LAUSR

Abstract The phosphorus (P) pollution and eutrophication in the aquatic environment are common and cause immensely adverse environmental health problems. In order to control the P pollution, the present study attempted to assess the phosphate-P removal capacity (PRC) of laterite soil (LS) and its application potentials in practical field. The physico-chemical characteristics of LS were analyzed using scanning electron microscopy coupled energy dispersive techniques, BET study and zeta potential. The PRC of LS was characterized by optimizing the sorption influencing parameters – contact time, solution pH, dosage of LS and concentration of phosphate-P as well as analyzing sorption isotherm and kinetics; and application potential of LS was evaluated by analyzing PRC in natural wastewater and by examining plant (Chick pea; Cicer arietinum) growth promoting properties of spent LS as phosphate fertilizer. The chemical characteristics revealed that LS is prevalently constituted by oxygen (48.52%), silicon (39.36%) and iron (10.57%) and aluminium (1.55%) and showed higher pore volume (1.678 cc/g), surface area (20.29 m2/g), particle density (2.25 g/cm3) and bulk density (1.94 g/cm3). LS demonstrated that contact time 390 min, pH 2.5, dosage 2.4 g/L and initial concentration 2 mg/L were optimum for highest phosphate-P sorption. Sorption data was well fitted by the Langmuir isotherm model and pseudo second order kinetic model. The phosphate-P sorption mechanism of LS is supposed to be governed by high porosity, surface area and specific chemical properties. LS showed excellent phosphate-P sorption (384.61 mg/g) and potential wastewater treatment properties. Phosphorous loaded spent LS also showed higher growth of Cicer arietinum (length of shoot, 38.21% and leaf number, 52.63%) than control. Therefore, the LS could ecofriendly be used as a low-cost sorbent for treating the polluted water and spent LS might be employed as a potentially fertile soil bed in yielding high amount of crop.