title: Effect of alkali cations on heterogeneous photo-Fenton process mediated by Prussian blue colloids.
abstract: This article evaluates Prussian blue (iron hexacyanoferrate) colloids as a heterogeneous photo-Fenton catalyst for the degradation of Rhodamine B. The emphasis is laid on the effects of alkali metal cations on the photo-Fenton process. The facts show that alkali cations strongly affect the degradation rate of organic species. The degradation rates of Rhodamine B, Malachite Green, and Methyl Orange in the presence of KCl, KNO(3), and K(2)SO(4), respectively, are faster than their degradation rates in the presence of the corresponding sodium salts. The average degradation rates of Rhodamine B in 0.2 M KCl, NaCl, RbCl, and CsCl solution, decline in sequence, and the rate in KCl solution is greater than that without any salt added deliberately. Thus, potassium ions accelerate the degradation rate, but sodium, rubidium, and cesium ions slow the rate. The order of the rates is R(K)>R>R(Na)>R(Rb)>R(Cs), which is consistent with that of the voltammetric oxidation currents of Prussian blue in the corresponding cation solutions. This phenomenon is attributed to the molecular recognition of the microstructure in Prussian blue nanoparticles to the alkali cations. The reaction mechanism of the photo-Fenton process has also been explored.
authors.affiliation: Provincial Key Laboratory of Environmental Science and Engineering, College of Chemistry and Bioengineering, Suzhou University of Science and Technology, Suzhou 215009, China. shouqing_liu@hotmail.com
authors.forename: Shou-Qing
authors.initials: SQ
authors.lastname: Liu
authors.forename: Shi
authors.initials: S
authors.lastname: Cheng
authors.forename: Lian-Rong
authors.initials: LR
authors.lastname: Feng
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Wang
authors.forename: Zhi-Gang
authors.initials: ZG
authors.lastname: Chen
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D002412:Cations; D003102:Colloids; D004563:Electrochemistry; D005295:Ferrocyanides / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010777:Photochemistry
chemical_list: D000468:Alkalies; D002412:Cations; D003102:Colloids; D005295:Ferrocyanides; C000170:ferric ferrocyanide