1. 1/29 DEGRADATION OF HUMIC ACIDS BY OZONATION Santiago Esplugas, Maria Homs Rio de Janeiro, July 29, 2008 Department of Chemical Engineering Research group advanced oxidation processes

2. 2/29 STRUCTURE OF THE PRESENTATION DISSOLVED ORGANIC MATTER HUMIC SUBSTANCES HUMIC ACID ADVANCED OXIDATION PROCESSES PRELIMINARY EXPERIMENTS CONCLUSIONS SOSTAQUA PROJECT

3. 3/29 1 B. New systems for removal of dissolved organic matter in seawater PROYECTO CENIT: CEN 20071039 CEN 20071039

4. 4/29 DESALINATION PILOT PLANT – PRAT DE LLOBREGAT (BARCELONA) 4.4 m3 / h 54.5 g NaCl/L 4.1 m3 / h 19.6 m3 / h

5. 5/29 DESALINATION PILOT PLANT – PRAT DE LLOBREGAT (BARCELONA)

6. 6/29 DESALINATION PILOT PLANT – PRAT DE LLOBREGAT (BARCELONA)

7. 7/29 DESALINATION PILOT PLANT – PRAT DE LLOBREGAT (BARCELONA) UF OUTLET SDI inlet = 22.9

8. 8/29 DESALINATION PILOT PLANT – PRAT DE LLOBREGAT (BARCELONA) OBJECTIVE: REDUCE BIOFOULING REMOVAL DISSOLVED OF ORGANIC MATTER MEMBRANE BIOREACTOR ADVANCED OXIDATION PROCESSES

9. 9/29 ORGANIC MATTER The organic matter presents in the sea consists of a complex mixture substances as: Hydrocarbons Carboxylic Acids Phenolic compounds Humic substances The source of most of the organic compounds in seawater is primary production by marine phytoplankton, being the terrestrial and atmospherical contribution very small compared to this. Carbohydrates Proteins Peptides Amino Acids Lipids Hydrocarbons Carboxylic Acids Phenolic compounds Humic substances Carbohydrates Proteins Peptides Amino Acids Lipids

10. 10/29 ORGANIC MATTER ORGANIC MATTER The organic matter in the sea can be divided into two categories Dissolved organic matter (DOM) Particulate organic matter (POM) POM includes those species that are retained by a glass fiber filter of 0.45 µm, as algae, bacteria, detrytus and vegetable remains. Aproximately a month in suspension. DOM is produced by POM degradation. Is a heterogenous mixture and diluted ( 1 ppm) that only 10 to 20% of this can be characterized. Is indefinitely in suspension.

11. 11/29 DISSOLVED ORGANIC MATTER Carbohydrates Amino Acids Lipids Humic Substances The most of humic substances are formed as a result of microbial activity in plant and animal debris. Humic characteristics Biologically refractory Biochemically stable Macromolecular nature Has not been characterized completely

12. 12/29 PROPERTIES HUMIC SUBSTANCES Humic acids – the fraction of humic substances that is not soluble in water under acidic conditions (pH<2) but is not soluble at higher pH values. Humic acids are the major component of humic substances. They are dark brown to black in the color. Fulvic acids – the fraction of humic substances that is soluble in water under all pH conditions. They remains in solution after removal of humic acid by acidification. Fulvic acids are light yellow to yellow-brown in color. Humin – the fraction of humic substances is not soluble in water at any pH value and in alkali. Humin are black in color.

13. 13/29 Owing to your high chemical stability and low biodegradability these organic compounds are not easy to get along with conventional technnicals, so is necessary to adopt systems more effective, among them the Advanced Oxidation Processes are found. Thus, has been chosen the Humic Substances, for to constitute the major fraction of DOM and in particular the Humic Acid for to be the major component of humic substances.

