Catalytic pyrolysis of coconut oil with Ni/SBA-15 for the production of bio jet fuel.

Catalytic pyrolysis of vegetable oil is one of the potential routes to convert oil to drop-in biofuels, known as renewable hydrocarbons. In this paper, we explored catalytic pyrolysis of coconut oil using SBA-15 impregnated with Ni in proportions of 1% to 5% to produce sustainable aviation fuel. The catalysts were synthesized, calcined and then characterized by XRD, FTIR, SEM, and EDS. In order to better understand the behavior of this process, thermal and kinetic studies were carried out by thermogravimetry. The TG curves of vegetable oil with (10%) and without catalysts were obtained at heating rates of 5, 15 and 20 °C min-1, in the temperature range between 30 and 600 °C. The kinetic parameters were calculated by the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) methods. In the kinetic study, lower heat rates promoted higher conversions and the KAS model suits the process. The results calculated for the OC sample using the two kinetic models showed an increase in the E a energy as the conversion progressed to a certain point. Catalytic pyrolysis experiments were performed in a one-stage tubular reactor at 500 °C with a catalyst loading of 10 wt% on the basis of mass of oil. The catalyst with 5% Ni showed greater presence of hydrocarbons and greater formation of water, indicating that the deoxygenation process occurred through decarbonylation. With this, the present study was successful in the development of methodologies for obtaining hydrocarbons with a composition close to that of drop-in fuels, compared to the process carried out with vegetable oil in the absence of catalysts.

Electrochemical treatment of real petrochemical effluent: current density effect and toxicological tests.

This work aims to investigate the electrochemical treatment of petrochemical industry effluents (from the northwest region of Brazil) mediated by active chlorine species electrogenerated at ruthenium-titanium oxide supported in titanium (Ti/Ru0.3Ti0.7O2) and boron doped diamond (BDD) anodes by applying 15 and 45 mA cm-2. Chemical oxygen demand (COD) determinations and toxicity analyses were carried out in order to evaluate the process extension as well as the possible reuse of the wastewater after treatment. Toxicity was evaluated by assessing the inhibition of lettuce (Lactuca sativa) stem growth, seed germination, and the production of nitrite (NO-2) and nitrate (NO-3) species. Results clearly showed that the best COD reduction performances were reached at the BDD anode, achieving almost 100% of removal in a short time. Degradation of nitrogen-organic compounds generated NO-2 and NO-3 which act as nutrients for lettuce. Toxicity results also indicated that the electrogenerated active chlorine species are persistent in the effluent after the treatment, avoiding the stem growth, and consequently affecting the germination.

The synergic persulfate-sodium dodecyl sulfate effect during the electro-oxidation of caffeine using active and non-active anodes.

It has previously been established during the elimination of organic matter that the addition of sodium dodecyl sulfate in solution is an important condition in the electrochemical oxidation approach that allows to increase the production of persulfate, enhancing the efficacy of the treatment. This outcome was observed when using the anodic oxidation with boron doped diamond (BDD), the extra production of persulfate was achieved after the SDS-sulfate released in solution and it reacts with hydroxyl radicals electrogenerated at BDD surface. However, this effect was not already tested by using active anodes. For this reason, the effect of sodium dodecyl sulfate (SDS) during the electrochemical treatment of caffeine was investigated by comparing non-active and active anodes performances. A significant decrease on the oxidation efficiency of caffeine was observed by using Ti/IrO2-Ta2O5 anode at high current density when SDS was added to the solution. Conversely, at BDD anode, the presence of SDS enhanced the degradation efficiency, depending on the applied current density. This behavior is mainly due to the degradation of SDS molecules, which allows to increase the amount of sulfate in solution, promoting the production of persulfate via the mechanism involving hydroxyl radicals when BDD is used. Meanwhile, no oxidation improvements were observed when Ti/IrO2-Ta2O5 anode was employed, limiting the caffeine oxidation. Results clearly showed that the surfactant concentration had little influence on the degradation efficiency, but this result is satisfactory for the BDD system, since it demonstrates that effluents with complex matrices containing surfactants could be effectively degraded using the electrooxidation technique. Degradation mechanisms were explained by electrochemical measurements (polarization curves) as well as the kinetic analysis. Costs and energy consumption were also evaluated.