There are several technologies for the treatment of oily wastewater generated by the oil industry, not only to separate the emulsified oil in water, but also to reduce its concentration in the aqueous effluent. Among the processes of separation, the separation using membranes should be highlighted when they become an effective material and it also resistant to high temperatures, have good corrosion resistance, easy to clean, and have long life operation, among others. This work aims to synthesize the material (ZSM-5, γ-alumina membrane, and zeolite membrane ZSM-5/γ-alumina) and to evaluate the membranes in the oil/water separation in a continuous flow system. From the XRD results of the individual materials, it can be observed the formation of all the characteristic peaks for each material. The EDX analysis of zeolite ZSM-5 showed the formation of this material with a Si/Al = 19. From the SEM image of these materials, it can be seen that the surface of the γ-alumina is completely covered with ZSM-5 zeolite crystals. The oil/water removing, using ZSM-5 γ-alumina membrane, showed high retention of the oil, obtaining a higher performance in relation to γ-alumina membrane. This reveals that the insertion of ZSM-5/γ-alumina in the material makes that this new material acquires a lower porosity, obtained by decreasing the passage of oil molecules through the membrane structure.
The aim of this work was to evaluate the catalytic properties for n-hexane isomerization of bifunctional monometallic (Ni or Pt) and bimetallic catalysts (Pt-Ni), using HMOR zeolite as support. The method used for metal dispersion in the zeolite was competitive ion exchange using ammine complexes [Ni(NH 3) 6 ]Cl 2 and [Pt(NH 3) 4 ]Cl 2 as precursors. The catalysts were characterized by X-Ray diffraction, X-Ray energy dispersion spectroscopy, temperature-programmed reduction and transmission electron microscopy. The n-hexane isomerization reaction using the catalysts was carried out to evaluate the catalyst activity. The reaction was carried out in a fixed bed reactor operating at 250˚C, 1 atm, H 2 /C 6 = 9 molar ratio. The profiles obtained from TPR suggest that, for bimetallic catalysts, the presence of platinum facilitates the reduction of Ni 2+ cations. The bimetallic catalysts presented a higher activity in the isomerization of n-hexane when compared to the monometallic ones, as well better stability as the Pt content in the solid increases.
The thermal and catalytic degradation of high‐ and low‐density polyethylene (HDPE and LDPE, respectively) and waste plastic film (polyethylene‐based plastic wastes) were analyzed through simultaneous thermogravimetry and differential scanning calorimetry in inert atmosphere. Catalytic degradation was performed using MFI (HZSM‐5) zeolites. Although the catalyst induces a large decrease of the degradation temperature for polyethylene, it has a smaller effect on the waste plastic (WP) degradation temperature. To check the activity of the catalyst after its use in the WP degradation, experiments were conducted with fresh HDPE which confirmed a significant loss of catalytic activity. Mixtures of WP with large paraffin were also analyzed (nC50). The results show that the presence of the hydrocarbon in the mixture grants some protection to the catalyst, allowing it to retain part of its activity during the process even in the presence of the waste contaminants. These findings suggest that larger hydrocarbon: waste plastic ratios promote higher protection to deactivation and that WP coprocessing with oil is feasible. Gas chromatography was used to analyze the products formed in the catalytic degradation of the WP in the presence C50 hydrocarbon at a ratio of 1:12, consisting mostly of light products in the range of C2 to C8 hydrocarbons.
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