Banca de DEFESA: JULIO CESAR FRANCISCO FERREIRA DE ARAUJO JUNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JULIO CESAR FRANCISCO FERREIRA DE ARAUJO JUNIOR
DATE: 27/08/2024
TIME: 09:00
LOCAL: Sala 24 do departamento de solos.
TITLE:

Lead adsorption in poultry litter composted with biochar. 

KEY WORDS:

poultry farming, biosorption, environmental contamination.

PAGES: 96
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

Due to the increasing production of chicken meat, large amounts of organic waste, generically known as poultry litter, have been generated, implying the need to give a sustainable destination to this material. Because it has macro and micronutrients in its composition, it has been widely used as an organic fertilizer. However, poultry litter can have variable concentrations of heavy metals in its composition, making it a potential contaminant for agroecosystems. One technique used to reduce the bioavailability of heavy metals is composting, however it has not proven to be efficient for lead. The use of biochar associated with poultry litter, during composting, and prior to its application to the soil, can enhance the adsorption of lead and reduce its bioavailability, consequently mitigating the risks of transfer to the food chain. Therefore, this study aimed to evaluate the effects of adding different doses of biochar combined with different composting times on the adsorption of lead in composted poultry litter. Biochar was added to poultry litter prior to composting in the following proportions: 0% (control); 5%; 10%, and 15% (based on dry weight). The composting times evaluated were: fresh material; 30; 60; and 90 days. The structural characterization of the residue in the different treatments was performed using carbon-13 nuclear magnetic resonance (13C-NMR) and chemometric analysis was performed using “The Unscrambler” software (version 10.4). The adsorption test was performed using the adapted Laboratory Batch method, using increasing concentrations of Pb(NO3)2 solution. The extracts were analyzed by atomic absorption spectrometry. IsoFit software, version 1.2, was used to select the most appropriate model to describe Pb adsorption in the compost. The following models were analyzed for model selection: Coefficient of Determination (R2); Corrected Akaike Information Criterion (AICc); AICc Variation (ΔAICc); and AICc Weighting (AICcw). The model that best fitted the experimental data for all treatments was the linear one. In treatments without biochar addition and with 5%, the structural changes promoted during the composting time reduced the distribution coefficient (Kd), demonstrating a reduction in Pb adsorption, possibly due to the increase in non-functionalized aliphatic carbon structures and the greater affinity of Pb for these structures. However, for the 10 and 15% biochar doses, there was a significant increase in Kd values with composting time, mainly at the 15% dose. In these treatments, a greater intensity of carboxylic carbon regions and functionalized aromatic carbons was observed during the composting process, evidencing an increase in the functionality of the structure and high aromaticity and, consequently, an increase in lead adsorption. Thus, the results obtained allow us to conclude that the addition of biochar to the compound favors greater adsorption of Pb and the formation of stable complexes capable of reducing the bioavailability of this element, consequently reducing the risks of entry into the trophic chain.

COMMITTEE MEMBERS:
Externa ao Programa - 1412091 - ERICA SOUTO ABREU LIMA - nullExterna à Instituição - FABIANA SOARES DOS SANTOS - UFF
Presidente - 387263 - NELSON MOURA BRASIL DO AMARAL SOBRINHO