查找使用阿拉丁产品的科研文献

Pyrene-functionalized halloysite nanotubes for simultaneously detecting and separating Hg(ii) in aqueous media: A comprehensive comparison on interparticle and intraparticle excimers

Haiyun Fan,Pengying Jia,Hailei Zhang,Zhiyi Su,Xinwu Ba,Yonggang Wu

The development of a facile approach to simultaneously detect and separate Hg( ii ) ions in an aqueous solution is a challenging topic in the chemosensing field. Herein, we focus on constructing the Hg( ii )-sensitive fluorescence “turn-on”-type composite materials by using halloysite nanotube (HNT) as substrate. Two types of HNTs-based chemosensors, HNTs-PHT and HNTs-BP, were developed in this study, which exhibit Hg( ii )-sensitive fluorescence “turn on” behavior by forming interparticle and intraparticle excimers, respectively. Fortunately, HNTs-PHT is able to effectively restrict the solvent relaxation of π–π* transition and make it a better detection tool in aqueous solution than HNTs-BP. The addition of Hg( ii ) can trigger a dramatical increase at 469 nm in emission curves of HNTs-PHT, which cannot exhibit emission behaviors without the addition of Hg( ii ). Furthermore, the formation of interparticle excimers makes Hg( ii ) serve as a crosslinker to aggregate HNTs-PHT into precipitations. Following this way, Hg( ii ) ions can be facilely removed from the water via a simple filtration or centrifugation approach. The as-prepared HNTs-PHT shows high specificity and precision in simultaneously detecting and separating Hg( ii ) without the recourse to energy consumption, which will give a novel insight to deal with heavy metal pollution.

Encapsulation of nano-sized ZIF-67 derived Co-NC on Au-loaded halloysite as composite catalyst for superior cooperative reduction of nitroaromatic pollutants

Jiasheng Fang,Zhenting Huang,Ming Chen,Shuo Zhao,Zhihui Liang,Qiongfang Zhuo,Yongfu Qiu

The utilization of natural clay minerals for synthesizing nano-sized metal-organic frameworks (MOFs) supported materials offers great advantages for rational design of innovative catalysts, which promotes the low-cost and large-scale environmental remediation applications. This work reported a facile and scalable encapsulation-pyrolysis strategy to prepare novel Au-HNTs@Co-NC core-shell catalyst for catalytic reduction of nitroaromatic pollutants. The HNTs were modified with aminosilane on the external surface for effectively anchoring well-dispersed and ultrasmall Au NPs. Uniform nano-sized ZIF-67 crystals controllably embraced the Au-HNTs via in-situ growth induced by electrostatic adsorption. The N 2 atmosphere pyrolysis at 550 °C resulted in Co NPs embedded into N-doped carbon substrates, and transformed ZIF-67 crystals into Co-NC layers for preferable encapsulation and stabilization of Au NPs. The as-prepared Au-HNTs@Co-NC-550 catalyst manifested splendid catalytic performance for p-nitrophenol reduction, and achieved the reaction rate constant and TOF value estimated as 2.025 min −1 and 49.25 min −1 , which significantly exceeded the behaviors of as-prepared control materials. Moreover, the catalyst also displayed excellent catalytic capability toward the reduction of nitroanilines and homologues and isomers of p-nitrophenol, indicative of its decent general applicability. After 8 cycles of reactions, the catalyst still retained brilliant reusability and structural stability with good magnetic property for expedient separation. The advantageous hollow core-shell structure combining HNTs and ZIF-67 derivatives enhanced the reactant diffusion and transfer. The N doping and electronegativity difference between Co and Au aroused higher electron uptake and facilitated electron transport during the reduction process. Meanwhile, the Co–H and Au–H bonds formed the strong synergistic effect for superior cooperative catalytic performance of the catalyst.

Electrospinning preparation and mechanical properties of PVA/HNTs composite nanofibers

Zhi-Lin Cheng,Xi-Xi Qin,Zan Liu,Dun-Zhong Qin

In this paper, the PVA/HNTs composite nanofibers with well-enhanced mechanical properties were successfully prepared by electrospinning technique. The structure and properties of the composite nanofibers were characterized by TEM, XRD, FT-IR, and DSC. The results indicated that the highly oriented and dispersed HNTs wrapped in polymer matrix were achieved by inducing function during electrospinning processing. The mechanical properties of the PVA/HNTs composite nanofibers depended on HNTs content were investigated, which showed 72.4% increase in tensile strength at optimal filling content. Copyright © 2016 John Wiley & Sons, Ltd.

