Work

Effective adsorption of Cd(II), Cr(VI) and Pb(II) ions from aqueous solutions using silica immobilized (pyridine)/(phenoxy)imine chelating agents

Year: 2025

Type: article

Abstract: Mesoporous silica materials, MCM-41 and SBA-15, were used to modify the Schiff base ligands: N-(pyridin-2-ylmethyl)-3-(triethoxysilyl)propan-1-amine ( L1 ) and 2-(((3-(triethoxysilyl)propyl)amino)methyl)phenol ( L2 ) to give the respective immobilized chelating agents L1@SBA-15 , L2@SBA-15 , and L2@MCM-41 . The immobilized chelating agents were characterized using various techniques, including FT-IR, ¹H NMR, SEM, EDX, TEM, PXRD, BET, VSM, and TGA-DTA/DSC. The adsorption capacities of L1@SBA-15 , L2@MCM-41 , and L2@SBA-15 of Cr(VI), Pb(II), and Cd(II) ions from aqueous solutions were assessed under different pH, contact times, initial concentrations, and chelating agent dosages. Adsorption capacities of 9.85 mg/g, 14.42 mg/g, and 13.38 mg/g for Cr(VI) anion (pH of 3) and Pb(II) and Cd(II) at pH 9 were obtained using L2@MCM-41 . Using L2@SBA-15 , an optimum pH of 3 for Cr(VI) and Pb(II) (120 min) and 9 for Cd(II) (480 min) were obtained, affording adsorption capacities of 9.84 mg/g, 14.99 mg/g, and 14.61 mg/g, respectively. Furthermore, L2@SBA-15 exhibited optimal dosages of 0.1 mg for Cd and Pb(II) cations and 10 mg for Cr(VI) anion and initial concentrations of 10 ppm, 20 ppm, and 80 ppm for Cr(VI), Pb(II), and Cd(II) ions, respectively. The adsorption kinetics followed a pseudo- second-order model, and the Freundlich adsorption isotherm best described the equilibrium data.

Source: Next Materials

DOI: 10.1016/j.nxmate.2025.101142

Authors: Siphosethu Maqinana, Chrispin O. Kowenje, Stephen O. Ojwach

Institutions: University of KwaZulu-Natal, Maseno 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: $1,280