Feasibility of using natural mineral ores for removing Cs and Sr from contaminated water

Proper and economical treatments of wastewater are among the important and potential solutions to increase the water budget. Although mineral ores are barriers of potentially toxic metal contaminants; however to what extent, can these ores stand successfully for decontaminating waters polluted with Cs or Sr is the question of the current study. Therefore a trial was carried out on some of these ores i.e. kaolinite, montmorillonite, and illite, to investigate their effects as decontaminants for waters polluted with either 50 μg Cs L^-1 or 50 μg Sr L^-1. Results showed that sorption of Cs and Sr increased with decreasing the ratio of the applied sorbents to the quantities of contaminated waters. Such a finding was more obvious when the rate of the sorbent: water was only 1 g L^-1. The highest sorption was attained by montmorillonite followed by kaolinite, then Illite. Thus, montmorillonite was selected to complete the sorption studies at a rate of 1 g L^-1. Sorption of both Cs and Sr and consequently their removal efficiencies increased with increasing the pH of the sorbents-contaminated waters suspensions up to 7 beyond which significant reductions occurred. Also, increasing the temperature of the suspension resulted in significant increases in the removal efficiencies of the investigated sorbents. Only 120 min were enough to attain the highest removal efficiency. Moreover, Ca-salts could successfully substitute sorbed Cs and Sr on surfaces of the montmorillonite used previously for decontamination of these elements from waters. Accordingly, this mineral ore can be reused successively for further decontamination processes.