Simple control of carbon mass loading in capacitive deionization for efficient deionized water production

Abstract

High-purity deionized (DI) water can be widely used in high-end manufacturing fields, but its efficient and energy-saving production is a huge challenge. Here, simple carbon mass loading control was developed for efficient DI water production via advanced capacitive deionization (CDI). Supercapacitor carbon (YEC-8) electrodes with diverse mass loading of 2.50, 5.81, 12.63 and 24.72 mg/cm2 were prepared for desalination. As expected, YEC-8–2.50 acquired the optimal CDI performance. High mass loading of 12.63 and 24.72 mg/cm2 not only caused an overt property drop but also serious wasted materials. Competitively, YEC-8–5.81 achieved a similar volumetric adsorption capacity (VAC) to YEC-8–2.50 as well as made up for the lack of total mass of YEC-8–2.50 and the resultant solution conductivity was as low as 1.89 μS/cm (grade III DI water). This strategy has been successfully extended to other carbon materials and carbons with suitable micro-meso pore distribution and high specific capacitance may be a better choice. Besides, the reverse effect of acetylene black (AB) mass on desalination was verified. To gain a high water recovery (WR), stopped flow (SF) discharge was introduced and realized a high WR of 82.2 %. Meanwhile, cycling tests indicated its splendid cycling stability. This study provides a universal direction for using low mass loading strategy for efficient DI water production.