Optimization of the Reaction Rate in the Photocatalytic Degradation of Sodium Lignosulfonate in a TiO2 Slurry Reactor: A Multivariate Study with Response Surface Analysis
✍ Scribed by Shoko, E. ;Diniz Costa, J. C. Da ;White, E. T.
- Publisher
- Curtin University of Technology
- Year
- 2008
- Tongue
- English
- Weight
- 603 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0969-1855
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
This report used a 2^3^‐factorial design to investigate the dependence of the reaction rate in the photocatalytic degradation of sodium lignosulfonate on solution pH, substrate concentration and TiO~2~ catalyst dosage in a slurry reactor. The objective was to locate an optimum for the combination of these variables by using a suitable multiple‐linear regression model and to identify any interaction effects among the variables. The region of exploration selected for this study was: substrate concentration, 40 mg/L ‐ 60 mg/L; catalyst dosage, 15 mg/L ‐ 35 mg/L and pH, 4‐8. A first‐order linear regression model could not adequately be fitted to the rate data, and the analysis of variance revealed significant interaction effects between pH and substrate concentration as well as pH and catalyst concentration. The nature of these interaction effects is discussed in detail. When a second‐order model was fitted to the data, an adequate description of the empirical relationship between the reaction rate and the three input variables was obtained. Analysis of the stationary point on the second‐order response surface revealed the existence of a saddle point within the region of exploration from where two near‐symmetric regions of high reaction rate were identified. The implications of these findings for practical reactor design are discussed.