Biochar is a carbon-rich material that is produced during the pyrolysis of biomass, and it has received increasing attention as an effective sorbent and a novel remediation material. This study found that the oxygen-containing organic components and the scattering silicon particles of rice straw derived biochars were two main regions of Al adsorption. The complexation of Al with organic hydroxyl and carboxyl groups and the surface adsorption and coprecipitation of Al with silicate particles both contributed to the Al adsorption of the biochars. Furthermore, due to the liming effect of biochar (alkaline), the aluminum species were converted to Al(OH)2+ and Al(OH)2+ monomers, which were strongly adsorbed by biochars. Interactions of aluminum with primary and oxidized biochars were compared to understand the changes in the adsorption properties of aged biochars. Oxidization (aging) introduced carboxylic functional groups on biochar surfaces, which served as additional binding sites for Al3+, thus promoting the adsorption of Al biochar, indicating that biochar had long-term effect on Al immobilization in acidic soil. The alleviation of aluminum phytotoxicity to wheat plants in a hydroponic system through the amendment of biochar was investigated to explore the possibility of applying biochar in acidic soil amelioration. Compared to the liming effect, the adsorption by biochar exhibited a sustainable effect on the alleviation of Al toxicity. Therefore, the biochar amendment appears to be a novel approach for aluminum detoxification in acidic soils.

Interaction mechanisms of biochars with aluminum and their alleviation effects in aluminum phytotoxicity

248th National Meeting (2014)

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