Kinetics, Equilibrium and Thermodynamic Studies on Fe۳+ Removal from Aqueous Solutions by Chemically Modified Brown Algae

Sargassum Vulgare was used as an effective biosorbent for the removal of Fe۳+ from aqueous solutions. Results for batch operation are presented for biosorption onto algal biomass, raw and modified with HNO۳, HCl, NaCl, and CaCl۲. NaCl was selected as the best modifier for the algae surface for the improvement of the sorption capacity. Optimum biosorption conditions were determined as a function of contact time, biomass dosage, initial metal concentration, and temperature. The Langmuir isotherm yields high regression values for a maximum monolayer sorption capacity of the modified biomass of ۳۰.۵۲ mg/g at optimum conditions (pH = ۲, dose = ۵ g/L, t = ۱۲۰ min, and T= ۲۹۸ K). This represents an increase of more than ۵۰ % concerning the raw algae. The kinetics of sorption followed the pseudo-first-order rate equations and is fast enough to prove the technique feasible. The thermodynamic parameters showed that the adsorption of Fe۳+ using algal biomass was feasible, spontaneous, and exothermic. Modified algae could be regenerated once using ۰.۰۰۱M EDTA solution, and a recovery of ۹۰% of Fe۳+ was obtained. Fourier Transform InfraRed (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM) were used to characterize the surface of modified algae.

کلیدواژه ها:

Biosorption ، Brown algae ، Chemical modification ، Fe۳+ ، Kinetic models ، FT-IR