Manganese Modified Activated Alumina through Impregnation for Enhanced Adsorption Capacity of Fluoride Ions

Abstract

Activated alumina, with low cost to implement and consistent performance, has been widely used as a defluoridation adsorbent in contaminated groundwater. However, its application was hampered by an undesirable adsorption capacity. In the recent research, an innovative adsorbent (manganese modified activated alumina, MAA) was synthesized by impregnation method and showed a more significant adsorption capacity than that of freshly activated alumina. The scanning electron microscope, Brunauer, Emmett and Teller, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared verified introduction of manganese oxides (MnOOH and MnO2) successfully, improvement of surface microstructure and nature of single-layer adsorption, which enhanced the adsorption ability. In a short period of adsorption, the MAA maximum capacity increased from 38% to 67%. Then, batch-scale kinetic and thermodynamic adsorption investigations were performed. The high correlation coefficients R2 (close to 1) of the quasi-second-order model, Langmuir kinetic model, and Langmuir isotherm model confirmed a better fit to the adsorption experimental data, further indicating that the diffusion of adsorbate was primarily governed by adsorption onto the active sites and the adsorption of fluoride on MAA was single-layer physical adsorption. This paper provides an approach to modifying activated alumina as a groundwater fluoride adsorbent.

Carbon-Enhanced Aluminum-Based Adsorbent for Highly Efficient Removal of Fluoride Contamination from Water

“…The effect of pH (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) on CDAA adsorption at 10 mg/L uoride solution was investigated, and the results are presented in Fig. 3b.…”

“…The high surface area of the adsorbent contributed to the adsorption performance, but more importantly, uoride ions could react with calcium ions to form calcium uoride and be effectively removed. Recently, other uorophobic rare earth elements including lanthanum (Yan, et al, 2022), yttrium cerium (Chen, et al, 2023) and manganese (Gao, et al, 2022) have been employed to modify aluminum-based adsorbents. Enhancing the performance of aluminum-based adsorbents to achieve comprehensive improvements in adsorption capacity, adaptability, kinetics, and reusability is a formidable challenge in the eld.…”

Simultaneous Removal of As(III) and Fluoride Ions from Water Using Manganese Oxide Supported on Graphene Nanostructures (GO-MnO2)

“…On the other hand, GO/Al 2 O 3 , produced by GO and γ-Al 2 O 3 [46], Graphene Oxide-Aluminum Oxyhydroxide (GO-Al-O(OH)) [47], Graphene Oxide Anchored Sand (ZIGCS) functionalized by Zr(IV) [48] and Graphene Oxide/Eggshell (GO/ES) [49] are some of the adsorbents based on graphene oxide and have been used in the literature for the removal of fluoride from water [15]. Manganese oxides, such as manganese modified activated alumina, MAA [50], bentonitesmectite rich clay [50] and manganese dioxide with dispersion over disposed earthenware (DEW) [37], were also tested for fluoride removal.…”

“…In addition, GO-MnO 2 nanocomposites are easier to separate from water, and their high conductivity can enhance electron transfer [51,52]. Considering the advantages of graphene, e.g., its large specific surface area and abundance in oxygen functional groups [53,54], and of manganese oxides, which exhibited a large specific surface area that can provide the reaction with additional active sites [50], this study involves testing the effectiveness of this material in the combined removal of arsenic and fluoride from water. The effect of the pH value, the initial concentration of As(III) and F ions and the dose of the adsorbent dose were investigated, while the structure and the morphology of GO-MnO 2 were analyzed using EDS, FTIR and SEM.…”

Application of Biochar, Adsorbent and Nanomaterials in Wastewater Treatment

“…The results show that the main mechanisms of arsenic removal using modified biochar are complexation, precipitation, and electrostatic interactions. The paper of Gao et al [9] proposes a novel modified activated alumina (AA) as the fluorine adsorbent for groundwater. Gao et al [9] synthesized manganese-modified activated alumina (MAA) using the impregnation method.…”