Work

Study of the Reaction Mechanism of the Excessive Adsorption of Mn2+ from Water by In Situ Synthesis of MnO2@SiO2 Colloid as an Adsorbent

Year: 2025

Type: article

Abstract: An in situ-generated MnO2@SiO2 colloidal (ISMC) composite was used for the adsorption of Mn2+ ions in water. The adsorption capacity of ISMC at a concentration of 1 mg/L at 25 °C was as high as 3017.97 mg/g for the original concentration of 50 mg/L Mn2+ ions. Material characterization revealed that it is a porous sponge with a fibrous structure with a rough surface, many folds, and abundant pores, and these features provide many adsorption sites, which are conducive to the attachment of Mn2+ ions on its surface. ISMC has an isoelectric point of 3.5, indicating a negative surface charge that favors electrostatic attraction of Mn2⁺ ions. The surface hydroxyl groups provide additional active sites that allow for strong complexation with Mn2⁺ ions. Adsorption conformed to the Freundlich isotherm model (R2 > 0.98), suggesting multilayer adsorption, followed by pseudo-second-order kinetics (R2 > 0.98), with an optimum adsorption time of approximately 12 h. Low temperatures favor physical adsorption, whereas higher temperatures promote chemisorption via hydroxyl group complexation. The adsorption capacity increased with pH, which was attributed to the increased presence of surface hydroxyl groups. These findings highlight the significant potential of ISMCs for cation adsorption in water treatment applications.

Source: International Journal of Molecular Sciences

DOI: 10.3390/ijms26072928

Authors: kun WANG, Yuchao Tang, Xinyu Zhang, Xianhuai Huang, Beiping Zhang

Institution: Anhui Jianzhu University

Language: English

Topic: Adsorption and biosorption for pollutant removal

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $3,499