UTILIZAÇÃO DE CARVÕES ATIVADOS POR PROCESSOS DE ATIVAÇÃO QUÍMICA PARA REMOÇÃO DE CÁDMIO EM MEIO AQUOSO: UMA REVISÃO SISTEMÁTICA

Resumo: Adsorção é um fenômeno físico-químico de transferência de massa no qual ocorre aumento da concentração de um adsorbato na superfície de um adsorvente. Entre as diversas aplicações para essa tecnologia, tem destaque a sua utilização em processos de tratamento de corpos hídricos contaminados com metais pesados. A partir de uma revisão sistemática, este trabalho objetiva descrever as metodologias desenvolvidas para a ativação química de carvões ativados empregados na adsorção de cádmio em meio aquoso. Os artigos, disponíveis no Portal de Periódicos da CAPES, foram selecionados a partir das palavras-chaves “adsorption of cádmium” e “chemical activation”. Foram identificados nove agentes ativantes, entre ácidos e bases, e a temperatura de ativação variou entre 90 ºC e 900 ºC. O carvão ativado com maior área superficial (1939 m2/g) e melhor potencial de adsorção (331 mg/g) foi o produzido com o agente ativante TiCl4 a 800 ºC. Desta forma, conclui-se que a metodologia de ativação química se apresenta como uma alternativa para aumentar a eficiência dos carvões ativados, possibilitando sua adoção nos processos de descontaminação de corpos hídricos, ou mesmo rejeitos industriais, contaminados com cádmio

Brachiaria brizantha (Syn. Uroclhoa brizantha) cv. Marandu bajo diferentes dosis de nitrógeno y fósforo en Humaitá-AM, Brasil

Se objetivó con este estudio evaluar la capacidad productiva de Brachiaria brizantha (Syn. Uroclhoa brizantha) cv. Marandu, sometidas a diferentes dosis de nitrógeno y fósforo. Para ello, se realizaron ensayos en condiciones de campo en el municipio de Humaitá-AM. El delineamiento experimental fue en bloques casualizados, en esquema factorial 4x4, siendo 4 dosis de nitrógeno: 0; 100; 200 y 300 kg ha-1 y 4 dosis de fósforo: 0; 100; 200 y 300 kg ha-1 y un testigo (sin fertilización), con 4 repeticiones. Las variables analizadas fueron biomasa verde y seca, en dos cortes con intervalo de 57 días. Las plantas respondieron con crecimiento lineal a las dosis crecientes de nitrógeno y fósforo durante el primer corte, mientras que el efecto residual sobre el segundo corte fue observado sólo para dosis más altas de fósforo. No hay respuesta a la fertilización fosfatada cuando no se aporta el nitrógeno y el crecimiento lineal de las plantas en función de diferentes dosis de nitrógeno es significativamente menor cuando no se aporta el fósforo.Objetivou-se com este estudo foi avaliar a capacidade produtiva de Brachiaria brizantha (Syn. Uroclhoa brizantha) cv. Marandu, submetidas a diferentes doses de nitrogênio e fósforo. Para tanto, foram realizados ensaios em condições de campo no município de Humaitá-AM. O delineamento experimental foi em blocos casualizados, em esquema fatorial 4x4, sendo 4 doses de nitrogênio: 0; 100; 200 e 300 kg ha-1 e 4 doses de nitrogênio: 0; 100; 200 e 300 kg ha-1 de fósforo: 0; 100; 200 e 300 kg ha-1 e uma testemunha (sem adubação), com 4 repetições. As variáveis analisadas foram biomassa verde e seca, em dois cortes com intervalo de 57 dias. As plantas responderam com crescimento linear às doses crescentes de nitrogênio e fósforo durante o primeiro corte, enquanto o efeito residual sobre o segundo corte foi observado apenas para doses mais elevadas de fósforo. Não há resposta à adubação fosfatada quando não aplicado o nitrogênio e o crescimento linear das plantas em função de diferentes doses de nitrogênio é significativamente menor quando não aplicado o fósforo.Objetivou-se com este estudo foi avaliar a capacidade produtiva de Brachiaria brizantha (Syn. Uroclhoa brizantha) cv. Marandu, submetidas a diferentes doses de nitrogênio e fósforo. Para tanto, foram realizados ensaios em condições de campo no município de Humaitá-AM. O delineamento experimental foi em blocos casualizados, em esquema fatorial 4x4, sendo 4 doses de nitrogênio: 0; 100; 200 e 300 kg ha-1 e 4 doses de nitrogênio: 0; 100; 200 e 300 kg ha-1 de fósforo: 0; 100; 200 e 300 kg ha-1 e uma testemunha (sem adubação), com 4 repetições. As variáveis analisadas foram biomassa verde e seca, em dois cortes com intervalo de 57 dias. As plantas responderam com crescimento linear às doses crescentes de nitrogênio e fósforo durante o primeiro corte, enquanto o efeito residual sobre o segundo corte foi observado apenas para doses mais elevadas de fósforo. Não há resposta à adubação fosfatada quando não aplicado o nitrogênio e o crescimento linear das plantas em função de diferentes doses de nitrogênio é significativamente menor quando não aplicado o fósforo

