Enhanced ozonation degradation of petroleum refinery wastewater in the presence of oxide nanocatalysts

Abstract

The catalytic activity of MnO, FeOOH and CeO nanoparticles was evaluated in the treatment of a synthetic petroleum refinery wastewater (SPRW) using O in a discontinuous reactor at 25°C and pH 5.5. The mineralization and partial chemical oxidation rates of SPRW using these metal oxides are in the same order of magnitude, and the catalytic activity in the mineralization of SPRW decreased in the order MnO>CeO> FeOOH. The mineralized fraction progressively increased with time in the catalytic process while in the non-catalytic process it remained constant. The effect of the operational conditions on the mineralization and partial chemical oxidation rates using MnO was investigated in detail. The mineralization rate was found to be lower than the partial oxidation rate due to the formation of partially oxidized by-products, and this is dependent on the solids dosage and pH. An investigation of the mechanism demonstrated that the enhancement effect could be attributed to the introduction of the manganese oxide nanoparticles, which could promote the utilization of O and/or enhance the formation of free radicals (•OH, •OH and •O) on the solid surface and further accelerate the degradation of the organic compounds present in the wastewater.

Ozonation of woodworking enterprises using a heterogeneous nanocatalyst

“…При химической трансформации озона под действием пероксида водорода, катализаторов, активированного угля, ультразвука в растворе образуются гидроксильные радикалы с более сильными окислительными свойствами (2,70 в) [9]. Из литературных данных известно, что использование катализаторов в процессе озонирования позволяет повысить эффективность очистки сточных вод [10][11][12][13][14][15][16][17][18][19][20][21][22]. В связи с этим нами проведено исследование эффективности очистки вышеуказанных сточных вод озонированием в присутствии доступных и наиболее изученных гетерогенных нанокатализаторов (Fe 2 O 3 , Al 2 O 3 , MnO 2 ).…”

“…During the chemical transformation of ozone under the action of hydrogen peroxide, catalysts, activated carbon, ultrasound, hydroxyl radicals with stronger oxidizing properties (2,70 V) are formed in the solution [9]. It is known from the literature that the use of catalysts in the ozonation process can improve the efficiency of wastewater treatment [10][11][12][13][14][15][16][17][18][19][20][21][22]. In this regard, we conducted a study of the effectiveness of the mentioned above wastewater treatment by ozonation in the presence of available and most studied heterogeneous nanocatalysts (Fe 2 O 3 , Al 2 O 3 , MnO 2 ).…”

Treatment of aqueous solutions of 1,4-dioxane by ozonation and catalytic ozonation with copper oxide (CuO)

“…In previous tests performed to select a suitable catalyst, involving a comparison of the TOC removal and ozone decomposition rate obtained using different non-noble metals (goethite, cerium oxide or copper oxide), copper oxide resulted in the highest catalytic activity [28,37].…”

“…Catalytic ozonation is an effective advanced oxidation process (AOP) for the removal of organic contaminants from water and wastewater [20][21][22][23], owing to its ability to decompose the ozone molecule to highly reactive radical species, which rapidly react with organic contaminants. Several solid catalysts, such as iron oxides [20,[24][25][26], ceria oxide [27,28], activated carbon [29,30] and Fe 0 [31], have been used successfully to catalyze the decomposition of organic compounds in wastewaters using ozone or hydrogen peroxide. In general, the catalytic activity is related to the BET surface area, crystallinity and ability to produce free radicals from ozone or hydrogen peroxide [32].…”

“…In general, hydroxyl radicals (•OH) react quickly and non-selectively with a large number of organic compounds in water, while O3 reacts quickly with unsaturated organic compounds and slowly with saturated ones [32]. However, hydroxyl radicals can also react with ozone (k•OH = 1 × 10 8 -2 × 10 9 M −1 s −1 ) and bicarbonate/carbonate (k• OH = 8.5 × 10 6 /3.9 × 10 8 M −1 s −1 ) [28]. Thus, it is expected that the •OH reaction with saturated hydrophilic organic species and by-products in the presence of ozone is relatively slow due to the competitive reaction of • OH and ozone [35].…”