Plasma is a simply ionization charged gas. It is described as the fourth state of matter. It consists of a mixture of electrons, ions, and neutral particles. Further energy is added to the gas, it dissociates into plasma. Examples of plasma in nature are lighting sparks coming from static electricity, fluorescent light, arc welding, and aurora borealis. 99.9 % of the universe is plasma. Application of plasma technology can be in the field of:

• Plasma processing of nanomaterials and nanostructures: synthesis, modification, and nanofabrication;
• Plasma deposition of functional coatings and treatment of inorganic and organic materials;
• Thermal plasma fundamentals and application;
• Plasma-assisted conversion, combustion, propulsion, and aerodynamics;
• Plasma agriculture;
• Plasma treatment of biomaterial;
• Plasma in and in contact with liquids;
• Plasma medicine;
• Plasma for environmental application, resource recovery, and environmental clean-up.

       Based on its benefits, we have begun research and application of plasma to the environmental application, resource recovery, and environmental clean-up. For resource recovery, we focus on hazardous waste, agricultural waste, and plastic waste. For the environmental clean-up, we focus on wastewater in the semiconductor industry and heavy metals in wastewater. Besides, we are focusing on the reuse of plasma by-products as an adsorbent, photocatalyst, and membrane. In addition, we also expand relationships with laboratories inside and outside Taiwan, especially, in Vietnam, Indonesia, and China. Here are some of our interesting research-topic, which had been accepted and published in the prestigious professional journals based on the Web of Science (WOS) as below:

• Effect of shell powder on the removal of metals and volatile organic compounds (VOCs) from resin in an atmospheric-pressure microwave plasma reactor. Journal of Hazardous Materials. 2020.
• Economic and environmental evaluation of flux agents in the vitrification of resin waste: A SWOT analysis. Journal of Environmental Management. 2020.
• Etc…

       However, the practical application of plasma is still very limited due to high-energy consumption and complex operation. In addition, most plasma by-products are rare to reuse, which is a cause of limitations for real-world applications. In this context, we are trying to develop a total solution for an environmental problem using a plasma system via circular economy thinking. As environmental scientists and environmental engineers, we are developing our research framework as below: