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Proceedings of the Estonian Academy of Sciences.

Chemistry

 

Volume 55 No. 3 September 2006

 

Degradation of lignins by wet oxidation: model water solutions; 132–144

Merit Kindsigo and Juha Kallas

(full article in PDF format)

Abstract. Nowadays many paper industries are faced with the problem of wastewaters being badly biodegradable because of tannins, lignins, etc. Wet oxidation (WO) is an appropriate method for the destruction of very complex, multi-dimensional, and permanent compounds. This paper studies the WO of lignin water as a model case with the aim of degrading lignin and enhancing water biodegradability. The experiments were performed at various temperatures (110–190 °C), partial oxygen pressures (0.5–1.5 MPa), and pH values (5, 9, and 12) in a batch stainless steel high pressure reactor. The experiments showed that increasing the temperature improved the processes efficiency. At the lowest temperature tested 75% lignin reduction was detected and a temperature increase improved the lignin removal to 100% at 190 °C. The effect of temperature on the COD removal rate was lower, but detectable: 20% of organics was oxidized at 110 °C, but 53% at 190 °C. Oxygen partial pressure changes affected the process results modestly. Lignin removal increased by about 10% and COD removal by 4% with an oxygen partial pressure increase from 0.5 to 1.5 MPa. The effect of pH occurred mostly on lignin removal. Increasing the pH enhanced the lignin removal efficiency from 60% to nearly 100%. In all cases, a good biodegradability (BOD/COD ratio over 0.5) was achieved starting at a temperature of 150 °C, pH 9, irrespective of the experimented pressures. The biodegradability (BOD/COD) of the remaining organic matter increased during WO and approached almost 1 at the highest temperature of 190 °C.

Key words: lignin, wet oxidation, COD, biodegradability.

 

 

References

 

1. Luck, F. Wet air oxidation: past, present and future. Catal. Today, 1999, 53, 81–91. doi:10.1016/S0920-5861(99)00112-1

 

2. Luck, F. A review of industrial catalytic wet air oxidation processes. Catal. Today, 1996, 27, 195–202. doi:10.1016/0920-5861(95)00187-5

 

3. Kolaczkowski, S. T., Plucinski, P., Beltran, F. J., Rivas, F. J. & McLurgh, D. B. Wet air oxida­tion: a review of process technologies and aspects in reactor design. Chem. Eng. J., 1999, 73, 143–160. doi:10.1016/S1385-8947(99)00022-4

 

4. Debellefontaine, H. & Foussard, J. N. Wet air oxidation for the treatment of industrial wastes. Chemical aspects, reactor design and industrial applications in Europe. Waste Manage., 2000, 20, 15–25. doi:10.1016/S0956-053X(99)00306-2

 

5. Genç, N., Yonsel, Ş., Dağaşan, L. & Onar, A. N. Wet oxidation: a pre-treatment procedure for sludge. Waste Manage., 2002, 22, 611–616. doi:10.1016/S0956-053X(02)00040-5

 

6. Freeman, H. M. Standard Handbook of Hazardous Waste Treatment and Disposal. Section 8.6. Wet Oxidation. McGraw-Hill Company, 1988. ISBN 0070220425

 

7. Klinghoffer, A. A., Cerro, R. L. & Abraham, M. A. Catalytic wet oxidation of acetic acid using platinum on alumina monolith catalyst. Catal. Today, 1998, 40, 59–71. doi:10.1016/S0920-5861(97)00122-3

 

8. Sun, X. F., Sun, R. C., Tomkinson, J. & Baird, M. S. Degradation of wheat straw lignin and hemicellulosic polymers by a totally chlorine-free method. Polym. Degrad. Stab., 2004, 83, 47–57. doi:10.1016/S0141-3910(03)00205-2

 

9. Ali, M. & Sreekrishnan, T. R. Aquatic toxicity from pulp and paper mill effluents: a review. Adv. Environ. Res., 2001, 5, 175–196. doi:10.1016/S1093-0191(00)00055-1

 

10. Chakar, F. S. & Ragauskas, A. J. Review of current and future softwood kraft lignin process chemistry. Ind. Crops Prod., 2004, 20, 131–141. doi:10.1016/j.indcrop.2004.04.016

 

11. Kellomäki, S. Papermaking Science and Technology. Forest Resources and Sustainable Manage­ment. Tappi Press, 1998.

 

12. Gullichsen, J. & Fogelholm, C.-J. (eds) Papermaking Science and Technology. Chemical Pulping. Tappi Press, 2000.

 

13. Sarkanen, K. V. & Ludwig, C. H. Lignins: Occurrence, Formation, Structure and Reactions. Wiley/Interscience, New York, 1971.