Preparation and anticorrosion properties of BTA@HNTs-GO nanocomposite smart coatings

Legang Chen,Zongxue Yu,Di Yin,Kunyao Cao

Functionalized HNTs nanocluster vulcanized natural rubber with high filler-rubber interaction

Lijuan Chen,Zhixin Jia,Xiaohui Guo,Bangchao Zhong,Yongjun Chen,Yuanfang Luo,Demin Jia

A novel functional rubber vulcanizator, halloysite nanotubes (HNTs) supported sulfur monochloride (HNTs-s-S) is prepared by chemically bonding sulfur monochloride (S 2 Cl 2 ) onto HNTs surface. Through this chemical reaction, high concentration of sulfur is supported onto HNTs inner and outer surface. Meanwhile, the functional nanotubes can not only vulcanize the rubber without sulfur and show the lower activation energy of vulcanization reaction, but also improve the filler-rubber interaction as a modifier due to the improved modification effect. Furthermore, the immobilized polymer layer and crosslinking density of rubber composites together indicate that this novel vulcanizing agent HNTs-s-S gives rise to significant improvement in the rubber-filler interfacial adhesion, which is on account of the promoted vulcanizing on the functional HNTs surface with the supported sulfur. After endowing the tubular nanofillers with vulcanized function, it may offer new scientific and technological opportunities for the preparation of high performance elastomer composites.

Synthesis and inhibition behavior of acid stimuli-responsive Ca-Na2MoO4-HNTs nanocomposite

Xuteng Xing,Jihui Wang,Wenbin Hu,Qiushi Li,Jing Yuan

Halloysite nanotubes (HNTs) are the natural clay mineral with a tubular structure, which can be used as the nanocontainer for loading corrosion inhibitor . In this work, Na 2 MoO 4 was loaded into HNTs (defined as “Na 2 MoO 4 -HNTs”) through vacuum negative pressure method. In order to control the release rate of Na 2 MoO 4 from Na 2 MoO 4 -HNTs, the insoluble CaMoO 4 complex was introduced at the end of tubes through the interaction between Na 2 MoO 4 and Ca 2+ to obtain Ca-Na 2 MoO 4 -HNTs. The surface morphology was investigated by transmission electron microscope (TEM), and the release behavior was determined by UV–vis spectrophotometer . The inhibition behavior of Ca-Na 2 MoO 4 -HNTs for Q235 steel in 3.5% NaCl solution was investigated by electrochemical impedance spectrum techniques. The results show that Ca-Na 2 MoO 4 -HNTs owns insoluble CaMoO 4 complex capping the end of HNTs, and the total loading capacity of Na 2 MoO 4 is about 14.6%. Moreover, the tunable release of Na 2 MoO 4 can be achieved by controlling the strength of the CaMoO 4 complex stoppers at the end of HNTs, and the release time of Na 2 MoO 4 can be prolonged to more than 600 min. Importantly, the release rate of Na 2 MoO 4 will increase sharply in acid solution, owing to the decomposition of CaMoO 4 complex. In addition, Q235 steel in 3.5% NaCl solution + 1.0 g/L Ca-Na 2 MoO 4 -HNTs exhibits higher inhibition efficiency (60.62% at 24 h) than Q235 steel in 3.5% NaCl solution.

Electrospun PAN-HNTs composite nanofiber membranes for efficient electrostatic capture of particulate matters

Shiqian Hu,Ruowang Chen,Peng Lu,Zida Zheng,Gangwei Gu,Mingyuan Wang,Xiaowei Zhang

