Functionalized HMS mesoporous silica as solid phase extractant for Pb(II) prior to its determination by flame atomic absorption spectrometry

Abstract

In this work, a mesoporous silica has been chemically modified with 5-mercapto-1-methyl-1-H-tetrazol using the homogeneous route (MTTZ-HMS). This synthetic route involved the reaction of 5-mercapto-1-methyl-1-H-tetrazol with 3-chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55 degrees C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41 x 10(-4 )mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52 x 10(-3) and 4.20 x 10(-3 )mM, respectively. The RSD for three preconcentration experiments was found to be <or= 2%. The linear working range for measurements was between 2 x 10(-3 )and 0.14 mM (y = 0.0136x + 0.0007, R(2 )= 0.9999).

Bulk hydrolysis and solid–liquid sorption of heavy metals in multi-component aqueous suspensions containing porous inorganic solids: Are these mechanisms competitive or cooperative?

“…It was further designated APMS-MCF. This surface modification was motivated by the fact that porous supports derivatized with some functional groups, mostly thiol or amine ligands, through either covalent (i.e., grafting and co-condensation) or non-covalent interactions (i.e., self-assembled monolayers) had been found to be excellent sorbents for toxic metals, metalloids, and oxyanions [26][27][28][29][30]. The specific surface area and pore structure parameters of the silica samples are reported in Supporting material.…”

Surfactant-templated sol–gel silica thin films bearing 5-mercapto-1-methyl-tetrazole on carbon electrode for Hg(II) detection

“…The MTTZ-siloxy derivative (triethoxysilyl-propyl-5-mercapto-1-methyl-tetrazole) was synthesized as previously described [38] and its structure (Scheme 1) confirmed by 13 C and 1 H NMR. Ethanol (95-96%, Merck) and HCl (37%, Aldrich) were used for precursor hydrolysis and film deposition, as well as for extraction of the surfactant template.…”

“…Recently, a more sophisticated ligand, 5-mercapto-1-methyl-1-H-tetrazole (MTTZ), has been grafted on mesoporous silica particles via 3-chloropropyltriethoxysilane acting as a linker between MTTZ and the silica surface, and the resulting hybrid material has been used to adsorb Pb(II) and Zn(II) species [38][39][40][41]. MTTZ was also attached to the surface of clay minerals by the same way and applied to thorium adsorption [42].…”

Pyridine-functionalized mesoporous silica as an adsorbent material for the determination of nickel and lead in vegetables grown in close proximity by electrothermal atomic adsorption spectroscopy

“…The choice of adsorbent is important in SPE to control various analytical parameters, such as selectivity, affinity, and capacity. Among the many types of adsorbent material used in SPE, functionalized mesoporous silica, such as MCM-48 mesoporous silica, has received great attention for the good mechanical and thermal stability coupled to the decreased susceptibility to swelling and shrinking of this material (Quintanilla, Sanchez, Hierro, Fajardo, and Sierra, 2007). In this report, pyridine-functionalized mesoporous silica, py-MCM-48, was prepared by refluxing of N-[3-(triethoxysilyl)propyl]isonicotinamide (TPI) with MCM-48.…”