Impact of acids on the structure of linde type a zeolites for use in reverse osmosis membranes for wastewater recovery

Membrane separations and osmotic processes are attractive options for wastewater reclamation, and with growing concerns over a depleting global water supply such technologies are rapidly becoming more valuable. Previously, hydrophilic Linde Type-A (LTA) zeolites have been incorporated into polyamide reverse osmosis membranes, creating high flux membranes called Thin Film Nanocomposite membranes^[1], ^[2]. In our ongoing work, we are exploring the use of zeolite nanocomposite membranes for the recovery of potable water from wastewaters. We are specifically interested in the wastewaters generated by NASA on the International Space Station (ISS). Currently, only 70% of the wastewater generated on the ISS is recovered; the remaining 30% of the water is stored for later disposal in the form of brine^[3]. With the retirement of the NASA space shuttle fleet, the need to minimize use of ground-based resources is a high priority; as a result, NASA desires to maximize water recovery^[4]. Our research focuses on using LTA zeolite nanocomposite membranes to recover water from the urine and urine brine wastewaters produced on the ISS. The small pore size of the LTA zeolite should make it ideally suited to allow passage of water, but rejection of small neutral organic molecules such as urea, a main component of urine^[5].