Advanced Materials Research Vols. 236-238

Abstract: The liquefaction of cellulose in the presence of phenol without or with sulfuric acid as catalyst was investigated. The liquefied products were characterized by GC/MS and FTIR. Results showed that reaction temperature and reaction time had obvious effects on liquefaction of cellulose. Sulfuric acid showed an excellent catalytic degradation. The chemical compositions of the liquefied products produced using sulfuric acid catalyst or not were almost identical, and the majority of the identified liquefied products were methylene bisphenol and its isomers. During the process of liquefaction, the degradation of cellulose and condensation polymerization occurred at the same time. The last liquefied products were greatly dependent on the reaction conditions.

Abstract: The liquefaction of cornstalk in the presence of polyhydric alcohols with sulfuric acid as catalyst was investigated. Effects of various liquefaction condition parameters on the liquefaction and its liquefied products were mainly investigated. Results showed that the liquefaction parameters had an obvious effect on the residue percent and the viscosity, acid and hydroxyl number of its liquefied products. The efficient liquefaction of cornstalk with low residue percent of 9.4% was obtained under the mild condition of a PEG #400/glycerin ratio of 7/3, a cornstalk/liquefaction reagent ratio of 1/5, a reaction temperature of 150°C, a reaction time of 30 min and a sulfuric acid amount of 4%, respectively. Under this condition, the viscosity, acid number and hydroxyl number of its liquefied products was 1430 cP, 18.5 mg KOH/g and 362.1 mg KOH/g, respectively.

Abstract: In this paper, the bast fibers of the Kosteletzkya virginica were degummed and separated into fine fibers, the chemical composition, morphology, microstructure and mechanical properties of the degummed Kosteletzkya virginica bast fibers were characterized by means of SEM, ART-FTIR, DSC-TGA, XRD and Instron tensile tester. The results showed that the surface of the Kosteletzkya virginica bast fibers was smooth, and there were many visible grooves along the vertical section. Typical celluloseⅠin the Kosteletzkya virginica bast fibers was confirmed by FTIR and XRD analysis.The crystallinity of the Kosteletzkya virginica bast fibers was higher than the cotton fibers and lower than the castor-oil plant bast fibers. The beginning and maximum decomposition temperature of the Kosteletzkya virginica bast fibers were 252 and 347 °C respectively, which indicated that the Kosteletzkya virginica bast fibers had an appropriate thermal stability. The Kosteletzkya virginica bast fibers had a better mechanical properties and excellent hygroscopicity. All the results showed that the Kosteletzkya virginica bast fiber was one of an ideal candidate for the new textile material.

Abstract: Solid solutions with different compositions, mNH₄Cl·KCl and NH₄Cl·nKCl (m，n≥1), were prepared by the constant speed cooling method. The thermal stability of the solid solutions was determined by TG-DTA. The results show that mNH₄Cl·KCl crystals change its crystal form at 180°C, decompose into ammonia and hydrogen chloride gas at 330°C, melt at 790°C, and finally evaporate at around 820°C. Its evaporation temperature increases with the increasing of potassium chloride content in the samples. The Solid solution of NH₄Cl·nKCl decomposes to ammonia and hydrogen chloride gas at 230°C, melts at 790°C, and evaporates at 800°C. The continuous specific heat curve of the solid solution (NH₄, K)Cl were also determined. These data provide a theoretical basis for further research on solid solution properties.

Abstract: NaY zeolite molecular sieves have been synthesized using diatomite as a main starting material via a hydrothermal method. In this approach, the mixture of diatomite and Na₂CO₃ in mass ratio of 1.0/1.46 was first calcined at temperature of 830 °C for about 1.5 h. The calcined materials were then dissolved in water to obtain a solution and the composition is 15.1 Na₂O : 1 Al₂O₃ : 11.5 SiO₂ : 832 H₂O. The solution was used to synthesize NaY zeolite by the crystals seeds (27.76Na₂O·1.00Al₂O₃·25.07SiO₂·305.66H₂O) via hydrothermal treatment. The hydrothermal temperature is 100 °C and the percentage of added crystal seeds is 10% (volume) relative to calcined materials. The obtained zeolite was identified by X-ray diffraction (XRD), and was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and nitrogen sorption analysis, which showed that a high yield of NaY type with a high crystalinity was obtained.

