Evaluation of Native and Chemically Modified Sargassum glaucescens for Continuous Biosorption of Co(II)
2009
Ebrahimi, Mina | Panahi, Reza | Dabbagh, Reza
In the present study, biosorption of stable cobalt was studied in an up-flow fixed-bed column using the brown alga Sargassum glaucescens treated with formaldehyde (FA) or MgCl₂. Notable increase in cobalt removal was observed for FA-treated biosorbent with 2.7 and 1.4 times higher dynamic capacity (DC) and uptake capacity (UC) than native alga, respectively. Consequently, FA-treated S. glaucescens was selected for further investigations. In particle size experiments, the DCs of 0.5-1 and 1-2 mm particles were both equal to 27.6 mg/g, and corresponding UCs were 34 and 38 mg/g, respectively. The maximum DC was obtained at residence time of 2.5 min. Studying the effect of additional ions indicated partial effect of Na⁺ and K⁺ ions on DC and UC, Mg²⁺ reduced highly the DC and slightly the UC while heavy metal ions (Ni²⁺, Cd²⁺, Cu²⁺, Zn²⁺, Pb²⁺ and Cr³⁺) caused decrease in both DC and UC about 1.5-4.7 and 1.8-3.2 times, respectively. Moreover, the column regeneration studies were carried out for four sorption-desorption cycles. The DC and the UC highly decreased in the second cycle, partially decreased or remained constant in the third and in the fourth one.
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