American oil palm from Brazil: genetic diversity, population structure, and core collection.

The American oil palm [Elaeis oleifera (Knuth) Cortés] has pronounced importance in oil palm breeding programs. Here, a germplasm bank (GB) of E. oleifera plants collected in the Amazon rainforest in Brazil was submitted to single nucleotide polymorphism (SNP) marker identification, selection, and use, aiming to characterize genetic diversity and population structure and to design a core collection (CC). Five hundred and fifty-three plants from 206 subsamples, collected at 19 localities spread throughout six geographic regions, were submitted to genotyping-by-sequencing analysis. A set of 1,827 high-quality SNP markers was then selected and used to run the genetic diversity and population structure analysis. The genetic diversity found is of moderate degree, and probably only a small portion of the species diversity is represented in the collection. The possible reason for that is the collecting strategy used, which collected subsamples only around the most prominent watercourses in the region. The average degree of genetic differentiation among subsamples is very high, indicating the presence of high interpopulation differentiation. The collection showed a low level of endogamy. The low average gene flow found indicates that genetic isolation caused by drift is occurring, and there is a need to review the conservation strategy. A set of 245 SNPs distributed throughout all 16 chromosomes was used to design CC based on maximizing the strategy of diversity. The optimal adjustment of the validated parameters, maintained while taking fewest subsamples, led to the choice of a model containing 20% of the entire collection as the ideal to form the CC

Atividade antifúngica de extratos vegetais sobre o crescimento in vitro de fitopatógenos

The use of pesticides in agriculture has taken risks to human health and frequent damage to the environment. Thus, the search for alternative methods to control plant diseases the aim of this study was to evaluate the in vitro fungitoxicity of plant extracts against Colletotrichum gloeosporioides fungi, Pyricularia oryzae and Fusarium oxysporum f. sp.vasinfectum. We used aqueous crude extracts of vegetative and reproductive parts of different plant species at a concentration of 20%, which were incorporated into the culture medium to evaluate the inhibition of mycelia growth. The aqueous extract of clove, controlled 100% mycelial growth of C. gloeosporioides, F. oxysporum f. sp. vasinfectum and P. oryzae. The aqueous extract of garlic has promoted high inhibition in the development of the mycelium of the fungi studied. The extracts of pepper and provided nin fungitoxicity on Fusarium oxisporum f. sp. vasinfectum and Pyricularia oryzae, respectively.O emprego de agrotóxicos na agricultura tem levado riscos à saúde humana e frequentes danos ao meio ambiente. Assim, na busca de métodos alternativos para o controle de doenças de plantas o objetivo deste trabalho foi avaliar a fungitoxidade in vitro de extratos vegetais contra os fungos Colletotrichum gloeosporioides, Pyricularia oryzae e Fusarium oxysporum f. sp vasinfectum. Foram utilizados extratos brutos aquosos de partes vegetativas e reprodutivas de diferentes espécies vegetais na concentração de 20%, os quais foram incorporados em meio de cultura para avaliação da inibição do crescimento micelial. O extrato aquoso de cravo-da-índia, controlou em 100% o crescimento micelial de C. gloeosporioides, F. oxysporum f. sp vasinfectum e P. oryzae. O extrato aquoso de alho promoveu alta inibição no desenvolvimento do micélio dos fungos estudados. Os extratos de pimenta e nin proporcionaram fungitoxidade sobre Fusarium oxysporum f. sp vasinfectum e Pyricularia oryzae, respectivamente

