A EVOLUÇÃO DOS ÁTOMOS

O objetivo deste trabalho é explicar o que são os átomos e sua importância na química e física, apontando também para a evolução dos modelos atômicos em nossa sociedade. Usualmente, temas que envolvem átomos são conteúdos de difícil compreensão, por isso é necessário muito estudo. É muito importante introduzir modelos atômicos na aprendizagem porque eles explicam como funcionam a matéria e seus fenômenos. Os cientistas que foram os principais pesquisadores e contribuintes para os resultados que temos hoje tiveram que gastar muito tempo estudando os modelos, mas eles ainda estão sendo aprimorados e podem ser refutados a qualquer momento, sempre com um estudo que contribua para as teorias atômicas. Os átomos começaram a ser figurados pelo modelo atômico de Dalton (bola de bilhar) que dizia que um átomo era uma esfera massiva e indivisível, e deste modelo surgir novas hipóteses, assim como novos modelos, logo após Thompson sugerir um modelo cuja forma era parecido com um “pudim com passas” de uma esfera carregada positivamente à qual estavam ligadas cargas elétricas negativas, e era possível dividi-la. Enquanto o modelo de Rutherford eliminou a ideia de que o átomo era uma esfera, mas separado entre um núcleo e a eletrosfera. (sistema planetário). O mais utilizado hoje nas escolas é o modelo atômico de Bohr, no qual o núcleo incluiu prótons e nêutrons e a eletrosfera é organizada em camadas, no qual estão localizados os elétrons. O modelo atômico de Schrödinger é uma forma comum usada para designar a descrição do átomo por meio da resolução da equação de Schrödinger. A equação é concebida com base em importantes observações obtidas dentro da mecânica quântica, trazendo uma justificativa robusta para a energia do átomo e do elétron. O átomo é baseado na dualidade onda-partícula, no princípio da incerteza. Trouxe grandes avanços para a compreensão da matéria, pois abriu caminho para uma compreensão mais sólida de átomos polieletrônicos

Metformin and lamotrigine sorption on a digestate amended soil in presence of trace metal contamination

12 Páginas.-- 7 Figuras.-- 3 Tablas. Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC)The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12-39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 - 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 861088.Peer reviewe

M2ex project. Trace metal fate in soil after application of digestate originating from the anaerobic digestion of non-source-separated organic fraction of municipal solid waste [Dataset]

Exploiting metal-microbe applications to expand the circular economy (M2ex) GA no 861088, 1 Excel fileDigestate originating from anaerobic digestion of non-source-separated organic fraction of municipal solid waste (OFMSW) is produced abundantly worldwide and generally discarded in landfills. However, it can be a valuable resource for many bioeconomy strategies as land restoration, only if a consolidated understanding of the contaminants’ presence and behaviour in digestate-amended soil is achieved. This study aimed to investigate the fate of trace metals, namely Zn, Cu, Pb, and Cr found in the digestate, along the soil profile after digestate application on soil, and the influence that other contaminants as pharmaceutical compounds can have on their behaviour in the soil system. For that, a 90-day soil column experiment was conducted using a fine loamy sand soil topped with a layer of digestate-amended soil. Digestate-amended soil had a soil to digestate proportion of 14 to 1 (dry weight). Two experimental conditions were tested: soil amended with digestate, and soil amended with digestate spiked with the antidiabetic drug metformin. Soil samples were taken at 4 depths on days 1, 7, 21, 35 and 90, and total trace metals concentrations and fractionation was determined via atomic absorption spectroscopy. Results showed that Zn, Cu, Pb ad Cr initially present in the digestate were transferred from the digestate-amended soil layer to the underlying soil layer over time, although in low amounts. Nevertheless, no transfer was detected to the deeper soil layers. Trace metals in soil were predominantly in immobile and less bioavailable forms associated with clay and silicate mineral groups, whereas in the digestate-amended soil they were in more bioavailable forms, which could be related also to metals’ migration in the soil layers below. Results also show that the presence of metformin had no influence on trace metal behaviour, giving insight also on possible interactions with other potentially present contaminants as microplastics. The current study showed that OFMSW digestate can be a promising organic nutrient-rich matrix for land restoration even if it may contain high metals’ concentrations because low metal mobility along the soil profile can be expected.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 861088.Peer reviewe

DataSheet1_Trace metal fate in soil after application of digestate originating from the anaerobic digestion of non-source-separated organic fraction of municipal solid waste.docx

Introduction: Digestate originating from anaerobic digestion of non-source-separated organic fraction of municipal solid waste (OFMSW) is produced abundantly worldwide and generally discarded in landfills. However, it can be a valuable resource for many bioeconomy strategies as land restoration, only if a consolidated understanding of the contaminants’ presence and behaviour in digestate-amended soil is achieved. This study aimed to investigate the fate of trace metals, namely Zn, Cu, Pb, and Cr found in the digestate, along the soil profile after digestate application on soil, and the influence that other contaminants as pharmaceutical compounds can have on their behaviour in the soil system.Methods: For that, a 90-day soil column experiment was conducted using a fine loamy sand soil topped with a layer of digestate-amended soil. Digestate-amended soil had a soil to digestate proportion of 14 to 1 (dry weight). Two experimental conditions were tested: soil amended with digestate, and soil amended with digestate spiked with the antidiabetic drug metformin. Soil samples were taken at 4 depths on days 1, 7, 21, 35 and 90, and total trace metals concentrations and fractionation were determined via atomic absorption spectroscopy.Results: Results showed that Zn, Cu, Pb ad Cr initially present in the digestate were transferred from the digestate-amended soil layer to the underlying soil layer over time, although in low amounts. Nevertheless, no transfer was detected to the deeper soil layers. Trace metals in soil were predominantly in immobile and less bioavailable forms associated with clay and silicate mineral groups, whereas in the digestate-amended soil they were in more bioavailable forms, which could be related to metals’ migration in the soil layers below. Results also show that the presence of metformin had no influence on trace metal behaviour, giving insight also on possible interactions with other potentially present contaminants as microplastics.Conclusion: The current study showed that OFMSW digestate can be a promising organic nutrient-rich matrix for land restoration even if it may contain high metals’ concentrations because low metal mobility along the soil profile can be expected.</p