M.Sc. / In this study, natural and modified clinoptilolite (CLI) reinforced polypropylene (PP) composites possessing improved mechanical and adsorptive properties were prepared through melt-mixing. Determination of morphological, structural and thermal properties was achieved by means of different techniques (FTIR, TGA, DSC, electron microscopy and x-ray spectroscopy). Electron microscopy revealed that increasing filler loading beyond 20% leads to agglomeration of clinoptilolite particles reducing their dispersion within the matrix. Thermal studies showed that the reinforced composites had a lower thermal stability than the neat PP polymer, suggesting that the clinoptilolite interfered with polymer chain arrangement and bonding. It also showed that percentage crystallinity increased with increasing filler loading indicating that the filler particles acted as nucleating agents within the polymeric matrix during composite synthesis. Prior to the ion-exchange studies, water sorption behaviour of fabricated composites was evaluated because ion-exchange/adsorption studies were to be performed in aqueous media. It was therefore observed that the hydrophobic polymer, PP attained the property of water sorption mainly due to the porous structure of the composites created by mixing and extrusion and also by the addition of the hydrophilic filler material.