application of ferocarpholit nano-crystal as a natural adsorbent for removal of th(iv) and eu(iii) ions from aqueous solution by batch process

Radioactive waste has been created by humans as a by-product of various endeavors since the discovery of radioactivity. radioactive pollutants can be dangerous and it takes many years until radioactive substances are no longer considered dangerous. therefore, to protect human health and the environment from hazards caused by radioactive waste and to avoid any undue burden to future generations, radioactive waste needs to be managed responsibly [1]. zeolites due to easy access and high resistance against radiations for separating radioactive compounds of nuclear waste are used. zeolites are crystalline hydrated aluminosilicates. their structure is built up of tetrahedral sio4 and alo4 units bridged by oxygen atoms generating secondary building units. the trivalent aluminum in the structure generates a negative charge in the framework that imparts the ion exchange properties to the material [2-3]. there are great resources of natural zeolite in iran. in this study, first, ferocarpholit in rock form was supplied from tabriz mines and were characterized by x-ray diffraction spectrometry (xrd), x-ray fluorescence spectroscopy (xrf), infrared spectroscopy (ir) and scanning electron microscopy (sem) methods. then, the adsorption behavior of th(iv) and eu(iii) ions from aqueous solutions was studied. the adsorption efficiencies of the sorbent were found to be ph dependent. the maximum adsorption of th(iv) and eu(iii) ions was obtained at phs 4 (99.85%) and 5 (25.05%), respectively. selective separation of these ions can be achieved by controlling the aqueous phase ph. however, the studied zeolite was shown to be an adsorbent with lower adsorption percentage towards eu(iii) ions. the other parameters such as the initial concentration of studied ions, contact time, mass of sorbent and temperature have been investigated. it is found that under optimum conditions i.e. ph=4, 10 min. by 0.01 g of the adsorbent, for th(iv) ions, and ph=5, 60 min., 0.12 g of the adsorbent for eu(iii) ions, the metal ions can be quantitatively removed from 20 ml aqueous solutions containing 20 mgl-1 of metal ions. the results show that th(iv) ions in less time and with lower adsorbent dose has the highest adsorption compared to eu(iii) ions. the experimental data showed a good agreement with second-order equation and freundlich isotherm for studied ions.