Volume 11 Issue 1

Efficient pretreatment is the key step in catalytic biomass conversion. Herein, a mixed ball-milling method was used to pretreat cellulose with a solid catalyst. The method was tested with solid acid and commercial 5 wt% Ru/C in water, and the effect of pretreatment on yield was measured by the hydrolytic-hydrogenation of cellulose to sugar alcohols, which are the platform compounds for the production of gasoline and fine chemicals. The influence of ball-milling mode, time, and reaction parameters was studied. The properties of cellulose and the catalyst were also analyzed before and after treatment. The yield of sugar alcohols reached 90.3% at 463 K with amorphous zirconium phosphate (ZrP) and Ru/C and a mixed ball-milling time of 2 h. The high sugar alcohol yield was achieved 12 times faster than with the single ball-milling method under the same reaction conditions for 24 h. This effect is ascribed to the enhanced contact between cellulose and catalyst, which promotes the rate-determined cellulose depolymerization to obtain high sugar alcohols yield.

Growing demand for sustainable products has led to increased interest in the use of paperboard as a structural material. Paperboard products are almost exclusively manufactured by embossing, pulp molding, and bending processes. Other well-known forming methods, such as deep or stretch drawing, are only rarely applied to paperboard. This is primarily ascribed to the lack of knowledge concerning the process design and limits when paperboard is employed. In the present work, the applicability of well-established design strategies and characterization methods for metals to paperboard is investigated. Therefore, forming limit diagrams for paperboard are determined in a first step. Additionally, significant material parameters are identified in order to describe the material influence upon the forming limit. Furthermore, the influence of a hydrostatic counter pressure onto the forming limit is investigated. To predict the forming behaviour of a complex formed paperboard demonstration part, a numerical model of a hydroforming process is set up, executed, and validated.

Biodegradable chitosan can be applied as a coating on the surface of kraft paper in order to improve its barrier properties against water vapor and air. The food packaging industry can benefit from the addition of chitosan to its current packaging, and in turn reduce pollution from plastic packaging plants. This paper discusses the film formation of chitosan, the permeability of paper coated with a chitosan layer, and the influence on the paper’s surface and barrier properties under different process conditions. SEM (scanning electron microscope), AFM (atomic force microscope), ATR-FTIR (Fourier transmission infrared spectroscope with attenuated total reflection), and PDA (penetration dynamics analysis) were used to analyze the properties of chitosan’s film formation and permeability. A controlled experiment showed that the chitosan layer was smoother than the surface of the uncoated kraft paper, had better film formation, and that there was no chitosan penetration through the kraft paper. The barrier properties against water vapor were strongest when there was a higher concentration of chitosan solution at the optimum pH, stirring speed, and those with a thicker coating on the kraft paper.

Water plays a very important role in wood and wood products. The molecular motion of water in wood is susceptible to thermal activation. Thermal energy makes water molecules more active and weakens the force between water and wood; therefore, the water molecules dynamic properties are greatly influenced. Molecular dynamics study is important for wood drying; this paper therefore focuses on water molecular dynamics in wood through fast field cycling nuclear magnetic resonance relaxometry techniques. The results show that the spin-lattice relaxation rate decreases with the Larmor frequency. Nuclear magnetic resonance dispersion profiles at different temperatures could separate the relaxation contribution of water in bigger pores and smaller pores. The T1 distribution from wide to narrow at 10 MHz Larmor frequency reflects the shrinkage of pore size with the higher temperature. The dependence of spin-lattice relaxation rate on correlation time for water molecular motion based on BPP (proposed by Bloembergen, Purcell, and Pound) theory shows that water correlation time increases with higher temperature, and its activation energy, calculated using the Arrhenius transformation equation, is 9.06±0.53 kJ/mol.

Predicting paper properties based on a limited number of measured variables can be an important tool for the industry. Mathematical models were developed to predict mechanical and optical properties from the corresponding paper density for some softwood papers using support vector machine regression with the Radial Basis Function Kernel. A dataset of different properties of paper handsheets produced from pulps of pine (Pinus pinaster and P. sylvestris) and cypress species (Cupressus lusitanica, C. sempervirens, and C. arizonica) beaten at 1000, 4000, and 7000 revolutions was used. The results show that it is possible to obtain good models (with high coefficient of determination) with two variables: the numerical variable density and the categorical variable species.

