The oil obtained from the thermal cracking of low-density polyethylene (LDPE) is formed mainly by linear hydrocarbons with a high quantity of olefins, which hinders the possible application of this product in the formulation of transportation fuels. However, hydroreforming of this oil using bifunctional catalysts with high accessibility to the active sites would allow for the properties of the gasoline and diesel fractions to be significantly upgraded. This is the case of the catalyst employed here because it consists of hierarchical Beta zeolite (with a bimodal micro-mesoporosity) and containing 7 wt % Ni. The presence of nickel in the catalyst increased the share of gasolines with regard to the h-Beta support. The effect of the main variables involved in the hydroreforming process has been investigated and optimized, showing that the extent of hydrocracking is favored when increasing the temperature, the pressure, and the catalyst/feed ratio, leading to enhanced gasoline yields at the expense of heavy (C 19 −C 40 ) and especially light (C 13 −C 18 ) diesel fractions because of the faster diffusion of the latter. Ni/h-Beta proved to be an especially adequate catalyst for obtaining gasolines; therefore, a maximum in the selectivity toward gasoline (up to 68.7%) was found in the hydroreforming at 40 bar of hydrogen pressure. On the other hand, the values of the bromine index indicated that 80−100% of the olefins present in the raw oil were hydrogenated depending upon the reaction conditions. In addition, the Ni/h-Beta catalyst showed high activity for aromatization and, especially, hydroisomerization reactions. Thus, a 53% share of isoparaffins in the gasolines was obtained at long reaction times. The gasoline and diesel fractions obtained showed a high research octane number (RON) (>80) and cetane indexes above specifications (>70), respectively, which is indicative of their high quality as transportation fuels.

The development of adsorption-based technologies for CO 2 capture in the postcombustion processes requires finding materials with high capacity of adsorption and low cost of preparation. In this study, the modification of a commercial activated carbon (Norit ROX 0.8), considered as a solid adsorbent for CO 2 capture, and the effects of different methods of activations, chemically (hydrogen peroxide, sulfuric acid, nitric acid, and urea) and thermally (at 800°C) on adsorption performance, have been investigated. Then, CO 2 adsorption capacity was studied at different temperatures and pressures to evaluate the effects of various agents on sample performance. The textural properties of the samples were determined using adsorption−desorption isotherms of nitrogen at −196°C. Finally, the obtained data were modeled by Response Surface Methodology (RSM) and Langmuir isotherm. The results showed that the prepared sample by successive treatments with nitric acid, urea, and thermal calcination has a higher uptake capacity than other modified samples.

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Janus-like amphiphilic carbon nanotubes (CNTs) were tested as catalysts in the oxidation of 2-nitrophenol (2-NP) with hydrogen peroxide. A biphasic oil-water medium was used to simulate oily wastewater contaminated with the lipophilic model pollutant 2-NP. The CNTs were synthesized by sequentially feeding ethylene and/or acetonitrile, used as carbon and carbon/nitrogen precursors, respectively. The results obtained for 2-NP removal using biphasic systems were compared with those obtained by CWPO using aqueous solutions. The most active catalyst in the CWPO of 2-NP in aqueous solution was the CNT synthesized only with ethylene. This was explained by its high lipophilic character, allowing the complete removal of 2NP after 24 h of reaction at 50°C, pH 0 = 3, C cat = 0.25 g L −1 , C 2-NP,0 = 0.5 g L −1 and the stoichiometric quantity of H 2 O 2 needed for the total mineralization of 2-NP. For the oxidation of 2-NP in biphasic medium, only the Janus-like amphiphilic CNTs (containing a lipophilic undoped section synthetized from ethylene and a hydrophilic N-doped section synthetized from acetonitrile) revealed catalytic activity for the removal of 2-NP. The conversion of 2NP reached in biphasic oxidation conditions was 76.7% after 24 h of reaction at 50°C, considering pH 0 = 3, C cat = 2.27 g L −1 of total volume (water/oil ratio of 16:50 v/v) and C 2-NP,oil,0 = 5 g L −1. This removal was ascribed to the formation of Pickering emulsions, by maximizing the interfacial area through an increased contact between the catalyst and both liquid phases. A kinetic model is proposed to accurately predict the experimental data and evaluate the rate constants of the process and its variation with the prepared CNTs.