Fly-ash-based Na-zeRoalwitesflypraosvhidgeetnserwid aocfti96) and Freundlich (>98) isotherms; hence, it can be concluded that the adsorption of Pb (II) to Na-zeolites is a hybrid process rather than a monolayer adsorption mechanism. The Lang- muir isotherm elucidates homogeneous monolayer ...