Avaliação da funcionalidade do processo de tratamento de água para a remoção de nanopartículas de prata provenientes da ação antrópica
Data
2024-10-24
Autores
Santos, Lúcia Fernanda dos 
Orientadores
Nascimento, Angerson Nogueira do
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Nanociências e Nanotecnologias (N&N) permitiram à humanidade um salto evolutivo, devido aos benefícios trazidos pelo número crescente de nanomateriais em diversas áreas, como na medicina, na cosmética, na engenharia e na têxtil. As nanopartículas de prata (AgNPs) são as mais estudadas atualmente e correspondem a mais de 50% dos nanomateriais produzidos. Mas, assim como diversas atividades antrópicas, a produção de nanomateriais com AgNPs também trazem preocupações, como estudos apontando intoxicações pelo seu uso, a presença de AgNPs em ambientes marítimos, o acúmulo em peixes, além da sua presença em ambientes de água potável. O processo de produção dos nanomateriais e o seu descarte pelo consumidor final podem gerar contaminação ambiental e humana. Nesse sentido, o presente trabalho teve como objetivo avaliar a funcionalidade do processo de tratamento de água para a sua remoção, bem como sua ecotoxicidade. A primeira etapa da pesquisa focou nas sínteses química e verde de AgNPs, utilizando como agentes redutores o borohidreto e o extrato de Camellia sinensis, respectivamente. Em ambas as sínteses, observou-se que, na presença do citrato de sódio, houve maior estabilidade das AgNPs. A segunda etapa focou na simulação do tratamento de água da Companhia de Saneamento Básico do Estado de São Paulo (SABESP), através do ensaio com o Jar test, onde avaliou-se que as AgNPs sofrem oxidação durante o processo. E, na terceira etapa, realizou-se os ensaios de ecotoxicidade, com o uso de Daphnia magna e Allium cepa. Para o ensaio de toxicidade aguda, foram adicionadas Daphnia magna em soluções com diferentes concentrações de AgNPs, Ag+ e em água tratada no Jar Test, além do controle negativo. Os resultados mostraram a taxa de mortalidade para a espécie, tanto em contato com AgNPs, como com os íons Ag+ e com a água tratada no Jar Test. No ensaio com as sementes, foram separados o grupo de sementes tratadas com AgNPs, o grupo controle positivo (tratado com íons Ag+) e o controle negativo (tratado com água ultrapura). Os resultados indicaram a bioestimulação das sementes, tanto em contato com AgNPs, como com os íons Ag+.
Advances in Nanoscience and Nanotechnology (N&N) have profoundly impacted various sectors, including medicine, cosmetics, engineering, and textiles, largely due to the unique properties of newly developed nanomaterials. Among these, silver nanoparticles (AgNPs) are the most extensively studied, accounting for over 50% of manufactured nanomaterials. However, like many anthropogenic materials, AgNPs raise environmental and health concerns, with reports documenting their presence in marine ecosystems, bioaccumulation in fish, and traces found in drinking water. The lifecycle of AgNPs — from production to disposal — presents potential risks of environmental and human contamination. This study aimed to evaluate the effectiveness of conventional water treatment processes in removing AgNPs and to assess their ecotoxicity. The research comprised three stages. First, AgNPs were synthesized via chemical and green methods, using sodium borohydride and Camellia sinensis extract as reducing agents, respectively. Stability studies revealed that sodium citrate enhanced the stability of AgNPs in both synthesis methods. In the second stage, a simulation of the water treatment process implemented by the Companhia de Saneamento Básico do Estado de São Paulo (SABESP) was performed using a Jar Test, where it was observed that AgNPs underwent oxidation during treatment. In the third stage, ecotoxicity assays were conducted using Daphnia magna and Allium cepa as bioindicators. In acute toxicity tests, D. magna were exposed to varying concentrations of AgNPs, Ag+ ions, and treated water from the Jar Test, with a negative control included for comparison. The results indicated significant mortality in D. magna exposed to AgNPs, Ag+ ions, and Jar Test-treated water. In the Allium cepa assays, seeds were divided into three groups: those treated with AgNPs, a positive control (exposed to Ag+ ions), and a negative control (exposed to ultrapure water). Results indicated biostimulation in seeds treated with both AgNPs and Ag+ ions.
Advances in Nanoscience and Nanotechnology (N&N) have profoundly impacted various sectors, including medicine, cosmetics, engineering, and textiles, largely due to the unique properties of newly developed nanomaterials. Among these, silver nanoparticles (AgNPs) are the most extensively studied, accounting for over 50% of manufactured nanomaterials. However, like many anthropogenic materials, AgNPs raise environmental and health concerns, with reports documenting their presence in marine ecosystems, bioaccumulation in fish, and traces found in drinking water. The lifecycle of AgNPs — from production to disposal — presents potential risks of environmental and human contamination. This study aimed to evaluate the effectiveness of conventional water treatment processes in removing AgNPs and to assess their ecotoxicity. The research comprised three stages. First, AgNPs were synthesized via chemical and green methods, using sodium borohydride and Camellia sinensis extract as reducing agents, respectively. Stability studies revealed that sodium citrate enhanced the stability of AgNPs in both synthesis methods. In the second stage, a simulation of the water treatment process implemented by the Companhia de Saneamento Básico do Estado de São Paulo (SABESP) was performed using a Jar Test, where it was observed that AgNPs underwent oxidation during treatment. In the third stage, ecotoxicity assays were conducted using Daphnia magna and Allium cepa as bioindicators. In acute toxicity tests, D. magna were exposed to varying concentrations of AgNPs, Ag+ ions, and treated water from the Jar Test, with a negative control included for comparison. The results indicated significant mortality in D. magna exposed to AgNPs, Ag+ ions, and Jar Test-treated water. In the Allium cepa assays, seeds were divided into three groups: those treated with AgNPs, a positive control (exposed to Ag+ ions), and a negative control (exposed to ultrapure water). Results indicated biostimulation in seeds treated with both AgNPs and Ag+ ions.