Avaliação do potencial adsortivo da farinha da semente do abacate (Persea Americana) como alternativa sustentável na remoção do azul de metileno em efluentes industriais

• Ano de defesa: 2025
• Autor(a) principal: Brito, Katyusca Karla Henrique de
• Orientador(a): Vieira, Fernando Fernandes
• Banca de defesa: Silva, Vera Lúcia Meira de Morais, Luiz, Marcia Ramos, Leite, Valderi Duarte
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual da Paraíba; 24004014005P9
• Departamento: Centro de Ciências e Tecnologia - CCT
• País: BR
• Palavras-chave em Português: adsorção; azul de metileno; biossorvente; semente de abacate; modelagem cinética e isotérmica
• Área do conhecimento CNPq: ENGENHARIAS
• Link de acesso: https://repositorio.uepb.edu.br/handle/123456789/76817

The contamination of industrial effluents by synthetic dyes constitutes a significant environmental problem, driving the search for alternative, efficient, and sustainable materials for their removal, with emphasis on agroindustrial residues as low-cost biosorbents. In this context, the adsorptive potential of avocado seed flour (Persea americana) for methylene blue removal was evaluated, beginning with biomass drying, in which a temperature of 60 °C was identified as the most suitable according to the Midilli model (R² > 0.97), preserving the integrity of the lignocellulosic matrix. Physicochemical characterization revealed a Point of Zero Charge (PZC) of 6.4, favoring interactions under alkaline pH conditions, and the presence of functional groups associated with cellulose, hemicellulose, and lignin, which are essential for the adsorption process. The methodology comprised the application of mathematical models to the drying process, followed by optimization of operational conditions using a full 2³ factorial design with three central points, evaluating the effects of adsorbent mass (0.2–0.4 g), initial dye concentration (40–100 mg·L⁻¹), pH (5–8), contact time (30–60 min), and particle size (40–100 mesh), with pH 8 and 100 mesh particle size identified as the dominant factors for maximum adsorbed amount (qt up to 12.45 mg·g⁻¹) and removal efficiency of up to 100%. Adsorption kinetics were best described by the pseudo-second-order model (R² = 0.99; qₑ = 6.75 mg·g⁻¹; k₂ = 3.26 g·mg⁻¹·min⁻¹), indicating chemical control of the process and equilibrium reached within 60 min, while adsorption isotherms showed a better fit to the Sips model (R² = 0.998; Qₘₐₓ = 40.70 mg·g⁻¹), revealing a heterogeneous surface and hybrid Langmuir–Freundlich behavior. These results demonstrate that avocado seed flour is a promising, sustainable, low-cost, and efficient biosorbent for the removal of cationic dyes, with potential application at laboratory and industrial scales.