Adsorção de Mn (II) e Zn (II) em soluções aquosas usando perlita expandida revestida com quitosana
In this work, chitosan was used as a coating of pure perlite in order to increase the accessibility of the groups OH- e NH2+the adsorptionof ions Mn2+ e Zn2+.The characterization results of the expanded perlite classified as microporous and whose surface area 3,176 m2 g-1after the change r...
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| פורמט: | Dissertação |
| שפה: | por |
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Universidade Federal do Rio Grande do Norte
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| גישה מקוונת: | https://repositorio.ufrn.br/jspui/handle/123456789/17645 |
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| סיכום: | In this work, chitosan was used as a coating of pure perlite in order to increase
the accessibility of the groups OH- e NH2+the adsorptionof ions Mn2+ e Zn2+.The
characterization results of the expanded perlite classified as microporous and whose
surface area 3,176 m2 g-1after the change resulted in 4,664 m2g-1.From the thermogravimetry(TG) it was found that the percentage
of coating was34,3%.The infrared analysis can prove the presence of groups Si-OH, Si-O e Al-O-Siresulting from the perlite and C=O, NH2and OH characterization of
chitosan. The experiments on experiments on the adsorption of Mn and Zn were
performed in the concentration range of10 a 50 mgL-1and the adsorption capacity inpH
5,8 e 5,2 was 19,49 and 23,09 mgg-1to 25 oC,respectively.The adsorption data were best
fitted to Langmuir adsorption model to Langmuir adsorption model
for both metalionsisindicative of monolayer adsorption. The kinetics of
adsorption were calculated from the equation of Lagergren fitting the model pseudo-second-order for all initial concentrations, suggesting that adsorption of ions Mn2+ and
Zn2+ follows the kinetics of pseudo-second-order
and whose constant Speedk2(g/mg.min) are 0,105 e 3,98 and capacity and maximum
removal qe 4,326 e 3,348,respectively.In this study we used a square wave
voltammetry cathodic stripping voltammetry to quantify the adsorbed ions,
and the working electrode glassy carbon, reference
electrode silver / silver chloride and a platinum auxiliary electrode. The attainment of
the peaks corresponding to ions Mn2+ and Zn2+ was evaluated in and electrochemical
cell with a capacity of 30 mL using a buffer system (Na2HPO4/NaH2PO4)at pH 4 and
was adjusted with solutionsH3PO4 0,1molL-1and NaOH 0,1 molL-1and addition of the
analyte has been a cathodic peak in- 0,873 Vand detection limit of2,55x10-6molL-1para
Zn.The dough used for obtaining the adsorption isotherm was 150 mg and reached in
120 min time of equilibrium for both metal
ions.The maximum adsorption for 120 min with Mn concentration 20 mgL-1 and Zn 10
mgL-1,was91, 09 e 94, 34%, respectively |
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