Papers by Author: Xue Gang Luo

Abstract: The blend films of ungelatinized and gelatinized starch/polyvinyl alcohol (PVA) were prepared by solution casting method. Their morphologies and thermal properties were analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A droplet phase was observed in the blends containing ungelatinized starch and a laminated phase was observed in the blends containing gelatinized starch. For both ungelatinized and gelatinized starch/PVA blends the melting temperature (T_m) (210230) of PVA was detected, and the T_m of gelatinized starch/PVA blends was higher than that of the ungelatinized starch/PVA blends. TGA results showed that over the rst 300 the weight loss for ungelatinized starch/PVA blends was higher than that for gelatinized starch/PVA blends, however the gelatinized starch/PVA blends showed the greater weight loss after scanning up to 400. Different morphologies and thermal properties of two types of blends were attributed to the different hydrogen bonding interactions between starch and polyvinyl alcohol.

Abstract: The porous composite adsorbent was prepared using directly the glycerol-plasticized poly (butylene succinate)(PBS) and corn starch that were melt blended by a twin screw extruder. The effect of different ratio of PBS to starch on volume stabilization of the composite adsorbent in the water was investigated, and the optimum mixing ratio was 100:25. The starch/PBS particles were treated by α-amylse on the condition of pH 5, the temperature 50. The major objective of this paper is to characterize the morphology in biodegradable PBS/starch blends using scanning electron microscopy. The effect of the dose of enzyme and hydrolysis time on removal efficiency of the composite adsorbent was studied. The results showed that the enzyme-treated starch/PBS particles had good adsorption efficiency for copper () ions compared to the starch/PBS particles. The optimum ratio of the starch to PBS was 100:25 and enzyme treatment condition was 2% (w/w) enzyme dosage (based on dry starch) and 8h hydrolysis time. Therefore the porous composite particles could be used as potential environmentally friendly materials.

Abstract: The expanded rice husk, a low-cost and environmental friendly absorbent, was used to remove Sr²⁺ from the simulated radioactive wastewater. The adsorption behaviors for the radionuclide ion Sr²⁺ was studied, and effects of various parameters including pH, temperature, expanded rice husk dose, initial concentration of Sr²⁺ and adsorbed time on the removal rate of ion Sr²⁺ from the simulated radioactive wastewater were evaluated. Results show that Sr²⁺ can be successfully removed from the simulated wastewater by the expanded rice husk, and the removal rate of ion Sr²⁺ on the expanded rice husk achieves as high as 99.37%, which is much higher than that on activated carbon (42.50%) at optimized conditions.

Abstract: The rheological properties of konjac glucomannan (KGM) solution were measured by HAAKE Rotational Rheometer, and the results indicated that KGM solution began to transform from Newtonian fluid to non-Newtonian fluid above 0.10 wt%, which represented the overlap of molecular chains. When the concentration exceeded 1.00 wt%, the entanglements of molecular chains became obvious, and the KGM sol formed. Furthermore, the rheological formulas of KGM solution were simulated very regularly, and the parameters of viscosity (η) and non-Newtonian index (n) held the relationship of exponential function to concentration (C), however, the consistency coefficient (κ) displayed a power function, then their concentration-dependence functions were as follows: η=-0.33+1.17e^16.80C, n=0.29+0.79e^-2.56C, and κ=29.11C^3.17. Finally, the rheological properties from diluted solution to KGM sol were revealed.

Abstract: The reaction in linear low density polyethylene/Calcium carbonate (LLDPE/CaCO₃) melting blend system with the presence of fatty acid extracted from Hogwash oil (HWOFA) was investigated by means of a Torque Rheometer during compounding. The characteristics of the products were evaluated by DSC and Universal Testing machine. The results showed that the maximum torque and equilibrium torque of the LLDPE/CaCO₃ blends with addition of 15wt% HWOFA decreased respectively by 23.83% and 27.55% which were lower than that without HWOFA. The tensile strength decreased by 23.94%and the elongation at break increased by 16.88%. The compatibility became poor with addition of more than 15wt% HWOFA. The above results indicated that the fatty acid extracted from Hogwash oil can be used as a lower-cost plasticizer, which provides a new method of utilization of Hogwash oil.

