Dual Effect of Acetic Acid Efficiently Enhances Sludge-Based Biochar to Recover Uranium From Aqueous Solution

Shoufu Yu; Xiaoyan Wu; Jian Ye; Mi Li; Qiucai Zhang; Xiaowen Zhang; Chunxue Lv; Wenjie Xie; Keyou Shi; Yong Liu

doi:10.3389/fchem.2022.835959

Dual Effect of Acetic Acid Efficiently Enhances Sludge-Based Biochar to Recover Uranium From Aqueous Solution

Front Chem. 2022 Feb 22:10:835959. doi: 10.3389/fchem.2022.835959. eCollection 2022.

Authors

Shoufu Yu¹, Xiaoyan Wu^{1

2

3}, Jian Ye^{1

2

3}, Mi Li^{1

2

3}, Qiucai Zhang^{1

4}, Xiaowen Zhang^{1

2

3}, Chunxue Lv¹, Wenjie Xie¹, Keyou Shi¹, Yong Liu^{1

4}

Affiliations

¹ University of South China, Hengyang, China.
² Hengyang Key Laboratory of Soil Contamination Control and Remediation, University of South China, Hengyang, China.
³ Key Laboratory of Radioactive Waste Treatment and Disposal, University of South China, Hengyang, China.
⁴ Decommissioning Engineering Technology Research Center of Hunan Province Uranium Tailings Reservoir, University of South China, Hengyang, China.

Abstract

Excess sludge (ES) treatment and that related to the uranium recovery from uranium-containing wastewater (UCW) are two hot topics in the field of environmental engineering. Sludge-based biochar (SBB) prepared from ES was used to recover uranium from UCW. Excellent effects were achieved when SBB was modified by acetic acid. Compared with SBB, acetic acid-modified SBB (ASBB) has shown three characteristics deserving interest: 1) high sorption efficiency, in which the sorption ratio of U(VI) was increased by as high as 35.0%; 2) fast sorption rate, as the equilibrium could be achieved within 5.0 min; 3) satisfied sorption/desorption behavior; as a matter of fact, the sorption rate of U(VI) could still be maintained at 93.0% during the test cycles. In addition, based on the test conditions and various characterization results, it emerged as a dual effect of acetic acid on the surface of SBB, i.e., to increase the porosity and add (-COOH) groups. It was revealed that U(VI) and -COO- combined in the surface aperture of ASBB via single-dentate coordination. Altogether, a new utilization mode for SBB is here proposed, as a means of efficient uranium sorption from UCW.

Keywords: acetic acid; excess sludge; sludge-based biochar; uranium; uranium-containing wastewater.