Kinetic studies of heavy metals biosorption by acidogenic biomass immobilized in clinoptilolite

The aim of this work was to establish the sorption equilibrium and kinetics of copper, Cu-(II), and iron, Fe-(II), removal by acidogenic biomass immobilized in clinoptilolite. The experimental methodology consisted of a series of batch studies in which immobilized acidogenic biomass was exposed to metallic solutions within a concentration range of: 0-300 mg/L CO(II), 0-800 mg/L Fe-(II) in single systems, and 0-1000 mg/L Cu-(II)-Fe-(II) in a binary system. It was found that copper and iron sorption by acidogenic biomass immobilized in clinoptilolite can be represented by the pseudo second-order type reaction. Data obtained from the equilibrium studies were adequately described by the Langmuir adsorption model. Although the predicted maximum biosorption capacity of copper increased from q(max) = 28.23 mgCu((II))/gSSV in the single system to q(max) = 35.46 mgCu((II))/gSSV in the binary system, it was found that co-existence of copper and iron ions decreased the actual biosorption capacity of the acidogenic biomass. The findings of this work indicate that acidogenic biomass immobilized in clinoptilolite is a promising low-cost biosorbent for the removal of copper and iron, but binary metal mixtures of copper and iron must be carefully selected to avoid low removal efficiencies during a biosorption-based wastewater treatment process. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.