Yan-Yan Dong

Environmentally friendly ultrosound synthesis and antibacterial activity of cellulose/Ag/AgCl hybrids

This study aims to investigate the fabrication and property of cellulose/Ag/AgCl hybrids. In this article, preparation of cellulose/Ag/AgCl hybrids was reported using the cellulose solution, AgNO₃, AlCl₃·6H₂O with ultrasound agitation method. The cellulose solution was synthesized by the dissolution of the microcrystalline cellulose in NaOH/urea aqueous solution. Influences of the experimental parameters of ultrasound treatment time and ultrasonic intermittent on the hybrids were investigated. The phase, microstructure, thermal stability, and morphology of the hybrids were characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). Results showed the successful synthesis of cellulose/Ag/AgCl hybrids with good thermal stability. Moreover, the hybrids displayed desirable antimicrobial activities. Compared with other conventional methods, the rapid, green, and environmentally friendly ultrasound agitation method opens a new window to the high value-added applications of biomass.

Cellulose/CaCO3 nanocomposites: microwave ionic liquid synthesis, characterization, and biological activity.

The purposes of this article are to synthesize the biomass-based hybrid nanocomposites using green method in green solvent and evaluate its biological activity. In this paper, microwave-assisted ionic liquid method is applied to the preparation of cellulose/CaCO(3) hybrid nanocomposites in the alkali extraction cellulose using CaCl(2) and Na(2)CO(3) as starting reactants. The ionic liquid acts as the excellent solvent for absorbing microwave and the dissolution of cellulose, and the synthesis of cellulose/CaCO(3) nanocomposites. The influences of reaction parameters such as the cellulose concentration and the types of solvent on the products were investigated. The increasing cellulose concentration favored the growth of CaCO(3). The morphologies of CaCO(3) changed from polyhedral to cube to particle with increasing cellulose concentration. Moreover, the solvents had an effect on the shape and dispersion of CaCO(3). Cytotoxicity experiments demonstrated that the cellulose/CaCO(3) nanocomposites had good biocompatibility and could be a candidate for the biomedical applications.

Compare study CaCO3 crystals on the cellulose substrate by microwave-assisted method and ultrasound agitation method

The purposes of this article were to investigate the influences of synthesis strategy on the CaCO(3) crystals on the cellulose substrate. In this study, CaCO(3) crystals were synthesized using cellulose as matrix by the microwave-assisted method and ultrasound agitation method, respectively. The CaCO(3) crystals on the cellulose substrate were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Experimental results demonstrated that the synthesis strategy had a dramatically influences on the phase, microstructure, morphology, thermal stability, and biological activity of the CaCO(3) crystals. The pure phase of vaterite spheres with the diameter of about 320-600nm were obtained by ultrasound agitation method, meanwhile, the mixed phases of calcite and vaterite with the diameter of about 0.82-1.24μm were observed by microwave-assisted method. In view of experimental results, one can conclude that the ultrasound agitation method do more favors to the synthesis of CaCO(3) crystals with uniform morphology and size, compared with microwave-assisted method. Furthermore, cytotoxicity experiments indicated that the CaCO(3) crystals on the cellulose substrate had good biocompatibility and could be a candidate for the biomedical applications.

Why to synthesize vaterite polymorph of calcium carbonate on the cellulose matrix via sonochemistry process

Vaterite is an important biomedical material due to its features such as high specific surface area, high solubility, high dispersion, and small specific gravity. The purposes of this article were to explore the growth mechanism of vaterite on the cellulose matrix via sonochmistry process. In the work reported herein, the influences of experimental parameters on the polymorph of calcium carbonate were investigated in detail. The calcium carbonate crystals on the cellulose matrix were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Experimental results revealed that all the reactants, solvent, and synthesis method played an important role in the polymorph of calcium carbonate. The pure phase of vaterite polymorph was obtained using Na2CO3 as reactant in ethylene glycol on the cellulose matrix via sonochmistry process. Based on the experimental results, one can conclude that the synthesis of vaterite polymorph is a system process.

Environmentally friendly microwave ionic liquids synthesis of hybrids from cellulose and AgX (X = Cl, Br)

The purpose of this article was to explore an environmentally friendly strategy to synthesis of biomass-based hybrids. Herein, microwave-assisted ionic liquids method was applied to fabricate the hybrids from cellulose and AgX (X=Cl, Br) using cellulose and AgNO3. The ionic liquids act simultaneously as a solvent, a microwave absorber, and a reactant. Ionic liquids provided Cl(-) or Br(-) to the synthesis of AgCl or AgBr crystals; thus no additional reactant is needed. The products are characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The cellulose-Ag/AgCl hybrid and cellulose-Ag/AgBr hybrid were also obtained by using cellulose-AgCl and cellulose-AgBr hybrids as precursors. This environmentally friendly microwave-assisted ionic liquids method is beneficial to the hybrids with high dispersion.

