During prolonged, large crew missions the environmental control and life support system (ECLSS) must be a closed regenerative system. Water recycling and waste water treatment are major concerns. The most cost effective process for water recovery to date is reverse osmosis (RO) filtration. RO filtration does not require a gas-liquid phase separator in zero gravity and has lower energy requirements than phase change processes.Presently, reverse osmosis membranes are of the hollow fiber (HF) or dual layer (DL) membrane type. The present DL and HF membranes have high fouling rates. The HF have low through put and lower salt rejection than the DL.In an ECLSS, total organic carbon reduction from 500 parts per million (ppm) to 50 ppm, dissolved solids reduction from 1000 ppm to 50 ppm and reduction of ammonium ion from 500 ppm to levels of 1 ppm is needed.We propose to develop a new semipermeable membrane material which will be more energy efficient, posses a lower fouling potential and will reduce the above mentioned constituents to the needed levels. The RO membrane material considered in this work is produced by selective combination of divergent dendrimer polymers shaped by using laser controlled charge-transfer dynamics.
Potential Commercial Applications:The proposed program is a basic material science proof of concept effort. If it is successful, as we believe it will be, it will introduce a new semipermeable membrane material into the reverse osmosis water reclamation and high purity water technology market. Because this new membrane material could initially be packaged as a spiral wound element it would quickly replace the DL type RO semipermeable membranes currently in use. This membrane material could be used to selectively reduce silica from the ppm level to ppb level, in the permeate, meeting an immediate need in the electronic waver manufacturing industry. In agricultural applications such as RO water reclamation of high nitrate containing water a dendritic based membrane could selectively reject the nitrates.
