Avaluació d'un dispositiu basat en membranes polimèriques per a la determinació de fosfat en aigües naturals

Abstract

Phosphorus is a naturally occurring element. It is an essential nutrient for many organisms and it develops a vital role in cellular physiology and biochemistry. Due to its nature, phosphorus in natural waters can be distinguished between inorganic phosphorus and / or organic. The inorganic form (ortofosfat) is the most bioavailable phosphorus, and it is often measured in natural waters and wastewater. Most inorganic phosphorus comes from the use of synthetic detergents, pesticides and fertilizers whereas the main source of organic phosphorus comes from food and human waste, which through biological action on the environment is finally converted into inorganic forms. The way that the phosphorus moves itself it is due to processes such as, for instance, the wind erosion, runoff and lixiviation. These are the main transport routes of the terrestrial phosphorus to the aquatic ecosystems. Too much phosphorus in the water can cause eutrophication of lakes, coastal waters and a reduction in the quality of the water. For these reasons, monitoring the concentration of phosphates is very important to maintain a good water quality and to minimize the pollution of the natural waters. This work pretends to evaluate a system of separation and preconcentration by using a device designed for this purpose and also with the use of a polymeric membrane, and two colorimetric methods such as vanadium-molybdenum or molybdenum blue method. The ideal conditions have been described for the use of a polymeric membrane PVC or CTA with Aliquat 336® as extractant. The method’s parameters have been optimized and the different interferences (arsenate) have been studied. The method is applied in different natural waters and in natural fortified waters with phosphates and / or arsenates. Acceptable results are obtained from the detection system and / or quantification of phosphates in small concentrations in natural waters