Shengtang Zhang

Graft copolymerization of artemisia seed gum with acrylic acid under microwave and its water absorbency

A super‐absorbent polymer was prepared by grafting copolymerization of acrylic acid onto Artemisia seed gum, using microwave irradiation and ammonium persulfate as an initiator. The effect of various preparation conditions on its water absorbency, such as the ratio of acrylic acid to Artemisia seed gum, degree of acrylic acid neutralization, amount of initiator and microwave irradiation time, was investigated by orthogonal tests. The optimal reaction conditions were 3 min (irradiation time), 70% neutralization degree of acrylic acid and 2% initiator on the basis of the mass of acrylic acid used. When the mass ratio of acrylic acid to Artemisia seed gum is 5:0.5, the product has a water absorbency close to 400 times at room temperature in distilled water, this indicated that is has a high water absorbency. The structure of the graft copolymer was confirmed by Fourier transform infrared spectrometer (FT‐IR) and thermogravimetric analysis (TGA). Further more, this microwave irradiation processing method to prepare water absorbent materials has no industrial cast off produced, that is to say, this method is environmentally friendly.

Synthesis and characterisation of seleno-Cynomorium songaricum Rupr. polysaccharide

In this article, the structural properties of Cynomorium songaricum Rupr. polysaccharide (CSP) after selenylation were investigated. The crude polysaccharide was obtained from C. songaricum Rupr. by water extraction followed by ethanol precipitation and freeze vacuum drying. Then selenylation of CSP has been accomplished by employing sodium selenite to modify the polysaccharide under the catalysis of nitric acid–barium chloride. After selenylation, the sugar content and the molecular weight increased but the protein content reduced. The maximum selenic content determined by ICP-AES was 2925 µg g−1. The selenide CSP (Se-CSP) was characterised by the methods of UV spectra, FT-IR, Raman spectra and X-ray photoelectron spectroscopy. The results showed that the hydroxyl hydrogen of the sugar moieties was substituted by Se=O. Thermal stability of Se-CSP was also measured by TG-DTA.

Immobilization of β-galactosidase on Tamarind Gum and Chitosan Composite Microspheres

A new composite microsphere support was prepared and characterized using tamarind gum and chitosan as a source. These new composite microspheres were prepared as well-shaped spheres in range of 230 to 460 m by suspension cross-linking technique. The composite microspheres had better stability in acid and alkaline environments with a swelling volume of 2.34mL/g; the thermal stability of the spheres was better than pure chitosan microspheres. The optimal pH of the immobilized enzyme is pH 8.3 and the optimal temperature is 42°C. The specific activity was 1.6u/g of microspheres and the Michaelis constant was 6.62 10 4. A modified and immobilized enzyme was characterized by means of infrared spectrometry, X-ray photoelectron spectroscopy, and elementary analysis.

Preparation and Characterization of Composite Magnetic Microspheres

In this study, composite magnetic microspheres of tamarind gum and chitosan were prepared in a well-shaped spherical form with a size range of 230—46 0 μm by the suspension cross-linking technique for use in the application of magnetic carrier technology. The magnetic material used in the preparation of the microspheres was prepared by precipitation from FeCl3 and FeSO4 solutions in basic medium. The morphological, magnetic properties and the functional groups of the microspheres were characterized by different techniques (i.e., Scanning Electron Microscope (SEM), magnetometry, and FT-IR). The results demonstrated that the stirring rate of the suspension and the Fe3O4/chitosan ratio are the most effective parameters for the size/size distribution and the magnetic quality of the microspheres, while the amount of tamarind gum has no significant effect on these properties. The best magnetic quality of the microspheres is around 4.11 emu/g microspheres at 8 KG magnetic field intensity. The thermal stability was measured by using DSC methods.

Composite Magnetic Microspheres of Tamarind Gum and Chitosan: Preparation and Characterization

In this study, composite magnetic microspheres have been synthesized based on tamarind gum and chitosan utilizing the suspension cross‐linking technique for use in the application of magnetic carrier technology. The properties of the composite magnetic microsperes, such as morphological, magnetic properties, thermal stability and the functional groups of the microspheres, were characterized by different techniques (i.e., SEM, magnetometry, DSC and FT‐IR). The swelling kinetics and pH responsive behaviors of the composite magnetic microspheres were also studied.

An Investigation of Two Kinds of Magnetic Chitosan Composite Microspheres

In this study, two composite magnetic microspheres made of tamarind gum with chitosan and artemisia seed gum with chitosan were prepared by suspension cross-linking for magnetic carrier applications. The magnetic material used in the preparation of the microspheres was prepared by precipitating FeCl3 and FeSO4 solutions in a basic medium. The morphological, thermal stability, and magnetic properties of the two composite magnetic microspheres were characterized by scanning electron microscope, magnetometry, and differential scanning calorimeter (DSC). The swelling kinetics and pH responsive behavior of the two microspheres were also studied.In this study, two composite magnetic microspheres made of tamarind gum with chitosan and artemisia seed gum with chitosan were prepared by suspension cross-linking for magnetic carrier applications. The magnetic material used in the preparation of the microspheres was prepared by precipitating FeCl3 and FeSO4 solutions in a basic medium. The morphological, thermal stability, and magnetic properties of the two composite magnetic microspheres were characterized by scanning electron microscope, magnetometry, and differential scanning calorimeter (DSC). The swelling kinetics and pH responsive behavior of the two microspheres were also studied.

Immobilized β-galactosidase : Preparation and characterization

A new enzyme support consisting of magnetic composite microspheres was prepared using artemisia seed gum, chitosan and magnetic fluid as a source, and characterized. The microspheres contained reactive aldehyde groups that react with the free amino groups of the enzymes. The β-galactosidase was largely immobilized by covalent binding to the surface of the activated magnetic carriers. The factors controlling the relative activity and the enzymic properties of the immobilized β-galactosidase were compared with those of its soluble counterpart, for which ONPG (o-nitrophenol β-D-galactopyranoside) was chosen as a substrate. The pH and thermal stability of the immobilized β-galactosidase were higher than those of the soluble one. The Michaelis constant, Km, was evaluated both for the immobilized β-galactosidase and for the soluble enzyme. The immobilized type exhibited better environmental adaptability and re-usability than the soluble one.