No abstract

Phenolic compounds are important industrial wastes, and are classified as hazardous substances contaminating groundwater resources. Therefore, the removal or diminish of these organics compounds in order to reach the permitted levels before discharging becomes a challenging. Several processes have been developed to remove phenolic compounds from waters, including electrochemical oxidation, redox reactions, membrane separation and photocatalytic degradation. Recently, tendency of phenolic compounds removal involves adsorption and photocatalytic process, using synthetic or natural particles, such as carbon materials and clays. Actually, materials in nanometric scale play an important role in the processes previously mention due to their unique chemical and physical properties. In this book chapter, the first part shows the chemical properties of phenolic compounds that play an important role in the removal process. In the second part, different materials in macro, micro and nanosize used as adsorbents or photocatalysts are reviewed. In addition, other removal processes of phenolic compounds as electrochemistry and redox reactions are included. The removal conditions in these process, such as pH, adsorbate and adsorbent concentration are analyzed and discussed. Furthermore, special emphasis is included in micro and nanocarbon materials, used as adsorbents or photocatalyst to remove phenol from water in recently researches.

Uma propriedade importante do solo é a capacidade de retenção de água, em especial no estado não saturado. Utilizando o método do papel filtro determinaram-se as curvas características de amostras compactadas considerando-se 3 condições 0%, 0,25% e 0,50% de fibras em peso. Utilizou-se no estudo a fibra natural pena de frango. Os resultados indicaram a contribuição das fibras para a redução da retração do material. O teor de fibras de 0,25% não apresentou mudanças relevantes na curva de retenção, o teor de 0,50% permitiu destacar o papel dos vazios da pena como fator fortemente influente no solo em condições não saturadas.

En este trabajo se presenta el estudio de las propiedades dieléctricas tales como capacitancia, permitividad relativa er:, (constante dieléctrica σ) en compuestos polímero-queratina. Varias muestras fueron medidas y analizadas para evaluar la influencia de la queratina a diferentes concentraciones. La capacidad de aislamiento eléctrico del polietileno se mantiene aun cuando se introducen fibras de queratina, además de bajar moderadamente su nivel de rompimiento dieléctrico, conservando su nivel de disipación resistiva. Por otro lado, el aumento en la concentración de queratina en compuestos de glicerol disminuye su capacidad dieléctrica y de aislamiento, disminuyendo significativamente su rigidez y pérdidas dieléctricas. De acuerdo a los resultados obtenidos es posible obtener nuevos materiales con distintas propiedades dieléctricas y de aislamiento eléctrico, basados en la utilización de un material considerado como desecho industrial (las plumas de ave), las cuales contienen altas concentraciones de queratina.

A near-field electrospinning configuration has been developed to fabricate 3D structures by layer-by-layer stacking. The system or experimental setup consists of a high voltage source, a syringe pump, and the electrospinning equipment which has been designed and built. It works with Arduino Uno as a controller for adjusting the procedural parameters through OpenBuilds CONTROL software using a firmware preloaded on the Arduino Uno. The proposed experimental configuration consists of a collinear arrangement between the spinner and the sharp electrode, which move in the XY directions, keeping the same disposition; this arrangement is designed with the aim of manipulating the electric field (EF) and reducing instabilities associated with the process. The displacement speed (DS) and the distance of work adjust automatically to modify nanofiber features, which improves the flexibility of the system. In order to be efficient and set the EF profile, this was simulated using COMSOL Multiphysics® software. Nylon 6,6 polymeric fiber films have been electrospun to evaluate the efficiency of the system setup and the influence of parameters. The fiber morphology is studied by scanning electron microscopy and the chemical structure features are studied by infrared spectroscopy. Parameters such as voltage and DS are studied experimentally and analyzed to determine their effects on the control of fiber deposition. Stacking of up to 15 layers was obtained where the structural characteristics notably depend on the operating parameters.