Ultrasonics Sonochemistry ( IF 8.4 ) Pub Date : 2022-10-19 , DOI: 10.1016/j.ultsonch.2022.106207 Sebastien J De-Nasri 1 , Varaha P Sarvothaman 1 , Sanjay Nagarajan 2 , Panagiotis Manesiotis 1 , Peter K J Robertson 1 , Vivek V Ranade 3
Hydrodynamic cavitation (HC) has been extensively investigated for effluent treatment applications. Performance of HC devices or processes is often reported in terms of degradation of organic pollutants rather than quantification of hydroxyl (OH) radicals. In this study, generation of OH radicals in vortex based cavitation device using coumarin dosimetry was quantified. Coumarin was used as the chemical probe with an initial concentration of 100 µM (15 ppm). Generation of OH radicals was quantified by analysing generated single hydroxylated products. The influence of operating parameters such as pH and type of acid used to adjust pH, dissolved oxygen, and inlet and outlet pressures was investigated. Acidic pH was found to be more conducive for generating OH radicals and therefore subsequent experiments were performed at pH of 3. Sulphuric acid was found to be more than three times effective than hydrochloric acid in generating OH radicals. Effect of initial levels of dissolved oxygen was found to influence OH radical generation. Performance of vortex based cavitation device was then compared with other commonly used cavitation devices based on orifice and venturi. The vortex based cavitation device was found to outperform the orifice and venturi based devices in terms of initial per-pass factor. Influence of device scale (nominal flow rate through the device) on performance was then evaluated. The results presented for these devices unambiguously quantifies their cavitational performance. The presented results will be useful for evaluating computational models and stimulate further development of predictive computational models in this challenging area.
中文翻译:
通过香豆素剂量测定法量化水动力空化中 OH 自由基的产生:操作参数和空化装置的影响
流体动力空化 (HC) 已被广泛研究用于废水处理应用。HC 设备或过程的性能通常根据有机污染物的降解而不是羟基 (OH) 自由基的量化来报告。在这项研究中,使用香豆素剂量测定法对基于涡流的空化装置中 OH 自由基的生成进行了量化。香豆素用作化学探针,初始浓度为 100 µM (15 ppm)。通过分析生成的单一羟基化产物来量化 OH 自由基的生成。研究了 pH 值和用于调节 pH 值的酸类型、溶解氧以及入口和出口压力等操作参数的影响。发现酸性 pH 更有利于产生 OH 自由基,因此后续实验在 pH 为 3 时进行。发现硫酸在产生 OH 自由基方面的效率是盐酸的三倍以上。发现初始溶解氧水平的影响会影响 OH 自由基的产生。然后将基于涡流的空化装置的性能与其他常用的基于孔口和文丘里管的空化装置进行比较。发现基于涡流的空化装置在初始每次通过系数方面优于基于孔口和文丘里的装置。然后评估设备规模(通过设备的标称流速)对性能的影响。这些设备的结果明确量化了它们的空化性能。所呈现的结果将有助于评估计算模型,并刺激预测计算模型在这一具有挑战性的领域的进一步发展。