Endress+Hauser Analytik Jena Multi X 2500, Руководство по эксплуатации

Страница: 53 / 124

multi X 2500 AOX determination
53
2. Add 25 ml of HNO
3
(conc.).
3. Top up with water to 1000 ml.
Preparing the sample:
1.
Make sure that the water sample has room temperature before initiating the
adsorption.
2. Add 5 ml of nitrate stock solution to 100 ml of the sample.
3. Set the pH-value of the solution to pH < 2 using HNO
3
.

The prepared solution is now ready for adsorption.
The sample is adsorbed into quartz containers filled with 50 mg of activated carbon
(AOX carbon). The activated carbon is fixed with ceramic glass wool plugs.
The samples for the column method can be adsorbed with the sample preparation
modules APU 28, APU 28 S, APU 28 SPE and their flexi versions, APU sim or AFU 3
(with the column method kit).
All devices and tools required for the preparation and execution of the AOX adsorption
are delivered with the sample preparation module.
The batch method requires more effort than the column method, but is often preferred
for the adsorption from turbid samples. Note that high chloride concentrations result
in a higher distortion than they produce with the column method.
1.
Add 100 ml of the sample, 5 ml of nitrate stock solution and 50 mg AOX carbon to
a 250-ml Erlenmeyer flask. Use a plug to seal the flask.
The AJ filling device is recommended for metering the AOX carbon.
2. Shake the suspension for 1 hour.
3. Use a membrane filter apparatus to separate water/activated carbon or
water/activated carbon/sludge with a chloride-free polycarbonate membrane filter
(0.45 µm, 25 mm diameter).
4. Add 50 ml of the nitrate stock solution to a 1-liter volumetric flask and top up the
flask with water (nitrate wash solution).
5. After passing the AOX carbon, use at least 25 ml of the nitrate wash solution to
wash the system in portions until it is free of chloride.
When filtering, make sure that as little laboratory air as possible is drawn in and
passed through the AOX carbon.
6. For the combustion in vertical operating mode, push the filter including the wet
filter cake into a chloride-free calcined frit container (18 x 6 mm or 18 x 8 mm)
and fix it using some ceramic glass wool.
For the combustion in horizontal operating mode (multi-purpose combustion
tube), the filter and the wet filter cake are pushed into a quartz glass boat with
holding-down clamp.
Column Method
Batch method