Advanced Materials Research Vols. 236-238

Abstract: It was presented a Fenton-like catalyst Mn/ZSM-5 to evaluate its activities in degradation of cellulose in this paper. The degree of polymerization (DP) and crystalline degree of cellulose were sharply decreased with 87% and 33.6% after the degradation. Some soluble sugars and small molecular chemicals were detected. The suggested mechanism reflecting the degradation process was proposed.

Abstract: Simultaneous saccharification and fermentation is an attractive process configuration for bioethanol. However, the process cost in SSF is still high. Further reductions in cost are expected with reduction of enzyme addition and the use of waste agricultural or industrial materials as feedstock. Surfactant addition is a simple method to reduce the amount of enzyme loading. In the present work we explore the effect of Gleditsia Saponin, an inexpensive and natural surfactant, on SSF of furfural residue, a main waste of furfural industry in China, for ethanol production. Gleditsia Saponin addition even at low concentration, 0.04 g/l, increased the ethanol yield by 9.9%. Meanwhile, when Gleditsia Saponin addition was 0.16 g/l, the yield was increased by 22.8% and the enzyme activity significantly increased in the liquid fraction at the end of SSF, which would contribute to recover and recycle enzyme. Gleditsia Saponin addition at 1.25 g/l had a better performance in improving SSF efficiency than that of 2.5 g/l Tween-20 addition. The positive effects of Gleditsia Saponin addition on SSF, such as less enzyme loading and shorter residence time could also been observed.

Abstract: A series of glucose char sulfonic acids (GCSA) were prepared via a two-step procedure involving sulfuric acid catalytic charring of glucose and successively sulfonation. GCSA prepared in this new route possess high sulfonic acid loading, and acid capacity of GCSA-2 reaches as high as 2.60 mmol g^-1 at charring conditions of sulfuric acid being 80%, ratio of glucose and sulfuric acid being 1:8, charring time being 3 h, charring temperature being 80 °C. All GCSA were found to be active in the esterification between n-butanol and acetic acid. GCSA-2 behaved with good activity with 95.6% conversion and 100% ester selectivity.

Abstract: The liquefied corn barn-based epoxy resin (LCBER) was synthesised through the glycidyl etherification reaction from liquefied corn barn (LCB) had having groups of bound phenol and epichlorohydrine under alkali conditions. The average molecular weights of LCBER in various reaction conditions were examined. The extreme high molecular weight portion of LCBER-30 was obtained using LCB at 30 min as raw materials. The epoxy functionality of LCBER was controlled by the amount of bound phenol in LCB. LCBER was cured with polyamide-650 (PA-650) and the thermal and mechanical properties were evaluated. Comparing to the petroleum-based bisphenol-A type epoxy resin (DGEBA), LCBER presented higher adhesive shear strength and good thermal stability. These suggested that LCBER would be more suitable to glue biomass materials.

Abstract: It is well known that microcystins (MCs) are the most abundant toxins produced by cyanobacteria in freshwater. The separation and characterization of MCs isomers are very important to the research of algal pollution in freshwater. In this paper MCs isomers were extracted by using methanol water solution and separated by reverse phase high performance liquid chromatography (HPLC). The different isomers were characterized by using HPLC-MS method. Different ratio of extract solvent and chromatographic conditions were discussed. Five MCs isomers were successfully extracted from cyanobacteria of Dianchi Lake. Three of which were characterized to be MC-RR, MC-YR and MC-LR, 1.5mg (92.3 purity) of MC-LR was prepared by using a semi-preparation HPLC system.

Abstract: This study evaluated the potential application of a biomass material, corncob lignocellulose (CL), as a novel adsorbent for the removal of basic dyes from aqueous solutions. The adsorption behavior and mechanism of basic dyes on CL was investigated via batch experiments. Both adsorption and desorption studies showed that the attachment of basic dyes onto CL was ascribed to a combined interaction involving electrostatic attraction and chemisorption. The decolorization efficiency of CL increased with increasing solution pH and temperature. Thermodynamic parameters demonstrated the spontaneous and endothermic nature of the adsorption. The dye uptake process was best described by the Langmuir isotherm. The adsorption capacity of CL for Methylene blue, Crystal Violet and Malachite Green at 30°C was calculated to be 145.8, 121.8 and 65.7 mg/g, respectively.

