INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Zhijun Guo,Guoliang Zhang,Lei Wang,Ping Li,Chunshan Li
To meet the increasing demand for methyl methacrylate, a series of Fe modified Cs–P/γ-Al2O3 catalysts were developed through the impregnation method and tested for the aldol condensation of methyl propionate with formaldehyde in a fixed-bed reactor. Through various characterization studies, the physicochemical properties of the catalysts were systematically studied, especially the relationship between the number of the acid sites and catalytic activity. The number of medium acid sites was increased effectively by the addition of Fe, and the catalytic selectivity was improved consequently. Moreover, the reaction conditions were also optimized, and the life span of the optimized catalyst was evaluated. The Cs–P–0.1Fe/γ-Al2O3 showed excellent reusability during a 260 h lifetime experiment.
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Materials
·
2020
·Vol. 13
·期 6
·1279
·
IF 3.057
Yanqin Xu,Liyue Xiao,Yating Chang,Yuan Cao,Changguo Chen,Dan Wang
In order to achieve a controlled release drug delivery system (DDS) for cancer therapy, a pH and redox dual-responsive mesoporous silica nanoparticles (MSN)-sulfur (S)-S- chitosan (CS) DDS was prepared via an amide reaction of dithiodipropionic acid with amino groups on the surface of MSN and amino groups on the surface of CS. Using salicylic acid (SA) as a model drug, SA@MSN-S-S-CS was prepared by an impregnation method. Subsequently, the stability, swelling properties and drug release properties of the DDS were studied by x-ray diffraction, scanning electron microscopy, Fourier transform infrared microspectroscopy, size and zeta potential as well as Brunauer–Emmett–Teller surface area. Pore size and volume of the composites decreased after drug loading but maintained a stable structure. The calculated drug loading rate and encapsulation efficiency were 8.17% and 55.64%, respectively. The in vitro drug release rate was 21.54% in response to glutathione, and the release rate showed a marked increase as the pH decreased. Overall, double response functions of MSN-S-S-CS had unique advantages in controlled drug delivery, and may be a new clinical application of DDS in cancer therapy.Keywords:mesoporous silica nanoparticles;double response;drug delivery;drug release
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
·
IF 3.99
Xin Liu,Jihui Wang,Wenbin Hu
The superparamagnetic Fe 3 O 4 /CS/inhibitor nanocomposite was synthesized by using ionic gel method with Fe 3 O 4 as superparamagnetic core, chitosan as nanocarrier and molybdate (MoO 4 2− ) and benzoate (C 6 H 5 COO − ) working as loaded inhibitors. The morphology, structure and magnetic property of nanocomposite were characterized by transmission electron microscopy , X-ray diffraction, Fourier transform infrared spectroscopy and vibrating sample magnetometer . The release behavior of nanocomposite with and without external magnetic field (“no MF” mode and “MF ON” mode) was conducted by UV–vis spectroscopy, and the corrosion inhibition performance of nanocomposite for carbon in 3.5% NaCl solution was investigated by polarization curve and electrochemical impedance spectrum methods. The results show that the obtained Fe 3 O 4 /CS/inhibitors was in a well-defined core-shell structure with MoO 4 2− and C 6 H 5 COO- loaded flake-like chitosan shell stacking closely to Fe 3 O 4 surface. Under no MF mode, the release behavior of nanocomposite was mainly ion exchange and Fickian diffusion mechanism. Under MF ON mode, the swelling of polymer chains and diffusion between magnetic nanoparticles were involved apart from the ion exchange and Fickian diffusion mechanism. With the addition of nanocomposite