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As nanoparticulas de prata (AgNPs) sao reconhecidas como eficazes agentes antimicrobianos e seus metodos tradicionais de sintese utilizam reagentes quimicos que podem ser toxicos e potencialmente perigosos a saude humana e ao meio ambiente. Por este motivo, diversos pesquisadores tem buscado alternativas que sejam mais limpas e ambientalmente corretas para a sintese desses nanomateriais. Dentro deste contexto, esse trabalho teve por objetivo propor um metodo de sintese verde para AgNPs, utilizando os compostos bioativos presentes no extrato de erva-mate (Ilex paraguariensis). A preparacao do extrato foi previamente avaliada, visando a obtencao de uma solucao com alto potencial redutor. Apos a realizacao dos testes de captura do radical 2,2-difenil-1-picrilhidrazil (DPPH), optou-se pela utilizacao do extrato hidroalcoolico a 33% (v/v), utilizando as folhas de erva-mate. Posteriormente, avaliou-se o efeito da concentracao desse extrato, da temperatura do meio reacional, do tempo de sintese e da concentracao da solucao de nitrato de prata, mantendo-se o pH do meio fixo em 8,0. Os parâmetros considerados mais satisfatorios para a sintese das nanoparticulas foram a concentracao do extrato de 25 mgmL -1 , a temperatura do meio reacional de 50 °C, o tempo de reacao de 30 min e a concentracao da solucao de nitrato de prata de 1,0 mmol L -1 . Por fim, a sintese foi reconduzida nessas condicoes, variando-se o pH do meio de 3,0 a 12,0. A caracterizacao por espectroscopia de absorcao molecular na regiao do ultravioleta e visivel e microscopia eletronica de transmissao revelou que as AgNPs sintetizadas nos diferentes pHs apresentam um maximo de absorcao na faixa de 425-480 nm e um diâmetro medio entre 2,5 a 34,9 nm, com diferentes formas e estados de agregacao. Considerando-se a abundância relativa de erva-mate na regiao da Serra Gaucha, a facilidade de preparacao do extrato, bem como a baixa toxicidade e a reduzida quantidade de reagentes utilizados no processo, o metodo desenvolvido revelou ser uma alternativa muito frente aos metodos tradicionais de obtencao de AgNPs. http://dx.doi.org/10.18226/23185279.v8iss1p39

Environmental industries are expanding their activities due to the current demand for preservation and remediation of human impact on ecological fields. These industries focus on the production of necessary goods by following the green chemistry principles, such as using renewable sources and reducing hazardous chemical usage. Therefore, considering the growth and importance of nanotechnology and its application, the development of sustainable green nanomaterials have emerged as an attractive option for environmental protection combined with sustainable manufacturing. This chapter presents recent developments in sustainable green nanomaterials and a perspective on their manufacture in industries. The chapter has been divided according to the nature of nanomaterials and their ecological applications. The main nanomaterials are metallic, ceramic, and composites that can be applied directly or through membranes, catalysts, and sensors. These nanomaterials are commonly used in water, wastewater, air, and soil treatment, as well as in environmental monitoring and renewable energy sources. The full sustainable process, from design to disposal, characterizes these green nanomaterials, as has been discussed in detail in this chapter.

A contaminacao de racoes animais por aflatoxinas causa inumeros danos as aves de corte, sendo a deteccao dessas toxinas de extrema importância para evitar prejuizos nos sistemas de producao. Dentro desse contexto, o presente trabalho teve por objetivo determinar o sistema de extracao mais adequado para a analise quantitativa das aflatoxinas B1, B2, G1 e G2 em racao animal para aves de corte por cromatografia liquida de alta eficiencia (CLAE) com deteccao por fluorescencia. Os sistemas de extracao avaliados foram o QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) e a Extracao em Fase Solida (SPE - Solid Phase Extraction) com silica gel e com coluna de fase reversa C18. Em geral, o sistema de extracao QuEChERS apresentou o melhor resultado, com uma recuperacao media de 102,5%, alem de uma reducao de 78% nos custos com reagentes e tempo de analise, em comparacao a SPE. Os limites de deteccao e de quantificacao para este metodo, em termos de aflatoxinas totais, foram de 0,46 ppb e 0,56 ppb, respectivamente. Alem disso, verificou-se que a utilizacao da CLAE com deteccao por fluorescencia e associada ao sistema de extracao QuEChERS, e uma alternativa precisa, confiavel e economicamente viavel para a analise quantitativa de aflatoxinas em racao animal para aves de corte. http://dx.doi.org/10.18226/23185279.v4iss3p148