The inhibitors derived from degradation of lignocellulose have adverse impacts on fermentation, which is considered to be a fundamental problem in bioethanol production. Fermentation of steam-exploded corn stover prehydrolyzate by Pichia stipitis showed that phenolic compounds had much higher inhibitory effects than weak acids and furan at high fermentation pH. Two types of organobentonite (cetyltrimethylammonium (CTMA)- and benzyltrimethylammonium (BTMA)-modified bentonite) were used to remove phenolic compounds in prehydrolyzate. The effectiveness of organobentonite treatment was evaluated by ethanol fermentation, which indicated that the organobentonite treatment improved the fermentability substantially, even though a noticeable difference was found in the phenol removal by the two organobentonites. Without organobentonite treatment, the sugar utilization ratio was only 68.1%, and the produced ethanol was 15.36 g/L. After CTMA- and BTMA-bentonite treatment, the sugar utilization ratios were beyond 95%; meanwhile, the ethanol production increased by 45.5% and 42.8%, respectively. This indicated that organobentonite treatment was a potential detoxification method.

Large amounts of ash, generated from biomass gasification, often contaminate syngas and the ecosystem. This study showed that the ash obtained from the gasification of pine wood was primarily composed of carbon (15% to 25%), minerals (~21%), and oxygen (52% to 63%), and exhibited low surface area (8.4 to 11.2 m2/g). The size of ash particles was between 600 nm and 600 μm. Calcium, potassium, and sodium were the three most common mineral elements in the ash. Leaching tests showed that adding ash to water raised the pH value from 5.7 to between 11.2 and 11.5, and, as time progressed, more mineral elements were released from the ash. For growing microalga Chlamydomonas debaryana in media containing ashes, no toxicity of pine ash was found.

The influence of TiO2 nano-particles (nano-TiO2) was studied relative to the mechanical and optical properties of CMYK printed paperboard after coating with a UV-curable varnish. Commercial duplex paperboard (glazed grayback paperboard, 230 g/m2) was printed with a CMYK offset printing process. Board samples were coated with a nano-TiO2 modified UV-curable varnish at four treatment levels (0, 0.2, 0.5, and 1%) using an industrial screen-coating machine. The samples were then dried using a UV lamp in an industrial UV drying machine. Sample discoloration was measured spectrophotometrically using CIELab parameters (L*, a*, b*, and ΔE) before and after coating. The whiteness, brightness, fold, and tear resistance of the ink films were also measured. The nano-treatment had a significant effect on the relative optical parameters, which resulted in increasing the lightness of the treated samples. Color change (ΔE) was recorded for all tested samples, and an unperceivable change was observed in case of the nano-treatment with 0.2% as the end value. The weakly perceivable changes were found in the cases of treatment with 0.5 and 1% nano-intensities. The nano-TiO2 treatment significantly improved the fold and tear resistance of the samples.

The bamboo industry plays a significant strategic role in the world’s economy. Laminated bamboo, with increasing yearly yields, is the intermediate material for bamboo products such as furniture, floor board, and container floor. The trilaminar straight joint glued-laminated bamboo production line is the leading enterprise in Fujian Province, and it was used to conduct a load analysis of the data collected from a year’s production, based on the life cycle assessment system. The results show that the processing of glued-laminated bamboo contributes notably to the acidification potential, eutrophication potential, global warming potential, and photochemical ozone creation potential, whereas resource depletion and ozone depletion are affected by the urea-formaldehyde resin adhesive, among which the urea contributes the most. As for processing, carbonization, desiccation, and thermo-compression, these have the greatest impacts on the environmental load, with a total contribution rate of greater than 67%, as the main source for the power depletion is from the processing of fossil fuel. In addition, the oxynitride, phosphide, sulfide, aromatic hydrocarbon, etc., that are discharged from the reaction intensify the eutrophication potential, the photochemical ozone creation potential, and the acidification potential.

Impregnating wood, assisted with ultrasound technology, could improve the impregnation efficiency by improving the permeability of wood, thus affecting the subsequent drying process. Poplar lumber and phenolic resin were applied to investigate the influence of ultrasound-assisted impregnation on the wood drying process. The ultrasonic frequency and processing time were analyzed and correlated. The results indicated that the average drying rate of impregnated wood was generally faster in the earlier stage and slower in the later period than the blank group. At the earlier drying stage, the drying rate exhibited a decreasing tendency with increasing ultrasonic time, as the frequency remained constant. However, with an unaltered processing time, a contrary trend was detected as the frequency was increased. The ultrasonic frequency and time caused an complex effect on the average drying rate during the later drying course. These findings could be applied to the impregnated wood drying industry to strike a balance between ultrasound-assisted performance and the related drying effectiveness.