Determination of Cu, Ni and Pb in aqueous medium by FAAS after pre-concentration on 2-aminothiazole modified silica gel

Abstract

Este trabalho descreve a síntese e caracterização da sílica gel modificada com grupos 2-aminotiazol (SiAT), e os resultados de um estudo de adsorção e pré-concentração (em batelada e em fluxo, utilizando-se um sistema por injeção em fluxo acoplado com um espectrômetro de absorção atômica) de Cu(II), Ni(II) e Pb(II) em meio aquoso. A capacidade máxima de adsorção da SiAT determinada para os íons metálicos estudados em mmol g -1 foram: Cu(II)= 1,18, Ni(II)= 1,15 and Pb(II)= 1,10. Os resultados obtidos nos experimentos em fluxo, mostraram uma recuperação de praticamente 100% dos íons metálicos adsorvidos em uma mini-coluna empacotada com 100 mg de SiAT, utilizando-se 100 µL de HCl 2 mol L -1 como eluente. A sorção-desorção quantitativa dos íons Cu(II), Ni(II) e Pb(II), permitiu a aplicação do sistema em fluxo na pré-concentração e posterior quantificação desses íons metálicos em amostras de águas naturais digeridas e não digeridas por oxidação com radiação UV.This work describes the synthesis and characterization of 2-aminothiazole modified silica gel (SiAT), and the results of a study of the adsorption and pre-concentration (in batch and using a flowinjection system coupled to an absorption atomic spectrometer) of Cu(II), Ni(II) and Pb(II) in aqueous medium. The adsorption capacities for each metal ions in mmol g -1 were: Cu(II)= 1.18, Ni(II)= 1.15 and Pb(II)= 1.10. The results obtained in the flow experiments showed a recovery of practically 100% of the metal ions adsorbed in a mini-column packed with 100 mg of SiAT, using 100 µL of 2.0 mol L -1 HCl solution as eluent. The sorption-desorption of the metal ions made possible the application of a flow-injection system for the pre-concentration and quantification by FAAS of metal ions at trace level in natural water samples digested and not digest by an oxidizing UV photolysis.

4-amine-2-mercaptopyrimidine modified silica gel applied in Cd(II) and Pb(II) extraction from an aqueous medium

“…Solid materials such as silica and cellulose have been used extensively due to the presence of reactive hydroxyl groups on their surfaces. These groups enable the attachment of organic molecules containing Lewis base, which can coordinate metal ions in solution 16,17 . The correct choice of a desired functional group for immobilization on silica or cellulose surfaces can yield materials that are highly selective for a given contaminant 15,18 .…”

Extraction of Trace Cd(II) in Real Samples using Multi Walled Carbon Nanotubes Carboxylate

“…are an important risk for humans and animals [1][2][3] . Also heavy metals at trace levels are components of the natural biosphere.…”

“…Coprecipitation [11][12][13] , membrane filtration 14,15 , electrodeposition 16 , cloud point extraction 17 and solvent extraction [18][19][20][21] are the popular methods for the preconcentration and separation of the traces transition metal ions. Solid phase extraction (SPE) of trace metal ions is also an important preconcentration/separation technique 1,[22][23][24][25] .…”

Attachment of 2,2-bipyridine onto a silica gel for application as a sequestering agent for copper, cadmium and lead ions from an aqueous medium

“…Modifi ed silica-based materials have been synthesized and applied in several fi elds of research, including medicine 6-8 and chemistry, as stationary phases for liquid chromatography 9, 10 and sequestering agents for metal ions in aqueous and ethanol media [11][12][13][14] . Their application stems from the fact that the surface reactivity and large surface area of silica, when coupled to a sol-gel process, allow for the synthesis of materials with desirable characteristics 15 .…”