Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory C/o FoE, Block E1A, #04-01, 1 Engineering Drive 2, 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2, 117576, Singapore.
Sembcorp-NUS Corporate Laboratory, National University of Singapore, Sembcorp-NUS Corporate Laboratory C/o FoE, Block E1A, #04-01, 1 Engineering Drive 2, 117576, Singapore; Department of Civil & Environmental Engineering, Faculty of Engineering, National University of Singapore, Block E1A, #07-01, 1 Engineering Drive 2, 117576, Singapore.
Chemosphere. 2021 Jan;263:127980. doi: 10.1016/j.chemosphere.2020.127980. Epub 2020 Aug 16.
Ozonation is a well-known and widely applied advanced oxidation process (AOP) for industrial wastewater treatment, while the ozonation efficiency might be limited by low mass transfer, poor solubility, and rapid decomposition rate of ozone molecules in the aqueous phase. The present study aims to investigate the feasibility of combined microbubble-catalytic ozonation process (M-O/Fe/GAC) for improving the ozonation efficiency during treatment of petrochemical wastewater (PCW). M-O/Fe/GAC process optimization was carried out with different pH conditions, ozone dosages and catalyst loadings. The optimum operating conditions were identified as 50 mg L ozone dosage, real PCW pH (7.0-7.5) and 4 g L catalyst loading. Among different ozonation processes, M-O/Fe/GAC process achieved the highest chemical oxidation demand (COD) removal efficiency of 88%, which is 18% and 43% higher than those achieved by the microbubble and macrobubble ozonation processes, respectively. Phenolic compounds presented in PCW could be reduced by 63% within 15 min in M-O/Fe/GAC treatment process. Long-term continuous flow studies suggested M-O/Fe/GAC process to be the most cost-effective technology for PCW treatment with an operating cost of S$0.18 kg COD and S$0.4 m with good catalyst stability. Liquid size exclusion chromatography with organic carbon detection (LC-OCD) data suggested humic substances to be the dominant organic species in PCW, M-O/Fe/GAC could achieve significant humic substances removal and biodegradability enhancement in PCW. Kinetics and mechanism studies revealed that organics removal in M-O/Fe/GAC was 1.8 times higher than that in microbubble ozonation process, and hydroxyl radical (OH) was the dominant oxidant specie for organics removal in M-O/Fe/GAC process.
臭氧氧化是一种广泛应用的工业废水处理高级氧化工艺（AOP），但臭氧分子在水相中的传质效率低、溶解度差和分解速率快，限制了其臭氧氧化效率。本研究旨在探讨微气泡-催化臭氧氧化工艺（M-O/Fe/GAC）在提高石油化工废水（PCW）处理中臭氧氧化效率的可行性。通过不同的 pH 值条件、臭氧剂量和催化剂负载量对 M-O/Fe/GAC 工艺进行了优化。确定的最佳操作条件为臭氧剂量 50 mg/L、实际 PCW pH（7.0-7.5）和催化剂负载量 4 g/L。在不同的臭氧氧化工艺中，M-O/Fe/GAC 工艺实现了最高的化学需氧量（COD）去除效率 88%，分别比微气泡和大气泡臭氧氧化工艺高 18%和 43%。PCW 中存在的酚类化合物在 M-O/Fe/GAC 处理过程中 15 分钟内可减少 63%。长期连续流动研究表明，M-O/Fe/GAC 工艺是处理 PCW 的最具成本效益的技术，运行成本为 S$0.18/kg COD 和 S$0.4/m，催化剂稳定性良好。带有有机碳检测的液相尺寸排除色谱（LC-OCD）数据表明，腐殖质物质是 PCW 中的主要有机物质，M-O/Fe/GAC 可显著去除腐殖质物质并提高 PCW 的生物降解性。动力学和机制研究表明，M-O/Fe/GAC 中的有机物去除速率是微气泡臭氧氧化过程的 1.8 倍，羟基自由基（OH）是 M-O/Fe/GAC 中有机物去除的主要氧化剂。
