An Assessment of U(VI) removal from groundwater using biochar produced from hydrothermal carbonization

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:92

Article

Kumar, Sandeep²  Loganathan, Vijay A.³  Gupta, Ram B.⁴  Barnett, Mark O.¹ 

[1] Auburn Univ, Dept Civil Engn, Auburn, AL 36849 USA

[2] Old Dominion Univ, Dept Civil & Environm Engn, Norfolk, VA 23529 USA

[3] Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA

[4] Auburn Univ, Dept Chem Engn, Auburn, AL 36849 USA

关键词: Hydrothermal carbonization;    Biochar;    Uranium;    Adsorption;    Remediation;    Permeable reactive barrier;   

DOI  :  10.1016/j.jenvman.2011.05.013

来源: Elsevier

【 摘 要 】

The ever-increasing growth of biorefineries is expected to produce huge amounts of lignocellulosic biochar as a byproduct. The hydrothermal carbonization (HTC) process to produce biochar from lignocellulosic biomass is getting more attention due to its inherent advantage of using wet biomass. In the present study, biochar was produced from switchgrass at 300 degrees C in subcritical water and characterized using X-ray diffraction, fourier transform infra-red spectroscopy, scanning electron micrcoscopy, and thermogravimetric analysis. The physiochemical properties indicated that biochar could serve as an excellent adsorbent to remove uranium from groundwater. A batch adsorption experiment at the natural pH (similar to 3.9) of biochar indicated an H-type isotherm. The adsorption data was fitted using a Langmuir isotherm model and the sorption capacity was estimated to be ca. 2.12 mg of U g(-1) of biochar. The adsorption process was highly dependent on the pH of the system. An increase towards circumneutral pH resulted in the maximum adsorption of ca. 4 mg U g(-1) of biochar. The adsorption mechanism of U(VI) onto biochar was strongly related to its pH-dependent aqueous speciation. The results of the column study indicate that biochar could be used as an effective adsorbent for U(VI), as a reactive barrier medium. Overall, the biochar produced via HTC is environmentally benign, carbon neutral, and efficient in removing U(VI) from groundwater. (C) 2011 Elsevier Ltd. All rights reserved.

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