Adriana D. Ballarini

A Simple Way to Produce γ-Alumina From Aluminum Cans by Precipitation Reactions

In this paper, a new way for γ-alumina synthesis was proposed, the raw material being aluminum powders obtained by high-energy milling of aluminum cans. This seems a good option for this metal recycling and energy saving, as well as hydrogen production. The materials were prepared by precipitation techniques, in which aluminum powders reacted with hydrochloric acid, giving aluminum chloride, which was subsequently transformed into aluminum hydroxide by reaction with ammonium hydroxide or sodium hydroxide as precipitant agents, and finally into γ-alumina by calcination. Results showed that the used preparation methods gave a γ-alumina structure, confirmed by XRD, with surface areas values (174 and 204 m2 g-1) close to those of a commercial γ-alumina Cyanamid Ketjen (180 m2 g-1) or an alumina prepared by a typical precipitation route (203 m2 g-1). Using sodium hydroxide as precipitant agent turned out to be more ecologically compatible since it did not release harmful environmental compounds.

Performance of Nickel Supported on γ-Alumina Obtained by Aluminum Recycling for Methane Dry Reforming

In this paper, Ni/Al2O3 catalysts were prepared by using alumina synthesized from aluminum can powders, with or without ink. The catalysts produced were tested for methane dry reforming and showed not only high methane conversion (68–80%), but carbon dioxide (75–90%), selectivity to hydrogen (80–83%) as well as and H2/CO molar ratio close to 1. Therefore, it is a promising idea for future industrial applications. The results also showed that contaminant metals present in aluminum cans could affect the catalysts properties.Graphical Abstract

n-DECANE DEHYDROGENATION ON BIMETALLIC PtSn AND PtGe CATALYSTS PREPARED BY DIP-COATING

The catalytic performance of Pt, PtSn and PtGe supported on γ-Al2O3 (γ-A) deposited by dipcoating of spheres of α-Al2O3 (α-A) was studied in the n-decane dehydrogenation. The effect of Sn and Ge addition to Pt on the activity and selectivity was analyzed. The catalytic characterization was carried out using cyclohexane dehydrogenation (CHD), cyclopentane hydrogenolysis (CPH), temperature-programmed reduction (TPR), hydrogen chemisorption, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and scanning electronic microscopy (SEM). Pt(0.5)Sn/γ-A/α-A catalyst had the best catalytic performance and showed a low electronic interaction between the metals, with a surface segregation of Sn and the presence of oxidized Sn stabilized on the support. PtGe catalysts presented strong interactions with probable alloy formation. The catalytic performance of these catalysts is comparable to that reported in the patents.