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The correlation between the physico-chemical properties of bare and Mo-doped nickel aluminate derived catalysts and product distribution during hydrogenolysis of glycerol with in situ produced hydrogen in continuous was investigated. Stoichiometric nickel aluminate spinel was synthesized via citrate sol-gel in a one-pot synthesis and subsequently doped it with 1 wt% Mo, using both sol-gel one-pot and impregnation methods. Catalytic runs were performed at 235 ºC/ 45 bar for 4 h TOS. The results indicate that Mo-doping increased the number of both metal and acid sites, leading to more selectivity towards deoxygenated products. 1,2-propylene glycol was the major liquid product, Mo/NiAl catalyst exhibited the highest yield (27%) and selectivity (39%). Post-reaction characterization revealed that leaching and oxidation of metals could potentially cause catalyst deactivation. 1 wt% Mo-doped nickel aluminate-derived catalysts possess potential for the selective production of 1,2-PG in a eco-friendly process through one-pot coupling H2 generation and hydrogenolysis reactions.

Biomass valorization is an essential strategy for converting organic resources into valuable energy and chemicals, contributing to the circular economy, and reducing carbon footprints. Glycerol, a byproduct of biodiesel production, can be used as a feedstock for a variety of high-value products and can contribute to reducing the carbon footprint. This study examines the impact of surface-level modifications of Mg, Cu, and Sn on Ni-Ce-Zr catalysts for the hydrogenolysis of glycerol, with in situ generated hydrogen. The aim of this approach is to enhance the efficiency and sustainability of the biomass valorization process. However, the surface modification resulted in a decrease in the global conversion of glycerol due to the reduced availability of metal sites. The study found that valuable products, such as H2 and CH4 in the gas phase, and 1,2-PG in the liquid phase, were obtained. The majority of the liquid fraction was observed, particularly for Cu- and Sn-doped catalysts, which was attributed to their increased acidity. The primary selectivity was towards the cleavage of the C–O bond. Post-reaction characterizations revealed that the primary causes of deactivation was leaching, which was reduced by the inclusion of Cu and Sn. These findings demonstrate the potential of Cu- and Sn-modified Ni-Ce-Zr catalysts to provide a sustainable pathway for converting glycerol into value-added chemicals.

In this work, we investigated the influence of the synthesis method of Ni-based CeZr catalysts on their physicochemical and catalytic properties in the hydrogenolysis (HDO) of glycerol with H2 in-situ produced by the aqueous-phase reforming (APR). Conventional impregnation method involved surface nickel deposition (NiCeZr-IM). The one-pot methods, which involved nickel embedment into CeZr lattice, included sol-gel (NiCeZr-SC) and coprecipitation (NiCeZr-CA and ultrasound-assisted NiCeZR-CS) methods. Differences in textural, structural, morphological, redox, and surface properties, together with and catalytic performance in the glycerol APR-HDO, were investigated systematically. As well, spent catalysts were deeply characterized. There were notable differences among textural properties, which significantly affected their activity in glycerol conversion. The structural characterization confirmed the successful integration of Ni into the CeZr lattice, especially for the catalysts synthesized using one-pot methods. One-pot synthesized catalysts showed stronger Ni-CeZr interaction, which affect the reducibility. The catalysts prepared by coprecipitation contained the highest metal-to-acid ratio, making them very active for C-O bond hydrogenation. Post-reaction characterization discloses a leaching of the nickel, in greater amount for both coprecipitated catalysts. This study revealed the potential of Ni-based catalysts derived from subsurface insertion of nickel into the CeZr matrix for the hydrogenolysis of glycerol without external hydrogen.

Waste glycerol obtained as by-product of biodiesel production has been submitted to a sequential physico-chemical treatment in order to make it suitable for continuous Aqueous-Phase Reforming (APR) in a tubular reactor. Special focus was given to the impact of impurities. APR was performed using 0.3%Pt/CoAl2O4 catalyst, at 260 °C and 50 bar within WHSV range 6–55 h−1 to cover whole conversion ranges. Glycerol conversion and yield to hydrogen reached 99.7% and 45.4%, respectively at WHSV = 6 h−1. The liquid product distribution strongly varied with glycerol conversion, maximum C-yield to 1,2-propylene glycol was attained in the 60–90% glycerol conversion range. APR of methanol and acetic acid aqueous feedstreams were investigated independently. It was concluded that acetic acid exerts a negative influence on catalyst stability since glycerol conversion decreased by 41% after 5 h TOS. Extensive characterization of fresh and exhausted catalysts revealed strong Co leaching, especially for acetic acid APR, oxidation of metals, and carbonaceous deposits. The basis for the regeneration of the spent catalyst, consisting of a reductive treatment at 500 °C, has been established. This work is expected to have significant implications for the development of APR technology for crude glycerol from biodiesel industry.

Porous materials based on bioapatite were prepared through the thermochemical activation of pork bone char, using different reagents (H2SO4 and K2CO3), heating atmosphere (inert and oxidizing) and activation temperature. Thermogravimetric analysis coupled to mass spectrometry was used to propose a detailed activation mechanism. Regarding the effect of each reagent on the activation, whereas that of H2SO4 is attributed to specific reactions, the effect of K2CO3 is ascribed to (i) the role of K+ as a catalyst for reactions such as the gasification of carbon and (ii) the incorporation of carbonates, involved in several reactions. The best textural properties are obtained in an oxidizing atmosphere at 350 ºC. The beneficial effect of the combustion reactions at an intermediate temperature results in a cost-effective preparation protocol. H2SO4 leads to a selective development of microporosity. The oxidizing atmosphere is involved in the generation of OH- functional groups. These results demonstrate the feasibility of configuring activation protocols to tailor the physicochemical properties of biapatite-based materials, for use in specific fields.

