (NBR) nanocomposites. The BT–PDA–Ag nanoparticles are synthesized by dopamine oxidative polymerization and electroless plating of silver. The Ag nanoparticles decorated on the BT nanoparticles enhanced the dielectric constant of NBR nanocomposites due to the increased conductivity of the filler/matrix interlayer and nanocapacitor structure. In addition, the incorporation of the BT nanoparticles prevented the continuous connection of Ag nanoparticles and suppressed the formation of a conductive path in the NBR matrix. Moreover, the ultrasmall Ag nanoparticles trapped the carriers by Coulomb blockade and quantum confinement effects, which results in low dielectric loss and electrical conductivity of nanocomposites. The proposed method with simplicity and scalability can be adapted to process high-dielectric polymer nanocomposites.
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Nanophotonics
·
2019
·Vol. 8
·期 10
·1719-1729
·
IF 6.908
Xiaofei Zhao,Chonghui Li,Zhen Li,Jing Yu,Jie Pan,Haipeng Si,Cheng Yang,Shouzhen Jiang,Chao Zhang,Baoyuan Man
An efficient electrospun aligned surface enhanced Raman scattering (SERS) and maize-like substrate of polyvinyl alcohol (PVA) composite and Ag colloid nanofibers decorated with thermal evaporated Ag nanoparticles (AgNPs) has been developed by taking advantage of electrostatic interactions. The synergistic effects of the evaporated AgNPs (niblets) and the Ag colloid in PVA (corncob) could arouse strong electromagnetic field between the lateral and vertical nanogaps which has been demonstrated by experiment and finite-different time-domain (FDTD) simulation. In this experiment, the aligned nanofibers possesses an excellent sensitivity by detection of crystal violet (CV) and malachite green (MG) molecule at low concentration. Moreover, the proposed flexible SERS sensor was measured with outstanding uniformity and reproducibility. We also carried out in-situ electrospinning on a curved surface to detect the mixture of Sudan I, CV and MG molecule, which demonstrates that flexible SERS sensor, has enormous potential in accurate and in-situ detection on the complex geometric structure.
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Catalysts
·
2018
·Vol. 8
·期 12
·628
·
IF 3.465
Lei Wang,Changbo Zhang,Rong Cheng,Jafar Ali,Zhenbo Wang,Gilles Mailhot,Gang Pan
Cyanobacterial blooms can cause serious damage to aquatic ecosystems. However, we have demonstrated that typical algae-blooming speciesMicrocystis aeruginosa (M. aeruginosa)combined with photocatalysts could synergistically facilitate the photodecontamination of tetracycline hydrochloride (TC) and Cr(VI). In this study, for the first time, harmful algae were successfully converted into photoreactive bionano hybrid materials by immobilizingM. aeruginosacells onto polyacrylonitrile (PAN)-TiO2/Ag hybrid nanofibers, and their photocatalytic activity was evaluated. The addition ofM. aeruginosasignificantly improved the photodecontamination, and the reaction rate constant (k) values of TC and Cr(VI) degradation byM. aeruginosa-PAN/TiO2/Ag nanofiber mats were 2.4 and 1.5-fold higher than that of bare PAN/TiO2/Ag nanofiber. Photoreaction caused damage to algae cells, but no microcystin was found that had been photodegraded simultaneously. The effects of various active species were also investigated, and the photodegradation mechanism was proposed. Recycling tests revealed that this flexibleM. aeruginosa-PAN/TiO2/Ag hybrid mat had potential application in the removal of mixed organic and inorganic pollutants with high efficiency and without secondary pollutants. Thus, harmful algae blooms could serve as an efficient materials to remove toxic pollutants in a sustainable way under visible light irradiation.Keywords:Microcystis aeruginosa;PAN nanofiber;TiO2photocatalytic;Ag nanoparticles;tetracycline;Cr(VI)
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CELLULOSE
·
2018
·Vol. 25
·期 12
·7211-7224
·
IF 3.809
Fu Feiya,Zhang Weilan,Zhang Ruihong,Liu Lin,Chen Shichang,Zhang Yupeng,Yang Binbin,Touhid Salvia,Liu Xiangdong,Zhou Jinping,Yao Juming
