Valuation of Biomaterial: Phragmites australis in the Retention of Metal-Complexed Dyes

The purpose of this research was to estimate the potential of cellulosic fibers of highly available and renewable Tunisian biomass Phragmites australis for the biosorption of an anionic metal complexed dye: Alpacide blue. The present study shows that the Phragmite australis were used successfully for the adsorption of Alpcide blue from aqueous solution. Equilibrium was reached after 5 h at 20°C and at pH 2. Optimal adsorption parameters for adsorption of dye onto fibers extract of upper rods were accomplished after 5 h of biosorption using an initial dye concentration of 50 mg L-1, biosorbent amount of 0.5 g of Phragmites australis, pH 2 and a granulometry size between 250 and 500 μm. In these conditions, the adsorbed amount of Alpacide blue is 6.11 mg g-1 and the biosorption percentage is 85.9%. When the temperature increases until 60°C, the retention rate increases also to reach a value of 90.5%. Regarding fibers extracted from roots, we notice improvement of the adsorbed amount which reaches 7.0 mg g-1 and the overall retention rate of 92.6% at 20°C. While at 60°C the amount adsorbed is 7.4 mg g-1 and the fixation rate reached 94%. The biosorption phenomenon seems to be endothermic. Moreover the adsorption process is fast, following the model of pseudo-second order for both parts of the plant stems and roots. Finally, mathematical modeling of adsorption isotherms showed that the Freundlich model perfectly describes the biosorption of organic dye studied by these fibers of Phragmites australis for both stems and roots.