Proposed concept, based on law of mass action uses addition of salt to increase chlorine ions produced in sodium hydrochlorite solutions, thereby increasing solution shelf-life. This technique is not costly. Usefulness will be determined by acceptability of salt in product undergoing long shelf-life

Copeland, E. J.

Edgerley, R. H.

English

NASA Technical Reports Server

May 1971	 Brief 71-10097 
NASA TECH BRIEF 
Manned Spacecraft Center 	
_4V 
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, Df. 20546. 
Salt Stabilizer for Preventing Chlorine Depletion and Increasing 
Shelf-Life of Potable Water: A Concept 
A proposed concept, based on the law of mass 
action, uses the addition of salt to increase the 
chlorine ions produced in sodium hypochlorite solu-
tions, thereby increasing solution shelf-life. Normally, 
the germicidal effectiveness of sodium hypochiorite 
for controlling microbial content in potable water 
supplies decreases as a function of shelf-life, with 
the decomposition occurring according to the equa-
tion:
HC10+H+2e =C[H-H20 
Attempts to reduce the pH so as to increase the 
concentration of hypochiorous acid (HCIOI), i.e., its 
geometrical effectiveness, drastically reduce the long-
term stability. 
However, in the proposed concept, a chlorine-solu-
tion is prepared with approximately 5000 parts per 
million (ppm) chlorine, using an analytical reagent 
grade solution of sodium hypochiorite (NaOCI) 
and distilled water. It is thoroughly mixed and 
strained through a 0.22 micron filter, and then al-
lowed to stabilize for at least 2 hours. Finally, 
the solution is adjusted for a chlorine concentra-
tion of 5000 ppm.
Detailed procedures have been developed to ensure 
that the ampules containing the solution are properly 
filled, sealed and bonded, and are stored in the 
proper environmentalconditions. 
Notes: 
1. This technique may have wide appeal due to its 
low cost; however, the usefulness will ultimately 
be determined by the acceptability of salt in the 
product undergoing long shelf-life. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Manned Spacecraft Center, Code JM7 
Houston, Texas 77058 
Reference: TSP71-10097 
Patent status: 
No patent action is contemplated by NASA. 
Source: Robert H. Edgerley
and Edgar J. . Copeland -of
North American Rockwell Corp.
under contract to
Manned Spacecraft Center 
(MSC-17153) 
Category 04 
This document was prepared under the 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.
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Salt stabilizer for preventing chlorine depletion and increasing shelf-life of potable water - A concept

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