Abstract
This study presents a photochemical kinetics model to describe the degradation of water-soluble PVA (Polyvinyl Alcohol) polymer in a UV/H2O2 batch reactor. Under the effect of UV light, the photolysis of hydrogen peroxide into hydroxyl radicals can generate a series of polymer scission reactions. For a better understanding and analysis of the UV/H2O2 process in the cracking of the PVA macromolecules, a chemical reaction mechanism of the degradation process and a relevant photochemical kinetics model are developed to describe the disintegration of the polymer chains. Taking into account the probabilistic fragmentation of the polymer, the statistical moment approach is used to model the molar population balance of live and dead polymer chains. The model predicts the PVA molecular weight reduction, the acidity of the solution, and hydrogen peroxide residual. In addition to previously published data collected in this laboratory, a new set of experiments were conducted using a 500 mg/L PVA aqueous for different hydrogen peroxide/PVA ratios for model validation. Measurements of average molecular weights of the polymer, hydrogen peroxide concentrations and pH of the PVA solution were determinant factors in constructing a reliable photochemical model of the UV/H2O2 process. Experimental data showed a decrease in the PVA molecular weight and a buildup of the solution acidity. The experimental data also served to determine the kinetics rate constants of the PVA photochemical degradation and validate the model whose predictions are in good agreement with data. The model can provide a comprehensive understanding of the impact of the design and operational variables.
Similar content being viewed by others
References
Aarthi T, Shaama M, Madras G (2007) Ind Eng Chem Res 46:6204–6210
Tayal A, Khan S (2000) Macromol 33:9488–9493
Swift G (1997) Polym Degrad Stab 59:19–24
Alfano O, Cassano A (2009) Scaling-up of photoreactors: applications to advanced oxidation processes. INTRC Publishers, Massachusetts, 229–286
Mohajerani M, Mehrvar M, Ein-Mozaffari F (2009) Int J Eng 3:120–146
Hamad D, Dhib R, Mehrvar M (2016) J Polym Environ 24:72–83
Ghafoori S, Mehrvar M, Chan PS (2012) Ind Eng Chem Res 51:14980–14993
Santos L, Poli A, Cavalheiro C, Neumann M (2009) J Braz Chem Soc 20:1467–1472
McCoy B, Madras G (2001) Chem Eng Sci 56:2831–2836
Solaro A, Corti A, Chillini E (2000) Polym Adv Technol 11:873–878
Ghafoori S, Mehrvar M, Chan P (2011) Chem Eng J 245:133–142
Hamad D, Mehrvar M, Dhib R (2014) Polym Degrad Stab 103:75–82
Hamad D, Dhib R, Mehrvar M (2016) Environ Technol 37(21):2731–2742
Christensen H, Sehested K, Corfitzen H (1982) J Phys Chem 86:1588–1590
Buxton G, Greenstock C, Helman W, Ross A (1988) Phys Chem Ref Data 17:513–886
Liao C, Gurol M (1995) Environ Sci Technol 29:3007–3014
Crittenden JC, Hu S, Hand DW, Green SA (1999) Water Res 33:2315–2328
Weinstein J, Bielski B (1979) Am Chem Soc 101:58–62
Bielski B, Cabelli D (1991) Int J Radiat Bio 59:291–319
Elliot A, Buxton G (1992) Chem Soc 88:2465–2470
Linden K, Sharpless C, Andrews S, Atasi K, Korategere V, Stefan M, Suffet I (2005) Innovative UV technologies to oxidize organic and organoleptic chemicals. IWA Publishing, London
Whittmann G, Horvath I, Dombi A (2002) Ozone Sci Eng 24:281–291
Kodera Y, McCoy B (1997) AIChE J 3205–3214
Metha K, Madras G (2001) Am Inst Chem Eng J47:2539–2545
Smagala T, McCoy B (2003) Ind Eng Chem Res 42:2461–2469
Peng Z, Kong LX (2007) Polym Degrad Stab 92:1061–1071
Taghizadeh MT, Yeganeh N, Rezaei M (2015) J Appl Polym Sci 32(25):42117–42129
Romero R, Alfano O, Cassano A (1997) Ind Eng Chem Res 36:3094–3109
Sterling J, McCoy B (2001) AIChE J 47:2289–2303
Hulburt H, Katz S (1964) Chem Eng Sci 19:555–574
Acknowledgements
The financial support of the Natural Sciences and Engineering Research Council of Canada (NSERC) and Ryerson University is greatly appreciated.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hamad, D., Mehrvar, M. & Dhib, R. Photochemical Kinetic Modeling of Degradation of Aqueous Polyvinyl Alcohol in a UV/H2O2 Photoreactor. J Polym Environ 26, 3283–3293 (2018). https://doi.org/10.1007/s10924-018-1190-y
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10924-018-1190-y