Document text
May 1972
B72-I0230
• NASA TECH BRIEF
Langley Research Center
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546.
Water Purification by Reverse Osmosis Using Heterocyclic Polymer Membranes
Recent tests conducted using direct osmosis measure-
ments of water, salt and urea fluxes through Pyrrone
membranes, indicate Pyrrones may outperform cellulose
acetate membranes in water purification by reverse
osmosis. Successful fabrication of asymmetric Pyrrone
membranes could lead to substantial improvements in
water purification.
The Pyrrone (polyimidazopyrrolone) polymers are a
new class of thermally stable, radiation and chemical
resistant aromatic-heterocyclic polymers. In addition to
having a high water absorptivity, Pyrrones feature greater
chemical and mechanical durability than cellulose acetate.
They have a high compressive strength and the ratio of
intrinsic water to salt permeabilities are 100 times greater
than ratios calculated from cellulose acetate data. The
salt rejection is much higher at lower applied pressures
which facilitate higher recoveries of purified water at
lower pressures than have been attainable. Water flux,
salt rejection, and desalinated water recovery can be
further increased by using Pyrrones that are more porous
and permeable to water than cellulose acetate as they
can withstand similar pressures because of greater
strength.
This study indicates the need for further testing but
also indicates the superiority of the Pyrrone polymer
at this point over the best reverse osmosis membrane
developed to date. Absolute water flux is low, and
dramatic improvement of it is needed. It should be
noted however, that the application of Pyrrone polymer
is limited by the complex and costly production pro-
cess involved in their manufacture.
This information and additional information contained
in the reference material may be of special use and/or
interest to agencies combating water pollution, the office
of saline water (Dept, of the Interior), and the manu-
facturers of polymer membranes.
Notes:
1. The following documentation is available from:
National Technical Information Service
Operations Division
Springfield, Virginia 22151
Single document price $3.00
(or microfiche $0.95)
Reference: NASA CR-1648 (N70-38436) Evalu-
ation of Pyrrones as Membranes
2. Requests for further information may be directed to:
Technology Utilization Officer
Langley Research Center
Hampton, Virginia 23365
Reference: TSP72-10230
Patent status:
No patent action is contemplated by NASA.
Source: H. Scott of
Franklin Institute Research Laboratories
under contract to
Langley Research Center
(LAR-10514)
Category 04
This document was prepared underthe sponsorship of the National
Aeronautics and Space Administration. Neither the United States
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the
information contained in this document, or warrants that such use
will be free from privately owned rights.