The fine particulate matter (PM) pollution has become a serious concern to public health. As the core part of PM air filters, high-performance electrostatic nanofiber membranes are urgently needed. However, the existing air filters remain challenging to further decrease the pressure drop to improve the wearer comfort. On the other hand, the rapidly disappearing static electricity of the existing electrostatic nanofiber inevitably gives rise to a relatively short service life. Here, we demonstrate a novel and enhanced electrostatic nanofiber membrane by introducing the halloysite nanotubes (HNTs) to the traditional electrospun PAN nanofiber membrane. The optimal PAN-HNTs nanofiber membrane shows a high removal efficiency of 99.54%, a low pressure drop of 39 Pa, and a high quality factor of 0.89 Pa−1. This greatly improved filtration performance can be attributed to the increased surface area and diameter of nanofiber after introducing the HNTs as additives with suitable doping concentrations. More importantly, compared with the pure PAN nanofiber membrane, the electrostatic capacity of the PAN-HNTs nanofiber membrane is significantly enhanced, which is confirmed by the leaf electroscope. After introducing the HNTs as additives, the surface of the PAN-HNTs nanofiber membrane becomes hydrophilic, which benefits for preventing foulants from attaching to the surface. We anticipate that the PAN-HNTs nanofibers as high-performance membrane air filters will bring great benefits to public health.

Dual-functional LaFeO3/CdS/HNTs heterojunction: Combining antibiotic degradation with green H2O2 production

Wei Liang,Zongxue Yu,Kexi Liao,Huiyuan Liu,Zehua Cai,Yunfeng Tian,Lidan Deng,Jingyu Zheng

Novel Z-scheme heterojunctions for photocatalytic breakthroughs. • Dual functions: antibiotic degradation and H 2 O 2 generation. • Integrate environmental remediation with resource conversion. • Optimize key factors for balanced dual functionality. To address antibiotic pollution, high carrier recombination, and the risks associated with externally applied hydrogen peroxide, this study constructs a LaFeO 3 /CdS Z-scheme heterojunction on halloysite nanotubes (HNTs) via hydrothermal-calcination. HNTs prevent nanoparticle agglomeration, while the Z-scheme mechanism reduces recombination and preserves redox activity, enabling synergistic antibiotic degradation and H 2 O 2 production. The HLC catalyst achieves 91.73% tetracycline degradation, 333 μmol/L H 2 O 2 yield, and 80% E. coli antibacterial rate. It performs well under various water qualities and coexisting salts. Mechanistic analysis indicates that tetracycline degradation is primarily driven by the superoxide anion radical as the core active species, whereas hydrogen peroxide generation is hole-dominated; both processes are achieved through the synergistic interaction of multiple active species with photo-generated electrons. Furthermore, in situ-generated H 2 O 2 can undergo self-Fenton reaction with Fe 2+ in the material, further enhancing antibiotic degradation capacity. This study is the first to integrate HNTs with a LaFeO 3 /CdS Z-scheme heterostructure, overcoming the limitations of traditional catalysts. It achieves dual benefits-environmental remediation and in-situ green oxidant synthesis-offering a new design paradigm for low-cost, high-performance multifunctional photocatalysts with strong practical potential for water pollution control. Download: Download high-res image (184KB) Download: Download full-size image

Preparation of high performance NBR/HNTs nanocomposites using an electron transferring interaction method

Shuyan Yang,Yanxue Zhou,Peng Zhang,Zhuodi Cai,Yangping Li,Hongbo Fan

Interfacial interaction is one of the key factors to improve comprehensive properties of polymer/inorganic filler nanocomposites. In this work, a new interfacial interaction called electron transferring interaction is reported in the nitrile-butadiene rubber/halloysite nanotubes (NBR/HNTs) nanocomposites. The X-ray photoelectron spectroscopy (XPS) and in-situ controlling temperature Fourier transform infrared spectroscopy (FTIR) have confirmed that electrons of electron-rich −CN groups in NBR can transfer to the electron-deficiency aluminum atoms of HNTs, which packs a part of NBR molecules onto the surface of HNTs to form bound rubber and stabilize the homogeneous dispersion of HNTs with few agglomeration as revealed by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA) performances, even at high HNTs addition, resulting in high light transmittance. The tensile strength of NBR/30wt%HNTs nanocomposites is about 291% higher than pure NBR, without sacrificing the elongation at break.