Abstract Cellulose hybrid fibers embedded with silver nanoparticles (Ag NPs) were prepared from a spinning dope through a bottom-up approach. Instead of using toxic agents or high temperature, an alkaline cellulose dope was directly used as a reducing agent for in situ synthesis of Ag NPs. The regenerated cellulose fibers displayed a dense circular microstructure and Ag NPs with a mean diameter of 40.1 nm were inlaid on its surface and inside. By increasing the spinning drawing ratio, the diameter and Ag content of the nanohybrid fibers decreased while its tensile strength in dry state increased significantly. Because of the embedded structure of NPs, the width of inhibition zone for the nanohybrid fibers against S. aureus and E. coli was small. However, both bacteria could be killed within 5 h in the presence of the nanobybrid fibers. In particular, the nanobybrid fibers showed excellent antibacterial durability and low cell toxicity. Besides, it was demonstrated that the nanobybrid fibers with lower diameter showed better catalytic activity and the catalytic efficiency could reach 99.3% for methyl orange. This biosynthesis approach is expected to offer a sustainable method for scale-up fabrication of functional cellulose fibers. Graphical abstract
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Min Yang,Yujia Yan,Huanxian Shi,Cunjin Wang,Enzhou Liu,Xiaoyun Hu,Jun Fan
In the design of new fluorescence sensors, exploration of new sensors with excellent performances and smart designs for the detection of ions and biomolecules is of continuing interest. Therefore, we designed an inner filter effect (IFE) based sensor by effectively combining between CdTeS quantum dots (QDs) and Ag nanoparticles (NPs). Ternary alloyed CdTeS QDs were synthesized by two steps and using 3-mercaptopropionic acid (MPA) as stabilizer , polyvinylpyrrolidone (PVP) stabilized Ag NPs were prepared by crystal-seed. The emission peak of CdTeS QDs and the absorption peak of Ag NPs could availably overlap by changing the Te/S molar ratios and l -ascorbic acid (AA) concentrations. The CdTeS QDs/Ag NPs (QNs) with an obviously emission at 580 nm were used as IFE-based sensors for l -cysteine (L-Cys). The QNs fluorescence was increasing with addition of l -Cysteine (L-Cys), the fluorescence (PL) intensity (F/F 0 ) was linearly proportional to the L-Cys concentrations ranging from 20 μM to 400 μM with the correlation coefficient (R 2 ) of 0.9942 and the detection limit was calculated to be 0.025 μM (S/N = 3), where F and F 0 were the PL intensity in the presence and absence of L-Cys at 580 nm, respectively. Moreover, there was no interference to some potential interfering substances, which showed high sensitivity and selectivity for L-Cys.
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TALANTA
·
2018
·
IF 4.244
Bin Chen,Junjie Liu,Tong Yang,Lin Chen,Jia Hou,Changhao Feng,Cheng Zhi Huang
Ag + as one of the most commonly seen toxic heavy metal ions is involved in numerous vital biological processes, which would cause fatal damages and environmental contamination when Ag + is excessive. In the present work, CdTe quantum dots (QDs) with green, orange, and red emission capped by mercaptoacetic acid (TGA) were synthesized at one time by controlling the synthesis time and utilized for Ag + detection. Both fluorescence spectral red-shift and intensity decrease could be used for Ag + discrimination. Fluorescence lifetime , Zeta potential , and XRD, etc. were carried out to analyze the detection mechanism. Results displayed that surface passivation and electron transfer due to binding effects of Ag + to Te atom on traps of QDs could be relied on to explain the sensing mechanism. Additionally, in accordance with PCA analysis, Ag + could be also be successfully differentiated from Hg 2+ and the other metal ions. Importantly, a home-made portable device based on a 32 bit embed Micro Control Unit (MCU) system was first proposed for Ag + detection. The power supply system adopt the mini-sized lithium cell instead of the power supply system, which ensure its practical applicability. The relative position of light source and detector is set at 90° to minimize the interference. According to the detection results, the linear detection range using the device was from 5 nM to 200 nM (with a larger coefficient of determination, R 2 ), and the detection limit was calculated to be about 5 nM, which indicated that this proposed method and device could fulfil the practical application requirements.
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