For such systems, competition will change the adsorbent-adsorbate attractions. A multicomponent adsorption model should be based on fundamental soundness, speed, and simplicity of calculation. This is mainly because of the complexity brought about by the increasing number of parameters needed for process description which complicates not only the process modeling but also the experimental data collection. Since most industrial colored effluents contain several components including dyes, having a strong knowledge about the scope of competitive adsorption process is a powerful key to design an appropriate system. The chemical nature is also confirmed by Fourier transform infrared (FT-IR) analysis.Īdsorption is one of the several techniques that has been successfully used for dyes removal. The values of ΔH, ΔS, ΔG, and Ea suggest that adsorption is spontaneous, exothermic, and chemical in nature. min–1 for the Red 357 and Black 210 dyes, respectively, demonstrating that intraparticle diffusion is the predominant mass transfer mechanism of these dyes.However, the intraparticle diffusion were of the order of 10–8 and 10–11 m2 The boundary layer mass transfer coefficient was in the order of 10-6 and 10-5 m The kinetic data were evaluated using boundary layer mass transfer and intraparticle diffusion models. Langmuir, Brunauer–Emmett–Teller (BET) and Henry isotherm models were used to fit the adsorption equilibrium data, respectively. In this paper the nature and mechanisms of dyes adsorption by chromium-tanned leather waste (CTLW) are proposed and discussed on the basis of isotherms, adsorption kinetics, and thermodynamics of three dyes: Red 357, Black 210, and Yellow 194 in aqueous solutions. Tannery solid waste (leather) is a possible adsorbent of dye contaminants in wastewater. Furthermore, the effective tetracycline diffusion coefficient in the pore volume gradually increased with greater meso-and macropore volume and larger surface area of the adsorbent, indicating that the tetracycline adsorption rate is directly related to the accessibility of this molecule to the microporous structure of the materials. This indicates that surface diffusion does not play a major role in tetracycline dif-fusion on the different adsorbents. It was also found that the tetracycline adsorption rate is controlled by intraparticle diffusion and that diffusion in the pore volume represents >80% of total intraparticle diffusion. The first-order kinetic model provided the best interpreta-tion of tetracycline adsorption kinetics on all adsorbents, and its rate constant varied in a linear manner the macro-and mesopore volume of the adsorbents.
Experimental data on tetracycline concentration decay curves were interpreted with kinetic mod-els (first-order, second-order, Langmuir, and intraparticle diffusion) and diffusional models (pore volume diffusion model and surface diffusion model). This study investigated the global adsorption rate of tetracycline on adsorbents obtained from treatment sludge.