Adsorption of dye using natural clay from water

Removal of the dye Methylene Blue from water at different concentrations, adsorbent pH and times was investigated. The natural clay was treated by cation exchange, which was confirmed by XRD and IR analyzes. Experimental results have shown that the high pH promotes adsorption. The adsorption isotherms are described by the equation of Langmuir and Freundlich isotherms. It is important to note that the quantity of CaO corresponding to calcite is higher in natural clay (9.7 % by weight) compared to Na-montmorillonite fraction (2.01% weight). It clearly shows that the clay dhkl spacing increased from d = 13.58 to d = 17 Å, which could be attributed to natural clay and Na-montmorillonite which confirms good clay purification. The maximum capacity of dyes adsorbed on Natural clay and Na-monmorillonite (Qmax) are (142.85 to 250 mg g−1) and (80 to 277.77 mg g−1) respectively. The correlation coefficients R2 = 0.99 of the Freundlich and Langmuir model for natural clays and Na-montmorillonte have the same values this indicates that the two models are best for the adsorption of dye Methylene Blue on natural clay and Na -montmorillonite.