Assessment of a fabricated Nano-polymeric membranes function on rejection of some cations and Sodium Absorption Ratio of an agricultural drainage water

The huge volume of saline agricultural drainage water and necessity of avoiding it's undesirable environmental side effects which caused by discharge to water bodies, beside critical situation caused by shortage of water availability, necessitated of planning and proceeding to depletion and reuse of such marginal waters. The objective of this study was assessing and evaluation of a laboratory made nano-polymeric membrane in rejection of sodium absorption ratio (SAR) and ralated cations in agricultural drainage water. The Nano-polymeric membrane fabrication was performed by using % 80 polyethylenes with film grade (PE020) and %20 polyolefin elastomer (POE) polymeric composition. Natural agricultural drainage water was collected from Khorramshahr irrigation & drainage project located in Khuzestan province. In this experiment, the effect of feed agricultural drainage water salinity and membrane permeability on reduce of Electrical Conductivity (EC), SAR, Na monovalent cation and divalent cations of Ca2 was studied. Experiments defined in five dilution levels of drainage water (0, 0.2, 0.4, 0.6 and 0.8). The characterization of the membrane showed that mean pore radius was about 0.778 nm, the thickness about 20 (µm) and membrane porosity was 36.42%. Salt rejection sequence was: CaCl2>NaCl>Na2SO4 which showed that the membrane is positively charged. The rejection rate of Na and Ca2 of agricultural drainage water in all dilution levels were between 39.76-50.71% and 19.34-40.95%, respectively. The rejection rate of EC and SAR were changed between 37.10-46.18% and 30.80-36.38 %, respectively. Finally, the efficiency of this laboratory-made Nano-polymeric membrane was compared with a commercial membrane (NF2, Spero). Results showed that despite of lower permeability of PE membrane, its EC rejection rate was higher than commercial membrane in all dilution levels.