Effects of Selected Properties of Semi-Arid Soil of Dutse, Jigawa State on Adsorption of Pb and Cd Ions

Abstract

This study determined the effects of some selected physical and chemical properties of semi-arid soil on heavy metal sorption. Soil samples were collected randomly from Federal University Dutse within Nigeria's Sudan Savannah agroecological zone. Nitrate salts were used to prepare three different concentrations (10, 20, 30 mg/kg) of CdCl2 and PbCl2. The equilibrium sorption of the study soil was determined. The equilibrium sorption data were fitted into Langmuir and Freundlich isotherms. Langmuir and Freundlich isotherm model's r2 values (1) were at par. The boundary energy b (1 mg-1) from the Langmuir isotherm model was determined to be -110.0 and 47 for Pb and Cd, respectively. Freundlich isotherm sorption intensity (n) of 1.92 and 1.67 indicated a favorable sorption, revealing physical adsorption rather than chemical adsorption. Correlation analysis established the relationship between the heavy metal sorption capacity and soil properties. The R values of 0.92 and 0.72 showed a positive relationship between Pb and Cd adsorption with soil silt content. Positive relationships (R) were obtained from the organic matter (0.68), Total Nitrogen (0.99 and 0.60), as well as particle size on adsorption of both metals. Adsorption of heavy metals was positively affected by the physical and chemical properties of the semi-arid soil.