Solar light driven oxidation of gentisic acid on ZnO. (15th January 2017)

• Record Type: Journal Article
• Authors: Antil-Martini, Katerine; Contreras, David; Yáñez, Jorge; Cornejo, Lorena; Santander, Paola; Mansilla, Héctor D.
• Is Part Of: Solar energy. Volume 142(2017)
• Page Start: 26
• Page End: 32
• Publication Date: 2017-01-15
• Subjects: EE/O -- Gentisic acid -- Photocatalysis -- ZnO; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2016.12.005
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: The photocatalytic oxidation of gentisic acid using ZnO and solar light was achieved. The oxidation of gentisic acid was optimized using Factorial Design through Response Surface methodology (RSM) Figures of merit such as Average Oxidation State (AOS) and Electric Energy per Order (EEO) were calculated. The effect of scavengers was evaluated to determine the role of hydroxyl radicals and holes. The relative concentration of hydroxyl radicals were determined using fluorescence technique. Abstract: The photocatalytic oxidation of 2, 5-dihydroxybenzoic acid (2, 5-DHBA) has been performed using ZnO. The reaction was carried out using a UVA lamp and direct solar light for the catalyst activation. The response surface methodology was used in order to achieve optimal values of pH and proper amount of catalyst. The conditions found to be the best were pH 5.4 and 1.33 g L −1 of ZnO. Under such conditions 86% removal of 2, 5-DHBA was attained after 15 min of reaction. Additionally, 80% and 70% depletion were found for total organic carbon (TOC) and chemical oxygen demand (COD) values, respectively. Moreover, under optimized conditions the catalyst does not show activity lost by photo-corrosion. The calculated electrical energy per order (EE/O) shows that the energy required for the decrease of the initial concentration in one order of magnitude is quite high (260 kW h m −3 ). However, it was also found that the reaction can be carried out using direct solar light making the process significantly cost-effective.