Carlos Antônio Pereira de Lima

Development of Polymer Membranes Modified with a Porogenic Agent

Membrane is a barrier that separates two phases and limits wholly or partially carrying one or several chemical species present in the phases. In this study, membranes with a polyamide6 porogenic agent were obtained. The membranes were prepared as thin films by phase inversion method using the immersion technique, precipitation by varying the percentage of porogenic agent introduced and the time of exposure of the membranes during the process of immersion-precipitation. The membranes obtained were characterized by scanning electron microscopy (SEM). From the SEM photomicrographs, a large morphological change was observed over the entire surface layer of the membranes, significantly affecting the size and number of pores. Furthermore, porogenic agent promoted the formation of pores and the increase in planar microporous membranes obtained.

Study of Hybrid Membranes Prepared with the Addition of Calcium Chloride

In this work, hybrid membranes were obtained with the addition of calcium chloride (CaCl2). Hybrids were obtained by the melt intercalation method. Membranes were prepared by phase inversion technique. Hybrid and hybrid membranes were characterized by differential scanning calorimetry (DSC). The DSC curve of the polymer and polymer membrane was changed by addition of the clay, increasing the degree of crystallinity. For all membranes, it was observed the existence of two endothermic peaks corresponding to the two crystalline phases of the polymer characteristics, in the range of 220 °C related to the alpha phase and, in the range of 210 °C related the gamma phase. In addition, there was the appearance of an endothermic peak at about 70 °C, related to the temperature of the dry polymer glass transition. The addition of CaCl2 changed the crystalline behavior of hybrids, becoming less evident the nucleating effect of the clay.

Influence of the Addition of Inorganic Salt in Obtaining Hybrid Membranes

The membrane separation processes have low power consumption, higher separation efficiency, simplicity of operation and high quality end product. In this work, hybrid membranes of polyamide6 with bentonite clay were obtained by adding an inorganic salt. The hybrids were obtained by the melt intercalation method. The membranes were prepared by phase inversion technique by varying the percentage of inorganic salt and the time of exposure of the membranes during the immersion-precipitation process. The hybrid and hybrid membranes with and without the addition of the inorganic salt were characterized by X-ray diffraction (XRD). The results from XRD showed that the hybrid and hybrid membranes with and without inorganic salt presented an exfoliated and/or partially exfoliated structure. The addition of the inorganic salt did not cause significant changes with respect to the crystalline behavior of the polymer under study.

Effluent Treatment of Synthetic Tanning by Nanomaterials Photocatalytic

The industry is one of the most polluting sectors of the aquatic ecosystem. Conventional treatment methods no longer have full effectiveness. The heterogeneous photocatalysis, using TiO2 as the semiconductor (photocatalyst) is one of the most promising techniques for polishing industrial effluents. In the present study determines the best pH range, to optimize the phenomenon of adsorption, and evaluates the reduction of hexavalent chromium and the removal of organic matter in synthetic samples, using a reactor with glass plate impregnated with TiO2 and making use of solar radiation. It was observed that the acidic pH is optimal for the photocatalytic process and that there was a minimum removal efficiency of 62% and 60% for Cr (VI) and organic matter, respectively.