Abstract: The thermal decomposition characteristics of Mg (NO₃)₂·H₂O and MgCl₂·6H₂O composite were studied by integrated thermal analysis. Results show that there are five steps during the thermal decomposition of phase change material (PCM): the starting temperature of each step is 35.5°C, 93°C, 196°C, 260°C and 318°C, respectively. PCM was calcined at different temperatures at each decomposition step. The composition and morphology of the calcined product was characterized by XRD and SEM. Two major reactions including dehydration and hydrolysis occur in the thermal decomposition progress. Dehydration is the main process below 196 °C, while hydrolysis is predominant process when the temperature is higher than 196 °C.

Abstract: Dicarboxylic anhydride esterified Konjac glucomannan (DCKGM) was prepared to reduce the unusual water absorbency of native Konjac Glucomannan (KGM). The dependence of degree of substitution (DS) on the reaction conditions and influence of the DS on water absorbency were studied. The esterification was conducted using refluxing KGM in hot acetic acid which contains phthalic anhydride and pyridine catalyst. The chemical structure and characteristic of DCKGM were analyzed by GPC-MALLS and FI-IR. The results showed that the water absorbency for DCKGM is inversely proportional to DS increase. DCKGM may be a promising biomaterial in application of drug carrier, heavy metal ion adsorption and functional packing materials.

Abstract: The absorption of Cu²⁺ and Pb²⁺ in the heavy metal wastewater by distillers' grains can not only solve the problem of environmental pollution, but also change distillers' grains waste into resource. Structural characteristics of distillers' grains and its adsorption behaviors for the heavy metal ions of Cu²⁺ and Pb²⁺ were studied and effects of various parameters including pH, temperature, distillers' grains dose, initial Cu²⁺ and Pb²⁺ concentration and absorbed time on the absorption of Pb²⁺ and Cu²⁺ were evaluated. Sorption isotherms were also investigated. Results show that the rough surface, loose internal structure and hydroxy and amide groups of the distillers' grains are beneficial to the adsorption of Cu²⁺ and Pb²⁺ in the wastewater. The removal rate of the distillers' grains for Pb²⁺ (20.00 mg L−1) and Cu²⁺ (20.00 mg L−1) are, respectively, 96.72% and 87.70% under optimized conditions. The equilibrium sorption data are well demonstrated by Langmuir model.

Abstract: The adsorption of Cd(II) ions from aqueous solution by sodium hydroxide-treated bamboo powder（STB） was studied in a batch adsorption system. Characteristics of STB were investigated by scanning electron microscopy (SEM) and electron dispersive spectroscopy (EDS). Factors influencing adsorption such as pH of the solution, adsorbent dosage, cadmium concentration and temperature have been studied. The adsorption process was relatively fast and equilibrium was achieved after 120 min, and the maximum adsorption of Cd(II) ions occurred at around pH 6.5. The equilibrium data were fitted using Langmuir, Temkin and Freundlich isotherm models to calculate isotherm constants. And the adsorption isotherm fitted well Langmuir isotherm, and the maximum adsorption capacity was 8.987 mg/g.

Abstract: Expansion-treated rice husk (ERH) had been used as adsorbent for removing copper(II) ions, and showed strong adsorption ability and removal efficiency for copper(II) ions. In this paper, the surface and bulk structures of ERH adsorbent were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM), ERH was treated by water solution with different pH value, and the adsorption performance of ERH for copper(II) ions was investigated through adsorption static experiments in order to study the adsorption mechanism. The result showed that ERH treated by alkaline solution had high removal efficiency for copper(II) ions, the reason ascribed to the large surface area of ERH. ERH had competitive adsorption for H⁺ and Cu²⁺, and a monolayer adsorption process played an important role in the whole process.