Hanna Instruments HI 4009 - Manual (Page 15)

15
sensor membrane. Store dry disassembled electrode in
storage box provided with electrode.
XV XV XV XV XV. . . . . Conversion T Conversion T Conversion T Conversion T Conversion Tables ables ables ables ables
For CN For CN For CN For CN For CN
-----
Multiply by Multiply by Multiply by Multiply by Multiply by
Moles/L (M) to ppm (mg/L) 2.602 x 10 4
ppm (mg/L) to M (moles/L) 3.843 x 10 -5
XVI. XVI. XVI. XVI. XVI. Disposal of Cyanides Disposal of Cyanides Disposal of Cyanides Disposal of Cyanides Disposal of Cyanides
Sodium Cyanide is a deadly poison and extreme care must
be taken during use and in disposal after use.
Test solutions and standards may be neutralized before
discharging. Consult your waste manager for exact
procedures. The overview of the process is below.
Caution: Neutralization reactions should be carried out in a
hood.
1) Cyanide is oxidized to cyanate at an elevated pH. pH
and ORP measurements can aid the progress of this
reaction.
CN
- +OH - + HOCl - -> CNO -
2) Cyanate is then oxidized to N
2
and CO
2
which bubble
off as harmless gases. pH and ORP measurements
can aid this step also.
2CNO - +2OH - +HOCl - ->Cl - +2CO
2
+N
2
+2H
2
O