The Research On Structural Features And Pyrolytic Utilization Of Mulberry(Morus Spp.) Branches

Mulberry(Morus spp.) is an allogamous perennial deciduous woody plant. It is widely distributed in geographic and vertical height. There are a large number of mulberry branches produced due to the pruning of branches each year. Most of the branches are abandoned and a small part of the branches are burned as fuel. The burning of the branches produces environmental pollution and waste of resources. In order to make full use of mulberry branches and improve the economic benefits of mulberry industry, this paper investigated several varieties of mulberry branch structure characteristics. Then we pyrolyzed the branches and analyzed the performance of activated carbon(AC) and the components of wood vinegar(WV) liquid. This study will provide a scientific basis for the highly valuable utilization of the mulberry branches. The results are as follows.1. The structure characteristics of the mulberry branches.In order to investigate the relationship between the xylem and the pyrolysis products, we chosed four varieties and measured the proportions of xylem in the sections of the branches. The results showed that the xylem percentage of shansang 402 was 20.95% which was the smallest. It was significantly different with the other materials. Shansang 305 was less than the Shin Ichinose on xylem proportion, but the differences were not significant. The xylem proportion of the seeding mulberry was 55.50% which was the largest.2. The adsorption properties and yield of AC.In order to prepare the AC, the mulberry branches were pyrolyzed through the physical methods using water as the activator. And we evaluated the performance of the AC. The results showed that the xylem ratio has a certain influence on the yield of the AC. The yield was between 11.6%~18.0%. The AC from Shin Ichinose and Shansang 305 reached the first national standards. The iodine adsorption was between 1100~1130 mg/g and the methylene blue decoloration was between 255~270 mg/g. The adsorption property of AC from seeding mulberry was close to the second national standards. The yield of AC from Shansang 402 was the largest, but the adsorption property was below the national standards. It need to further study the preparation process to improve the performance of AC.3. The physical and chemical properties of WVThe smell of the raw WV and refined WV both were the smell of the burning smoke. The density and refining yield of different materials have no significant differences. The refractive index of refined WV was lower and the color was lighter. Refined WV had lower organic acid content and higher p H. The relative content of organic acids from the raw WV of seeding mulberry was 9.66% which was the highest, while the refined WV from Shin Ichinose was 1.14% which was the lowest.4. Antibacterial activities of WVThe antibacterial test was carried out in order to investigate the differences of antimicrobial activities of WV from different materials. The results showed that all of the WV had antibacterial activity. There were no significant differences between raw and refined WV. Each WV had a certain effect on the inhibition of bacteria. The seeding mulberry WV was the best. The Shin Ichinose was better than the Shansang 305 and Shansang 402. The inhibition effect of WV on the bacteria was stronger than on the mold.To quantitatively compare the differences of WV from different mulberry branches on the inhibition of bacteria, each WV was half diluted into a various ratio respectively. Then, the antibacterial effect of WV on five kinds of plant pathogenic bacteria was detected.The EC50 of Shin Ichinose was among 7.59~12.00 mg/ml which meant it was the strongest.5. The GC-MS analysis of WVTo investigate the composition of each WV, GC-MS was used to analyze the constituents of each WV. GC-MS analysis indicated that the components of each mulberry braches were mainly ketones, phenols, organic acids and alcohols etc. The compounds components detected by GC-MS from the WV of the mulberry braches were between 23~39 and seeding mulberry was more than the other ones. The ketones and alcohols content of Shansang 305 36.28% and 28.11% which were the highest. The Shansang 402 had the highest phenols content which was 42.04%.In summary, pyrolysis mulberry branches would fair use the resources and reduce waste. The AC prepared from three varieties of mulberry reached the national standard. The WV of mulberry branches had a very strong bacteriostatic action, especially on the plant pathogenic bacteria. The WV can be used as a natural antimicrobial agent reduced the use of pesticides. It would reduce environmental pollution and had broad application prospect.