Original scientific paper

Relaxation Time of Proton Adsorption from Solution onto Magnetite and Anatase: Classical and New Theoretical Approach

Wojciech Piasecki ; Group for Theoretical Problems of Adsorption, Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland
Piotr Zarzycki ; Group for Theoretical Problems of Adsorption, Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland
Wladyslaw Rudziñski ; Group for Theoretical Problems of Adsorption, Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland

Abstract

The pH dependence of relaxation time of proton adsorption was analyzed by the classical Theory of Activated Adsorption and Desorption (TAAD) and the recently developed Statistical Rate Theory of Interfacial Transport (SRT). It was found that both models predicted different behaviour of relaxation time as a function of pH. Since SRT and TAAD give an identical result for relaxation time of adsorption of uncharged species, it is suggested that the surface potential is a key factor in ion adsorption kinetics. Additionally, only the order of magnitude of the ion adsorption rate constant can be estimated from the analysis of experimental data because the surface potential and the total concentration of adsorption sites are not known exactly.

Keywords

magnetite; anatase; proton adsorption; kinetics; relaxation time; statistical rate theory

Hrčak ID:

18658

URI

https://hrcak.srce.hr/18658

Publication date:

30.11.2007.

Visits: 1.649 *