Removal mechanisms of aqueous Cr(VI) using apple wood biochar: a spectroscopic study

JOURNAL OF HAZARDOUS MATERIALS

卷:384

Article

Liu, Na¹  Zhang, Yuting¹  Xu, Chao²  Liu, Peng³  Lv, Jing¹  Liu, YingYing⁴  Wang, Qiaoying⁵ 

[1] Jilin Univ, Coll Environm & Resources, Key Lab Groundwater Resources & Environm, Changchun 130021, Peoples R China

[2] Sinochem Environm Holdings CO LTD, Beijing 100070, Peoples R China

[3] China Univ Geosci, Sch Environm Studies, 388 Lumo Rd, Wuhan 430074, Hubei, Peoples R China

[4] Univ Waterloo, Dept Earth & Environm Sci, Waterloo, ON N2L 3G1, Canada

[5] Tongji Univ, Coll Environm Sci & Engn, Shanghai Inst Pollut Control & Ecol Secur, State Key Lab Pollut Control & Resource Reuse, Shanghai 200092, Peoples R China

关键词: Apple wood biochar;    Chromium (VI);    Removal mechanism;    X-ray absorption near-edge structure;    Confocal micro X-ray fluorescence maps;   

DOI  :  10.1016/j.jhazmat.2019.121371

来源: Elsevier

【 摘 要 】

Highly toxic Cr(VI) poses huge threats to human health and ecosystem. This study utilized biochar obtained from apple wood which is favorable for the formation of high C content biochar for removing Cr(VI) from aqueous media. Cr(VI) removal was highly pH-dependent with the highest Cr(VI) removal efficiency (99.9%) at pH 2.0. Fourier-transform infrared spectroscopy (FTIR) results showed that the functionalities C-O and C=O on biochar were likely involved in Cr(VI) treatment. Results of X-ray photoelectron spectroscopy (XPS) analysis and X-ray absorption near-edge structure (XANES) spectra indicated that the majority of Cr exhibited as the reduced Cr(III) on the biochar. Confocal micro X-ray fluorescence (mu-XRF) maps confirmed the heterogeneous distribution of Cr on biochar. The electrostatic attraction, Cr(VI) reduction, Cr(III) complexation, and ion exchange likely accounted for the principal processes of Cr(VI) removal from water. These results showed that biochar can be an effective reactive medium for remediation of Cr(VI) in an aqueous solution. This study firstly integrated the Cr(VI) removal data with XANES and confocal mu-XRF mapping to obtain a deeper understanding of Cr speciation and distribution on biochar, which was critical for identifying the key role of functional groups and Cr(VI) removal mechanisms using apple wood biochar.

【 授权许可】

Free