Synthesis and Characterization of Mesoporous Silica Modified with Purpald and Its Application in the Preconcentration of Cu2+ and Cd2+ from Aqueous Samples through Solid-Phase Extraction

Author(s)

Wondracek, Marcos Henrique Pereira ; Jorgetto, Alexandre de Oliveira ; da Silva, Adrielli Cristina Peres ; Schneider, Jose Fabian ; Pedrosa, Valber de Albuquerque ; Saeki, Margarida Juri ; de Castro, Gustavo Rocha

• Document type: Journal article
• Source: SEPARATIONS; v. 10, n. 2, p. 20-pg., 2023-02-01.

Abstract

The synthesis of an organofunctionalized mesoporous silica was accomplished by a two-step process involving (1) the co-condensation of a silylant agent at the surface of silica, followed by (2) the immobilization of Purpald (ligand) at the organic termination of the silytant agent. The characterization of the organofunctionalized material indicated the presence of NH2 groups, and the immobilization of the ligand was confirmed by Si-29- and C-13-nuclear magnetic resonance. The material's surface area was determined as 370 m(2) g(-1). Batch adsorption experiments enabled the determination of optimum pH conditions for the adsorption of Cu(II) and Cd(II). Under optimal pH, the pseudo-second-order kinetic model and Langmuir model provided the best correlations to describe the materials adsorption behavior, suggesting a chemisorption mechanism. When tested in continuous-flow preconcentration experiments, the flow rate and eluent concentration demonstrated to affect the removal of Cu(II) and Cd(II), while the buffer concentration had an effect only over the adsorption of Cu(II). Under optimized preconcentration conditions, it was possible both to determine the concentrations of Cu(II) and Cd(II) in samples such as mineral water, ground water, tap water and river water. Ions commonly found in drinking and natural waters (Na+, K+, Ca2+, Mg2+, Fe3+, Ba2+, Cl-, SO42-, HCO3-, and H2PO(4)(-)) did not affect the preconcentration of any of the studied analytes. Reutilization experiments indicated that the adsorbent material can withstand at least 40 adsorption/desorption preconcentration cycles with no efficiency loss. (AU)

• FAPESP's process: 18/18787-0 - Study of the (photo)catalytic properties of tin oxides modified with graphene and/or noble metals for the elucidation of the degradation mechanisms of organic contaminants
• Grantee: Alexandre de Oliveira Jorgetto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/04791-8 - Synthesis and application of modified polyvinyl chloride (PVC)to a solid phase extraction of Cu(II), Ni(II), Cd(II) and Pb(II), from aqueous samples
• Grantee: Gustavo Rocha de Castro
• Support Opportunities: Regular Research Grants