Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India.
Department of Chemical Engineering, Indian Institute of Technology Ropar, Rupnagar 140001, India.
Water Res. 2024 Oct 1;263:122148. doi: 10.1016/j.watres.2024.122148. Epub 2024 Jul 25.
Conventional water treatment systems frequently exhibit diminished efficiency at high salinity - a significant issue especially for real industrial effluents - mostly due to the creation of intricate structures between pollutants and salts. One of the primary obstacles associated with high salinity conditions is the generation of by-products that pose additional hurdles for treatment. In this work, we have investigated the novel advanced oxidation process a so-called ozone nanobubble technology for degradation of the pollutants at high salinity conditions. The mass transfer is often the rate-limiting step in gas-liquid process and the poor rate of mass transfer diminishes the overall efficacy. One of the primary disadvantages associated with ozone is its restricted solubility and instability when dissolved in an aqueous solution. These characteristics impose limitations on its potential applications and need the use of specialized systems to facilitate gas-liquid interaction. In this work, we have also suggested enhancing the ozonation process through the utilization of ozone nanobubbles. The findings of our experiment and subsequent analysis indicate that the presence of nanobubbles enhances the process of ozonation through three key mechanisms: (i) an increased mass transfer coefficient, (ii) a higher rate of reactive oxygen species (ROS) generation attributed to the charged interface, and (iii) the nanobubble interface serving as an active surface for chemical reactions. The predicted mass transfer coefficients were found to range from 3 to 3.5 min, a value that is notably greater than that seen for microbubbles. The study showcased the degradation of methylene blue dye through the utilization of ozone nanobubbles, which exhibited a much higher rate of dye degradation compared to ozone microbubbles. The confirmation of the radical degradation mechanism was achieved by the utilization of electron spin resonance (ESR) measurements. The developed process has high potential for application in industrial scale textile wastewater treatment.
传统的水处理系统在高盐度下效率降低-这是一个重大问题，尤其是对于实际的工业废水，主要是由于污染物和盐之间形成了复杂的结构。高盐度条件下存在的一个主要障碍是副产物的产生，这给处理增加了额外的障碍。在这项工作中，我们研究了一种新的高级氧化工艺，即所谓的臭氧纳米气泡技术，用于在高盐度条件下降解污染物。传质通常是气液过程的限速步骤，而传质速率的降低会降低整体效率。臭氧的一个主要缺点是其在水溶液中溶解度有限且不稳定。这些特性限制了它的潜在应用，需要使用专门的系统来促进气液相互作用。在这项工作中，我们还提出通过利用臭氧纳米气泡来增强臭氧氧化过程。实验和随后的分析结果表明，纳米气泡的存在通过三种关键机制增强了臭氧氧化过程：（i）传质系数增加，（ii）由于带电界面而产生更高的活性氧（ROS）生成速率，以及（iii）纳米气泡界面作为化学反应的活性表面。预测的传质系数范围为 3 到 3.5 分钟，这一值明显大于微气泡的传质系数。该研究展示了利用臭氧纳米气泡降解亚甲基蓝染料的过程，与臭氧微气泡相比，该过程具有更高的染料降解速率。自由基降解机制的确认是通过利用电子自旋共振（ESR）测量来实现的。所开发的工艺在工业规模的纺织废水处理中有很高的应用潜力。
