A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Environmental Engineering and Management

Thesis (M. Eng.) - Asian Institute of Technology, 2023

A capacitive deionization (CDI) is a promising desalination technology. It can use for treating low salinity water. Ions can be trapped in electrode by using electrosorption mechanism. Advantages of this technology is low frequency of membrane replacement, simple operation, and low energy requirement. In this study, optimization of low-cost electrode materials and desalination performance on low salinity water on various operating parameters was investigated. There are three materials for electrode fabrication. Activated carbon (AC), carbon black (CB), and polytetrafluoroethylene (PTFE) as polymer binder was optimized in this study. Ethanol was used as solvent for making carbon slurry. The electrode was fabricated by using manual blade coating method and spray coating method. However, the presence of cracking on electrode was occurred in manual blade coating. There was no cracking for spray coating. Therefore, spray coating was selected for further electrode fabrication. Then, there are three electrode composition (AC:CB:PTFE) which are 9:0:1, 8:1:1, and 7:2:1. The electrode 8:1:1 is the easiest to fabricate. Therefore, it was investigated for the lab-scale CDI reactor desalination performance on various applied voltage and spacer distance. It was tested on 1.2 V, 1.4 V, 1.6 V, 1.8 V, and 2.0 V applied voltage and also tested on 1.0 mm., 2.0 mm., and 4.0 mm. spacer distance. The highest condition for desalination performance is 2.0 V applied voltage and 2.0 mm. spacer distance. Removal efficiency is equal to 23.75%. Salt adsorption capacity is 0.0208 mg/g of electrode. Average salt adsorption rate is 3.4636E-04 mg/g/min. The volumetric and molar energy consumption are equal to 0.0934 kWh/m3 and 0.0067 kWh/mol respectively.