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O estudo químico de plantas classificadas como medicinais desperta o interesse na composição química das mesmas. A presente pesquisa teve como objetivo realizar testes fitoquímicos em espécies vegetais medicinais do Bioma Pampa da Microrregião da Campanha Ocidental do Estado do Rio Grande do Sul. Cascas e folhas foram coletadas, baseado em informações adquiridas com pessoas residentes na região, que utilizam e conhecem plantas usadas para fins medicinais. As características de cada espécie foram anotadas. A triagem fitoquímica das plantas coletadas foi realizada pela metodologia da Prospecção Preliminar, realizando testes para as classes de metabólitos de taninos, saponinas, alcalóides, terpenos, flavonóides, esteróides e triterpenóides. Os extratos foram feitos com etanol 95% e os testes foram realizados com reagentes específicos para cada classe de substâncias pesquisada. Os testes foram considerados positivos por reações de precipitações, coloração e formação de precipitado. Com os dados obtidos, verificou-se a classe de metabólitos que apresentam maior expressividade. Normalmente a população procura plantas que acreditam ter atividades antinflamatória, digestiva, antibacteriana, antifúngica, dentre outras. As classes de metabólitos podem sinalizar preliminarmente as possíveis atividades das plantas medicinais.

A Quimica e uma ciencia que busca compreender os processos naturais e nao-naturais que ocorrem no nosso meio, tornando-se importante a compreensao no que tange a alimentacao do ser humano. A intencionalidade deste estudo se faz acerca dos habitos alimentares saudaveis por estudantes do ensino medio da Educacao de Jovens e Adultos – EJA, no municipio de Alegrete/RS. A proposta se da em tres etapas: a primeira denominada de Pre-Oficina que foi realizada por meio de um questionario investigativo. A segunda foi a abordagem de conceitos de Carboidratos, Proteinas e Lipidios e sua finalizacao, por meio de uma palestra. E a terceira etapa foi a Pos-Oficina, na qual foi realizado um questionario avaliativo. Com os resultados obtidos, verificou-se que os estudantes desconheciam os conceitos “corretos” referentes ao Colesterol e que houve evolucao nas concepcoes dos estudantes acerca dos topicos estudados, bem como da tematica abordada. Desta forma, contatou-se que a intervencao promoveu a contextualizacao dos conteudos quimicos e uma proximidade com a ciencia.

Polycyclic aromatic hydrocarbons (PAHs) are classified as persistent organic pollutants found in all environmental compartments and in certain concentrations may present health risks. This work com...

Wheat husks (Fagopyrum esculentum) were modified by treatment with sulfuric acid. The precursor material (FEWS) and the modified material (TFEWS) were characterized by different techniques to identify the structural changes promoted by the chemical treatment. Subsequently, TFEWS was applied as an adsorbent to remove the 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide from aqueous solutions. Adsorption studies considered the pH effects and adsorbent dosage on the sorption capacity. Also, it evaluated the kinetics, equilibrium, and thermodynamic behavior. Also, the TFEWS was used to treat spiked-pesticide river waters to check its applicability in actual situations. It was found that the pH of the solution had a strong influence on the adsorption process, selecting pH 2 for the subsequent experiments. Regarding the adsorbent dosage, the best relationship between the percentage of herbicide removal (45%) and the material’s adsorption capacity (24 mg g-1) occurred at 0.95 g L-1. The Avrami-fractional order (also known as Bangham) kinetic model better represented the experimental data. In contrast, the Liu model showed the best adjustment of the equilibrium isotherms of the system, reaching a Qmax of 161.1 mg g-1 at 298 K. The thermodynamic behavior pointed to be spontaneous, favorable, and exothermic, consistent with a mechanism involving electrostatic interactions. The material application in situations close to the actual ones presented 76.00 and 76.30% removals for the simulated effluent of the “Conceicao” and “Jacui” rivers, respectively.

In the present work, multi-walled carbon nanotubes (MWCNTs) were used as support material for the impregnation of metallic nanoparticles (MNPs) produced by green synthesis. The influences of the plant extracts (pomegranate (Punica Granatum), Eucalyptus, and pecan (Carya illinoinensis, leaves), metal species (copper and iron), metallic concentrations, and type of functionalization (OH and COOH) on the characteristics of the obtained materials were studied. The precursor and impregnated MWCNTs were characterized through X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, point of charge, N2 adsorption/desorption isotherms and, X-ray photoelectron spectroscopy. All the synthesized materials were tested as adsorbents to remove glyphosate (GLY) in an aqueous medium. The MWCNTs were resistant to withstand the synthesis process, preserving its structure and morphological characteristics. The copper and iron on the surface of MWCNTS confirm the successful synthesis and impregnation of the MNPs. The MWCNTs impregnated with high metallic concentrations showed favorable adsorption of GLY. The adsorption capacity and percentage of removal were 21.17 mg g−1 and 84.08%, respectively, for the MWCNTs impregnated with iron MNPs using the pecan leaves as a reducing agent. The results indicated that an advanced adsorbent for GLY could be obtained by green synthesis, using MWCNTs as precursors and pecan leaves as a reducing agent.

