3D modeling of the overall adsorption rate of metronidazole on granular activated carbon at low and high concentrations in aqueous solution

Liquid–Solid Mass Transfer in Adsorption Systems—An Overlooked Resistance?

“…This is the case where (see Figure 1) adsorbate surface and pore diffusion are both relevant, termed "case (a)" in Table 2, which lists the information of interest for the present discussion as elaborated from the original articles. In the studies presented by Ocampo-Perez et al, 37 Souza et al, 38 Di ́az-Blancas et al, 39 and Froḧlich et al, 40 Bi results with order (10) mean that both external and internal resistances are important in driving the mass flux, with the internal one characterized by comparatively higher relevance. When the value of k f is significantly lower as in the work by Yakub et al 41 (about 10 −6 vs 10 −2 to 10 −3 cm/s reported in the other papers), the two resistances have the same order of magnitude as witnessed by Bi (1).…”

Three-Dimensional Mass Transfer Modeling of Hydroquinone Adsorption on Phragmites australis Biochar

“…The PVSDM 3D model was able to better In addition, in terms of the contribution of surface diffusion, there is a tendency for surface diffusion to increase overall as time increases, which could explain this behavior from the start by adsorbing molecules to sites that require higher energy and where these adsorbed molecules do not have sufficient energy to desorb from one site and diffuse to another adsorption site [29]. Once the active sites with higher adsorption energies are occupied, molecules will be adsorbed on sites with lower adsorption energies; therefore, more molecules can be desorbed and transferred from one site to another [5].…”

“…This indicates that surface diffusion flux is more important than pore volume diffusion [29]. From the characterization results of PAC (SEM, FTIR, XPS, XRD), it was found that the PAC surface is rich in adsorption active sites, which may be the reason for the surface diffusion flux being larger than the pore volume diffusion [2,5]. It is essential to assess the contribution of each diffusion mechanism to the overall intraparticle diffusion and the percentage contribution of surface diffusion (SDCP%) to the total intraparticle diffusion.…”

“…Biochar is prepared from different biomass wastes, making it a hot topic for adsorbent research due to its low cost, high adsorption efficiency, and simple preparation process [ 3 , 4 ]. However, at the same time, special attention should be paid to three aspects when designing biochar adsorption systems: the adsorption equilibrium isotherm and its dependence on the operating conditions (solution pH, temperature, and ionic strength), the total adsorption rate and mass transport mechanisms, and the interpretation and modelling of breakthrough curves [ 5 ]. Of these, kinetic studies are important for the interpretation and elucidation of adsorption phenomena as well as for the optimisation of adsorption system design.…”

Exploring the use of carbon materials as cathodes in electrochemical advanced oxidation processes for the degradation of antibiotics

“…The high uptake of metronidazole on carbon CQ is expected due to the large micropore volume of the material and its low functionalization (Table 3). Aromatic compounds are usually well retained in carbon adsorbents of such characteristics due to dispersive π-π interactions [38,39]. For carbon HC, the low uptake is due to its poor porosity; in the case of carbon CB, the low adsorption capacity despite favorable porous features (micropore volume) is associated to its hydrophilic nature (see surface pH in Table 3) owing to a high amount of O-surface functionalities of the carbon (ca.…”