Remazol Brilliant Blue dye is a noxious dyes, so the snail shell powder was used as a adsorbent surface because of its high efficiency to remove the remazol brilliant blue dye from aqueous solutions where the removal percent was (99.09%). Also, the factors affect the efficiency of adsorption (equilibrium time, adsorbent weight, PH, ionic strength, temperature and using "Langmuir, Freundlich and Temkin" modelels were studied. The experimental data of isotherm showed that it is in good agreement with the freundlich and temkin equation it to take the form (S-curve) according to the Giles classification, and it does not agree with the Langmuir equation. The thermodynamic functions (ΔS, ΔH, ΔG) were calculated and explained in the mean of the chemical structure of the adsorbant.