inhibitors in NaCl solution, the charge transfer resistance and inhibition efficiency of steel increased firstly and then decreased with the prolonging of immersion time. The highest inhibition efficiency of nanocomposite inhibitors in NaCl solution under on MF and MF ON mode was located in 30 min and 90 min respectively. The inhibition of nanocomposite for carbon steel in NaCl solution is resulting from the reduction of aggressive Cl- concentration in the solution due to the ion exchange between Cl- ions in solution and MoO 4 2− and C 6 H 5 COO- ions in the nanocomposite, and the formation of ferric/ferrous molybdate, ferric/ferrous benzoate and basic ferric benzoate inhibition films on steel. This novel as-prepared composite owns superior loading capacity of inhibitors and its preparation process is especially simple relative to other nanocomposites in previous reported works.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 31
·期 2
·1547-1553
·
IF 2.195
Jiang Wenya,Peng Cong,Yuan Yanyu,Yang Shibo,Li Xifeng
In this paper, the indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) with chitosan (CS) gate dielectric are prepared by the conventional photolithography technique on a pilot line. As-prepared devices on 200 × 200 mm substrate is very uniform, and have good performance of high on/off drain current ratio ~ 10 −6 , low subthreshold swing ~ 0.24, low-threshold voltage ~ 0.20 V and high-visible light transmittance > 90%. The glucose oxidase is drop-cased on the CS gate dielectric surfaces to make fully transparent CS-based IGZO TFTs with sensitivity to glucose. It is found that the current noticeably changes with increasing glucose concentrations. Herein, the glucose detection range from 0.5 to 30 mM covers the normal range of human blood glucose concentration. Moreover, the response time for glucose sensing is < 10 s, which is effective in detecting glucose. The results suggest that the CS-based IGZO TFTs can be used to detect glucose and provides a simple process to achieve low-cost- and larger-area fabrication of biosensors.
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Journal of Cleaner Production
·
2023
·
IF 11.1
Kang Li,Junjie Xie,Zhuonan Shi,Changli Min,Zichen Yin,Ruixin Ma,Shina Li
Rubidium and cesium are highly-priced and important rare alkali elements but they always co-exist with large amount of sodium and potassium in a complex system resulting very difficult and expensive to recover. Hexacyanoferrates (MHCFs) is one of the most efficient methods to separate Rb + and Cs + if we don't consider certain drawbacks such as too small particle size and too viscous liquids to be precipitated. In this study, a new kind of hexacyanoferrate, magnesium (II) hexacyanoferrate (RbCs–MgHCF) has been fabricated at room temperature and applied for the first time to recover Rb + and Cs + from high-salty solutions. Compared with traditional divalent transition elements, such as CuHCFs, ZnHCFs, NiHCFs, CoHCFs or FeHCFs, RbCs–MgHCF had excellent precipitation property and large particle size of about 300 nm. The structure, morphology and composition were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Inductively coupled plasma (ICP), and Energy dispersive spectroscopy (EDS). The effects of various factors (divalent metal cations, surfactant, Mg 2+ /(Rb + +Cs + ) mole ratio, pH value and titration rate) on the recovery of Rb + and Cs + were explored in 50 mL batch experiments. Scale-up experiment were conducted in 6 and 18 L. Results identified that deposition ratio for Cs + and Rb + were 99% and 95% among pH ranges of 4.0–11.0. The composition of RbCs–MgHCF was confirmed to be Rb 0.61 Cs 1.20 K 0.17 Mg 1.01 Fe(CN) 6 by ICP and EDS and the synthesis mechanism of RbCs–MgHCF is proposed.
