Optimization of carbamazepine removal in O 3/UV/H 2O 2 system using a response surface methodology with central composite design

• Published in: Desalination Vol. 285; pp. 306 - 314
• Main Authors: Im, Jong-Kwon, Cho, Il-Hyoung, Kim, Seung-Kyu, Zoh, Kyung-Duk
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31.01.2012
• Subjects: Carbamazepine; Hydroxyl radical; Ozone; Response surface methodology; UV; Ozone; Response surface methodology; Carbamazepine; Hydroxyl radical
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2011.10.018

This study used an ozone/ultraviolet/hydrogen peroxide (O 3/UV/H 2O 2) system to remove carbamazepine (CBZ) from water using a second-order response surface methodology (RSM) experiment with a five-level full-factorial central composite design (CCD) for optimization. The effects of both the primary and secondary interactions of the photocatalytic reaction variables, including O 3 concentration ( X 1 ), H 2O 2 concentration ( X 2 ), and UV intensity ( X 3 ), were examined. The O 3 concentration significantly influenced CBZ and total organic carbon (TOC) removal as well as total inorganic nitrogen ion production (T-N) ( p < 0.001). However, CBZ, TOC removal, and T-N production were enhanced with increasing O 3 and H 2O 2 concentrations up to certain levels, and further increases in O 3 and H 2O 2 resulted in adverse effects due to hydroxyl radical scavenging by higher oxidant and catalyst concentrations. UV intensity had the most significant effect on T-N production ( p < 0.001). Complete removal of CBZ was achieved after 5 min. However, only 34.04% of the TOC and 36.99% of T-N were removed under optimal concentrations, indicating formation of intermediate products during CBZ degradation. The optimal ratio of O 3 (mg L − 1 ): H 2O 2 (mg L − 1 ): UV (mW cm − 2 ) were 0.91:5.52:2.98 for CBZ removal, 0.7:18.93:12.67 for TOC removal, and 0.94: 4.85:9.03 for T-N production, respectively. ► Response surface method to optimize carbamazepine removal in O 3/UV/H 2O 2 reaction. ► O 3 concentration significantly influenced CBZ and TOC removals. ► UV intensity had the most significant effect on T-N production. ► CBZ removal was enhanced up to certain levels of O 3 and H 2O 2 concentrations. ► Central composite design was used to determine the optimal removal efficiency of CBZ.