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SPIROGYRA AS AN EFFICIENT BIOSORBENT OF CADMIUM:

A MECHANISTIC APPROACH

ATIF YAQUB1*, MUHAMMAD SHARIF MUGHAL2 AND HAMID MUKHTAR3

1Department of Zoology, Government College University, Lahore, Pakistan

2Department of Fisheries and Aquaculture, University of Veterinary and Animal Sciences, Lahore

3Institute of Industrial Biotechnology, Government College University, Lahore-54000, Pakistan

*Corresponding author’s e mail: atifravian@gmail.com

Abstract

The biosorption capacity of Spirogyra sp. biomass was evaluated for removal of cadmium (Cd) from wastewater. Batch experiments were conducted to optimize various parameters, such as pH, contact time and biomass concentration which affect biosorption. The recorded maximum biosorption capacity was 47 mg/g, while the optimum values for pH, temperature, contact time, and biosorbent concentrations were  5.0, 30°C, 120 min, and 1mg/L, respectively. The data were fitted for various adsorption isotherms, such as Langmuir, Freundlich, and Temkin; Langmuir theorem was found to be the most suitable, showing monolayer adsorption. Pseudo-second order kinetic model was fitted for the interpretation of kinetic modeling and was found to be compatible with interpretation of the data. Various thermodynamic parameters, such as as entropy (∆H), enthalpy (∆S), Arhenius constant (Ao) and the energy of activation (Ea) were calculated which indicated that the process was spontaneous, endothermic and feasible under the experimental conditions. FTIR spectra showed the presence of a number of electronegative functional groups on algal surface that were capable of binding to Cd (II) ion.

Key words: Biosorption, Green algae, Heavy metals, Wastewater, Equilibrium, Kinetic, Thermodynamic, FTIR.