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ANALYTICAL BIOCHEMISTRY
·
2023
·
IF 2.9
Yan Xiong,Shu Zhu,Hua Zhao,Jin Li,Yanting Li,Tao Gong,Yanru Tao,Jiangling Hu,Hongmei Wang,Xinhui Jiang
For patients receiving organ transplants, monitoring the blood concentration of MPA can provide timely information on whether MPA has reached the effective therapeutic window to better function while reducing the incidence of rejection or adverse reactions. In this study, an electrochemical sensor for the detection of MPA was built using a nanocomposite made of CS-MWCNT and AuNPs. At the same time, the high performance liquid phase (HPLC) method for MPA was established and compared with this sensor. The surface morphology, structure, and roughness of the material on the electrode were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and atomic force microscopy (AFM). In addition, the electrochemical behavior of the modified electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The standard curve was obtained in blank plasma, not pure buffer solution. The peak current was linearly related to the MPA concentration in the linear range of 0.001–0.1 mM with a detection limit of 0.05 μM and good anti-interference ability. Moreover, the sensor was employed with success for the determination of MPA in rat plasma with good recovery. The electrochemical sensor presented here is eco-friendly, and sensitive, and offers a great possibility for practical applicability.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Xinsheng Li,Katam Srinivas,Manigandan Ramadoss,Fei Ma,Yue Wang,Mengya Wang,Hesheng Yu,Ziheng Zhang,Yu Wu,Yuanfu Chen
The sluggish kinetics of oxygen evolution reaction (OER) becomes one of the big obstacles for large-scale electrolytic water splitting. It is urgent to develop low-cost and efficient OER catalyst with fast reaction kinetics and low energy barrier. Herein, a novel OER catalyst of carbon nanotubes (CNT) supported cesium-doped NiFe-layered double hydroxide nanosheets (Cs–NiFe-LDH) is synthesized via a facile one-pot solvothermal reaction. The porous Cs–NiFe-LDH@CNT catalyst delivers an ultralow overpotential of 240 mV @10 mA cm −2 , a small Tafel slope of 56.22 mV dec −1 , and excellent long-term stability. The outstanding catalytic performance is mainly attributed to the synergistic effects of Cs doping and CNT network: the modification of the electronic structure of NiFe-LDH by Cs doping and the conductivity enhancement by CNT network can facilitate the electron transfer and kinetics; the Cs doping and CNT introduction can generate rich active sites; the nanoporous architecture can facilitate the ion diffusion and O 2 bubble release. This work provides a synergistic strategy to design and synthesize transition metal based OER catalysts with low-cost, fast kinetics and good stability for water splitting.
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Defence Technology
·
2023
·
IF 5.1
Yujie Yan,Bo Jin,Rufang Peng
Biomass chitosan (CS) was used as a template, graphitic phase carbon nitride (g-C 3 N 4 ) with high nitrogen content and certain catalytic activity was used as a dopant, and nano-transition metal cobalt (Co) was used as a catalytic center point. The carbon aerogel (C (CS)/g-C 3 N 4 /Co) with a three-dimensional network-like structure was prepared by assembling the three materials through experimental operations such as freeze-drying and high-temperature carbonization. It was demonstrated by scanning and transmission characterization that the CS in the carbon aerogel could provide more active sites for the cobalt nanoparticles, and the doping of graphite-phase carbon nitride as a template dispersed the cobalt nanoparticles and changed the conductivity of the CS. To investigate the catalytic effect of carbon aerogel on ammonium perchlorate (AP), it was investigated by differential thermal analyzer and TG thermal analysis. This carbon aerogel was very effective in catalyzing AP, and the 10 wt% content of the catalyst reduced the AP pyrolysis peak from 703.9 to 595.5 K. And to further investigate the synergistic effect of the three materials, further carbon aerogels such as C (CS)/Co, g-C 3 N 4 /Co were prepared and applied to catalyze AP, and the same ratio reduced the AP pyrolysis peak by 98.1 °C and 97.7 °C. This result indicates a synergistic effect of the assembly of the three materials.
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JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION
·
2018
·
IF 1.911
Fang Wang,Jian Yuan,Qian Zhang,Siqian Yang,Shaohua Jiang,Chaobo Huang
Poly (lactic-co-glycolic acid) (PLGA) nanoparticles are an ideal paclitaxel (PTX)-carrying system due to its biocompatibility and biodegradability. But it possessed disadvantage of drug burst release. In this research, a layer-by-layer deposition of chitosan (CS) and sodium alginate (ALG) was applied to modify the PLGA nanoparticles. The surface charges and morphology of the PLGA, PLGA/CS and PLGA/CS/ALG particles was measured by capillary electrophoresis and SEM and TEM, respectively. The drug encapsulation and loading efficiency were confirmed by ultraviolet spectrophotometer. The nanoparticles were stable and exhibited controlled drug release performance, with good cytotoxicity to human lung carcinoma cells (HepG 2). Cumulatively, our research suggests that this kind of three-layer nanoparticle with LbL-coated shield has great properties to act as a novel drug-loaded system.
