Plasma Discharge in Water

Abstract

Publisher Summary The key issue in large cooling systems is precipitation and removal of mineral ions such as calcium and magnesium from circulating cooling water so that the CaCO3 scales can be prevented at the condenser tubes and at the same time the cycle of concentration (COC) can be increased. Also the availability of clean water is an issue that has paralleled the continual increase in water consumption due to both global population growth and the economic development in a number of developing countries. High-voltage (HV) electrical discharges in water are able to induce various reactions including the degradation of organic compounds, the destruction of bacteria and viruses, the oxidation of inorganic ions, and the synthesis of nanomaterials and polymers. This chapter discusses four experiments relating to plasma generation and discharge in water. The first experiment is designed to study the dynamics of non-equilibrium plasma in liquid water. This experiment demonstrates that discharge in liquid water develops in nanosecond time scale, and the trailing edge of the nanosecond pulse generates a significant electric field and the excitation of the media. This effect can be considered as a proof that there was no void formation or phase transition during the first stage of the discharge. The second experiment deals with the application of spark discharge for scale removal on filter membranes, results of which helps in the third experiment that illustrates plasma-assisted CaCO3 precipitation. The fourth experiment highlights the application of plasma discharge in mineral fouling mitigation in heat exchangers. The chapter also discusses the application of plasma discharge for sterilization of water, focusing on the role of ultraviolet radiation, pulsed spark discharge, and comparison of different types of plasma discharge for water sterilization.