Estudo do fenômeno de adsorção dos metais Pb2+, Cu2+ e Ni2+ em microplástico de polietileno

• Ano de defesa: 2020
• Autor(a) principal: Vasconcelos Neto, Joaquim Rodrigues de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Polietileno; Microplásticos; Isotermas; Metais pesados
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/66605

Concerns surrounding environmental pollution by microplastics (PMs) that are plastics smaller than 5 mm and their potential for pollutant concentration and transport, such as heavy metals, are on the current agenda in the scientific community. The combination of its pollutant effects increases the problem of PMs in the environment. The present work aimed to study the process of adsorption of metal ions Pb2+, Cu2+ and Ni2+ in polyethylene (PE). The characterizations (TGA, SEM - EDS, FTIR) made of the MP, allowed the verification of the material as PE. With the use of the XRF technique it can be seen that an adsorption occurred. The solution used for the adsorption tests was prepared at pH 3.0 in a multi-element form. In the study of adsorption kinetics in multielementary and monoelementary systems, the models of pseudo-first and pseudo-second order were used, being verified this as the main mechanism that governs the adsorption speed. The Weber and Morris intraparticle diffusion model followed a very rapid diffusion of metals in the initial instants despite the small resistance of external film on the PE surface. Adsorption equilibrium tests were performed, in which the concentration levels of the multi-element metallic solution were used in order to determine the maximum PE adsorption capacity. The results reveal that Ni2+ has good determination coefficients in all models (Langmuir, Freundlich and Sips). Pb2+ showed a greater adsorption capacity among the studied metals. Langmuir and Sips models use the same sequence for maximum adsorption capacity of Pb2+ > Cu2+ > Ni2+ metals. For Langmuir's Separation Factor (RL), an adsorption proves to be a favorable process for all metals. In monoelementary tests, all ions were adjusted to the three models, except Pb2+ to the Langmuir model. In general, Ni2+ adds greater affinity and adsorption capacity, demonstrating that the presence of other ions had a negative influence on its adsorption. The Separation Factor continued an increase in favorability of adsorption with increasing ion preferences.