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APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Yi Ma,Jingan Li,Yifan Zhou
Magnesium alloys have become the focus of attention as a new generation of vascular stent materials due to their excellent mechanical properties and degradability. However, their rapid degradation rate and poor surface endothelialization performance have become key factors limiting their clinical application. In this study, the Mg-Zn-Y-Nd (ZE21B) surface was modified with the magnesium fluoride (MgF 2 ) corrosion-resistant layer, and the polydopamine (PDA) layer was used to immobilize the chitosan (CS)-ferulic acid (FA)/vanillic acid (VA) bioactive composite coating. The results of the electrochemical and hydrogen evolution experiments showed that the corrosion current density and hydrogen release of the modified ZE21B alloy significantly decreased, and its corrosion resistance was enhanced; the results of the hemolysis rate and whole blood experiments showed that the adhesion of blood components such as white blood cells and platelets on the surface of the modified ZE21B alloy significantly decreased, improving the blood compatibility of the magnesium alloy; the results of in vitro cell experiments showed that the modified ZE21B alloy effectively promoted endothelial cell (ECs) adhesion and proliferation, and inhibited smooth muscle cell (SMCs) pathological proliferation. These enhancements suggest that the CS-FA/VA coating significantly improves both the corrosion resistance and biological compatibility of the ZE21B alloy.
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RSC Advances
·
2016
·Vol. 6
·期 90
·86829-86835
·
IF 3.289
Ling Chang,Shuquan Chang,Wei Han,Wei Chen,Zheng Li,Zheng Zhang,Yaodong Dai,Da Chen
Novel porous permutite/carbon nanobeads/amidated alginic acid nanocomposites were successfully fabricated via a gamma radiation method. The carbon nanobeads are 40–60 nm in diameter. The cross-linked amidated alginic acid is well dispersed on the surface of carbon nanobeads and permutite. The preparation parameters such as reactant ratio, carbonization conditions and radiation dose were optimized. The influences of contact time, pH and initial concentration of the Cs+ solution were investigated. Contact time = 4 h and pH = 9 are ideal conditions for Cs+ removal. The Cs+ removal efficiency and adsorption capacity can reach 98% and 60.1 mg g−1 respectively. They have good stability and adsorption–desorption properties. The adsorption capacity can maintain more than 85% after 4 adsorption–desorption cycles. The preparation strategy and adsorption mechanism were also discussed. Gamma radiation technology exhibits distinguished advantages to improve the dispersion and stability of organic/inorganic hybrid materials. This method can be easily applied to prepare other similar porous hybrid adsorbents.
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PLoS One
·
2014
·Vol. 9
·期 10
·e108647
·
IF 3.534
Yankai Du,Meishan Pei,Youjun He,Faqi Yu,Wenjuan Guo,Luyan Wang
Fe 3 O 4 (Fe 3 O 4 -CS) coated with magnetic chitosan was prepared as an adsorbent for the removal of Orange I from aqueous solutions and characterized by FTIR, XRD, SEM, TEM and TGA measurements. The effects of pH, initial concentration and contact time on the adsorption of Orange I from aqueous solutions were investigated. The decoloration rate was higher than 94% in the initial concentration range of 50–150 mg L −1 at pH 2.0. The maximum adsorption amount was 183.2 mg g −1 and was obtained at an initial concentration of 400 mg L −1 at pH 2.0. The adsorption equilibrium was reached in 30 minutes, demonstrating that the obtained adsorbent has the potential for practical application. The equilibrium adsorption isotherm was analyzed by the Freundlich and Langmuir models, and the adsorption kinetics were analyzed by the pseudo-first-order and pseudo-second-order kinetic models. The higher linear correlation coefficients showed that the Langmuir model (R 2 = 0.9995) and pseudo-second-order model (R 2 = 0.9561) offered the better fits.
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