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Hello,
When treating a complex pharmaceutical wastewater with ozone (and with/without UV) the online measured ORP gets very negative (from +90mV to
-700mV !!). One would expect an oxidation. Measuring the ORP (of samples taken in time) of this treated wastewater after a day (when all radicals are gone) gives a rise in time. When treating the same water with peroxide (w & w/o UV) and oxygen together the online measured ORP rises as it should. The pH-measurement in all cases gives reproducable results.
Could it be that the ozone radicals interfere with the glass membrane and give a wrong result? Or are radicals much stronger reducing agents than
oxygen and UV are oxidizers (which seems pretty weird to me)?
We are using a Yokogawa redox combined glass electrode with gold surface ring in a flow through cell.
Any clues/experiences ?
Johan Vereecken
Vito - PRODEM
Boeretang 200 2400 Mol Belgium
voice: +32 14 33 69 35 fax: +32 14 32 65 86
mailto:[email protected] http://www.vito.be
For e-mail security and authenticity:
PGP DH/DSS Key ID: 0x8F44FDB4
When treating a complex pharmaceutical wastewater with ozone (and with/without UV) the online measured ORP gets very negative (from +90mV to
-700mV !!). One would expect an oxidation. Measuring the ORP (of samples taken in time) of this treated wastewater after a day (when all radicals are gone) gives a rise in time. When treating the same water with peroxide (w & w/o UV) and oxygen together the online measured ORP rises as it should. The pH-measurement in all cases gives reproducable results.
Could it be that the ozone radicals interfere with the glass membrane and give a wrong result? Or are radicals much stronger reducing agents than
oxygen and UV are oxidizers (which seems pretty weird to me)?
We are using a Yokogawa redox combined glass electrode with gold surface ring in a flow through cell.
Any clues/experiences ?
Johan Vereecken
Vito - PRODEM
Boeretang 200 2400 Mol Belgium
voice: +32 14 33 69 35 fax: +32 14 32 65 86
mailto:[email protected] http://www.vito.be
For e-mail security and authenticity:
PGP DH/DSS Key ID: 0x8F44FDB4