Application of Ulva sp. biomass for single and binary biosorption of chromium(III) and manganese(II) ions: Equilibrium modeling

Abstract

The ability of green algal biomass of Ulva sp. to biosorb Cr(III) and Mn(II) from single‐ and binary‐ solute systems was investigated. Experimental results showed that pH 4.5 resulted in highest metal uptake by Ulva sp. biomass. Determined levels of maximum biosorption capacities were 2.89 and 1.07 mmol g−1 for Cr(III) and Mn(II), respectively, during single‐solute systems. Isotherms were modeled using the Langmuir, Freundlich, and Redlich‐Peterson models with the later able to describe the biosorption isotherms with high correlation coefficients and low % error values. The removal kinetics were described using pseudo ‐first and ‐second order models. Desorption was possible using 0.01 M HCl and with this elutant, Ulva sp. biomass was reused for three cycles of sorption‐desorption. Experiments with binary metal solutions showed that Ulva sp. biomass preferred Cr(III) (2.03 mmol g−1) compared to Mn(II) (0.34 mmol g−1) at pH 4.5. Binary isotherms were described using the extended Langmuir, Freundlich, and Redlich‐Peterson models incorporated with interaction factor. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 147–153, 2014