Preparo de biomassas vegetais modificadas quimicamente e aplicação em estudos adsortivos de Cd(II), Pb (II) E Cr (III)
| Ano de defesa: | 2016 |
|---|---|
| Autor(a) principal: |
Schwantes, Daniel
 |
| Orientador(a): |
Gonçalves Júnior, Affonso Celso
|
| Banca de defesa: |
Campagnolo, Marcelo Angelo
,
Dragunski, Douglas Cardoso
,
Tarley, César Ricardo Teixeira
,
Braccini, Alessandro de Lucca e
|
| Tipo de documento: | Tese |
| Tipo de acesso: | Acesso aberto |
| Idioma: | por |
| Instituição de defesa: |
Universidade Estadual do Oeste do Parana
Marechal Cândido Rondon |
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Agronomia
|
| Departamento: |
Centro de Ciências Agrárias
|
| País: |
BR
|
| Palavras-chave em Português: | |
| Palavras-chave em Inglês: | |
| Área do conhecimento CNPq: | |
| Link de acesso: | http://tede.unioeste.br:8080/tede/handle/tede/1476 |
Resumo: | This research relates the development and use of modified adsorbents from agroindustrial residues. The following solid agroindustrial residues were obtained: pine bark (Pinus elliottii), solid residue from the manufacture of wood; Crambe cake (Crambe abyssinica Hochst), solid residue from oil extraction (biodiesel agroindustry); and cassava peels (Manihot esculenta Crantz), a byproduct of cassava industrialization. Biosorbents P. in natura, C. in natura and M. in natura (natural adsorbents or biosorbents) were produced from these agroindustrial residues, which had no or low market value, from which were produced the modified adsorbents, by washing the biomass with solutions of H2O2, H2SO4 and NaOH 0.1 mol L-1, resulting the modified adsorbents of pinus P. H2O2, P. H2SO4 and P. NaOH; crambe C. H2O2, C. H2SO4 and C. NaOH, and cassava M. H2O2, M. H2SO4, M. NaOH. In the first step of the study of these adsorbents (in natura and modified) the adsorbent materials were characterized, namely: chemical composition of the adsorbents, pHPCZ, infrared spectra (FT-IR), scanning electron microscopy (SEM), thermogravimetry (TG and DTG), BET and BJH isotherms (porosity and surface area). After the characterization of the adsorbent materials, adsorption studies were carried out for the evalution of Cd(II), Pb(II) and Cr(III) removal, which aimed to evaluate the performance of the materials on the influence of the pH of contaminant solution (ideal adsorption conditions), ie, the adsorption of metal ions as a function of increasing masses and the pH of the medium; the influence of adsorption time (adsorption kinetics), the influence of increasing concentrations of metal ions and isotherm linearization (adsorption equilibrium studies), the effect of temperature on the sorption process (adsorption studies) as well as the reuse of these adsorbent materials by acid elution (desorption studies). The scanning electron microscopes indicated changes in the adsorbents surface; the pHPZC of the modified adsorbents was distinct from the biosorbents. In addition, changes were also observed in the bands of the functional groups in the infrared spectrum, with new functional groups observed, such data indicate that modifications occurred to the adsorbents as a function of the chemical treatment applied. The results showed that, in general, the modified adsorbents present higher adsorption capacity of Cd(II), Pb(II) and Cr(III) metal ions than in natura materials. The modified adsorbents based on pinus, crambe and cassava did not show significant variation in relation to the studied pH range, which is a great advantage, because the adsorbents developed adapt to a wide pH range of contaminated water. An average time of 40 minutes was found for adsorption equilibrium, indicating that the sorption process is fast and occurs in the first few moments. The adsorption of the toxic ions occurs in mono and multilayer, in agreement with the good adjustments observed for Langmuir and Freundlich. In general, the adsorbents presented good reuse capacities, except when used for Cr(III) adsorption, because in this case it is difficult to reuse the adsorbents due to the low desorption rates of this metal, possibly due to chemisorption. Based on the results obtained, it can be concluded that the adsorbents of pinus, crambe and cassava present themselves as excellent, renewable, high availability and low cost, being an attractive alternative for the industry, through its use in advanced treatment systems, for the removal of metals such as Cd(II), Pb(II) and Cr(III) |