Ageing of rice husk biochar along a freeze-thaw cycles
Shenyang Agricultural University, Biochar Engineering Technology Research Center of Liaoning Province, Shenyang 10086, China
In order to elucidate the aging possess of biochar, the experiment with treatment biochar with soil were performed. For accelerating aging process, freeing-thawing cycle were conducted to simulate the changing process of the physical and chemical properties of biochar and explore the roles of biochar in the changes of the soil nutrition. Aging treatment has a significant impact on the physical and chemical properties of biochar. The pH values, element composition, oxidation of the surface, absorption capacity of biochar changed in the ageing process. In the simulation test of freeze-thaw cycles, pH of biochar displayed upward trend after the first decline in 25 cycles, and then return to the initial level, indicating that the pH of biochar is not easy to change. Biochar surface oxidation occurs rapidly and significantly in the early, and then stabilized in the latter stage. Surface oxidation degree is higher than the whole. The results showed that surface oxide of biochar protect the internal particles from further oxidation. In the first 25 freeze-thaw cycles, adsorption capacity of biochar to hydroquinone changes from the 5.928 mg.g-1 to 11.73 mg.g-1, indicating that freeze-thaw cycle treatment increase adsorption capacity of biochar.
© Owned by the authors, published by EDP Sciences, 2016
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