Preparation of functional bamboo by combining nano-copper with hemicellulose and lignin under high voltage electric field (HVEF)

Enhancement of separation selectivity of hemicellulose from bamboo using freeze-thaw-assisted p-toluenesulfonic acid treatment at low acid concentration and high temperature

The cellulose-rich residual solids are obtained with p-toluenesulfonic acid (p-TsOH) treatment. However, better fractionation of hemicellulose and separation is difficult to obtain during treatment. This study aims at investigating the separation selectivity of bamboo hemicellulose using freeze-thaw-assisted p-TsOH (F/p-TsOH) treatment. The desired separation effect was achieved at freezing temperature -40 °C, freezing time 20 h, p-TsOH concentration 3.0 %, treatment temperature 130 °C and time 80 min. 93.26 % hemicellulose separation was found, which was 32.88 % higher than that of conventional p-TsOH treatment. Furthermore, the separation yield of lignin decreased significantly from 69.29 % to 13.98 %. The distinct lignin characteristic absorption peaks were found, while that of hemicellulose was difficult to observe. The fiber crystallinity index increased from 50.42 to 56.55 %. Furthermore, greater selectivity for hemicellulose separation was achieved. The results provide a new research thinking for efficient fractionation of lignocellulosic biomass by organic acid treatment.

Study on Bamboo Longitudinal Flattening Technology

In this paper, we introduced a bamboo longitudinal flattening technology and analyzed the effects of the softening–flattening process on the physical and mechanical properties of moso bamboo. This is a newer bamboo processing technology that can enhance the utilization and reduce pollution compared with traditional bamboo-based products. Results showed that the parenchyma cells distorted and compacted due to the flattening process. The hemicellulose and cellulose content decreased, while the content of lignin presented an increasing tendency. As expected, the dimensional stability of moso bamboo enhanced due to the decrement of hemicellulose. The softening–flattening process positively contributed to the micro-mechanical properties of treated bamboo specimens. For example, the hardness and modulus of elasticity of the untreated bamboo sample increased from 0.58 and 15.7 GPa to 0.8 and 17.5 GPa, respectively. In addition, the changes in cellulose crystallinity and mechanical properties were also investigated in this paper. The cellulose crystallinity increased from 37.5% to 43.2%, significantly. However, the modulus of rupture of the flattened bamboo board decreased from 9000 to 7500 MPa due to the grooves made by the flattening roller. The MOE of flattening bamboo board showed the same decreasing tendency.

Change in Micro-Morphology and Micro-Mechanical Properties of Thermally Modified Moso Bamboo

In recent years, saturated steam heat treatment has been considered as an environmentally friendly and cost-effective modification method compared with traditional heat treatment media. In this study, bamboo was treated by saturated steam, and the change in chemical composition, cellulose crystallinity index, micro-morphology, and micromechanical properties were analyzed by a wet chemistry method, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), nanoindentation, and so on. Results illustrated that the parenchyma cell walls were distorted due to the decomposition of hemicellulose and cellulose in bamboo samples. As expected, the hemicellulose and cellulose content decreased, whereas the lignin content increased significantly. In addition, the cellulose crystallinity index and thus the micromechanical properties of bamboo cell walls increased. For example, the hardness increased from 0.69 GPa to 0.84 GPa owing to the enhanced crystallinity index and lignin content.

Carbohydrate degradation contributes to the main bioheat generation during kitchen waste biodrying process: A pilot study

Biodrying is a promising method for processing kitchen waste (KW) with high moisture content into reusable solid recovered fuels (SRFs). During biodrying, a large amount of bioheat generated from biodegradation of biochemical components results in KW dehydration. However, the degradation rules of these components and their contribution to the bioheat in KW biodrying have not been systematically clarified. Here, a pilot experiment was performed to investigate the variations in biochemical components, hydrolase activities, and bioheat generation during three successive cycles of biodrying processes. Results showed that KW could be rapidly converted into SRFs with low calorific values of 6705-7062 kJ/kg and moisture content of 31.26%-35.21%. Analyses of hydrolase activities and mean fluorescence intensity suggested that the biodrying process pioneered the degradation of lipids and proteins in the warming stages, while carbohydrates (i.e. amylum, celluloses, etc.) underwent rapid decomposition in a large extent in the high-temperature and cooling stages. Carbohydrates with minimal difficulty in degradation, contributed 73.37%-89.92% to the total degradation mass and 59.23%-60.80% to the bioheat source during the three-cycle biodrying process. The generated bioheat was 4.32-4.56 times the amount of the theoretical heat used for water removal, indicating that internal bioheat could significantly enhance water evaporation and was sufficient for the expected water removal mass. Therefore, the evaluation of the main components to bioheat generation and its utilization efficiency makes a prominent contribution that can greatly clarify the conversion of KW biodrying into SRFs in order to efficiently promote renewable bioenergy and support the bioeconomy.

Determination of the Effects of Superheated Steam on Microstructure and Micromechanical Properties of Bamboo Cell Walls Using Quasi-Static Nanoindentation

In this paper, quasi-static nanoindentation was applied for investigating the influence of superheated steam on microstructure and micromechanical properties of Moso bamboo cell walls. The changes of mico-morphology, chemical composition, cellulose crystallinity index, micro-mechanical properties of bamboo were analyzed via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nanoindentation. As expected, the content of hemicellulose and cellulose showed a downward trend, whereas the relative lignin content increased. Elastic modulus and hardness of the cell wall increased compared with that of the untreated sample. The elastic modulus and hardness of bamboo increased from 11.5 GPa to 19.5 GPa and from 0.35 GPa to 0.59 GPa. Furthermore, results showed that the creep resistance positively correlated to treatment severity.