Available free online at www.medjchem.com Mediterranean Journal of Chemistry 2015, 4(2), 85-92 *Corresponding author: Layachi Khamliche E-mail address: Khamliche@yahoo.fr DOI: http://dx.doi.org/10.13171/mjc.4.2.2015.08.04.11.19/khamliche Biosorption of Copper Cu (II) in aqueous solution by chemically modified crushed marine algae (Bifurcaria bifurcata): Equilibrium and kinetic studies Nawal Benzidia 1 , Anas Salhi 2 , Salem Bakkas 1 and Layachi Khamliche 1,* 1 Laboratory of Organic Chemistry, Bioorganic and Environment 2 Laboratory of Water and Environment Faculty of Science, University Chouaïb Doukkali, El Jadida, Morocco. Abstract: The Moroccan coastlines are known to be rich in marine algae species. Among these seaweed species; Bifurcaria bifurcata with its important biomass has been employed as a new adsorbent for the removal of copper in aqueous solution. Indeed, adsorption tests showed that the equilibrium is established after 60 minutes. Our experimental results demonstrate that the adsorption of copper on the algae is dependent on the pH of the solution and the initial concentration of copper. The adsorption capacity was determined using the Langmuir and the Freundlich isotherms. The maximum adsorption capacity is 101,9 mg.g -1 . The kinetic studies carried out showed that the adsorption of copper by the algae follows pseudo-second order kinetic model with high R 2 values. Keywords: Bifurcaria bifurcata; adsorption; biosorption; Copper, pollution; environment. Introduction Copper is an element found naturally in the earth's crust and diffuses into the environment through natural phenomena. This compound, essential for the development of all known forms of life, is widely used in metallurgy for making alloys and especially as a fungicide in viticulture 1,2 . The increase in its production in recent years is the origin of the increasing amounts found in nature. Copper is one of the most toxic heavy metals. Therefore, when the soil contains high amounts of copper (II) ions, the effects are harmful on humans and other living beings. Acute poisoning due to inhalation following exposure to copper (II) ions is very common and can cause irritation, headaches, stomach upsets, dizziness, vomiting and diarrhea 3 . In contrast, oral poisoning is very rare, usually accidental and is accompanied by renal insufficiency, and in severe cases, loss of consciousness or other disorders leading to death 3 . Decontamination of heavy metals from wastewater has been a challenge for a long time. A number of methods have been developed for removal of copper from industrial effluents in order to protect the environment and to possibly re-use water, especially in arid countries 4,5 . However, these conventional technologies are expensive 6,7 . Hence, an alternative adsorption on biological materials (ie biosorption); available and relatively inexpensive; may give rise to a technically reliable and economically viable clearance process. In this work, we proposed to study at first the biosorption capacity of copper by a marine biomass Bifurcaria bifurcata, from aqueous solutions prepared in the laboratory with different concentrations of copper. Thereafter, to optimize the influence of some key parameters on biosorption, we performed a modeling of isotherms and a kinetic study. Materials and methods Chemical pretreatment of biomass Once collected from the Atlantic coast of the city of El Jadida (Morocco), algae Bifurcaria bifurcata were washed with water, dried in an oven at 60 ° C for 24 hours, then ground and sieved to obtain the fraction size of 0,50 mm. The crude material has been activated by successive immersions in solutions of NaOH (0,75 M), HCl (0,75 M) then NaCl (2 M) following a method developed in the laboratory.