The pollution of hydric sources by pharmaceuticals is an issue in many countries, particularly in Brazil. The presence of these substances causes deleterious effects on the environment and human health. One of the main sources of this contamination is domestic sewage, due to the expressive amount of medicines released in their unaltered form. Unfortunately, traditional wastewater treatment is not effective for the removal of pharmaceuticals and, for this reason, membrane technology is an attractive alternative to overcome this issue. In this regard, hydrophilic polymers, such as poly(vinyl alcohol) (PVA), are the most suitable. However, their high affinity with water causes intense swelling, leading to severe modifications in the membrane properties. In view of all these facts, the present work evaluated the swelling of PVA-based membranes, with the aim of finding the membrane preparation method that has the lowest swelling, thereby providing the most suitable characteristics for pharmaceutical removal from wastewater. The membranes were prepared by the casting of a polymeric solution, with PVA as a basis polymer, citric acid as a crosslink agent and glycerol and silver nanoparticles as performance additives. The process optimization was performed using a design of experiments with posterior analysis by the response surface methodology (RSM). The RSM assessed the effect on the membrane swelling of the factors, including citric acid concentration and the time and temperature of crosslinking. The membrane characterization was performed by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy coupled with a field emission gun (SEM-FEG) and water contact angle (WCA) measurements. Overall, the condition that showed the lowest swelling was obtained with 10% of citric acid and crosslinking for 4 h at 130 °C. Under these conditions, the membrane had a mass swelling of 42% and a dimensional swelling of 24%. Additionally, our statistical analysis revealed that the factors with the dominant effects were the citric acid concentration and the temperature of crosslinking. The FT-IR analysis suggested that the crosslinking occurred by an esterification reaction, as showed by the stretching frequencies of C=O at 1710 cm-1 and ester C-O at 1230 cm-1. Moreover, the SEM-FEG images revealed a smooth and flat surface and a dense cross section with a thickness of ~113 μm. Concerning the WCA, the angle was at ~80°, which is characteristic of hydrophilic materials. Finally, the data suggested that it is possible to optimize the membrane preparation process with adequate properties so that it can be subsequently applied to the removal of pharmaceuticals from hospital wastewater. A contaminação dos corpos hídricos por fármacos está sendo observada em diversos países, especialmente no Brasil. A presença dessas substâncias provoca efeitos nocivos, tanto ao meio ambiente quanto à saúde dos seres humanos. O esgoto doméstico é a principal fonte dessa contaminação, uma vez que uma grande quantidade de fármacos ingeridos pelo homem é excretada na sua forma inalterada. Infelizmente, o tratamento convencional de efluentes é pouco eficiente na remoção dessas substâncias e, nesse sentido, uma alternativa é processo de separação por membranas (PSM). Para essa aplicação, os polímeros hidrofílicos, como o poli(vinil álcool) (PVA), são os materiais mais apropriados. Entretanto, essa característica faz com que as membranas de PVA sofram um inchamento intenso quando em contato com a água, o que altera propriedades importantes para os PSM. Nesse contexto, o presente trabalho teve por objetivo avaliar o inchamento de membranas de PVA, a fim de determinar o método de preparação que proporciona o menor inchamento, fornecendo as características mais adequadas para a remoção de fármacos de efluentes. As membranas foram preparadas pelo espalhamento de uma solução polimérica contendo PVA como polímero base, ácido cítrico como agente reticulante, e glicerol e nanopartículas de prata como aditivos de performance. A otimização do processo foi realizada por meio de um planejamento experimental com posterior análise de superfícies de resposta, avaliando-se a influência da concentração de agente reticulante, além do tempo e da temperatura de reticulação no inchamento da membrana. As membranas foram ainda caracterizadas por meio das técnicas de espectroscopia de infravermelho com transformada de Fourier (FT-IR), microscopia eletrônica de varredura com emissão de campo (MEV-FEG) e ângulo de contato com água (WCA). A condição de melhor desempenho foi obtida utilizando-se 10% de ácido cítrico e reticulação por 4 h a 130 °C. Nessas condições, a membrana teve um inchamento mássico de 42% e dimensional de 24%. Também se verificou que a concentração do ácido cítrico e a temperatura de reticulação foram os fatores de maior influência, de acordo com a análise estatística. De modo geral, a análise de FT-IR indicou a reticulação da membrana por meio de uma reação de esterificação, evidenciada pelos estiramentos das ligações C=O em 1710 cm-1 e de C-O de ésteres em 1230 cm-1. As imagens de MEV-FEG, por sua vez, revelaram uma superfície lisa e plana, além de uma secção transversal densa com aproximadamente 113 μm de espessura. O ângulo de contato foi de aproximadamente 80°, típico de materiais de caráter hidrofílico. Finalmente, o conjunto de dados evidenciou que foi possível aperfeiçoar a preparação de uma membrana com características adequadas para a subsequente aplicação na remoção de fármacos de efluentes hospitalares.

