Sodium citrate/citric acid was found to be an effective buffer for pH control when used with sodium hypochlorite. The mixture does not corrode aluminum. The buffer appears to form a type of conversion coating that may provide corrosion-resistant properties to aluminum in other applications

Nash, J. R.

Veeder, L. N.

English

NASA Technical Reports Server

March 1969
	
Brief 69-10084 
NASA TECH BRIEF 
NASA Teèh Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Improved pH Buffering Agent for Sodium Hypochiorite 
The effectiveness of sodium hypochiorite as a water 
disinfectant is strongly dependent on pt-I. To maintain 
the pt-1 of the hypochlorite solution at the desired value, 
sodium dihydrogen phosphate has been used as a 
buffer. However, this buffer in the presence of the 
hypochlorite corrodes aluminum systems (such as the 
potable water supply system on Apollo). It has been 
found that sodium citrate /citric acid is an effective 
buffer for pH control when used with. sodium hypo-
chlorite, and the mixture does not corrode aluminum. 
The buffer consists of 100 to 200 ppm of sodium citrate 
with sufficient citric acid to bring the pt-I to 7.0-
7.5. In addition, the buffer appears to form a type of 
conversion coating that may provide corrosion-resis-
tant properties to aluminum in other applications.
Note: 
This Tech Brief is complete in itself. No additional 
information is available. 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: J. R. Nash and L. N. Veeder 
of North American Rockwell Corporation 
under contract to

Manned Spacecraft Center
(MSC-15443) 
Caterogy 03 
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.
https://ntrs.nasa.gov/search.jsp?R=19690000084 2020-03-16T17:52:45+00:00Z


Improved pH buffering agent for sodium hypochlorite

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server