Removal of cationic dyes from a synthetic effluent using a calcium surfactant

The present study aimed to evaluate the removal efficiency of two types of cationic dyes of different classes – methylene blue (MB) and malachite green (MG) – from a synthetic effluent using a calcium surfactant (CaSF) originated from used frying soybean oil. The Fourier Transform Infrared Spectroscopy (FTIR) spectra showed that the functional groups present on the surface of CaSF can form surface complexes or bonds with the dye molecules and, consequently, promote their adsorption. The adsorption kinetics studies indicated that the equilibrium point of the process is reached in 90 min for both dyes. Equilibrium studies indicated that the adsorption isotherm models that best fit MB and MG were the Langmuir and the Dubinin–Radushkevich models, respectively. The maximum adsorption capacities of MB and MG, according to the Langmuir model, were 199 and 123 mg·g−1, respectively. In the sight of the high MB and MG removal efficiency (84 and 100%, respectively), the use of CaSF is an excellent alternative for the treatment of effluents contaminated by cationic dyes. The adsorption–desorption cycle studies showed that CaSF maintains a good dye removal efficiency for up to three cycles. HIGHLIGHTS Calcium surfactant (CaSF) was manufactured from the frying soybean oil residues.; CaSF is a good adsorbent for cationic dyes.; CaSF was used to remove methylene blue (MB) and malachite green (MG) from synthetic effluent.; CaSF has a high adsorption capacity (MB – 199 mg g−1; MG – 123 mg g−1).; CaSF removed 84% of MB and 100% of MG.

Removal of Toxic Metal Ions from Aqueous Solutions in Integrated Clay Adsorption and Electroflotation

Most galvanic process industries treat their effluents by chemical precipitation methods. Such a method produces an amount of galvanic sludge that is often disposed of inappropriately to the environment, causing major environmental damage. These rejects present high concentrations of toxic metallic ions, such as copper (Cu(II)), lead (Pb(II)), nickel (Ni(II)), and cadmium (Cd(II)). Several alternatives have been proposed to contribute in a cheaper and efficient way to treat these effluents. This study aimed to describe the results obtained in the removal of the concentrations of Cu(II), Ni(II), Cd(II), and Pb(II) ions, present in an aqueous solution, by the use of a hybrid system combining the adsorption and electroflotation processes simultaneously. The adsorbent materials used were two Brazilian soil clays classified as sodium clay (SC) and ferric clay (FC). For the electroflotation process, aluminum, iron, and stainless-steel electrodes were used. The obtained data showed good efficiency in the removal of the four metallic ion concentrations. The best results presented a reduction in the concentration of Cu(II), Ni(II), Cd(II), and Pb(II) ions of 50.11%, 36.71%, 21.59%, and 23.43%, respectively, when it was used the hybrid system formed by the ferrous clay as adsorbent and the aluminum electrode for the electroflotation process

Antibacterial enhancement of antibiotic activity by Enterolobium contortisiliquum (Vell.) Morong

Objective: To identify the main chemical classes of compounds from aqueous extract of Enterolobium contortisiliquum (E. contortisiliquum) seed bark and to evaluate its antibacterial activity, as well as its potential to increase the activity of antibiotics against strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Methods: Different classes of compounds in the aqueous extract of E. contortisiliquum were evaluated based on the visual changes in the coloration and the formation of precipitate after the addition of specific reagents. The antibacterial activity of the extract and its potential to increase of antibiotic activity of antibiotics drugs, gentamicin and norfloxacin was determined by using the microdilution method. Results: Our results demonstrated that the following secondary metabolites were presented in E. contortisiliquum seed bark: flavones, flavonols, xanthones, flavononols, chalcones, aurones, flavones and catechins. The extract itself had very low antibacterial activity against all bacterial strains tested (MIC ≥ 1 024 μg/mL), but there was an increase in the antibiotic activity of gentamicin and norfloxacin when combined in the sub-inhibitory concentration (i.e., MIC/8). Conclusions: Our data suggests that E. contortisiliquum seed bark may be an alternative source for new drugs with the potential to increase antibiotic activity against different strains of bacteria