The potential of nitrate removal from groundwater of Bani-Suif west area, Egypt using nanocomposite reverse osmosis membranes

The excessive use of nitrogen-based fertilizers during flood irrigation, pesticide, waste disposal and industrial waste,seepage from septic tanks and evaporation processes during flood irrigation affects to the extent onto the groundwaterquality of the shallow Quaternary aquifer of Bani-Suif west area, Egypt. A combination of major, heavy metals andnitrate has been used to characterize the groundwater in the investigated area. For this aspect, thirteen groundwatersamples belong to that aquifer were collected. The total dissolved salts were varied between 327 and 2436 mg/l. Despite,the majority of the groundwater salinity was under the permissible limit for drinking, it was found to be unsuitable forhuman drinking, where they have had high concentrations of nitrate, which ranges from 366.41 to 1535.9 mg/l(exceeding the permissible limit, 45 mg/l). Because the aquifer has a high potentiality of groundwater, therefore, it is amust to re-use this high quantity of groundwater. Membrane technology was found to be the most suitable technique toovercome this problem. Therefore, three different types of thin film composite membranes (PA, PA/SiO2, and PA/SW- CNT's) were prepared using the interfacial polymerization technique. The change of surface morphology of membranesbecause of addition of nanomaterials was characterized using Scanning Electron Microscopy, where the surface of thenanocomposite membranes was shown to be rougher than the unmodified membrane. In addition, the membranes weretested with a cross-flow apparatus to determine their performance in terms of water flux, salt rejection, and nitrateremoval. However, the nanomaterials have been added to enhance the membrane water flux and even the salt rejection. Itwas observed that; nitrate rejection was shown to be decreased in the order of PA/SW-CNT's > PA/SiO2 > PA. Where,PA/SW-CNTs reduced the nitrate concentration of a natural groundwater sample from 366.41 to 21.98 mg/l, i.e. underthe permissible limit.