Chinese Journal of Chemical Engineering, Vol.26, No.12, 2581-2591, 2018
Electric conductivity and electric convertibility of potassium acetate in water, ethanol, 2,2,2-trifluoroethanol, 2-propanol and their binary blends
Salinity gradient energy between the concentrated and diluted electrolyte solutions can be converted to electric energy by using reverse electrodialysis (RED) technology. Electrolyte solution is a vital factor that impacts the energy conversion efficiency. Potassium acetate (KAc) was chosen as solute, and water, ethanol, 2,2,2-trifluoroethanol (TFE), 2-propanol (IPA) and several of their binary mixtures were selected as solvents. Electric conductivity of these solutions were measured under varying conditions. KAc was easily ionized in water and possessed the maximum electric conductivity, following by KAc-H2O-TFE and KAc-H2O-ethanol, and then KAc in pure TFE, ethanol, and IPA respectively. For electric convertibility of these solutions working in a RED power generation system, it was found that the KAc-H2O possessed the maximum power density, and the KAc-ethanol-H2O possessed the larger open circuit voltage than aqueous KAc solution under the same working condition. Besides, it was observed that both the electric conductivity and electric convertibility were significantly influenced by the concentration and temperature of solution. With the increasing of concentration, electric conductivity of these solutions increased firstly and then reached to the peak, but later it decreased. Solution temperature took a positive impact role to the electric conductivity. Electric conductivity of these solutions can be estimated by using a modified amplitude version of Gaussian peak function. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.