Resumo Carvão ativado granular foi impregnado com 1% de ferro e 0,5% de manganês (m/m) para remoção de glifosato em soluções aquosas. O adsorvente foi caracterizado por microscopia eletrônica de varredura, espectroscopia de energia dispersiva, técnicas de adsorção de nitrogênio e análises de potencial zeta. Estudos em batelada foram realizados para investigar os mecanismos de equilíbrio, cinética de adsorção e informações termodinâmicas. Com relação ao tempo de contato e capacidade máxima de adsorção, a adsorção de glifosato aumentou com o tempo de contato e alcançou o equilíbrio em 24 h, com uma capacidade máxima de adsorção de 9,19 mg g-1 a 45°C. Os dados experimentais cinéticos em batelada foram ajustados ao modelo de pseudo-segunda ordem com R2>0,99. Experimentos de equilíbrio foram realizados a 5, 15, 25, 35 e 45°C. As isotermas de adsorção ajustaram-se melhor usando o modelo de Freundlich (R2>0,98), indicando uma adsorção multicamadas do glifosato. Estudos termodinâmicos mostraram que a adsorção de glifosato sobre carvão ativado granular impregnado com manganês e o ferro foi espontânea e viável (ΔG°<0), endotérmica (ΔH°= 20.924 kJ mol-1) e com ΔS° de -73,250 J mol-1 K-1, indicando uma diminuição da entropia do sistema na interface sólido-líquido durante o processo de adsorção do glifosato ao adsorvente.. Assim, o adsorvente desenvolvido neste trabalho mostrou-se uma alternativa para a remoção do glifosato em processos de tratamento e purificação de água.

Abstract Granular activated carbon was loaded with 0.5% manganese and 1.0% iron (m/m) for glyphosate removal from aqueous solutions. The adsorbent material was characterized by scanning electron microscopy, dispersive energy spectrometry, nitrogen adsorption techniques and zeta potential analyses. Batch studies were performed to investigate the adsorption equilibrium, kinetics mechanisms and to obtain thermodynamic information. Glyphosate adsorption increased with the contact time and achieved equilibrium within 24 h, with a maximum adsorption capacity of 9.19 mg g-1 at 45°C. Batch kinetic experimental data obeyed the pseudo-second-order model with R2>0.99. Adsorption isotherm experiments were carried out at 5, 15, 25, 35 and 45°C. The adsorption isotherms presented a better fitting using the Freundlich model (R2>0.98), indicating a multilayer adsorption of glyphosate. Thermodynamics studies showed that the adsorption of glyphosate onto granular activated carbon loaded with manganese and iron was spontaneous and feasible with negative values of ΔG°, endothermic with ΔH° of 20.924 kJ mol-1 and ΔS° of -73.250 J mol-1 K-1, suggesting a decrease in randomness at the solid-liquid interface between glyphosate and the adsorbent. The experimental results demonstrated that activated carbon loaded with manganese and iron may be an alternative for glyphosate removal in water, wastewater treatment and purification processes.

In this article was developed a green synthesis of CuO nanoparticles on vegetal activated carbon (VAC), using pomegranate leaf extract as reducing and stabilizing agent in the removal of multiple pollutants. The impregnated carbons with CuO nanoparticles were characterized morphologically and structurally. The SEM and XRD analysis, after carbons modification, showed that the surface structure remained porous with CuO nanoparticles sizes between 40 and 78 nm. As concern to the contaminants atrazine, caffeine and diclofenac, it is observed that the maximum adsorption capacities practically did not suffer interference by the presence of 1.5% Cu nanoparticles, keeping their values very close to those obtained with pure carbon. The nitrate removal was favored by the impregnation of CuO nanoparticles, from 0.93 mg g-1 to 4.09 mg g-1. The results are promising and demonstrate that it is possible to obtain VAC impregnated whit nanoparticles of CuO by a non-polluting and low cost method.

Neste trabalho avaliou-se a eficiência de diferentes agentes coagulantes no processo de coagulação/floculação no tratamento de efluente de uma indústria de galvanoplastia. Foram avaliados coagulantes do tipo inorgânico (cloreto férrico e sulfato de alumínio) e orgânico (quitosana e sementes de moringa, Tanfloc SG e Acquapol C1). Os parâmetros avaliados foram cor e turbidez. Os testes foram realizados em Jar-Test, utilizando uma velocidade de 120 rpm e um tempo de 1,5 min para a mistura rápida e 20 rpm e 15 min para a mistura lenta. O agente coagulante quitosana apresentou-se como mais promissor para a remoção de cor e turbidez em efluentes de galvanoplastia, removendo 97,76% de cor e 98,06% de turbidez, para a concentração de 7 ppm e tempo de sedimentação de 20 min.

In this work it was evaluated the efficiency of different coagulants agents in the process of coagulation/flocculation in the treatment of effluent from an electroplating industry. The following coagulants were evaluated: inorganic (ferric chloride and aluminum sulfate) and organic (chitosan and seeds of moringa, Tanfloc SG and Acquapol C1). The parameters evaluated were color and turbidity. The experiments were carried out in Jar-Test using a speed of 120 rpm and a time of 1.5 min for fast mixture and 20 rpm and 15 min for the slow mixture. The chitosan coagulant agent presented as more promising for the removal of color and turbidity in effluents from electroplating, removing 97.76% to 98.06% of color and turbidity, respectively for the concentration of 7 ppm and the sedimentation time of 20 min.

This paper describes the synthesis of asymmetric polymer membranes used for the production of drinking water. Filtration of water through the membranes is an alternative method for water treatment, where the membrane acts as a selective barrier which blocks the passage of some components. Water samples for this study were inoculated with 10(7) to 10(8) colony forming units (CFU) of Escherichia coli per ml. The process used was phase inversion, and the membranes were prepared beginning with polymer solutions, including polysulfone and polyvinylidene fluoride. In both cases polymethyl methacrylate was added to the polymeric solutions, using N,N-dimethylformamide as solvent. Some of the membranes prepared achieved bacterial removal of 99 to 100%, at a flow of 300 L/h m²

En este trabajo se presenta un estudio sobre la síntesis de membranas poliméricas asimétricas para la producción de agua potable. La filtración usando membranas es un proceso alternativo para el tratamiento de aguas, donde la membrana actúa como una barrera selectiva que bloquea el pasaje de algunos componentes. En este trabajo algunas muestras de agua fueron infectadas con 10(7) a 10(8) unidades formadoras de colonias (UFC) por ml con la bacteria Escherichia coli. El proceso utilizado fue la inversión de fases y las membranas fueron preparadas a partir de soluciones poliméricas, con polisulfona y con fluoruro de polivinilideno. En ambos casos, se agregó poli metacrilato de metilo a las soluciones poliméricas, usando N,N-dimetilformamida como solvente. Algunas membranas removieron entre 99 y 100% de las colonias bacterianas, con un flujo de 300 L/h m²