Publicação
Economia circular na valorização do licor negro
| Resumo: | The circular economy is a fundamental concept for sustainable economic growth. Therefore, this thesis shows a case study of promotion of circular economy in the pulp and paper industry, by valuing one of its byproducts: black liquor. One of the components of black liquor is lignin. From lignin, it is possible to produce a wide range of value-added products, presenting different applications in numerous fields. In this sense, the work developed in this dissertation had as main objective the production of nanoparticles from lignin isolated from black liquor and its application. Lignin nanoparticles were synthesized through experimental methods of self-assembly and acid precipitation, according to the literature. The resulting particles of self-assembly showed spherical shapes, sizes between 177 nm and 489 nm and phenolic content between 2.97×10-5 mgGAE/mL and 3.06×10-5 mgGAE/mL. On the other hand, the morphology of the nanoparticles resulting from acid precipitation couldn’t be clearly observed, having presented sizes between 80 nm and 129 nm and phenolic content between 1.50×10-6 mgGAE/mL and 3.00×10-5 mgGAE/mL.The optimal conditions for the preparation of nanoparticles were analyzed for an elaborate experimental method. Using the JMP® Pro 16 software, it was found that lignin concentration has a greater effect on phenolic content, followed by pH and surfactant concentration. On the other hand, pH has greater relevance in particle size, followed by surfactant concentration and lignin concentration.The desirable values for minimizing nanoparticle size and maximizing phenolic content are 422.96 nm and 4.53×10-3 mgGAE/ml, respectively. These values would be achieved with a lignin concentration of 35 mg/mL, a surfactant concentration of 10% (m/v lignin) and a pH of 5.It was concluded that surfactants does not produce significant effects on the morphology, size, phenolic content and stability of nanoparticles.The antibacterial activity of lignin nanoparticles against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa bacteria was evaluated. There was only a small activity against the bacterium Staphylococcus aureus. |
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| Autores principais: | Marques, Joana Queirós Correia |
| Assunto: | Economia circular Lenhina Planeamento fatorial completo Self-assembly e precipitação ácida Nanopartículas Circular economy Lignin Full-factorial design Self-assembly and acid precipitation Nanoparticles |
| Ano: | 2022 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Coimbra |
| Idioma: | português |
| Origem: | Estudo Geral - Universidade de Coimbra |
| Resumo: | The circular economy is a fundamental concept for sustainable economic growth. Therefore, this thesis shows a case study of promotion of circular economy in the pulp and paper industry, by valuing one of its byproducts: black liquor. One of the components of black liquor is lignin. From lignin, it is possible to produce a wide range of value-added products, presenting different applications in numerous fields. In this sense, the work developed in this dissertation had as main objective the production of nanoparticles from lignin isolated from black liquor and its application. Lignin nanoparticles were synthesized through experimental methods of self-assembly and acid precipitation, according to the literature. The resulting particles of self-assembly showed spherical shapes, sizes between 177 nm and 489 nm and phenolic content between 2.97×10-5 mgGAE/mL and 3.06×10-5 mgGAE/mL. On the other hand, the morphology of the nanoparticles resulting from acid precipitation couldn’t be clearly observed, having presented sizes between 80 nm and 129 nm and phenolic content between 1.50×10-6 mgGAE/mL and 3.00×10-5 mgGAE/mL.The optimal conditions for the preparation of nanoparticles were analyzed for an elaborate experimental method. Using the JMP® Pro 16 software, it was found that lignin concentration has a greater effect on phenolic content, followed by pH and surfactant concentration. On the other hand, pH has greater relevance in particle size, followed by surfactant concentration and lignin concentration.The desirable values for minimizing nanoparticle size and maximizing phenolic content are 422.96 nm and 4.53×10-3 mgGAE/ml, respectively. These values would be achieved with a lignin concentration of 35 mg/mL, a surfactant concentration of 10% (m/v lignin) and a pH of 5.It was concluded that surfactants does not produce significant effects on the morphology, size, phenolic content and stability of nanoparticles.The antibacterial activity of lignin nanoparticles against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa bacteria was evaluated. There was only a small activity against the bacterium Staphylococcus aureus. |
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