Textile industries are responsible for producing large amounts of highly contaminated effluents by several types of synthetic dyes, which are characterized by being toxic and reactive. Biosorption technique has been used as a promising treatment way to the pigments that do not adhere to the tissues fibers during dyeing process. Among the diversity of materials, macrophytes can act as biosorbents of conventional pollutants, heavy metals and organic compounds. Batch experiments were carried out for biosorption of Acid Orange 7 dye onto macrophyte Salvinia natans. Effects of initial dye pH, contact time and temperature were investigated. Chemical and morphological characteristics of the biosorbent were evaluated before and after biosorption process using methods such as Scanning Electron Microscopy (SEM) and Infrared Spectroscopy (FT-IR). Sorption kinetics was conducted and followed pseudo-second order kinetic model. Equilibrium data were well represented by Langmuir model. The Salvinia natans exhibited a maximum uptake of 60.3 mg of dye per gram of macrophyte. The results indicated that Salvinia natans is a promising low-cost technology bioadsorbent for the removal of waste dyes.
