Removal of Fe and Mn from polluted water sources in Lesotho 3 using modified clays

Abstract: This paper reports the use of unfunctionalized and phenylalanine functionalized clays as an alternative cost effective, environmental friendly and efficient sorbent for the removal of Mn and Fe from polluted drinking water sources in Lesotho. Mn and Fe were found to be the most prevalent metal pollutants in rivers supplying three drinking water treatment plants situated in Maseru, Roma and Quthing. The Mn and Fe metals were adsorbed on two different clays (clay A – a black clay and clay B – a yellow clay) collected from Ha-Teko in Maseru (clay A) and Phoqoane in Mafeteng district (clay B) in Lesotho. As a common assessment for adsorption materials, comprehensive batch test studies were performed to assess the effect of pH, stirring time, initial concentration and 26 kinetic studies of the adsorption of these metals. The adsorption of the metals was greater at higher pH and equilibrium was reached at pH 8.0 after 30 min of stirring. The phenylalanine functionalized clays displayed improved adsorption efficiency of up 100 % (Fe adsorption using modified clay A in 30 min) while the unfunctionalized clays gave relatively low adsorption of up to 70 % (Fe and Mn adsorption using modified clay A). This was observed on real and simulated water samples. The findings of this work suggest that the clays, which are 31 present in abundance in Lesotho, can be effectively used for the removal of Fe and Mn from drinking water sources in Lesotho