Biochars derived from giant reed (Arundo donax L.) with different treatment: characterization and ammonium adsorption potential
2017
Zhao, Yaqi | Huang, Lei | Chen, Yucheng
The adsorption characteristics of Arundo donax L.(AD) biochars for ammonium(NH₄ ⁺-N) were investigated. Absorbents were characterized through scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy analyses. AD-500 and AD-800 were produced from raw AD and pyrolyzed from room temperature to 500 and 800 °C, respectively. PD-500 was prepared by impregnating AD with a mild alkali solution and pyrolyzing from room temperature to 500 °C. The feasibility of the use of AD-500, AD-800, and PD-500 removing NH₄ ⁺-N from an aqueous solution was examined. The adsorption system followed the pseudo-first-order model. Results showed that the adsorption capacities of AD-biochars for NH₄ ⁺-N were enhanced after the final pyrolysis; temperature was increased or the mild alkali pretreatment was administered. When the initial NH₄ ⁺-N concentration was changed from 4 to 8 mM, the NH₄ ⁺-N sorption capacity of the biochar increased from 23 to 51%, with the final pyrolysis temperature increasing from 500 to 800 °C. The improved ratios were 12 to 33% when the biochar was prepared at 500 °C after the mild alkali pretreatment, and NH₄ ⁺-N sorption was enhanced due to ion exchange in the PD biochar. Graphical abstract Biochars derived from giant reed (Arundo donax L.) with different treatment :characterization and ammonium adsorption potential.
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