Abstract: Bio-oil, with high oxygen-containing character, which was prepared from flash pyrolysis of rice stalk powders, was upgraded by the method of catalytic esterification with methanol. The esterified oil was distilled stepwise from 60 °C to 105 °C, and the fractions were analyzed with Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectroscopy (GC/MS) for the distribution of species. It was found that 58% of the components were detected in the fraction of 60 °C-80 °C, with 1,1-dimethoxypropan-2-one was the most abundant species. The residue, in which the boiling point of species were higher than 105 °C were resolved in acetone, and also analyzed with GC/MS. The results showed that phenols are the most abundant species, and following the ketones and hydrocarbons.

Abstract: 5-hydroxymethylfurfural (5-HMF) is a kind of new green platform chemical with wide application. Glucose, which is the unit compound of cellulose, is one of the most important starting chemicals from biomass. With its low cost and wide supply, the conversion of glucose to HMF has attracted the interests of researchers. In this work, a systematic study has been conducted to evaluate the catalytic performance in the conversion of glucose to 5-HMF using Zr(H₂PO₄)₂ solid acid catalyst in isobutanol-water (1.6:1/V:V) two-phase system. An optimized 5-hydroxymethylfurfural yield of 42.32% was obtained within 1.5 h at 180 °C over Zr(H₂PO₄)₂ with ratio of 1:1 and the glucose conversion was 94.83%. The catalyst stabilities was studied and results showed that Zr(H₂PO₄)₂ had higher stabilities.

Abstract: Lignocellulosic materials are regarded as an alternative energy source for bioethanol production to reduce our reliance on fossil fuels. Pretreatment is an essential step in the enzymatic hydrolysis of biomass and subsequent production of bioethanol. Adding formic acid with catalyst dosage (4%) in saturated formic acid will be good for cellulose degradation and glucose production; when the cellulose hydrolyses to glucose, the glucose degrades simultaneously. Kinetic models can have practical applications for the optimization of the process and performance analysis, or economic estimations, so investigate the wheat straw hydrolysis kinetics is necessary. In this paper, effects of temperature and time on wheat straw hydrolysis in saturated formic acid with 4% hydrochloric acid solution reaction kinetics have been investigated. The results showed that the hydrolysis velocities of wheat straw were 0.0190 h⁻¹ at 60 °C, 0.0325 h⁻¹ at 65 °C, 0.0683 h⁻¹ at 70 °C and 0.0931 at 75 °C. The degradation velocities of glucose were 0.0285 h⁻¹ at 55 °C, 0.0448 h⁻¹ at 65 °C, 0.1098 h⁻¹ at 70°C and 0.1436 h⁻¹ at 75 °C. The activation energy of wheat straw hydrolysis was 106.35kJ/mol, and the activation energy of glucose degradation was 111.00kJ/mol.

Abstract: The mixture of wheat straw (WS) and polyester (PC) was liquefied in supercritical ethanol. Liquefied products produced and liquefied residue from the liquefaction under different supercritical conditions were analyzed by GC-MS, SEM and IR. GC-MS analysis of the liquefied products indicates that ethanol would decompose. And the most compounds in the liquefied product had the structure of phenol and phenol derivatives, which came from the degradation products of PC and WS. SEM analysis show that the wheat straw powder possessed larger particles with smooth surfaces while the residue from liquefaction had smaller particles with rough surfaces because of drastically degraded from the wheat straw powder surface under supercritical conditions. FT-IR analysis showed that the lignin was easily degraded during the liquefaction process, and also found to the cellulose is very difficult to liquefy for its crystalline structure.