Removal of iron and manganese from aqueous solution using some clay minerals collected from Saudi Arabia

The existence of excessive concentrations of iron and manganese in water results in economic, technological and health problems. The adsorption characteristics of four clay minerals collected from different localities of Saudi Arabia, Osfan (OS1 and OS2) and Gholaa (GH1 and GH2), on the adsorption of Fe3+ and Mn7+ ions were investigated. The quantitative phase composition of the selected samples was calculated from their X-ray diffraction technique, while the chemical constitution was determined through X-ray fluorescence technique. The adsorption of Fe3+ onto different clays was complied with Langmuir isotherm (R-2 = 0.9996, 0.9956, 0.9840 and 0.9932, respectively). OS1 and OS2 (Q(max) = 6.872 and 8.258; 1/b = 0.315 and 0.296, respectively) have higher adsorption capacity than GH1 and GH2 (Qmax = 2.109 and 3.457; 1/b = 0.596 and 0.465, respectively). The adsorption of Fe3+ onto OS1, OS2, GH1 and GH2 clay minerals cannot be described by Freundlich isotherm model where R-2 = 0.831, 0.92, 0.70 and 0.52, respectively. The mean adsorption energy recorded indicates that the sorption process is physisorption.