Ag@Fe3O4@cellulose nanocrystals nanocomposites: microwave-assisted hydrothermal synthesis, antimicrobial properties, and good adsorption of dye solution

AbstractIn this paper, Ag@Fe3O4@cellulose nanocrystals (CNC) nanocomposites were synthesized by a facile and green microwave-assisted hydrothermal method. In the procedure, CNC was used as a reducing agent for the synthesis of Ag. During the whole synthesis process, there were no additional reducing agents or toxic solvents used. The nanocomposites were characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectrum, transmission electron microscopy, thermogravimetric analysis, and differential thermal analysis. In addition, Ag@Fe3O4@CNC nanocomposites were also synthesized by microwave-assisted method and hydrothermal method. Both the effects of reaction time and synthetic procedures on the reduction process of Ag+ by CNC were explored. The results showed that Fe3O4 was formed with sphere-like structure and dispersed uniformly. Ag@Fe3O4@CNC nanocomposites exhibited good adsorption of dye solution, which showed potential applications in water treatment. The antibacterial results showed that Ag@ Fe3O4@CNC nanocomposites had good antibacterial activities toward both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The green and facile strategy reported in this paper may be broadly used in synthesizing other metal nanoparticles, as well as organic–inorganic nanocomposites.

Hydrothermal synthesis, characterization, and bactericidal activities of hybrid from cellulose and TiO2

The purpose of this study was to explore a new strategy to improve the high value-added applications of biomass. Hybrid from cellulose and titanium dioxide (TiO2) was successfully prepared by using tetra-n-butyl titanate and cellulose solution via a hydrothermal method at 180°C for 24h. The phase, microstructure, morphology, and thermal stability of the hybrid were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The influences of the tetra-n-butyl titanate concentration and the types of solvent on the products were investigated. The TiO2 nanoparticles were dispersed on the surface of cellulose and/or in the cellulose matrix. The hybrid possessed an antimicrobial activity against the model microbes Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive), and were a promising antimicrobial material for the applications in the biomedical field.

Compare study cellulose/Ag hybrids using fructose and glucose as reducing reagents by hydrothermal method.

The primary objective of this work was to evaluate the effect of reducing reagents on the hybrids from cellulose and Ag, which have been successfully synthesized by using fructose and glucose as reducing reagents via a hydrothermal method, respectively. The hybrids were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The influences of the various reaction parameters including the heating time, heating temperature, and types of reducing reagents on the hybrids were investigated. Silver particles can be better dispersed in the cellulose matrix by adjusting reaction parameters. Experimental results demonstrated that the types of reducing reagents played an important role in the shape and dispersion of silver particles in hybrids.

Environmentally-friendly sonochemistry synthesis of hybrids from lignocelluloses and silver

The purpose of this study was to explore a green strategy about the high value-added applications of biomass. Hybrids from lignocelluloses and silver have been successfully prepared using NaBH4 as reducing reagent by an environmentally-friendly sonochemistry method. The phase, microstructure, and morphology of the hybrids were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). The influences of the various reaction parameters including reaction time, lignocelluloses concentration, and types of reducing reagents on the products were investigated in detail. Silver particles can be better dispersed on the lignocelluloses matrix by adjusting reaction parameters. These hybrids may be a promising antimicrobial material for their applications in the biomedical field. This environmentally-friendly synthetic strategy reported here opens a new window to the high value-added applications of lignocelluloses.

Understanding the mechanism of ultrasound on the synthesis of cellulose/Cu(OH)2/CuO hybrids.

Understanding the mechanism of ultrasound from metal hydroxide to oxides via an ultrasound irradiation method is of great importance for broadening and improving their synthesis and industrial applications. The purpose of this article was to explore the mechanism of ultrasound on the synthesis of cellulose/Cu(OH)2/CuO hybrids. The influences of various reaction parameters including the volume of H2O2, heating method, pulse mode of ultrasound irradiation, sonication time, and power density on the cellulose/Cu(OH)2/CuO hybrids were investigated in detail by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDS), thermogravimetric analysis (TGA), and derivative thermogravimetry (DTG). The experimental results indicated that all the parameters have effects on the cellulose/Cu(OH)2/CuO hybrids, power density had an effect on the phase transformation of Cu(OH)2 to CuO, and the addition of H2O2 played an important role in the shape of cellulose hybrids, which provided an indirect evidence on the H2O2-induced oxidation route for the transformation process from Cu(OH)2 to CuO during the ultrasound irradiation process. These results maybe direct the synthesis and potential applications of cellulose hybrids in the near future.