RESUMEN
In this study, activated carbon produced from oak cupules (ACOC) was prepared using chemical activation with H3PO4. ACOC is subsequently used as an adsorbent to facilitate the removal of an acidic dye, naphthol blue black (NBB), and basic dye crystal violet (CV) from aqueous solutions. The ACOC was characterized by FTIR spectroscopy, XRD, and SEM. The adsorption isotherm data fits well with the Langmuir model for NBB and CV. The kinetic models of adsorption of NBB and CV by ACOC were pseudo-first order and pseudo-second order, respectively. Thermodynamic parameters were evaluated and indicated that the adsorption of both dyes onto ACOC was endothermic and spontaneous. The adsorption capacity of ACOC reached 208 mg g-1 for NBB and 658 mg g-1 for CV. ACOC was shown to be a promising adsorbent for the removal of NBB and CV from aqueous solutions.
Asunto(s)
Quercus , Contaminantes Químicos del Agua , Colorantes/química , Carbón Orgánico , Adsorción , Cinética , Contaminantes Químicos del Agua/análisis , Termodinámica , Agua , Violeta de Genciana/química , Cationes , Concentración de Iones de HidrógenoRESUMEN
Three hair dyes of Arianor madder red 306003 (R), Arian or Straw Yellow 306005 (Y), and Arianor ebony 306020 (E) were removed from an aqueous solution in a batch mode using a powder of oak cupules coated with ZnO (COZ). The COZ-adsorbent material was characterized in terms of XRD, FT-IR, and SEM analysis. The best conditions for the uptake of hair dyes by COZ were investigated. For Y dye, the best uptake was estimated on 0.06 g of COZ at 7.0 pH for 150 min. The E dye uptake requires 120 min on 0.05 g of COZ at 9.0 pH. For E hair dye, kinetic data revealed a pseudo-first-order model for E hair dye and a pseudo-second-order model for R and Y. Equilibrium data exhibited consistency with the Langmuir isotherm model for the adsorption of E dye onto COZ, and the Freundlich isotherm model for the adsorption of R and Y hair dyes onto COZ. Isotherms models of D-R and Temkin were also examined. The thermodynamic parameters (-ve ∆G and +ve ∆H and ∆S) demonstrated that the removal of hair dyes by COZ is spontaneous, endothermic, and feasible. The adsorption capacity of COZ for R, Y, and E uptake was found to be 55.5, 52.6, and 135.1 mg·g-1, respectively. Furthermore, COZ reusability was demonstrated after five cycles of regeneration, with a negligible decline in adsorption extent (13.08%, 13.85, and 10.20% for R, Y, and E, respectively) in comparison to its initial capacity.