Abstract. Babassu endocarp were used to prepare activated carbons by physical activation via microwave radiation for the first time. The pyrolysis temperature was 600°C and the derived biochar were activated in CO 2atmosphere at 700, 750 and 800°C for 30 min. The material was characterized using scanning electron microscopy (SEM). The porous properties of the activated carbons obtained including the Brunauer-Emmett-Teller (BET) surface area, pore volume, and average pore diameter were determined by nitrogen adsorption isotherms at 77.32 K. The experimental results showed that most pores occurred during the activation predominantly as micropores. Endocarp babassu can be used as precursor to produce activated carbon with a rather well-developed porosity by pyrolysis and physical activation by two-steps with CO2 activation via microwaves radiation. The activated carbon, with a low production cost, could be suitable for applications in gaseous pollutant adsorption, adsorb iodine, methylene blue, and residual chlorine.
The high temperature oxidation behavior of two ferritic stainless steels type AISI 430A and AISI 430E is examined at low oxygen pressure and high temperatures. The AISI 430A steel is ferritic up to 860 °C. Above this temperature, this steel is bi-phased: presence of austenite and ferrite phases. The 430E steel is stabilized with Nb, and is ferritic at all temperatures. The oxidation experiments were performed in a thermobalance SETARAM TGDTA 92, in the range of 850-950 °C, in Ar/H 2 /H 2 O atmosphere, under oxygen partial pressures lower than 1.3 x 10 -18 atm. The microstructure and the composition of the oxide scales were analysed by scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). Different oxidation behaviors in AISI 430A and AISI 430E stainless steels were observed. At 850 °C, the oxidation of the 430A steel is greater than that of the 430E steel, but above 900 °C the oxidation of the 430A steels is lower than that of the 430E steel. The oxidation rate of the 430A steel shows low dependence on temperature, while the oxidation of the 430E follows an Arrhenius law, with an activation energy corresponding to the chromia scale growth.
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