1. 22 august, 2008 1 QSPR prediction of pharmaceutical removal with GAC Delft David de Ridder Carbamazepine

2. 22 august, 20082 Problem statement micropollutants 100.000+ different micropollutants in surface water Variable mixture RIWA Rijn measures about 250 org. micropollutants Analysis programs costly and time consuming QSAR can be used as a screening tool

3. 22 august, 20083 QSAR werk David de Ridder Singular processes Activated carbon (AC) Aeration Ozone UV Combinations of processes AC-UV/H2O2-AC (RBF)-NF-AC

4. 22 august, 20084 Activated carbon Research objectives Estimate: Influence of turbulence on adsorption kinetics Influence of water quality Influence of preloading carbon Construction of QSPR model Accuracy of QSPR prediction Ce, qe

5. 22 august, 20085 Experiment set-up pharmaceutical selection -+0-+0

6. 22 august, 20086 Experiment set-up matrix Demi waterSurface waterWaste water Regenerated carbon Kinetic (car, mix) Kinetic low turbulence (mix) Equilibrium (car, met, car+met, mix) Preloaded carbon Equilibrium (mix)Kinetic (mix) Equilibrium (mix)

7. 22 august, 20087 Experiment set-up 2 litre solution Kinetic @ 200 mg carbon Adsorption time 1 day – 6 weeks Equilibrium @ 20-2000 mg carbon Adsorption time 8 weeks Carbon 0,63-0,71 mm

8. 22 august, 20088 Results Kinetic experiments

9. 22 august, 20089 Results Kinetic experiments

10. 22 august, 200810 Results Kinetic experiments

11. 22 august, 200811 Results Kinetic experiments Lower turbulence decreases adsorption significantly Preloading large influence on negatives, and no significant effect on positives.

12. 22 august, 200812 Results - Equilibrium

13. 22 august, 200813 Results - Equilibrium

14. 22 august, 200814 Results - Equilibrium

15. 22 august, 200815 Results initial remarks MW in range 200-300 D no significant influence Log D has higher impact on removal of negatives At similar pKa, higher log D yields higher removal At similar log D, positives are removed 1,2-2 times more effective than negatives In wastewater: Positives comparable removal as surface water Neutrals better removal than in surface water Significant removal of 4 negatives in blank!

16. 22 august, 200816 Results hypotheses Preloading creates a negatively charged layer onto the carbon, rejecting negatives and attracting positives In the MW range of 200-300 D, probably most carbon micropores will be available for adsorption In wastewater, (bio)degradation of negatives is preferred.

17. 22 august, 200817 Results - QSPR construction 4 (out of 21) compounds excluded for verification MLR (multivariable linear regression) prediction model

18. 22 august, 200818 Results - QSPR prediction

19. 22 august, 200819 Results - QSPR validation

20. 22 august, 200820 Results – model accuracy Specific mispredictions Consequent over/underprediction Less data available

21. 22 august, 200821 Results – Freundlich parameters

22. 22 august, 200822 Initial conclusions Model prediction Applied carbon dose too high -> ultrapure models inaccurate Initial degradation negatives wastewater -> negatives not taken properly into account Surface water: general underprediction Ce at higher carbon dose Wastewater: Specific overprediction Ce (Terbutaline, Salbutamol, metropolol, Clenbuterol, Aminopyrine) Demiwater PL: consequent over/underprediction

23. 22 august, 200823 Further research Dataset Larger variation MW (if relevant) Process conditions Carbon type Change preparation preloaded carbon Lower carbon doses pH variation at same water quality (decrease charge negatives, lower log D negatives & higher log D positives) Analysis ATP to check for biological activity NOM characterisation (blank & adsorbed (?)) Carbon characterisation (PSD, hydrophobicity, carbon pKa)

24. 22 august, 200824 ¿Questions/remarks?

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