Effect of Organic Matter Removalon Sorption Studies of Phosphate by Selected Soils in Northern Part of Kwara State, Nigeria

The effect of organic matter removal and adsorbate solution composition on phosphate sorption by selected soil in Moro Local Government of Kwara State (Malete and Elemere) was studied. The organic matter was removed by treating the soil with hydrogen peroxide. This is referred to as the treated sample while the untreated samples were those to which hydrogen peroxide was not added. The adsorbate solution used was KH2PO4+KCl. The sorption study for maximum adsorption capacity was carried out with 1g of soil in 20ml phosphate solution at different concentration. The maximum adsorption capacities of treated and untreated Malete soil were observed to be 0.29mg/g and 0.23mg/g respectively while those of treated and untreated Elemere soil were observed to be 0.24mg/g and 0.14mg/g respectively. The phosphate sorption data were fitted to both Langmuir adsorption isotherm, the R2 values for the samples (Malete=0.870, Elemere=0.792) and Freundlich (Malete =0.013, Elemere=0.043). The adsorption data of Malete and Elemere soils were observed to fit Langmuir II adsorption isotherm.