Novel Silica Hybrid Adsorbent Functionalized with l-Glutathione Used for the Uptake of As(V) from Aqueous Media

Abstract

A hybrid silica mesoporous material with l-glutathione (LG) (SG-LGPS) was synthesized by a modified sol–gel process. The chemical and structural characterization of the SG-LGPS material was achieved by Fourier transform infrared, solid-state 13C and 19Si NMR, and X-ray diffraction. Surface analysis showed a specific surface area of 466.8 m2 g–1. X-ray photoelectron spectroscopy and energy dispersive X-ray spectrometry measurements demonstrated the chemical composition of the hybrid material and the presence of As­(V) after the uptake process. The adsorption performance for SG-LGPS reached a maximum arsenic uptake of 45.22 mg g–1 at pH = 4; kinetics and equilibrium results were better described by the pseudo-second-order and Temkin models, respectively. Competitive ion adsorption studies were also performed. The uptake mechanism proposed for this material is a bidentate arsenic–glutathione complex. The present material proposed is as follows: (1) a new scope for environmentally friendly materials with amino acids and (2) a versatile adsorption application extended to other heavy metal ions due to the LG functional group composition.

Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR

“…For the specific application of porous silica materials in heterogeneous catalysis, drug delivery, and ion conductors, it is necessary to modify the pore surfaces by covalent attachment of organic molecules to the silanol groups at the silica pore walls in many cases. – Such functionalization changes the hydrophilicity of the surface and, thus, the chemical affinities toward molecules inside the pores. – The dynamics of guest molecules in the direct vicinity of the pore walls are affected by the geometry and chemical nature of the walls. These perturbations are noticed by a change in mobility of the guest molecules, , which in turn influences thermodynamic processes such as melting, freezing, adsorption, or desorption .…”