Biochar is produced by the combustion of biomass under limited oxygen conditions. It is a fine-grained and porous substance and has been applied recently to remove dyes from aqueous solutions.

Recently, Dr. YANG Yuyi under the supervision of Professor WANG Jun from Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden evaluated the adsorption potential of bamboo biochar for the removal of metal-complex dye acid black 172 (C.I. Acid Black 172) from solutions.

The study found that Freundlich model was more suitable for the adsorption process of bamboo biochar than Langmuir isotherm, indicating multilayer adsorption of acid black 172 on a heterogeneous bamboo biochar surface. Adsorption kinetics analysis of pseudo-second-order and Weber–Morris models revealed that intraparticle transport was not the only rate-limiting step. The bamboo biochar exhibited a good adsorption performance even at high ionic strength. Analysis based on the artificial neural network indicated that the temperature with a relative importance of 29 % appeared to be the most influential parameter in the adsorption process for dye removal, followed by time, ionic strength, pH and dye concentration. The results in this study provided the operational parameters for bamboo biochar used for removing acid dyes in effluents.

This work was supported in part by Grants from the Science and Technology Project of Zhejiang Province (2010C13G2010074), National Natural Science Foundation of China (31070079), the Science and Technology Project of Zhejiang Province (2008C13014-3), the International Cooperation Project in Science and Technology of Zhejiang Province (No. 2008C14038), the National Key Technology Rand D Program (2012BAC17B04), and Open Funding Project of the Key Laboratory of Aquatic Botany and Watershed Ecology, Chinese Academy of Sciences.

The results were published in International Journal of Environmental Science and Technology entitled "Evaluation of adsorption potential of bamboo biochar for metal-complex dye: equilibrium, kinetics and artificial neural network modeling”.

Article link: http://link.springer.com/article/10.1007/s13762-013-0306-0 

 Effects of initial dye concentration and temperature, ionic strength on the adsorption capacity of bamboo biochar for acid black 172 (Image by Dr. YANG)