Regulating Surface Wettability and Charge Density of Porous Carbon Particles by In Situ Growth of Polyaniline for Constructing an Efficient Electrical Percolation Network in Flow-Electrode Capacitive Deionization

Abstract

Both electrical conductivity and surface wettability are required for the selection of active carbon materials in flow-electrode capacitive deionization, while a trade-off exists between these two properties. In this work, a hybrid material with a thin layer of polyaniline (PANI) coating on activated carbon (AC/PANI) was successfully developed to retain excellent electrical conductivity and acquire good surface wettability. By adjusting the dosage of initiator, AC/PANI composites with different loading fractions of PANI were obtained. The electrochemical testing demonstrated that the AC/PANI composites have higher specific capacitance and lower ion diffusion resistance compared to pure AC, resulting in better desalinization performance. Specifically, with a feed concentration of 1600 mg/L, excellent adsorption capacity and high charge efficiency can be simultaneously achieved at 13.51 mg/g and 92.21%, respectively. Benefiting from the formation of a continuous electrical percolation network and reduced solid/liquid interfacial transport resistance, a 39% enhancement of average salt adsorption rate (from 0.54 to 0.75 μmol/min/cm2) was obtained.

Insights into the Particle Hydrophilicity and Electrical Conductivity for the Construction of a Highly Efficient Electrical Percolation Network in Flow Electrode Capacitive Deionization

“…Generally, a surface with better hydrophilicity would show a smaller initial contact angle and faster spreading of the water droplet on the surface. 36 The contact angles of APEX and YP-80F were 133 and 117°, respectively, indicating the hydrophobic nature of the two ACs. For YP-50F and SE-I, the contact angle decreased as a function of time; this was because water penetrated the gap of AC particles.…”

“…The corresponding contact angle value was analyzed and is summarized in Figure b. Generally, a surface with better hydrophilicity would show a smaller initial contact angle and faster spreading of the water droplet on the surface . The contact angles of APEX and YP-80F were 133 and 117°, respectively, indicating the hydrophobic nature of the two ACs.…”

“…FCDI experiments were carried out in batch mode operation, and the flow electrodes were circulated under an isolated-closed-cycle mode and operated at a flow rate of 20 mL/min, which was the same as the earlier work . Specifically, 200 mL of NaCl solution with a concentration of 1600 mg/L was continuously circulated between the FCDI cell and a vessel by a peristaltic pump (BT-100, LONGER, China) at a flow rate of 10 mL/min.…”

“…mode and operated at a flow rate of 20 mL/min, which was the same as the earlier work. 36 Specifically, 200 mL of NaCl solution with a concentration of 1600 mg/L was continuously circulated between the FCDI cell and a vessel by a peristaltic pump (BT-100, LONGER, China) at a flow rate of 10 mL/ min. The conductivity of the feed solution was recorded every 5 min by a conductivity meter (FE38, METTLER TOLEDO, Zurich, Switzerland).…”

Carbon Nanotubes and Silica@polyaniline Core–Shell Particles Synergistically Enhance the Toughness and Electrical Conductivity in Hydrophobic Associated Hydrogels

“…Conductivity is a highly valued parameter to examine for strain sensor applications. It has been found by the research staff that conducting polymers (e.g., polyaniline, − poly-pyrrole, − polyacetylene , ), carbon nanomaterials (e.g., graphene oxide, − carbon nanotubes , ), and metal nanoparticles with inherent electronic conductivity have been widely used to optimize the conductive function of hydrogels. Among them, polyaniline exhibits excellent electrical conductivity, and a series of works have been carried out to make it stable in the hydrogel network.…”