The Research Of White-rot Fungi Degrading Pb Polluted Rice Straw And Passivating Pb

The white-rot fungi degrading Pb polluted rice straw matrix was studied during fermentation. The degrading function of hemicellulose, cellulose and lignin and the changing regulation of organic matter, pH value, organic matter, organic nitrogen, and humus (humic acid and fulvic acid) were monitored during fermentation under four different Pb concentration. Distribution coefficient of each fraction of Pb was studied before and after fermentation. There are five kinds of compound forms of the heavy metal Pb, which is the solution state and exchange state, the carbonate combination state, the iron manganese oxide state, the organism combination state and the remnant state. and humus carbon were discussed during fermentation under the different Pb concentration. Then Pb passivated action of heavy metal ions in matrix was also researched during hemicellulose, cellulose and lignin was degraded. The principle of passivation was discussed, and the affection and reason was analyzed for passivating Pb under the different Pb concentration.The result showed that white-rot fungi had certainly capability in enduring poison of metal iron ,under the Pb existing it showed that it had a strong capability for degrading organic such as lignin which were difficultly degraded in rice straw. And it was obviously that observed that white-rot fungi passivated Pb when it was degrading Pb polluted lignin, Pb was turned from actions to inaction so that poison of Pb was controlled and the effectiveness of organism was cut down. The figures of succession experimental results reflected that Pb ions could promote increment of the white-rot fungi, the 200 mg/kg Pb concentration was the most applicably in the four concentrations of the experimental results, and under this concentration that white-rot fungi not only grew best, but also had a strong capability in degrading organic such as hemicellulose, cellulose and lignin in rice straw and was superior to other concentration.The degradation rate of hemicellulose, cellulose and lignin reached 52.36%, 32.29% and 44.16%.The weight loss rate of matrix weight and contents of humus carbon reached 142.01 mg/g. That white-rot fungi growing and...