Abstract: Cellulose crystalline and FTIR spectra of Artocarpus heterophyllus Lam wood and its main chemical compositions were analyzed.The result showed that the FTIR spectra of original wood samples from Artocarpus heterophyllus Lam wood present the same basic structure of all wood samples, the FTIR spectra of extracted wood samples were compared with the original wood sample, some of their absorption peaks of the band shifted to long or short wave, the wood and the solvent had little chemical reaction in the extracting process. FTIR spectra crystalline index of nitric acid-ethanol cellulose from Artocarpus heterophyllus Lam wood is NO′KI₁ 0.984, O′KI₂ 1.59, X-ray diffraction crystalline index of nitric acid-ethanol cellulose from Artocarpus heterophyllus Lam wood is 0.794.

Abstract: SiC whiskers were prepared through carbonthermal reduction in two steps. Firstly raw rice husks (RHs) were pyrolysed in a graphite vacuum furnace at 460°C for 2 hours and coked rice husks were pyrolysed at 1400°C in argon atmosphere. Scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) was employed to characterize the morphology and phase composition of SiC whiskers. The results show that the diameters of SiC whiskers range in 20-200 nm and their lengths are in the range from hundreds of microns to several millimeters. The whiskers are straight and slightly rough and consist of β-SiC crystals with bamboo-like structure. Vapor-solid (VS) mechanism plays a key role at the early stage of SiC formation and VLS mechanism and vapor phase mechanism of the whiskers are involved during the growth of SiC whiskers.

Abstract: Two-stage complete mixing ferment process was used for developing carbon source with primary sludge. The effects of hydrolysis retention time (HRT) and sludge retention time (SRT) on the ferment system were studied. The results showed that the effective HRT was between 32 h and 36 h, and the effective SRT was between 4 d and 7 d. Under above conditions, the average effluent SCOD was in the range of 980 mg/L and 1180 mg/L, and supernatant MLSS was in the range of 50 mg/L and 80 mg/L. And then, the separation effect of the sludge thickener was clearly. Acidogenic bacteria and methanogenic bacteria could be separated effectively in the conditions.

Abstract: Characterization of rice husks (RHs) of pyrolysed partly at 320°C and adsorption Ni²⁺ ions in the NiSO₄ solution and the wastewater of electroless nickel plating on magnesium alloys were investigated. The morphology of partly carbonized rice husks（PCRHs）was porous and particles and it consisted of amorphous carbon and silica. Thermogravimetric（TG） curve showed that rice husks mass decreased sharply at 280°C until 360°C. Raw RHs and PCRHs had good adsorption of Ni²⁺ in the NiSO₄ solution or wastewater of electroless nickel plating on magnesium alloys. Removal capacity of Ni²⁺ was higher for PCRHs than that of RHs due to PCRHs were mainly microporous with narrow pore size distribution.

Abstract: Steam reforming of benzene was carried out over Ni catalysts supported on modified olivine (MO). The MO was prepared by moulding olivine powder with calcium aluminate cement followed by calcination. It was found that calcination temperature of the support significantly influenced its physiochemical properties and the catalyst activity. The effects of reaction temperature, steam to carbon ratio (S/C) and liquid hourly space velocity (LHSV) on the catalytic activity were studied. The Ni/MO catalyst was shown to be very active at the reaction temperature above 750 °C. A close to 100% C-conversion was obtained at the conditions with reaction temperature 800 °C, LHSV 0.8 h^–1 and S/C ratio 2.5. No obvious deactivation of the catalyst was observed during 500 min stability test.