Adsorption of zinc on manganite (γ-MnOOH): particle concentration effect and adsorption reversibility

Article type: Research Article

Authors: QIN, Yan-wen | PAN, Gang^; | ZHANG, Ming-ming | LI, Xian-liang

Affiliations: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,Beijing 100085, China | Qingdao University of Science & Technology, Qingdao 266042, China

Note: [] Corresponding author. E-mail: [email protected]

Abstract: The adsorption and desorption processes of Zn(II) on γ-MnOOH as a function of particle concentrations (C_p) were studied. An obvious C_p effect was observed in this adsorption system. The degree of adsorption hysteresis increased greatly with the increasing of C_p, indicating that the extent of the real metastable-equilibrium states deviating from the ideal equilibrium state was enhanced with the increasing of C_p. The C_p-reversibility relationship confirmed the metastable-equilibrium adsorption (MEA) inequality (Pan, 1998a), which was the core formulation of the MEA theory. Because the MEA inequality was based on the basic hypothesis of MEA theory that adsorption density Γ is not a state variable, the C_p-reversibility relationship gave indirect evidence to the basic hypothesis of MEA theory.

Keywords: zinc, γ-MnOOH, adsorption reversibility

Journal: Journal of Environmental Sciences, vol. 16, no. 4, pp. 627-630, 2004