Microbubble-enhanced water activation by cold plasma

Plasma activated water (PAW) is water treated by ionized gas. As a clean and sustainable technology, PAW attracts intensive attention from various fields of wastewater treatment, disinfectant, food processing and smart agriculture. However, the current challenge is high processing efficiency in production of PAW. In this work, we investigate bubble-enhanced plasma technology to activate a flow of water. Gaseous plasma is supplied through self-suction to water flowing in a Venturi tube. A large amount of microbubbles transfer reactive species in the gas phase into the water flow. The degradation of a model compound shows that with the same energy input, our approach can achieve more than 5 times higher activation efficiency, compared to the configuration in absence of microbubbles. Meanwhile, computational fluid dynamic simulations are performed to model the gas volume fraction, pressure, velocity distributions and bubble behaviors during cold plasma activation. To the best of our knowledge, this is the first time integrating bubbles in plasma activation to transfer active species from the gas phase into the flow of water. The design reported in this work may lead to efficient activation of water on a large scale as a green and sustainable technology for disinfection, food industry and agriculture.