© 2020 Global NEST.In this study, the potential textile dye biosorption capacity of a low-cost biosorbent (P. animale) was tested as functions of pH, biosorbent type, initial dye concentration, temperature, contact time and biosorbent dosage at batch scale level. The optimal conditions are 2, dried biosorbent, 93.16 mg/L, 45 °C, 1440 minutes and 4 g/L for pH, biosorbent type, initial dye concentration, temperature, contact time and adsorbent dosage, respectively. Dried P. animale removed 99.66 % of Remazol Black B (RBB). The isotherm and kinetic models were analyzed for biosorption mechanism and characteristic. According to the results, Langmuir isotherm and pseudo second order kinetic models were compatible with the experimental data obtained for RBB biosorption on algal biosorbent. Also FTIR and elemental analysis were done and resulted that the functional groups on the surface of algae had significant role in biosorption process. The results of this study supported that P. animale is an effective, inexpensive and eco-friendly biosorbent for treatment of textile dye wastewater.