Study on Leaching Rule of Nano Particles from Cunninghamia Lanceolata Wood
The resin in Chinese-fir (Cunninghamia lanceolata), which has been widely planted in south China is very liable to bring about the occurance of both holes and spots in paper, to aggravate the pollution of waste water, to shroten the fixed number of service year of equipment, to increase the consumption of chemicals, to relieve the rate of delignification, and to reduce the the permeability of flows in the process of pulping and paper-making. In order to overcome the above-mentioned negative effects, the extractives of the fresh Cunninghamia lanceolata shavings, which were obtained by using both the sorbitic- and supersonic-extracting approaches, were analyzed by ZETA and SIZER to find out the leaching rule of nano particles in Chinese-fir wood. The results are as follows: (1) During the the sorbitic-extracting process, the extracted quantity of nano particles rapidly increases firstly, then slightly increases with the extracting time. Based on the evaluating indicator of the volume fraction and the mass fraction, 63.63% and 66.87% of the particles are mainly distributed in the range of 37.8-91.3 nm and 28.2-68.1 nm in diameter, respectively, despite volume fraction 0.7%, 20.5% and 20.5% of the particles with the diameter of 4150-6440 nm, 459-825 nm and 825-4800 nm, respectively, it is enough for these particles to be able to result in the obstructive effects on the permeability and the pulping. (2) During the the supersonic-extracting process, the particles with the diameter of 32.7-78.8 nm and 32.7-58.8 nm occupy 88.8% and 90.5%, respectively, while there is no particles in the diameter of more than 190 nm. Therefore, it can be drawn a conclusion that not only the extraction mass of the particles is enhanced, but also the agglomeration degree of the leached nano particles is lowered on Cunninghamia lanceolata wood for the supersonic-extracting approach.