Competitive Adsorption of Methylene Blue and Rhodamine B on Natural Zeolite: Thermodynamic and Kinetic Studies

Abstract

A batch system was applied to study the adsorption behavior of methylene blue (MB) and rhodamine B (RB) in single and binary component systems on natural zeolite. In the single component systems, the zeolite presents higher adsorption capacity for MB than RB with the maximal adsorption capacity of 7.95×10 -5 and 1.26×10 -5 mol/g at 55 ℃ for MB and RB, respectively. Kinetic studies indicated that the adsorption followed pseudo-secondorder kinetics and could be described by a two-step diffusion process. For the single component systems, the adsorption isotherm could be fitted by the Langmuir model. In the binary component system, MB and RB exhibit competitive adsorption on the zeolite. The adsorption is approximately reduced to 50% and 60% of single component adsorption systems of MB and RB, respectively at an initial concentration of 6×10 -6 mol•L -1 at 25 ℃. In the binary component system, kinetic and adsorption isotherm studies demonstrate that the experimental data are following pseudo-second-order kinetics and Langmuir isotherm and kinetic data are fairly described by a two-step diffusion model. Effect of solution pH on adsorption of MB and RB in both single and binary component systems was studied and the results were described by electrostatic interactions.

Porous BiOBr/Bi2MoO6 Heterostructures for Highly Selective Adsorption of Methylene Blue

“…Similar effects have been reported for BiPO 4 /BiOBr, Cu 2 O/BiOBr, g- C3N4 /BiOBr, and BiOBr/BiOI heterostructures . MB + adsorption on the Br/Mo heterostructures reaches equilibrium after about 60 min, which is significantly higher than that for some other adsorbents. , …”

“…52 MB + adsorption on the Br/Mo heterostructures reaches equilibrium after about 60 min, which is significantly higher than that for some other adsorbents. 53,54…”

“…52 MB + adsorption on the Br/Mo heterostructures reaches equilibrium after about 60 min, which is significantly higher than that for some other adsorbents. 53,54 The pH seriously affects the active sites of adsorbents as well as the dye speciation during the adsorption process. 55−58 In addition, pH has a significant effect on the electrostatic charges that are imparted by the ionized dye molecules between the adsorbent and adsorbate.…”

Rapid and Efficient Removal of Microcystins by Ordered Mesoporous Silica

“…The adsorption data were simulated by models of Langmuir and Freundlich isotherms. It is found that the data fit the Langmuir adsorption isotherm better (SI Table S3), with the linear coefficient R 2 values closer to 1 . Furthermore, the Langmuir model is served to estimate the maximum MCs uptake values.…”

“…It is found that the data fit the Langmuir adsorption isotherm better (SI Table S3), with the linear coefficient R 2 values closer to 1. 39 Furthermore, the Langmuir model is served to estimate the maximum MCs uptake values. The saturated adsorption capacities for MC-LR are 4.80 and 5.99 mg g −1 at 10 Compared with other silica-based adsorbents reported in earlier papers, 16,17 the ordered mesoporous silica SBA-15 exhibits much higher adsorption capacity for MCs.…”