Ma J, Zhu C, Lu J, Ouyang B, Xie Q, Liu H, Peng S, Chen T. Kinetics analysis of interfacial electron-transfer processes in goethite suspensions systems.
CHEMOSPHERE 2017;
188:667-676. [PMID:
28923730 DOI:
10.1016/j.chemosphere.2017.09.029]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 09/04/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
The photochemical behavior of goethite has been one of the most important topics in the field of environmental science due to it plays a significant role in the removal and transformation process of numerous pollutants. However, the interfacial electron transfer process of goethite is not clear. Using a nanosecond laser flash photolysis spectrometer, we report the transient spectroscopic observations of interfacial electron-transfer reactions in goethite dispersion under UV irradiation. Excitation of goethite generated conduction-band electron (ecb-) and hole (h+). The conduction band electron (ecb-) reacted with an electron acceptor, methylviologen dichloride hydrate (MV2+), forming reduced methylviologen (MV+) with a second-order rate constant of (2.6 ± 0.3) × 109 L mol-1 s-1. The concentration of MV+ was strongly influenced by MV2+ initial concentration and pH values. The flat band potential of goethite was calculated to be Efb (goethite, pH = 7) = 0.24 V (vs NHE). Oxygen did not react with conduction band electron of goethite. The present study provides a reliable method to investigate the photo-induced interfacial charge transfer of goethite.
Collapse