化学
吸附
齿合度
X射线光电子能谱
斯沃特曼矿
傅里叶变换红外光谱
羧酸盐
无机化学
铬
硫酸盐
核化学
水溶液
解吸
立体化学
金属
物理化学
有机化学
化学工程
针铁矿
工程类
作者
Xiaofei Li,Chuling Guo,Xiaohu Jin,Chucheng He,Qian Yao,Guining Lu,Zhi Dang
标识
DOI:10.1016/j.jhazmat.2021.125781
摘要
Hexavalent chromium (Cr(VI)) mobility, reactivity and bioavailability in the acid mine drainage (AMD) are restricted by adsorption reactions on schwertmannite. However, the Cr(VI) adsorption mechanisms remain unclear. In this study, batch adsorption/desorption experiments, X-ray photoelectron spectroscopy (XPS), and in‒situ attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) in combination with a multivariate curve resolution– alternating least squares (MCR-ALS) analysis were employed to characterize Cr(VI) adsorption on schwertmannite. The results of batch experiments suggested that two kinds of anion exchange reactions occurred on Sch surface: the outer-sphere complexes and the inner-sphere complexes of sulfate were successively substituted by aqueous Cr(VI) to form inner-sphere complexes. XPS analysis showed that the adsorbed Cr (VI) tended to exchange with sulfate rather than with surface hydroxyl groups on schwertmannite. In-situ ATR-FTIR spectroscopic results confirmed that the Cr(VI) coordination species contained bidentate inner-sphere (C2ν) and monodentate inner-sphere complexes (C3ν). MCR-ALS analysis revealed that monodentate complexes were dominant at pH 5.0–8.0. The proportion of bidentate complexes decreased from 47% to 25% when pH increased from 5.0 to 8.0. Thus, we concluded that a transition occurred between bidentate to monodentate complexes. In addition, the Cr(VI) concentration exerted little influence on the change of surface complexes.
科研通智能强力驱动
Strongly Powered by AbleSci AI