Effects of pretreatment on physical and ion exchange properties of naturalclinoptilolite

Four pretreatment procedures have been applied to natural clinoptilolite to establish the influence of the pretreatment process on the properties of t he material under investigation. Modification of material properties is imp osed for its use in wastewater treatment via ion exchange processes. Batch pretreatment procedures as well as continuous flow column have been studied by using sodium chloride, sodium hydroxide and nitric acid solutions in de ionized water. Measurements of the effective opacity, the diffusion coeffic ient in the solid state and examination of the crystal structure have been employed to assess the effect of each specific pretreatment on the material under test. The effective capacity is improved in all cases, by a factor o f 2.4 to 3.6, while the diffusion coefficient values depend strongly on the type of pretreatment used and fall in the range of 0.03-1.37x10(-8) cm(2)s (-2) at 20 degreesC. The crystal structure remains unaltered as evidenced b y XRD measurements.