I read on http://www.epa.gov/ogwdw000/mdbp/pdf/alter/chapt_4.pdf
Section 220.127.116.11 that chlorine dioxide changes its effectiveness to kill pathogens when the pH is varied - so I must have been mistaken, chlorine dioxide may exist at neutral or even alkaline pH values! The document cites the scientific literature that a higher pH is more effective.
I really don't understand chlorine dioxide and how it stays in molecular form in an alkaline solutions.
The document also says that chlorine dioxide is more effective at higher temperatures (Section 18.104.22.168).
A search on Google showed possible use of phosphate based buffer solutions to achieve near neutral pH with chlorine dioxide. I guess it must be possible with the correct buffer chemicals.
I'll post more on this subject as I learn more about it.