Author ORCID Identifier
TiO2/UV photocatalysis, 2k design, BBD, TOC reduction
The Canadian pulp and paper industry has been concerned with reducing annual emissions of pollutants into water bodies, air and landfills. Black liquor is a major byproduct from pulp mills such as Kraft. Black liquor is utilized in boilers to produce steam and electricity. Black liquor is a low-value chemical and researchers have employed thermal and chemical processes to produce products such as oils, adhesives, and dispersants. In recent years, photocatalysis has become an alternative to degrade black liquor into short chain carbon chemicals.
This study aims to optimize the performance of black liquor photocatalytic degradation using the TiO2/UV system. Five practical factors were selected to develop the optimal total organic carbon (TOC) reduction. A two-level 2k design was used as the preliminary study for examining the optimal initial concentration of black liquor and TiO2. A three-level Box-Behnken design (BBD) with three factors that included pH, temperature, and particle size was then applied to further enhance the photocatalytic performance. The greatest TOC removal of 36.2±4.0% after 4 hours UV irradiation was obtained for 230 mg TS·L-1 black liquor and 2 g·L-1 TiO2. The black liquor concentration had larger impact on TOC removal in comparison with TiO2 concentration. A response surface methodology (RSM) model was developed to predict the maximum 4-hour TOC reduction of 51.6% under optimal conditions of a pH of 7.87, 37 ℃, and a catalyst particle size of 5 nm. Compared with the preliminary study, an additional improvement of 15% TOC removal efficiency was observed using the BBD.
Dr. Nihar Biswas
Dr. Paul Henshaw
Master of Applied Science
Civil and Environmental Engineering
Major Research Paper