Banca de DEFESA: IZABELA GOUVEIA NASCIMENTO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : IZABELA GOUVEIA NASCIMENTO
DATE: 28/08/2023
TIME: 09:30
LOCAL: Departamento de Solos
TITLE:

Evaluation of the potential use of residual diatomaceous earth and malt bagasse as heavy metal biosorbents


KEY WORDS:

Biosorption, residual diatomite, adsorption mechanism, agro-industrial waste.


PAGES: 91
BIG AREA: Engenharias
AREA: Engenharia Ambiental
SUBÁREA: Saneamento Básico/Esgotos/Reator Anaeróbico
SUMMARY:
Despite the socioeconomic importance that the agro-industrial sector has for the country, this activity generates an amount of 291 million tons of organic waste per year which, without proper treatment and disposal, are seen as sources of environmental contamination. Thus, following the assumptions of the circular economy, one of the ways to reuse these residual biomasses would be as low-cost biosorbents in the removal of heavy metals. The present study aimed to evaluate the reuse potential of malt bagasse (BM) and residual diatomaceous earth (TDR) brewing waste in the adsorption process of Pb, Cu and Cd. The chemical and morphological characteristics of the residues were determined through pH analyzes of residues in water, Point of Zero Charge (pHPCZ), evaluation of functional groups and surface area. To evaluate the adsorption of Pb, Cd and Cu in BM and TDR, an adsorption assay was carried out through laboratory adaptation of the Batch Method, with increasing concentrations (0, 30, 60, 120, 200 and 280 mg L-1) of Pb(NO₃)₂ and CuCl2, and (0, 38, 46, 58, 82, 130 and 288 mg L-1) of CdCl2. Next, in order to determine the type of adsorption established between waste and metal, a desorption test was carried out by adding 1 mol L-1 KCl solution to the residue remaining from the previous process. Because they have a pH of 10.28 (TDR) and 7.18 (BM), these were corrected until the solution reached a range between 5.4 and 6.2, considered optimal for better process efficiency. The evaluation of the waste reuse potential was carried out by selecting the isotherm model that best described the adsorption process of Pb, Cu and Cd. The parameters of the adsorption isotherms were determined using the IsoFit program. The comparison of isothermal models was performed using the Coefficient of Determination (R2), corrected Akaike Information Criterion (AICc), Corrected Akaike Criterion Variation (ΔAICc) and Corrected Akaike Criterion Weighting (AICw). For TDR, the results showed that the Linear model obtained the best fit to describe the sorption process of Pb, Cu and Cd. The adsorption occurred in a specific way, in inner sphere complexes, reaching sorption ranges of 96, 37 (Pb), 98.15 (Cu) and 92.60% (Cd). Such results can be attributed to the negative electrical charges present on the surface of the TDR and to the silicate functional groups. For the BM, the isotherm model with the best fit was also the Linear one, for all metals. The adsorption of Pb, Cu and Cd occurred in a specific way, in inner sphere complexes, with maximum sorption capacities equivalent to 99.89, 94.74 and 80.54%, respectively. The results can also be attributed to the negative electrical charges present on the surface of the residue and to the carbonyl, carboxylic and aromatic functional groups that are present and related to the presence of lignocellulosic compounds (lignin, cellulose and hemicellulose) that make up the malt. It can be concluded that the agro-industrial waste diatomaceous earth and malt bagasse can be reused as sustainable technologies in the removal of heavy metals Pb, Cu and Cd present in aqueous media. In addition to behaving as excellent biosorbents, BM and TDR have the advantages of being low-cost and easily accessible materials, and can be used in their “raw” form, without the need to undergo a previous treatment, which facilitates the reuse in the agricultural sector and in rural properties aiming at the treatment of effluents. Despite the socioeconomic importance that the agro-industrial sector has for the country, such activity generates an amount of 291 million tons of organic waste per year that, without treatment and destination adequate, are seen as sources of environmental contamination. Thus, following the assumptions of the circular economy, one of the ways to reuse these residual biomasses would be as low-cost biosorbents in the removal of heavy metals. The present study aimed to evaluate the reuse potential of malt bagasse (BM) and residual diatomaceous earth (TDR) brewing waste in the adsorption process of Pb, Cu and Cd. The chemical and morphological characteristics of the residues were determined through pH analyzes of residues in water, Point of Zero Charge (pHPCZ), evaluation of functional groups and surface area. To evaluate the adsorption of Pb, Cd and Cu in BM and TDR, an adsorption assay was carried out through laboratory adaptation of the Batch Method, with increasing concentrations (0, 30, 60, 120, 200 and 280 mg L-1) of Pb(NO₃)₂ and CuCl2, and (0, 38, 46, 58, 82, 130 and 288 mg L-1) of CdCl2. Next, in order to determine the type of adsorption established between waste and metal, a desorption test was carried out by adding 1 mol L-1 KCl solution to the residue remaining from the previous process. Because they have a pH of 10.28 (TDR) and 7.18 (BM), these were corrected until the solution reached a range between 5,

COMMITTEE MEMBERS:
Presidente - 1740899 - ERIKA FLAVIA MACHADO PINHEIRO
Interno - 2213075 - EVERALDO ZONTA
Externa à Instituição - CAMILA DA COSTA BARROS DE SOUZA - UFRRJ
Notícia cadastrada em: 23/08/2023 13:03
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