查找使用阿拉丁产品的科研文献

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.

Polyoxometalate-modified halloysite nanotubes-based thin-film nanocomposite membrane for efficient organic solvent nanofiltration

Hongru He,Pan Xu,Daming Wang,Hongwei Zhou,Chunhai Chen

Polyoxometalate-modified halloysite nanotubes (POM@MHNTs) were synthesized and doped into the polyamide (PA) matrix by interfacial polymerization to prepare doped POM@MHNTs thin-film nanocomposite (TFN) membranes for organic solvent nanofiltration (OSN). Likewise, thin-film composite (TFC) and TFN membranes doped with HNTs were fabricated. It is worth noting that the methanol flux of the TFN can be efficiently enhanced by tuning the contents of POM@MHNTs. The as-synthesized optimal sample (TFN-0.10) exhibits superior methanol flux of TFN-0.10 membrane of 14.80 L m −2  h −1  bar −1 (1.76 times of that of undoped TFC membrane and 1.12 times of that of doped HNTs membrane (TFN-HNTs-0.10). These are mainly due to the tubular structure of POM@MHNTs providing additional solvent transfer channels and the ridge-valley morphology of the membrane surface increasing the contact area between the membrane and the solvent. Meanwhile, the POM@MHNTs nanohybrids are similarly electrostatically attracted by the amide groups on the polyamide chains produced by interfacial polymerization, improving the compatibility of POM@MHNTs with polyamide membranes. TFN-0.10 OSN membrane showed stable chemical properties in medium polar organic (methanol, ethanol, THF), acid polar organic (acetonitrile), and strong polar organic (DMF) solvents. Prepared TFN OSN membranes exhibited strong long-term operation capability and organic solvent resistance after 80 °C DMF immersion for 7 days with inconspicuous separation performance changes. This work offers the prospect of using organic-inorganic hybrid modified nanomaterials to improve OSN performance.

Gold@Halloysite nanotubes-chitin composite hydrogel with antibacterial and hemostatic activity for wound healing

Puxiang Zhao,Yue Feng,Youquan Zhou,Cuiying Tan,Mingxian Liu

Infection and healing of wounds after injury has always been an unavoidable problem in daily life, so design of a biomaterial with antibacterial and good wound healing properties is highly needed. Herein, a wound healing hydrogel dressing with halloysite clay and chitin as the main components was prepared, which combines the advantages of the biomacromolecule and clay. Halloysite nanotubes (HNTs) are extremely biocompatible clay materials with a hollow tubular structure, and the inner and outer surfaces of HNTs are composed of SiOx and AlOx layers with different charges. Au nanoparticles with diameter in 5–10 nm were filled into the HNTs' lumen to endow photothermal effect of the clay materials. [email protected] was then mixed with chitin solution to prepare flexible composite hydrogel by crosslinking by epichlorohydrin. The antibacterial properties, biocompatibility and hemostatic properties of the hydrogel material were investigated by antibacterial experiments, cell experiments, mouse liver and tail hemostatic experiments. After infecting the back wound of mice with Staphylococcus aureus, the hydrogel was applied to the wound to further verify the killing effect on bacteria and wound healing effect of the hydrogel material in vivo. The [email protected] composite hydrogel exhibits high antibacterial and hemostatic activity as well as promoting wound healing function with low cytotoxicity. This study is significant for the development of high-performance wound dressings based on two commonly used biocompatible materials, which shows promising application in wound sterilization and healing.

Functionalized halloysite nanotubes endowing epoxy resin with simultaneously enhanced flame retardancy and mechanical properties

