47
Figure 3.3 Biodegradability test experimental set up
3.3 Analytical Methods
3.3.1 COD Chemical Oxygen Demand determination
Chemical oxygen demand determination was performed using HACH analytical equipment Method 8000 that was approved by Standard Method for the
Wastewater Analysis, USEPA. This parameter is very important to monitor the degradation of alkanolamine and the concentration of the test compound in
bioreactor. Two ml of sample was oxidized using the standard chemical from HACH and digested at 150 ˚C for two hours on the DRB HACH digester. The COD reading
was obtained by using HACH DR 5000 spectrophotometer. The range of COD measurement is 0
– 1500 mgL COD. Furthermore, COD removal at 30 minute was calculated by:
48
100
30 30
x COD
COD COD
COD
removal
3.2
where: COD
removal 30
= percentage of COD removal at 30 minute, COD
= COD value at 0 minute, and COD
30
= COD value at 30 minute
3.3.2 TOC Total Organic Carbon determination
Total organic carbon determination was conducted using HACH analytical equipment Method 10128 that was approved by Standard Method for the Wastewater
and Industrial Waters Analysis, USEPA. Measurement of this parameter was done to compare the profile of COD reduction and TOC re
duction in the Fenton’s process. 0.3 ml sample was digested using the standard reagent
from HACH at 105 ˚C for two hours on the DRB HACH digester, and the TOC was measured using HACH
spectrophotometer DR 5000. The range of TOC measurement was 100 – 700 mgL C.
Further, TOC removal at 30 minute was calculated by:
100
30 30
x TOC
TOC TOC
TOCremoval
3.3
where: TOC
removal 30
= percentage of TOC removal at 30 minute, TOC
= TOC value at 0 minute, and TOC
30
= TOC value at 30 minute
49
3.3.3 Un-reacted alkanolamine and identification of degradation product using HPLC
An Agilent series 1100 brand of HPLC was used to monitor the degradation products and un-
reacted alkanolamine after Fenton’s treatment. YMC-Pack PolymerC18 reverse phase column was used with 100mM Na
2
HPO
4
100mM NaOH 6040, pH 12 as eluent and UV 215 nm and 253nm detector. Flow rate of the
eluent was 1 mlminute. Degradation product determination was performed by comparison of the sample with the standard compound which was assumed.
Qualitative analysis was based on the retention time of each compound in the chromatogram, while quantitative un-reacted alkanolamine analysis was based on the
calibration curve prepared using standard alkanolamine. The calibration curve for MEA and DEA are expressed below:
MEA : Area = 0.210[MEA]
– 2.267 3.4
DEA : Area = 0.443[DEA] + 10.076
3.5
3.3.4 Identification of the functional groups using FTIR
