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Chemical Oxygen Demand (COD) for determination by the
dichromate reflux method cannot be accurately measured in water
containing more than 2,000mg/l of Cl-. Though the procedure 〝
remove chloride─dichromate reflux〞 is developed currently
to measure COD in water containing high chloride concentration
that the interference may be overcome, the disadvantage is
time consuming and waste generation of hazardous mercury.
Therefor,in this study adopt procedure of Ultra-Violet
spectroscopy and remove chloride-dichromate reflux simultaneously
to measure COD in water containing high chloride concentration.
Furthermore, comparing result of measuring COD with deferent
operation procedure. To assess reasonableness the COD are
measured in water containing high chloride by Ultra-Violet
spectroscopy.
Otherwise,the objective for rapid determination of COD,real-
time monitoring in water,and overcome interference for chloride
that also simulated model of monitoring for COD to mill water,
which relative between multiwavelength absorption and COD value
for suitable reference material(RM) of COD with regressive
method.
The result have shown that: (1) The use of Ultra-Violet
Spectroscopy measure COD in water containing high chloride
concentration not only rapidly but also simply;moreover it is
applied to measure COD of low concentration as Method Detection
Limit(MDL) = 0.4mg/l. (2)Ultra-Violet spectroscopy is a suitable
method for monitoring COD in water containing high chloride
concentration if the water will not contain organic SS and
similar to Ultra-Violet absorptive character of reference
material. (3) The use of referf ence material for potassium acid
phthalate、 sodium oxalate, and that mixing solution measured COD
in water by Ultra-Violet spectroscopy,it is quite accuracy for
result to predict by 〝standard type model〞 with 250-300nm
wavelength.
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