zNano Forward Osmosis Membrane for Wastewater Treatment Processes

Abstract

Forward osmosis (FO) is used as a pretreatment to minimize reverse osmosis (RO) membrane fouling in short and long term spacecraft wastewater treatment processes. Commercially available FO membranes have low water flux rates resulting in large size and mass requirements in Forward Osmosis and Reverse Osmosis (FO/RO) systems. Large system size translates to higher launch cost. Therefore, FO membranes that have higher water flux rates improve the overall FO/RO system economics. This paper describes the ML-1 zNANO LLC lipid based FO membranes testing results. The zNANO membranes are based on a lipidbilayer that can be used both in microfiltration and FO processes. zNANO membranes can be manufactured in a variety of layers configurations and electrical charges. This ability to manipulate membrane surface charges can be particularly useful as one can fabricate a membrane tailored for a specific process. This research characterized the unsupported zNANO ML-1 membranes in order to optimize their performance in terms of water flux rates and contaminant rejection. Initial testing results indicated that t h e M L 1 zNANO membranes have 12 times the water flux rates than that of commercially available membrane when deionized water was used as the feed and with 2 mol/l sodium chloride solution was used as the brine. When secondary wastewater was used as the feed solution, the ML-1 zNANO membrane has 4.4 times the water flux rates than that of the commercially available membrane. In addition, the zNANO ML-1 membrane reject 82±14ppm, 90±7ppm, 92±4ppm, 92±3ppm, 88±3ppm, and 86±17ppm of ammonium, potassium, magnesium, calcium, nitrate, sulfate, and total organic carbon respectively.