Table 2 N and O atomic ratios and functional groups with respect to C from the high resolution XPS spectrum used to quantify the EPS extracted from SAC-incubated sludge
Group | Elemental composition (molar ratios with respect to total carbon) | Chemical function (relative ratio (%)) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
O/C | N/C | C-(C,H) | C-(O,N) | O = CO- -C-O | O = CHO O = C-O-R | Nnonpr | Npr | O = C C-P = O | HO-C C-O-C | |
0% | 0.54 | 0.11 | 19.1 | 28.6 | 9.62 | 1.25 | 5.07 | 1.44 | 9.49 | 22.1 |
0.1% | 0.54 | 0.17 | 21.9 | 25.5 | 10.2 | 0.72 | 5.84 | 3.25 | 18.3 | 10.2 |
0.5% | 0.51 | 0.20 | 15.2 | 27.2 | 10.2 | 1.89 | 7.29 | 3.64 | 13.1 | 14.6 |
1% | 0.53 | 0.20 | 19.2 | 21.3 | 7.16 | 2.93 | 5.83 | 4.03 | 10.5 | 15.7 |
2% | 0.49 | 0.14 | 24.1 | 10.3 | 3.76 | 1.68 | 3.78 | 1.80 | 12.7 | 15.1 |
5% | 0.48 | 0.16 | 28.9 | 17.5 | 11.0 | 0.68 | 6.94 | 1.82 | 11.0 | 16.7 |
10% | 0.50 | 0.19 | 19.2 | 20.3 | 7.16 | 2.93 | 3.45 | 4.42 | 9.21 | 20.0 |