Development of a new biosorbent based on the extract residue of marine alga Sargassum vulgare: application in biosorption of heavy metals

Meriem Tarbaoui, MINA OUMAM, Mourad Benzina, Ahmed Bennamara, Abdelmjid Abourriche

Résumé


In the present work, we conducted research in order to study the possibility of producing a new biosorbent from a sub-product of seaweed; it is the extract residue of the marine alga Sargassum vulgare, which represents more than 80% by weight of the raw material. It is a natural residue that we could turn into biosorbent under the effect of chemical activation with phosphoric acid which allows the development of a large pore in the activated material. To optimize the conditions for elaboration of our biosorbent, experimental design was applied to reduce the number of experiment trials needed to evaluate some parameters (percentage of phosphoric acid, temperature and time of activation) and their effects on the responses (capacity of biosorption of methylene blue, yield biosorbent). The product obtained under the optimal conditions has good textural and structural properties and developed surface functions. The application of optimized biosorbent in the removal of some heavy metals (Pb(II), Cu(II), and Cd(II)) from aqueous solutions was studied. The impact of various parameters such as pH, biosorbent dose, and contact time on the removal was evaluated by batch method. The biosorption isotherms were studied using Langmuir, Freundlich, Dubinin–Radushkevich (D–R), and Temkin isotherm models. Langmuir isotherm provided the best fit to the equilibrium data. The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent biosorbent and to recover the adsorbed metal ions.

Mots-clés


Biosorbent, Marine alga, Sargassum vulgare, Biosorption, Heavy metals, Biosorption isotherms, Biosorption kinetics, Desorption.

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