uranium removal from aqueous solutions using iranian natural zealite – riched by clinoptiolite

abstract uranium is a natural heavy metal widely dispersed across the earth crust. in many cases due to anthropogenic disturbance, it has been found beyond its natural abundance which resulted in soil-water pollution. the objective of this study was to investigate the capability of iranian natural zeolite clinoptilolite for removal of uranium (vi) from aqueous solutions. in order to optimize removal efficiency of uranium, bath techniques were used as a function of various parameters, i.e., initial uranium concentration, ph solution, shaking time and dose of zeolite. the sorption of uranium was investigated by using langmuir and freundlich model. maximum uranium uptake by zeolite achieved at 200 mg u l-1, ph 5 and 20 h contact time. the results of the experiment also revealed that langmuir model was able to predict uranium adsorption mechanisms by zeolite more accurate than freundlich model. considering low cost and great natural resource of zeolite in iran, it is suitable for environmental applications.