14. 14/29 HUMIC ACID Is a degradation product of lignin, carbohydrates and protein. Are complex aromatic macromolecules with amino acids, amino sugars, peptides, aliphatic compounds involved in linkages between the aromatic groups. Hypothetical structure

15. 15/29 Ozone based AOPs OzonationOzone/UV Catalytic Ozonation Photocatalysis TiO 2 /UV Ultrasound and others High temperature and pressure oxidation processes Supercritical Wet Oxidation Wet Oxidation Wet Peroxide Oxidation Hydrogen Peroxide based AOPs Photo-oxidation with H 2 O 2 Fenton Fenton-like Photo-Fenton ADVANCED OXIDATION PROCESSES (AOPs)

16. 16/29 OZONATION OF HUMIC ACIDS Technnical chemical oxidation that produces the completely or parcial descomposition of organic pollutants that are difficult to degradate by convencional treatments. The pH of the medium affects the action of ozone on the organic matter, that may be a direct or an indirect (free radical) ozonation pathway. pH<4 the direct ozonation dominates pH<4 the direct ozonation dominates pH 4-9 both are present pH 4-9 both are present pH>9 the indirect pathway prevails pH>9 the indirect pathway prevails Solution of 100 mgL -1 humic acid, Aldrich (Spain)

17. 17/29 Ozonation device O 3 + 2H + + 2I -  I 2 + H 2 O

18. 18/29 Analytical methods TOC (total organic carbon) COD (chemical oxygen demand) UV absorbance The following parameters were measured: pH BOD (biological oxigen demand)

19. 19/29 First experimental results UV 254 aromaticity decreases UV 400 solution turns transparent 60 min = 0.7 mg ozone/L 100 mgL humic acid 100 mgL -1 humic acid

20. 20/29 First experimental results First order kinetic constant values at different initial concentration of humic acids (50 – 500 mg L -1 ) were calculated for each pH. First order of kinetic constants for COD removal increased with pH.

21. 21/29 First experimental results Effect of salt on COD [HA] o = 50 mg/L, pH free The presence of 500 mg/L of salt produces a similar reduction in COD, 43% without salt and 36% with salt. The presence of 31000 mg/L of salt achieved a slight greater reduction, from 39% without salt to 52% with salt. [HA] o = 150 mg/L, pH free

22. 22/29 First experimental results Effect of salt on Absorbance Reductions UV absorbance were not influenced by the presence of salt.

23. 23/29 liquid chromatography mass spectrometry Moreover, Humic Acid aqueous solution before and after ozonation was analyzed by liquid chromatography mass spectrometry with negative electrospray ionitzation (USEPA method 625). [HA] 0 = 100 mg/L, pH=11, Ozone dose = 0.76 g/L Mass spectrum (ESI-, Full Scan) t=0Mass spectrum (ESI-, Full Scan) t=60 a significant simplification There is a significant simplification in the signs of humic acids.

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25. 25/29 DISSOLVED ORGANIC MATTER

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27. 27/29 CONCLUSIONS ozone is able to degrade  At the experimental conditions used in this study, ozone is able to degrade the humic acids. removal of organic matter measured as COD  The strongest removal of organic matter measured as COD is produced during the first 15-20 minutes, but from 40 minutes, the ozone is not able to continue degrading the organic matter.  At pH 7 and 11  At pH 7 and 11, the gratest degradation rates take place, round 55-60% COD removal.  A 80-85% aromatic reduction and colour reduction are achieved, and a very slight increase on the biodegradability.  The presence of salts has not a meaningful influence in the reduction of aromatic and colour contents, as well as, in the COD despite the huge concentration used.

28. 28/29 FUTURE WORK  ATP analysis.  TOC at high salinity.  SDI analysis.  Real seawater.

29. 29/29 Thanks for the attention.

30. 30/29 DEGRADATION OF HUMIC ACIDS BY OZONATION Santiago Esplugas, Maria Homs Rio de Janeiro, July 29, 2008 Department of Chemical Engineering Research group advanced oxidation processes