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Updated: Oct 4, 2025
Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites
Published on: November 28, 2014
Modification of sludge-based biochar using air roasting-oxidation and its performance in adsorption of uranium(VI)
Yiwei Sun1, Baiyan Zeng1, Yatang Dai2
1State Key Laboratory of Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang, Sichuan 621010, P.R. China; School of Environment and Energy, Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, South China University of Technology, Guangzhou, Guangdong 510006, P.R. China; China-Singapore International Joint Research Institute (CSIRI), Guangzhou 510006, P.R. China.
Abstract:
Modification methods for sludge-based biochar are often complex and generally ineffective. In this study, sludge-based biochars were prepared at low cost using a simple air roasting-oxidation modification method and the adsorption performance on U(VI) was investigated. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results together indicated that more carbon-oxygen functional groups were formed on the surface of oxidized biochar (OBC) compared to unoxidized biochar (BC). The adsorption performance of 550-OBC (biochar oxidized at 550 °C) on U(VI) was explored in batch experiments. The maximum adsorption capacity was up to 490.2 mg/g at 25 °C and pH 6, exceeding most of the reported biochars. 550-OBC also showed good adsorption performance at low U(VI) concentration, with 96% removal at pH 6 and an initial U(VI) concentration of 1 mg/L. Density functional theory (DFT) calculations indicated that the H-bond length between the solvated U(VI) and functional groups on the OBC was about 1.7 Å, which forms stronger H-bonds between them compared to that between U(VI) and BC (4.21 Å), and the adsorption energy value for this complex was highly negative -31.82 kcal/mol. In addition, 550-OBC exhibited high selectivity for U(VI) adsorption and excellent regeneration performance, making it a cost-effective and high-performance adsorbent.
