Performances and Mechanism of Methyl Orange and Congo Red Adsorbed on the Magnetic Ion-Exchange Resin

Abstract

Effective removal of azo dyes is a stringent issue. In this study, the adsorption behaviors of methyl orange (MO) and congo red (CR) on the magnetic ion-exchange (MIEX) resin were investigated by batch experiments. Attaining adsorption equilibrium of MO and CR takes 90 and 150 min, respectively. The equilibrium adsorption capacity of MO (42.32 mg mL −1 ) on the MIEX resin is much larger than that of CR (30.57 mg mL −1 ). The kinetic processes of MO and CR adsorbed on the MIEX resin follows the Elovich model. At 288 K, the Langmuir model can simulate the equilibrium adsorption data of MO and CR. However, the equilibrium data can be well fitted by the Freundlich model at 293 and 303 K. The thermodynamic parameters show that the adsorption of MO and CR are both thermodynamically spontaneous, endothermic processes. The MIEX resin can well remove MO (80%) and CR (50%) at pH 5.0−9.0. Ion exchange dominates the mechanism of CR adsorbed on the MIEX resin. For MO, however, physical adsorption plays a role to some extent besides ion exchange. Sodium chloride (187 mg) is needed to regenerate per milliliter of spent the MIEX resin. After eight times adsorption−desorption cycles, The MIEX resin retains still efficient adsorption. As a summary, the MIEX resin can be considered as a promising adsorbent to remove azo dyes from water and wastewater due to its high adsorption capacity, short adsorption time, and simple regeneration.

N, S doped carbon quantum dots inside mesoporous silica for effective adsorption of methylene blue dye

“…In order to evaluate the effects of the temperature and thermodynamics behaviors of the dye adsorption process, the equilibrium data was measured by using the Eqs. (8,9,10) [48,49]: as shown in Fig. 9a, with increasing the temperature from 303 to 343 K, the MB removal efficiency was decreased gradually at different initial concentrations.…”

Application of Chemometrics Into Removal of Dyes by NaX Nanozeolites: Simultaneous Model

“…Thus, at a pH above this point, the adsorbent surface has a negative charge and at a lower pH, the surface charges become positive. In order to determine pHPZC, 10 mL of NaCl solution (0.1 M) was poured into separate test tubes and the solutions were adjusted to different pH (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Hydrochloric acid (1 M) and sodium hydroxide (1 M) were used to adjust the pH.…”

“…There are different ways to remove the dye such as reverse osmosis, ultra-filtration, ion exchange, and adsorption [10][11][12][13][14][15][16]. Adsorption is one of the acceptable techniques to reduce the concentration of dissolved dyes in aqueous solutions.…”

Synthesis of adsorbents from wheat hulls, extracted cellulose and modified with Cetyl trimethyl ammonium chloride to remove Congo Red in aqueous solution

“…This indicates that the process occurs by chemical adsorption with multilayer formation, due to the heterogeneity of the two adsorbents' active centres. (Jia et al, 2020). Thus, it is established that the limiting step is the formation of multilayers, with nonuniform heat distribution and adsorption affinities on the heterogeneous surface (Rani et al, 2017).…”