Preparation of a silica gel modified with 2-amino-1,3,4-thiadiazole for adsorption of metal ions and electroanalytical application

Abstract

Uma silica gel, com área específica de 382 m 2 g -1 e diâmetro médio de poro de 60 Å, foi modificada quimicamente com 2-amino-1,3,4-tiadiazol, com o propósito de adsorção seletiva de íons de metais pesados e possível utilização como um eletrodo de pasta de carbono quimicamente modificado (CMCPE). São discutidas as seguintes propriedades desta sílica gel funcionalizada: adsorção seletiva de íons de metais pesados, medida pelas técnicas "batch" e coluna cromatográfica, e utilização como agente de preconcentração em um eletrodo de pasta de carbono quimicamente modificado (CMCPE), para determinação de mercúrio(II). A seletividade química deste grupo functional e a seletividade da voltametria foram combinadas para preconcentração e determinação.Silica gel with a specific area of 382 m 2 g -1 and an average pore diameter of 60 Å was chemically modified with 2-amino-1,3,4-thiadiazole, for the purpose of selective adsorption of heavy metals ions and possible use as a chemically modified carbon paste electrode (CMCPE). The following properties of this functionalized silica gel are discussed: selective adsorption of heavy metal ions measured by batch and chromatographic column techniques, and utilization as preconcentration agent in a chemically modified carbon paste electrode (CMCPE) for determination of mercury(II). The chemical selectivity of this functional group and the selectivity of voltammetry were combined for preconcentration and determination.

Highly Productive Synthesis, Characterization, and Fluorescence and Heavy Metal Ion Adsorption Properties of Poly(2,5-dimercapto-1,3,4-thiadiazole) Nanosheets

“…2,5-dimercapto-1,3,4-thiadiazole (bismuthiol, BT) is a heterocyclic aromatic mercaptan, which combines the features of pyrrole and thiophene according to its chemical structure. It has been reported that BT and its derivatives demonstrate excellent antibacterial properties [8,9,10,11,12] and strong coordination abilities to heavy metal ions [13,14,15] because of the sulfur (S)- and nitrogen (N)-rich subgroups and their extremely high total molar content (56%) in BT molecules. Hence, BT can be used to easily coordinate a variety of heavy metal ions, such as Co(II), Ni(II), Cu(II), Zn(II), and Au(III), to form BT-M n+ (2:1) metal coordination polymer [16,17], depending on the strong coordination ability of electron-rich nitrogen and sulfur subgroups.…”

Using the organofunctionalised SBA-15 nanostructured silica as a carbon paste electrode modifier: determination of cadmium ions by differential anodic pulse stripping voltammetry

“…6,9,10 Carbon paste electrodes modified with functional ligands have been more widely used to pre-concentrate and quantify trace metal ions. [11][12][13][14][15][16][17] The pollution of cadmium is one of the most serious environmental problems because of our stability in contaminated site and complexity of mechanism in biological toxicity. Once absorbed, cadmium can be accumulated in the body and greatly threaten the health of human.…”

Electrode Materials (Bulk Materials and Modification)

“…Examples are available for organo-functional groups such as propylamine, 616,712,713 a wide range of functions exhibiting high affinity for Hg(II) species (i.e., mercaptopropyl, 615,714 benzothiazolethiol, 715 3-(2-thiobenzimidazoyl)propyl, 716 2,5-dimercapto-1,3,4-thiadiazole, 717 or 2-aminothiazole 718 ), several groups binding preferably Cu (II) species (i.e., aminopropyl, 616 2-aminothiazole, 719 the carnosine dipeptide, 720 propylsulfonate, 721 salicylidine, 722 or cyclam derivatives 618 ), some functions leading to Pb(II) detection (mercaptopropyl, 714 cyclam-acetamide 619 or 2-aminopyridine 723 ), as well as some others likely to recognize other metal ions, alone or in mixture. 724,725 Finally, nonsiliceous metal oxides have been also used to modify CPEs 726 because of their attractive catalytic properties, such as ruthenium oxides (mainly RuO 2 ), 727 copper oxides (Cu 2 O, CuO), 728,729 and to less extent cobalt and nickel oxides. 730 …”