Zinc oxide nanoparticles (ZnONPs) was produced using Ilex paraguariensis (mate) leaves extract using a green synthesis process. The influence of ethanolic and aqueous plant extract and zinc source on the green synthesis of ZnONPs was studied. Cyclic voltammetry and Fourier transform infrared spectroscopy (FTIR) were used for the assessment of the mechanism route of ZnONPs while the formation of this nanomaterial was confirmed by X-ray diffraction (XRD) analysis. The morphology and size of the ZnONPs synthesized were evaluated using field emission scanning microscopy (FESEM) and transmission electron microscopy (TEM) analysis. In general, all different synthesized ZnONPs exhibited a hexagonal crystalline structure whereas the size and shape varied depending on the extract and zinc salt used. Nonetheless, the most uniform and smallest ZnONPs were obtained using ethanolic extract and zinc nitrate, showing spherical morphology and a diameter of about 18 nm. With the use of cyclic voltammetry and FTIR analysis, it was concluded that the formation of ZnONPs through green synthesis occurred due to complexation of Zn(II) ions by antioxidants compounds present in the Ilex paraguariensis extract and further thermal degradation of the complexes. Concerning the cytotoxicity assays, the L929 cell viability decreases in a dose-dependent manner for all samples tested. In general, nanoparticles with reduced size and uniform shape exhibited no cytotoxic effects up to a concentration of 10 μ g mL−1. However, higher ZnONPs concentrations caused a decrease in cell viability. This was possibly due an autophagic induction process triggered by the internalization of the nanomaterial. Finally, this work provides a better understanding of the mechanism route to obtain ZnONPs via green method and their potential to be used as a biomedical material.

Traditional methods for synthesizing metallic nanoparticles include the use of toxic chemicals, which can have negative impacts on the environment and human health. A safer alternative to produce these nanomaterials is based on the concept of Green Chemistry, which uses less harmful chemicals from renewable sources. In this work, we describe a specific approach for the green synthesis of silver nanoparticles (AgNPs) using the extract of Ives cultivar (Vitis labrusca) pomace, their characterization, and their immobilization in a polymer matrix of chitosan aiming the disinfection of a raw wastewater sample. The influence of some experimental parameters on synthesis such as pH, stabilization time as well as the temperature has been investigated. The grape pomace extract was initially characterized regarding its content of phenolic compounds and then used as stabilizing-reducing agent. The obtained AgNPs were analyzed by ultraviolet-visible spectroscopy, transmission electron microscopy, zeta potential, scanning electron microscopy coupled with energy dispersive spectroscopy, and raman spectroscopy. In general, the AgNPs were spherical in shape and very stable. Aiming to explain the reaction, we also proposed a mechanism of formation of AgNPs based on gallic acid molecule. Concerning the antimicrobial properties, the results demonstrated the synergistic activity of chitosan-AgNPs pellets against Gram-positive and Gram-negative bacteria. Additionally, these materials led to a reduction of 47% of the bacterial count of Escherichia coli on the disinfection of the wastewater. Finally, it was concluded that the extract of Ives cultivar pomace is capable of producing stable AgNPs that can be used as auxiliaries in wastewater disinfection.