Real hospital wastewater was effectively treated by a promising technology based on degradation reaction catalyzed by Fe0 under microwave irradiation in this work. Fe0 powders were synthesized and characterized by different techniques, resulting in a single-phase sample with spherical particles. Optimum experimental conditions were determined by a central composite rotatable design combined with a response surface methodology, resulting in 96.8% of chemical oxygen demand reduction and 100% organic carbon removal, after applying MW power of 780 W and Fe0 dosage of 0.36 g L−1 for 60 min. Amongst the several organic compounds identified in the wastewater sample, diclofenac and ibuprofen were present in higher concentrations; therefore, they were set as target pollutants. Both compounds were completely degraded in 35 min of reaction time. Their plausible degradation pathways were investigated and proposed. Overall, the method developed in this work effectively removed high concentrations of pharmaceuticals in hospital wastewater En este trabajo, las aguas residuales hospitalarias reales fueron tratadas eficazmente mediante una tecnología prometedora basada en la reacción de degradación catalizada por Fe0 bajo irradiación de microondas. Los polvos de Fe0 se sintetizaron y caracterizaron mediante diferentes técnicas, dando como resultado una muestra monofásica con partículas esféricas. Las condiciones experimentales óptimas se determinaron mediante un diseño central compuesto giratorio combinado con una metodología de superficie de respuesta, lo que resultó en una reducción del 96,8% de la demanda química de oxígeno y una eliminación del 100% de carbono orgánico, después de aplicar una potencia de MW de 780 W y una dosis de Fe0 de 0,36 g L − 1. durante 60 min. Entre los varios compuestos orgánicos identificados en la muestra de aguas residuales, el diclofenaco y el ibuprofeno estaban presentes en concentraciones más altas; por lo tanto, se establecieron como contaminantes objetivo. Ambos compuestos se degradaron completamente en 35 min de tiempo de reacción. Se investigaron y propusieron sus posibles vías de degradación. En general, el método desarrollado en este trabajo eliminó de manera efectiva las altas concentraciones de productos farmacéuticos en las aguas residuales de los hospitales.

Carbon nanotubes with multiple walls (MWCNTs) were modified via green synthesis methodology, with metal nanoparticles (MPNs-Fe). The prepared material (MWCNT/MPNs-Fe) was characterized and used to remove the herbicide glyphosate (GLY) from an aqueous matrix through the adsorption process. The characterization results indicated the presence of MPNs-Fe incorporated between the tangled wires of the MWCNTs, thus confirming the green synthesis success. The kinetic studies showed a percentage of GLY removal of up to 86.23% (for C0 = 35 mg L−1), with the process equilibrium being reached in 120 min. The pseudo-first-order model demonstrated a greater prediction capacity for the system. The Sips isotherm model was best suited to the equilibrium data, providing a maximum adsorption capacity of 43.66 mg g−1 (298 K). The thermodynamic behavior showed that the process is spontaneous and favorable, with exothermic nature. The material's application in close to real circumstances presented the removals of 68.38% and 40.33% for two simulated effluents with different compositions. The adsorption regeneration tests found that the adsorption kept similar adsorption capacities after six cycles. Therefore, it can be concluded that the MWCNT/MPNs-Fe synthesized in the present work is a promising alternative as an adsorbent in the treatment of effluents and waters containing GLY.

Rare earth elements (REE) are classified as light and heavy and present the lanthanide contraction effect, which keeps ionic radius and ΔfH° values between REE very close. Many information on thermodynamic parameters such as ΔfH°, ΔfS°, ΔfG° and S° of REE compounds have been reported in recent decades. To obtain a consistent mathematical interpretation of these data, a multivariate statistical study was performed using Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) to compile and compare relevant information about the thermodynamic properties of REE. The PCA identified four distinct groups of linkers: halides, oxyanions, REE3+ hydrate group and REE2+ halides group. Analysis of HCA performed with the values of ΔfH°, ΔfS°, ΔfG° and S°, separated the compounds (REE)FeO3, (REE)PO4, (REE)2O3, (REE)O2, (REE)2O2CO3 II, (REE)2Zr2O7 and REE(OH)3, according to their molecular characteristics. Due to the greater influence of ΔfH° in relation to the other parameters, an HCA considered only ΔfH° was performed, classifying REE into three groups, Eu, LREE and HREE. Therefore, this work shows how multivariate statistical tools can help us to better understand the thermodynamics of REE.