Research is centered on the use of the new materials of low cost, available locally, biodegradable adsorbent, manufactured starting from the natural sources, these last years, the synthesized biosorbents, starting from the residues of agriculture were largely used like adsorbent to treat the various effluents because of their very significant porous structure, their great specific surface and their great capacity of adsorption. The encapsulation within the sodium alginate is a method recently used to mitigate the difficulties which arise at the time the use of the adsorbents and in particular in the implementation with a difficulty of separation opposite treated water. The sodium alginate is the biopolymer the most used in the field of water treatment. It is one of the most general-purpose biopolymer. It is used in the agroalimentary sector and pharmaceutical industry because it has many advantages such as the availability, the cut price, not-toxicity, the biocompatibility and the biodeterioration. It is also one biosorbent effective by the presence of the active functional groups; in particular, its functions carboxylate allow a selective adsorption of the organic molecules charged positively. The goal of this work is the effective synthesis of composites used in the field of water treatment; we used the lemon peel for the preparation of these materials. Lemon peel was activated then encapsulated in a type of polysaccharides which is the sodium alginate. The prepared materials were characterized by the infra-red spectroscopy (IRTF), scanning electron microscope (SEM), specific surface (BET) and the isoelectric points were also given. Adsorption experiments were studied to investigate the efficacy of this new material in the removal of dyes from textile effluents.