Qiuru Bao,Ren He,Yuan Liu,Qi Wang,Chuhong Zhang

In order to impart epoxy resin (EP) with desired flame retardancy, thermal stability and mechanical properties, a novel flame retardant HNT@PZM@Fe(OH) 3 with hierarchical core–shell-dot structure was successfully constructed in this work. The shell layer composed of polyphosphazene (PZM) effectively facilitated the interface interaction between halloysite nanotube (HNT) and polymer matrix, and significantly reinforced the EP nanocomposites (26.6 % increase in tensile strength and 31.5 % increase in impact strength when introduced with 5 wt% HNT@PZM@Fe(OH) 3 ). Owing to the interfacial catalysis of transition metal compounds and barrier effect of HNT, EP/HNT@PZM@Fe(OH) 3 performed remarkably in flame retardancy and smoke suppression. Upon the incorporation of 5 wt% HNT@PZM@Fe(OH) 3 , EP nanocomposites possessed the limiting oxygen index (LOI) of 30.8 %, reaching UL-94 V-0 rating. Cone calorimeter tests proved a distinct fall in the peak of heat release rate (PHRR) and smoke production rate (SPR) of EP/5HNT@PZM@Fe(OH) 3 , being respectively 65.8 % and 57.1 % compared to EP. The relevant tests revealed that the interfacial charring catalysis of transition metal oxides was beneficial to the formation of residual char structure with higher graphitization degree, which further improved the fire safety. Our work has provided a   research basis   and promising prospect for the production of high-efficient flame retardant EP nanocomposites.

Multifunctional nanocomposite based on halloysite nanotubes for efficient luminescent bioimaging and magnetic resonance imaging

Tao Zhou,Lei Jia,Yi-Feng Luo,Jun Xu,Ru-Hua Chen,Zhi-Jun Ge,Tie-Liang Ma,Hong Chen,Tao-Feng Zhu

Amphiphilic halloysite nanotube enclosing molybdenum oxide as nanoreactor for efficient desulfurization of model fuels

Junzhen Guo,Liang Chu,Haibin Yang,Zhi Huang,Mu Yang,Ge Wang

Hollow nanomaterials are regarded as the outstanding supports due to their confinement effect and stable carries, which can enhance the performance of the supported catalysts and even simplify the process. In this work, halloysite nanotubes (HNT) are chosen as the support due to their monoclinic tubular structures with two different surface compositions and charges. By a simple impregnation-calcination approach, MoO x is immobilized in the internal surface of HNT, then modify with organosilanes on the external surface of HNT to yield the amphiphilic Mo/HNT/S nanoreactor. The catalyst exhibits prominent activity for oxidative desulfurization in solvent-free system, the desulfurization rate of dibenzothiophene (DBT) reaches 100 % and the turnover frequency (TOF) value reaches 67.5 h −1 at 60 °C with 15 min, which is higher than most reported Mo-based catalysts. The hydrophobic surface enables the nanoreactor to be well dispersed in oil phase, and H 2 O 2 solution in the hydrophilic cavity can extract DBT to form a concentrated microenvironment of the reactants and reactive oxygen species. The confinement function of the HNT nanoreactor can enhance the activity and stability of active ingredients (MoO x ) over at least 5 cycles. Additionally, oxidation products can be retained in the hydrophilic lumen and completely separated from the model fuel. This amphiphilic catalytic system eliminates the following solvent extraction step in the ODS procedure. Thus, the catalyst is a promising candidate for large-scale industrial application.

Tandem Co–O dual sites on halloysite with promoted reaction kinetics for sulfur reduction

Qiang Zhang,Yinyin Qian,Ji-Jun Zou,Ruijie Gao,Huaming Yang

Facilitating sulfur reduction reaction (SRR) is a promising pathway to tackle the polysulfide shuttle effect and enhance the electrochemical performance of lithium-sulfur (Li-S) batteries. Catalysts with a solo active site can reduce a reaction barrier of a certain transition-intermediate, but the linear scaling relationship between multi-intermediates still obstructs overall SRR. Herein, we construct tandem Co–O dual sites with accelerating SRR kinetics by loading highly dispersed cobalt sulfide clusters on halloysite. This catalyst features Co with upshifted d -orbital and O with downshifted p-orbital, which cooperatively adsorb long-chain polysulfide and dissociate an S–S bond, thus achieving both optimal adsorption–desorption strength and reduced conversion energy barrier of multi-intermediates in SRR. The Li-S coin batteries using the electrocatalyst endows a high specific capacity of 1224.3 mAh g −1 at 0.2 C after 200 cycles, and enhances cycling stability with a low-capacity decay rate of 0.03% per cycle at 1 C after 1000 cycles. Moreover, the strategy of the tandem Co–O dual sites is further verified in a practical Li-S pouch battery that realizes 1014.1 mAh g −1 for 100 cycles, which opens up a novel avenue for designing electrocatalysts to accelerate multi-step reactions.

