A comprehensive review of capacitive deionization technology with biochar-based electrodes: Biochar-based electrode preparation, deionization mechanism and applications

Expanding the circularity of plastic and biochar materials by developing alternative low environmental footprint sensors

“…The heterogeneous electron transfer constant was calculated voltammetrically (k 0 , Marcus' theory, eqn (1)) and impedimetrically (k 0 ′, Randles's theory, eqn (2)). k 0 and k 0 ′ were calculated using the following equations: 15,16…”

“…The heterogeneous electron transfer constant was calculated voltammetrically ( k 0 , Marcus’ theory, eqn (1)) and impedimetrically ( k 0 ′, Randles's theory, eqn (2)). k 0 and k 0 ′ were calculated using the following equations: 15,16 where D O and D R are the diffusion coefficients for ferricyanide ( D O ) and ferrocyanide ( D R ), ν is the scan rate (V s −1 ), n is the number of electrons involved in the process, T is the temperature (K), F is the Faraday constant (mol −1 ), R is the universal gas constant (J K −1 mol −1 ) and α is the dimensional transfer coefficient. However, the parameter φ is based on the potential difference between the anodic and cathodic peaks (Δ E ).…”

“…13 In recent years, biochar has emerged as a valuable and effective electrode material and modifier, owing to its electrochemical properties combined with eco-friendly, economical, and renewable characteristics. 14–16 Biochar's electrochemical properties (pseudo-capacitance, electron conductivity, and double-layer capacitance) result from its heterogeneous composition, which consists of an organic aromatic matrix with different levels of oxidation and inorganic constituents whose composition varies depending on the original feedstock and synthesis process. 17…”

Uniformly Dispersed Fe–N Active Centers on Hierarchical Carbon Electrode for High-Performance Capacitive Deionization: Plentiful Adsorption Sites and Conductive Electron Transfer

“…The desorption process is to apply a reverse voltage or directly short-circuit the electrodes to achieve regeneration. , The critical factor for CDI lies in the exploitation of high-quality electrodes. In general, ideal electrode materials should have a suitable pore size distribution, a large specific surface area, stability, and good conductivity and wettability . Carbonaceous materials, such as activated carbon, carbon nanotube, and biomass carbon, are widely used as electrode materials for CDI desalination. − However, their adsorption capacity is unsatisfactory because of the limited specific surface area, poor conductivity, unitary pore structure, and inadequate active sites. , Other new materials such as Prussian blue-based materials, layered double hydroxide-based materials, MXene-based materials, and pure metal-organic frameworks possess well CDI capability, but they suffer from poor stability, structural collapse, and nanosheet stacking more or less.…”

“…In general, ideal electrode materials should have a suitable pore size distribution, a large specific surface area, stability, and good conductivity and wettability. 13 Carbonaceous materials, such as activated carbon, carbon nanotube, and biomass carbon, are widely used as electrode materials for CDI desalination. 14−16 However, their adsorption capacity is unsatisfactory because of the limited specific surface area, poor conductivity, unitary pore structure, and inadequate active sites.…”