Macroscopic, theoretical simulation and spectroscopic investigation on the immobilization mechanisms of Ni(II) at cryptomelane/water interfaces. (November 2018)

• Record Type: Journal Article
• Authors: Wu, Chunfang; Chen, Lei; Yang, Shitong; Cai, Yawen; Xu, Lin; Wu, Xilin; Qin, Haibo; Liu, Zhiyong; Chen, Lanhua; Wang, Shuao
• Is Part Of: Chemosphere. Volume 210(2018)
• Page Start: 392
• Page End: 400
• Publication Date: 2018-11
• Subjects: Ni(II) -- Cryptomelane -- Theoretical simulation -- Spectroscopic analyses -- Immobilization mechanisms; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.07.029
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In the present study, the macroscopic sorption behaviors and microscopic immobilization mechanisms of Ni(II) at cryptomelane/water interfaces were explored using the combination of batch sorption technique, desorption procedure, theoretical simulation, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS) analyses. The good simulation of the pseudo-second-order model on the sorption kinetics data suggests a driving force of chemical sorption rather than mass transport or physical interaction. The sorption trends and uptake mechanisms are obviously related to the solution pH, with cation exchange or outer-sphere surface complexation at an acidic pH of 4.0, inner-sphere surface complexation in both the edge-shared (ES) and double corner-shared (DCS) modes at a neutral pH of 7.0, and precipitation of α-Ni(OH)2 (s) phase at a highly alkaline pH of 10.0. The gradual increase of Ni(II) sorption amount with solution temperature rising from 293 K to 333 K is consistent with the increased ratio of the weak DCS configuration. The research findings herein can help us better understand the migration and transformation trends of Ni(II) in the manganese mineral-riched aquatic environment. Graphical abstract: Image 1 Highlights: Interaction mechanisms of Ni(II) with cryptomelane were explored by combining multiple techniques. Relative contributions of different uptake processes were verified from ligand extraction data. Ni(II) binding modes were clearly identified with theoretical simulation and spectroscopic analyses. Temperature rising enhanced the sorption amount of Ni(II) in double corner-shared binding mode. Research findings facilitated the assessment of Ni(II) migration and fate in Mn-riched environment.