In the frame of the project analytical methods were developed, which have been specifically studied for leachates. Analytical protocols for phase-contrast optical microscopy (PCOM), scanning (SEM) and transmission electron microscopy (TEM) have been settled out and can be downloaded here (presently only in italian).
PCOM
Phase Contrast Optical Microscopy
SEM
Scanning Electron Microscopy
TEM
Transmission Electron Microscopy
Why specific protocols for leachates?
Leachates may contain high amounts of organic material, which may encapsulate the fibres and makes it difficult to observe them using microscopic techniques. For this reason, an analytical protocol suitable for leachates must have a pre-step for the elimination of this interfering organic matter. The project has developed a method which makes use of a microwave-assisted digester.
The digestion pre-treatment
The removal of the organic load is carried out in an acid solution under microwave irradiation.
A MARS5 CEM microwave system with 14 vessel was used. The following standard protocol have been developed for leachate samples with a COD lower than a specified threshold (2000 mg/L of O2):
| Leachate per vessel (ml) |
25 |
| H2SO4 conc. /vessel (ml) |
0,5 |
| H2O2 35% /vessel (ml) |
4 |
| Leachate/run (Max ml) |
350 |
| Temp. scan I (C°) |
90 |
| Temp. scan II (C°) |
160 |
| Pressure max scan I (psi) |
80 |
| Pressure max scan II (psi) |
250 |
| Power scan II (W-%) |
300 - 100% |
| Potenza rampa II (W-%) |
600 - 60% |
| Hold at 90° (min) |
1 |
| Hold at 160° (min) |
1 |
| Total irradiation time (min) |
22 |
| Cooling time (min) |
15 |
Other possible alternative procedures for samples with lager CODs have been tested. Moreover, an alternative treatment for MOCF sample have been suggested when the deposited membranes tend to be damaged by the acid solution.
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