Inhibitor loaded functional HNTs modified coatings towards corrosion protection in reinforced concrete environment

Yanli Zhang,Yujie Qiang,Huangwei Ren,Jun Cao,Linjing Cui,Zhifang Zong,Depeng Chen,Tengfei Xiang

In this work, the corrosion inhibitor sodium D-gluconate (SD) was successfully loaded into halloysite nanotubes (HNTs). After that, SD-HNTs-A3@CS/SA smart nanocontainers, achieving controlled release properties of inhibitors, were prepared by the layer-by-layer (LbL) self-assembly method. The BET analysis found that the pore size inside the halloysite nanotubes increased after etching by 3 mol/L H 2 SO 4 . According to the TG results, the loading capacity of corrosion inhibitors increased to three times of the original HNTs. The pH-responsive properties of nanocontainers could be demonstrated by UV–Vis spectroscopy under acidic/basic conditions. Furthermore, SD-HNTs-A3@CS/SA nanoparticles were embedded in epoxy resin to fabricate a smart composite coating . When the SD-HNTs-A3@CS/SA content was 2 %, the composite coating exhibited superior anti-corrosion performance towards steel corrosion in concrete simulation solution (containing 3.5 wt% NaCl), with its impedance at 0.01 Hz maintaining 6.4 × 10 6  Ω·cm 2 even after 18d of corrosion immersion. In addition, the anti-corrosion mechanism of SD for steel matrix was investigated by molecular modeling methods. These findings provide new insights into the preparation of smart coatings, expecting a wide range of applications in the corrosion protection of steel and other metals in reinforced concrete environments.

Enhanced activation of persulfate by FeS2/HNTs microspheres with nanochannels for rapid tetracycline degradation

Xinyu Lei,Limei Wu,Jiayu Li,Mengmeng Niu,Ning Tang,Meng Liu,Yi Zhou,Guocheng Lv

Tetracycline (TC), as a widely used antibiotic, poses severe threats to ecosystems and human health. In this study, the FeS 2 /halloysite nanotubes (FeS 2 /HNTs) microspheres as heterogeneous catalysts were used for sulfate radical-based advanced oxidation processes (SR-AOPs) to degrade TC. By assembling HNTs into the interior of FeS 2 microspheres, the diffusion of TC and persulfate (PS) to the active sites inside the FeS 2 microspheres was enhanced, thereby improving the degradation ability of the catalyst for TC. Within 90 min, the FeS 2 /HNTs + PS system achieved 85.13% removal efficiency of TC, over 30% higher than that of the FeS 2  + HNTs + PS system. Moreover, the FeS 2 /HNTs + PS system not only exhibited excellent degradation efficiency at a low catalyst dosage (0.05 g/L), but also demonstrated robust adaptability to TC concentrations of 10–60 mg/L and pH values of 3–9. The reactive oxygen species (ROS) in the system include · S O 4 − $·\mathrm{S}{\mathrm{O}}_4^{-}$ , ·OH, · O 2 − $·{\mathrm{O}}_2^{-}$ , and 1 O 2 , among which · S O 4 − $·\mathrm{S}{\mathrm{O}}_4^{-}$ and · O 2 − $·{\mathrm{O}}_2^{-}$ played a dominant role. Liquid chromatography-mass spectrometry identified 21 possible degradation intermediates. TC was mainly converted into small-molecule organics through pathways such as demethylation and ring opening. Furthermore, with the extension of degradation time, the mutagenicity and developmental toxicity of the intermediates decreased.

Synthesis of thickness-controllable polydopamine modified halloysite nanotubes (HNTs@PDA) for uranium (VI) removal

Tao Ou,Yuhua Wu,Weixing Han,Lingjun Kong,Gang Song,Diyun Chen,Minhua Su

Halloysite nanotubes (HNTs) are considered structurally promising adsorption materials, but their application is limited due to their poor native adsorption properties. Improving the adsorption capacity of HNTs for radioactive U(VI) is of great significance. By controlling the mass ratio of HNTs and dopamine (DA), composite adsorbents ( [email protected] ) with different polydopamine (PDA) layer thicknesses were synthesized. Characterization of [email protected] demonstrated that the original structure of the HNTs was maintained. Adsorption experiments verified that the adsorption capacity of [email protected] for U(VI) was significantly improved. The effects of solution pH, temperature, and coexisting ions on the adsorption process were investigated. The removal efficiency was observed to be 75% after five repeated uses. The adsorption mechanism of U(VI) by [email protected] can be explained by considering electrostatic interactions and the complexation of C–O, –NH– and C–N/C N in the PDA layer. This study provides some basic information for the application of HNTs for U(VI) removal.