Removal of phosphorus from water using active barriers: Al2O3 immobilized on to polyolefins

Phosphorus is known to contribute to eutrophication of fresh water systems, as generally it is the limiting nutrient controlling algae growth. Laboratory studies were conducted to develop and test active barriers composed of aluminium oxide immobilized on to polyolefins to remove phosphorus from water. For this purpose, flat plates of polyethylene and polyethylene grafted with maleic anhydride were prepared and tested. The adsorption mechanism of phosphorus on to aluminium oxide was described by the Freundlich isotherm. The optimum pH interval for phosphorus removal was between 5.2 and 7.8, which includes the pH of natural waters. The maximum phosphorus removal capacity was around 11.1 microg/cm2 for both active barriers. Both barriers removed more than 90% of phosphorus from a 100 mirog/L solution in a static batch experiment carried out for 90 d. The in situ implementation of the active barriers developed in the present study might be a valuable strategy to sequester phosphate and thus to control eutrophication in natural ecosystems, though further work is required to evaluate possible interferences coming from other substances present in the water.