Session: 09-02 Solar Desalination

Paper Number: 114833

114833 - Potassium Hydroxide Activated Wood Converted Carbon for Electrochemical Water Desalination 

Potassium hydroxide (KOH) activation has been utilized as a typical approach to prepare porous carbon materials, which are widely used in promoting salt adsorption for water desalination by capacitive deionization. In this study, natural balsa wood precursor is carbonized into wood porous carbon materials. The carbon is further associated with KOH and activated at high temperatures. The amount of KOH affects the contacting area between activating agent and carbon while the temperature controls the chemical reaction. Both parameters generate auxiliary porous structures on wood converted carbon, enlarge the surface area and enhance the electrical performance. On the condition of large KOH amount and high temperature, the salt adsorption capacity of activated wood carbon reaches 13.34 mg g^-1, which is consistent with Freundlich modeling, while no salt adsorption occurs when there is no activation. Additionally, the carbon with higher activation temperature and less KOH amount usually results in a better surface area and electrical properties than the one under opposite activation circumstance. However, the salt adsorption behavior exhibits a reversed result. This phenomenon is the first time being reported in activation system using single carbon precursor and opposes the well-known salt adsorption mechanism nowadays, which could be explained by the porous structure created during activation and the induce of oxygen element. The large amount of KOH results in a uniformly distributed porous structure and sufficient oxygen being doped at low temperature, which enhance the salt adsorption enhancement despite the deficient material properties. Thus, except from the surface area and specific capacitance, the porous structure and element composition of the electrode are another critical parameters that affect the capacitive deionization mechanism.

Presenting Author: Rui He George Mason University

Presenting Author Biography: Rui He is a current graduate student in George Mason University, Mechanical Engineering department. His research focus on porous carbon preparation, electrochemical water desalination and polymer materials.