IWRA Proceedings

AbstractPollution of ground and surface waters by nitrates is a wide spread and serious problem. Heavy utilization of artificial fertilizers has been known to cause penetration of large quantities of nitrates into ground and surface waters. In this study, the removal of mineral ions (nitrates and orthophosphates ions) from aqueous solution by adsorption was studied. The batch process was used either to remove each anions singly or both anions as a multi-component system. The inert solid biomaterials (ISBM) used as adsorbant in the present work was obtained from ground dried of Carpobrotus edulis plant grown in south –western Morocco. The efficiency of the ISBM was investigated using batch adsorption technique under different experiment conditions by varying parameters such as the contact time, the initial anions concentrations, the temperature and the initial solution pH. The equilibrium time was found to be 30, 240 minutes for nitrate and orthophosphates ions respectively. The increase of temperature increase of adsorption capacity, which also increases with the decreasing solution pH. The optimum pH and temperature for adsorption in studied pH and temperature ranges were found as 2 and 40 °C, respectively for an initial anions concentration of 100 mg/l. The adsorption increased with an increasing initial concentration of nitrate and orthophosphates, and remained constant at high anions concentrations. The adsorption capacity was depending on the type of inert biomaterial as well as on the type of ions for the given plant (atomic weight, ionic radius, ionic charge and structure). The adsorption data were analyzed using the Langmuir, Freundlich and Temkin adsorption isotherms to determine the mechanistic parameters related to the adsorption process. The results generally showed that this ISBM could be considered as a potential adsorbent material the removal of nitrate and orthophosphates from single-ion solutions as well as from a mixture of them.