Acidity-activatable dynamic halloysite nanotubes as a drug delivery system for efficient antitumor therapy

Haimei Wu,Shuo Xu,Kaiwen Lin,Jin Xu,Datian Fu

An intelligent drug delivery system allows temporal, spatial and dose control of drug release, which is greatly important in cancer therapy. However, the low stability of the carrier and poor controllability of the anticancer drug may limit its biomedical application. To overcome these drawbacks, an acidity-activated dynamic halloysite nanotubes (HNTs) drug delivery system was designed to ensure efficient cancer therapy. HNTs are first modified with an aminosilane crosslinker, via (3-aminopropyl) trimethoxysilane (APTES). The latter was a linker to convert partial amino groups to hydrazone groups through stepwise organic transformations. Then, the anticancer drug, doxorubicin (DOX), is loaded through a covalent linkage to yield HNTs-NN-DOX. Finally, the soybean phospholipid (SP) is coated on the surface of HNTs-NN-DOX, named [email protected] to further enhance the stability and biocompatibility of HNTs. The acid-labile bond between the HNTs and DOX releases drugs immediately in response to the tumor microenvironment (TME). In vitro cell toxicity and imaging assay results indicated that the [email protected] has high cell cytotoxicity on 4T1 cells. We provide a new strategy for the biomedical application of HNTs in nanomedicine , which proved that HNTs selective to slight pH differences and promote release of cytotoxic compounds.

Structural engineering of NiFe-Layered double hydroxides and halloysite composites for efficient CO2 capture

Jian Wang,Yan Zhang,Jiwen Si,Wei Zhang,Qing Liang,Wenqing Li,Bo Jin,Shiding Miao

The cost- and use-effects for solid CO 2 adsorbents have accelerated development of the clay-based adsorbents. Herein, a series of NiFe-layered double hydroxides/halloysite (NiFe-LDH/Hal) composites were fabricated via facile hydrothermal strategy using calcined halloysites (Hal) as supports. Depending on treatment temperatures of halloysite, the supported NiFe-LDH exhibited different morphologies in form of nanoparticle or intertwined nanosheets. Based on the distinct morphology, these NiFe-LDH/halloysite composites displayed different textural properties and CO 2 adsorption performance. Particularly, the sample NiFe-LDH/Hal600 using halloysite calcined at 600 °C as support possessed 3D hierarchical structure, and displayed superior CO 2 adsorption capacity of 60.7 mg g −1 and 40.3 mg g −1 at 273 K and 298 K, respectively, much higher than those of NiFe-LDH/Hal composites supporting LDH nanoparticles. The high isosteric heat of adsorption calculated from Clausius-Clapeyron equation (21.7 kJ mol −1 ) indicated the strong interaction between basic NiFe-LDH surface and CO 2 molecules. It was validated that the dehydroxylation and forming of silanols groups during calcination process changed the activity of internal and external surface, resulting in distinct morphology and distribution difference of the supported NiFe-LDH. The prepared clay-based composites displayed satisfying recyclability of CO 2 adsorption at a high retention level after 25 cycles of adsorption–desorption.

Amino functionlized halloysite nanotubes optimizing composite solid electrolyte for advanced solid-state lithium metal batteries