 

14. Boudet, A.-M. Lignins and lignification: selected issues. Plant Physiol. Biochem., 2000, 38, 81–96. doi:10.1016/S0981-9428(00)00166-2

 

15. Elegir, G., Daina, S., Zoia, L., Bestetti, G. & Orlandi, M. Laccase mediator system: oxidation of recalcitrant lignin model structures present in residual kraft lignin. Enzyme Microb. Technol., 2005, 37, 340–346. doi:10.1016/j.enzmictec.2005.02.017

 

16. Wu, J., Xiao, Y.-Z. & Yu, H.-Q. Degradation of lignin in pulp mill wastewaters by white-rot fungi on biofilm. Biores. Technol., 2005, 96, 1357–1363. doi:10.1016/j.biortech.2004.11.019

 

17. Lara, M. A., Rodríguez-Malaver, A. J., Rojas,  O. J., Holmquist, O., González, A. M., Bullón, J., Peñaloza, N. & Araujo, E. Black liquor lignin biodegradation by Trametes elegans. Int. Biodeter. Biodegrad., 2003, 52, 167–173. doi:10.1016/S0964-8305(03)00055-6

 

18. Varnaitë, R. & Raudonienë, V. Enzymatic lignin degradation in rye straw by micromycetes. Int. Biodeter. Biodegrad., 2005, 56, 192–195. doi:10.1016/j.ibiod.2005.08.002

 

19. Wolfaardt, F., Taljaard, J. L., Jacobs, A., Male, J. R. & Rabie, C. J. Assessment of wood-inhabiting Basidiomycetes for biokraft pulping of softwood chips. Biores. Technol., 2004, 95, 25–30. doi:10.1016/j.biortech.2004.01.007

 

20. Verenich, S. & Kallas, J. Biodegradability enhancement by wet oxidation in alkaline media: delignification as a case study. Environ. Technol., 2002, 23, 655–661.

 

21. Fox, M. & Noike, T. Wet oxidation pretreatment for the increase in anaerobic biodegradability of newspaper waste. Biores. Technol., 2004, 91, 273–281. doi:10.1016/j.biortech.2003.06.001

 

22. Verenich, S. & Kallas, J. Coagulation as a post-treatment process for wet oxidation of pulp and paper mill circulation waters. Chem. Eng. Technol., 2001, 24, 1183–1188. doi:10.1002/1521-4125(200111)24:11<1183::AID-CEAT1183>3.0.CO;2-P

 

23. Hellenbrand, R., Mantzavinos, D., Metcalfe, I. S. & Livingston, A. G. Integration of wet oxidation and nanofiltration for treatment of recalcitrant organics in wastewater. Ind. Eng. Chem. Res., 1997, 36, 5054–5062. doi:10.1021/ie970417m

 

24. Rivas, F. J., Beltran, F. J., Gimeno, O. & Acedo, B. Wet air oxidation of wastewater from olive oil mills. Chem. Eng. Technol., 2001, 24, 415–421. doi:10.1002/1521-4125(200104)24:4<415::AID-CEAT415>3.0.CO;2-C

 

25. Mantzavinos, D., Livingston, A. G., Hellenbrand, R. & Metcalfe, I. S. Wet air oxidation of polyethylene glycols; mechanisms, intermediates and implications for integrated chemical-biological wastewater treatment. Chem. Eng. Sci., 1996, 51, 4219–4235. doi:10.1016/0009-2509(96)00272-2

 

26. Eaton, A. D., Clesceri, L. S. & Greenberg, A. E. (eds) Standard Methods for the Examination of Water and Wastewater, 8th ed. APHA, Washington DC, Part 5000, 1995.

 

27. Donlagic, J. & Levec, J. Comparison of catalyzed and noncatalyzed oxidation of azo dye and effect on biodegradability. Environ. Sci. Technol., 1998, 32, 1294–1302. doi:10.1021/es970643n

 

28. Rivas, F. J., Kolaczkowski, S. T., Beltran, F. J. & McLurgh, D. B. Development of a model for the wet air oxidation of phenol based on a free radical mechanism. Chem. Eng. Sci., 1998, 53, 2575–2586. doi:10.1016/S0009-2509(98)00060-8