Advanced Materials Research Vol. 937

Abstract: A novel magnetic adsorbent, magnetic EDTA/chitosan nanobeads was synthesized. The adsorption mechanisms of magnetic EDTA/chitosan nanobeads for removal of Cu (II) ions from aqueous solution were investigated in this paper. The interaction mechanisms of Cu²⁺ adsorption onto magnetic EDTA/chitosan nanobeads and active sites were interpreted by fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. Uniting the analysis results of FTIR and XPS, the functional groups of participating in chelating were confirmed, and the results indicated that Cu²⁺ adsorption was mainly through interactions with electron donating atom N and O. This adsorption property was similar to N·O-type chelating agent and the adsorption mechanism was put forward. This work was very significant to control adsorption influence factor and improve adsorption capacity of magnetic EDTA-chitosan nanobeads, and then succeed to apply to magnetic adsorption fields.

Abstract: A new solid high-proton conductor Na₇[CoW₁₁O₃₉Cd (H₂O)]·12H₂O has been synthesized for the first time. The percentage composition of the product were determined by Inductively coupled plasma (ICP) and X-ray photoelectron spectroscopy (XPS). The product was characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD), which indicate it possesses the Keggin structure. The TG-DTA curve shows the sequence of water loss in the compound, the amount of the loss, as well as the thermostability. Conductivity of the compound was investigated by four-electrode method at room temperature and different measuring temperatures, the results reveal that its proton conductivity is 4.87×10⁻⁴ S·cm^-1 at 27oC and the activation energy for proton conduction is 15.31 kJ/mol.

Abstract: Co₃O₄ multilayer nanosheets were synthesized by a hydrothermal method and a post annealing treatment process. The effect of solution concentration and ratio on the morphology of Co₃O₄ precursor was studied. The crystalline structure, morphology and elemental composition of Co₃O₄ multilayer nanosheets were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy technologies. When exposed to reducing gas such as ethanol, resistance of Co₃O₄ multilayer nanosheet sensor increases quickly, demonstrating that the Co₃O₄ multilayer nanosheets are p-type conductivity. For 100 ppm alcohol at 240 °C, the sensor response is as high as 32, indicating that the powder of Co₃O₄ multilayer nanosheets is a very promising low-powder gas sensing material.

Abstract: Ultrasonic assisted citrate sol-gel is used to synthesis LaCoO₃ (LCO) ultrafine particles. The influence of ultrasonic time on the properties of the samples was investigated. TG-DSC is applied to determine the phase transition of LCO gel precursor. XRD, FESEM and H₂-TPR were applied to characteristic crystalline phase structure, morphology, thermal stability of LCO samples. The results indicated that LCO particles exhibit a well-formed polycrystalline rhombohedral distorted perovskite structure, and their particles are well-decentralized, in a smaller size and better dispersivity as the increasing of ultrasonic time ranged from 0min to 60min. H₂-TPR implied that ultrasonic assistance can lower the reduction temperature of the product in the zone of low temperature and raise the temperature in the zone of high temperature. Ultrasonic assistance is not conductive to increase organic dye decolorization efficiency of LCO powders in darkroom when taking methyl orange and gold orange II as targeted dye.

Abstract: DNA nanorobots can be applied for patterned immobilization of other materials. However, for successful patterned immobilization, we need to design the self-organization process so that some shapes of DNA nanostructures are avoided. In this paper, we consider an approach to solve the problem of the avoidance of forbidden shapes of DNA nanorobots in patterned immobilization of other materials.

Abstract: A carbaryl molecularly imprinted capillary monolith was prepared by organic-inorganic hybrid approach. Methacrylic acid (MAA) as functional monomer, γ-methacryloxypropytrimethoxysilane (γ-MAPS) as crosslinker, carbaryl as template molecule, and acetonitrile/dichloromethane mixture (v/v, 1:4) were used as porogen. The molar ratio of 1:6:8 (carbaryl:MAA: γ-MAPS, for which the retention factor k was 7.57, was expected to be highest for carbaryl on the optimum capillary monolith. The condition of 20 mmol/L phosphate buffer with pH value 3.5 containing 30% acetonitrile favored the carbaryl separation from three carbamates (carbaryl, fenobucarb and metocarb) through the effective imprinted length of the column which was 15 cm. As far as the screening of carbaryl from a group of structural analogs, the MIP monolith combined with capillary electrochromatography was preferred.

Abstract: Herein, we report a novel approach to Methylthiouracil-templated formation of fluorescent Ag nanoclusters and its application to bioimaging. We used fluorescence assay and TEM to characterize the silver nanocluster. The complex can be directly employed into bioimaging HeLa cells. The cell toxicity (3-[4,5-dimethylthiazolyl-2]-2,5-diphenyltetrazolium bromide, MTT) assay demonstrated that the silver nanocluster has only little affect on the cytotoxicity to the cells, which further proves the applicability of the method in tumor cell imaging. This work successfully develops the capping Methylthiouracil scaffolds of silver nanoclusters.

Abstract: A facile, efficient, and low energy consumption detonation method to prepare few-layered graphene nanosheets has been developed using graphite oxide as a precursor at detonation induced temperature as low as 100 °C . The composition and structure of as-produced few-layered graphenes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Specific Surface (BET), Transmission Electron Microscopy (TEM), Raman Microscope, and Atomic Force Microscope (AFM). Results showed that the as-produced graphenes were transparent and few-layered with a high specific surface area (225.9 m²/g). The investigation opens a new road to prepare few-layered graphene nanosheets at low exfoliation temperature in a low-cost and facile way.

Abstract: The present study investigates the preparation of ferulic acid (FA) sustained-release cellulose acetate (CA) microparticles, in which a third component, polyvinylpyrrolidone (PVP), was included into the microcomposites for an improved sustained drug release profile. An electrospraying process was exploited for the fabrication of multiple-component microparticles. Under an applied voltage of 18 kV, FA/PVP/CA composite microparticles were successfully generated. Field emission scanning electron microscopic observations demonstrated that these microparticles had an indented surface morphology with an average diameter of 1.71 ± 0.56 μm. The drug presented in the polymeric microparticles in an amorphous state due to the favorable secondary interactions among the components, as verified by the X-ray diffraction (XRD) patterns and attenuated total reflectance Fourier transform spectra. The triple-component microparticles could provide a fine sustained release profiles with full release completeness and small tailing-off release time period. The electrospraying process is a useful tool for developing sustained release microparticles and multiple-component co-existence in the microparticles can be taken to adjust the sustained drug release profiles.

Abstract: Cornstalk, a cellulosic agricultural waste material, was modified by citric acid to improve the adsorption of rhodamine B (RB) and methylene blue (MB) from aqueous media. Characterization of SEM and FTIR spectra confirmed that the surface morphology of adsorbent changed and carboxylic groups were introduced into the raw cornstalk by chemical modification. The effects of pH, contact time, initial concentration and the amount of dried adsorbent were studied in batch experiments. There was no significant difference in the dye concentration remaining when the pH was increased from 4.0 to 10.0. Several models were used to fit experimental data and the results showed that experimental data fitted the Langmuir model and pseudo-second order model best. Compared with 58.71 and 81.71 mg g^-1 obtained by CS (raw cornstalk), the maximum adsorption capacities for RB and MB were 203.0 and 245.6 mg g^-1 by using CCS (cornstalk modified with citric acid), respectively.