Guoqiang Chen,Song Zhang,Bo Jin,Hui Liu

Battery systems are experiencing unprecedented growth due to the unprecedented application of new energy vehicles. However, most materials used in batteries are produced along with high energy consumption, inevitable pollution or other problems. In contrast with these materials, natural mineral resources have their own attractive advantages such as their unique structures formed in long process. Based on the situation and broad prospects of natural minerals utilized in practical solid-state lithium metal batteries (SSLMBs), this research focuses on polydopamine (PDA) modified halloysite nanotubes (HNTs) as the filler to co mpose a composite solid electrolyte (CSE), in which there are still bis-(trifluoromethane)sulfonimide (LiTFSI) as a lithium salt and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) as a polymer. As the one-dimensional (1D) materials, HNTs can provide mechanical strength and flame retardant while PDA adhered to HNTs can improve the dispersion of filler in the electrolyte, capture dissolved transition metal (TM) ions from cathode, and facilitate Li + ion transport. The fabricated CSE in this study exhibits a high Li + transference number of 0.48, a great ionic conductivity of 0.24 mS cm −1 , a broader electrochemical window of 4.8 V, and good cycling performance on Li||Li symmetrical cell for over 1000 h and LiNi 0.5 Co 0.2 Mn 0.3 O 2 ||Li (NCM523||Li) battery, with the capacity retention rates of 90% after 200 cycles at 0.5 C and 83.9% after 400 cycles at 1 C, respectively. Meanwhile, LiFePO 4 ||PHHP||Li (LFP||PHHP||Li) battery also provides a capacity retention rate of 89.6% and an average CE of 99.5% after 100 cycles at 0.5 C. This study introduces a new option for natural mineral materials to be applied to high-performance SSLMBs.

Selective Recognition of 2,4,6-Trichlorophenol by Molecularly Imprinted Polymers Based on Magnetic Halloysite Nanotubes Composites

Jianming Pan,Hang Yao,Longcheng Xu,Hongxiang Ou,Pengwei Huo,XiuXiu Li,Yongsheng Yan

Magnetic nanoparticles were attached to carboxylic acid functionalized halloysite nanotubes (HNTs−COOH) by high-temperature reaction of ferric triacetylacetonate in 1-methyl-2-pyrrolidone. Then, based on magnetic halloysite nanotubes particles (MHNTs), the magnetic molecularly imprinted polymers (MMIPs) were synthesized for the selective recognition of 2,4,6-trichlorophenol (TCP). MMIPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) analysis, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), elemental analysis, and Raman spectroscopy. MMIPs were demonstrated with an imprinted polymer film (5.0−15.0 nm) and exhibited magnetic property (Ms = 2.74 emu g−1) and thermal stability. Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics, and selective recognition. The Langmuir isotherm model was fitted to the equilibrium data better than the Freundlich model, and the monolayer adsorption capacity of MMIPs was 246.73 mg g−1 at 298 K. The kinetic properties of MMIPs were well-described by the pseudo-second-order equation, initial adsorption rate, and half-adsorption time. The selective recognition experiments demonstrated high affinity and selectivity toward TCP over structurally related phenolic compounds, and hydrogen bonds between TCP and methacrylic acid (MAA) were mainly responsible for the recognition mechanism. In addition, MMIPs could be regenerated, and their adsorption capacity in the fifth use was about 11.0% loss in pure TCP solution, about 16.1% loss in coexisting phenolic compound solution. The MMIPs prepared were successfully applied to the separation of TCP from environmental samples.

Preparation and characterization of poly(vinyl alcohol)/halloysite nanotubes composite sponges with improved mechanical properties

Tianxiang Chen,Sina Chen,Jinyun Wang,Tengfei Lin,Weihang Wu,Weijin Yang,Yu Wang

A novel polyvinyl alcohol (PVA)/halloysite nanotubes (HNTs) composite sponge with preferable properties was fabricated via water solution mixing and casting technique with a fixed PVA ratio and the various contents of nano-fillers. The morphology and physical properties of all the samples have been studied and characterized extensively. The results showed that HNTs were uniformly aligned along in the PVA matrix depending on good interfacial interactions between HNTs and PVA matrix. The addition of HNTs decreased the pore sizes and porosity of the sponges. Mechanical tests indicated that the incorporation of HNTs contribute to the reinforcement in mechanical properties of composite sponges under both dry and moist conditions. In addition, the composites showed better performances in thermal stability and water absorption capacity than pure PVA sponges. Rhodamine B and ibuprofen were employed to evaluate the control release ability. The results illustrated that increasing HNT contents can enhance the sustained release ability of PVA sponges.