The potential of natural apatite derived from pork bones to be used as a support of Ni catalysts for the Water-Gas Shift (WGS) reaction was investigated. Samples of bone char were chemically treated with either K2CO3 or H2SO4 and subsequently heated in inert or oxidizing atmosphere at various temperatures. Catalysts were characterized by ICP-AES, N2 physisorption, XRD, FTIR, TG-DTG, H2-TPR, XPS, H2 chemisorption and NH3-TPD, and tested in the WGS reaction, using both ideal and realistic (mixture of H2O, CO2 and H2) feed streams. Nickel was partly exchanged with Ca2+ ions in the support. Regarding the effect of the atmosphere, an inert atmosphere had a negative effect due to the collapse of the porous structure. On the contrary, the combination of an oxidizing atmosphere and treatment with K2CO3 allowed a superior WGS performance under real reformer conditions, with a substantial decrease in the methane formation (six-fold decrease, compared to the non-activated reference catalyst). The catalytic activity could be related to the apatitic phase growing geometry, which can be tailored by the activation method.

[EN] A morphological strategy consisting of nanocasting synthesis of nickel aluminate spinel precursor was addressed. Two nanocasted catalysts were synthesized involving different template-removal procedures (i.e., Teflon-assisted calcination vs. NaOH washing) for spinel recovery. As a reference, spinel NiAl2O4 supported by SBA-15 and bare nickel aluminate spinel were selected. The obtained solids were characterized in detail, examining their textural, acid–base, structural and compositional characteristics, either in the calcined or reduced forms. The as-obtained catalysts’ performance was evaluated in the aqueous-phase reforming of glycerol at 235 °C and 35 bar. Exhausted samples were also characterized to enlighten changes in catalyst properties during the aqueous-phase reaction. NiAl/SBA-15 and NiAl-NCF catalyst showed very poor catalytic performance for the glycerol transformation. NiAl-NCN catalyst presented improved activity with respect to NiAl, with a 20% higher hydrogen production rate but, as a drawback, higher methane formation for a whole range of glycerol conversions. Exhausted catalyst indicated nickel oxidized in liquid phase reaction.

This study examined the influence of process variables (glycerol concentration in feed, coupled temperature/pressure and space velocity) in the catalytic performance in the APR of glycerol over 0.3Pt/CoAl catalyst in a continuous fixed-bed reactor in order to maximize the production of H2. The effect of glycerol concentration in the feed was studied from 5 to 20 wt%, the coupled temperature/pressure varied from 225 °C/25 bar to 260 °C/50 bar and the spatial velocity was changed from 0.68 to 17 h-1. Our results reflected that H2 production was favored at higher reaction temperature/pressure (3.62 vs. 2.49 molH2/molGly-converted, at the most severe and mild conditions, respectively), lower WHSV (3.89 vs. 1.27 molH2/molGly-converted, at the lowest and highest space velocity, respectively) and more diluted feedstocks (3.95 vs. 1.44 molH2/molGly-converted, at the most diluted and concentrated freestreams, respectively). A threshold value at 10 wt% glycerol was found for the ratio of dehydrogenation to dehydration liquid products. The post-reaction catalyst was also characterized by several techniques, showing that Co leaching was the major drawback, especially at the mildest operation conditions, while carbonaceous deposits are negligible.

Sewage sludge-based porous materials were prepared through an integrated and energy-saving procedure that combines chemical activation with an alkali (NaOH or K2CO3) and physical activation with CO2 in a single step. The study was conducted in a wide temperature range (600–1000 °C), using higher temperatures than those commonly used. From the standpoint of textural properties, the impregnation results in a decrease in the optimum activation temperature: 800 °C for untreated samples, and 600–700 °C for impregnated samples. The impregnation increases the amount of –OH and –NH functional groups, and it also leads to the generation of new oxygen- and/or nitrogen-containing functionalities (above 800 °C for the impregnation with K2CO3 and in the whole temperature range for the impregnation with NaOH). The chemical treatment favors the development of magnetic properties on biochars, which is an advantage for its reuse in wastewater treatment, since it favors the removal of anionic surfactants and heavy metals such as lead, copper, zinc, and manganese. The uptake of phenol and methylene blue (MB) is maximized with the combination of the impregnation (with NaOH for phenol and K2CO3 for MB) and the use of a moderate temperature (600–700 °C). The optimum uptake values represent an increase of 87% and 152% for MB and phenol, respectively, compared to the highest value of non-impregnated samples (activated at 800 °C), with the advantage of the lower temperature required.

Light olefins (especially, ethylene and propylene) are the key building blocks of the petrochemical industry and they are mainly used to produce polyolefins (polyethylene and polypropylene). Nowadays, light olefin demand is continuosly increasing, where ethylene demand shows an annual average rate of 3-5% and propylene of 5-7%. Ethylene demand is satisfied by ethane steam cracking (SC) process. However, in order to fulfill the propylene demand, the selectivity achieved by conventional technologies (SC and fluid catalytic cracking (FCC)) should be improved. Furthermore, these industrial technologies show a great dependence on fossil fuels and a high energy consumption.Thus, improving these conventional technologies, as well as developing alternative processes based on rewenable sources are the main challenges for the refineries and the petrochemical industries. In this work, the main applications of light olefins and their worldwide demand are firstly analyzed. Then, the conventional technologies (from fossil fuels) are described; and, finally, other sustainable techonologies are discussed, which are based on the valorization of biomass and wastes.; Olefina arinak (bereziki, etilenoa eta propilenoa) industria petrokimikoko oinarrizko lehengaiak dira eta poliolefinak (polietilenoa eta polipropilenoa) ekoizteko erabiltzen dira nagusiki. Gaur egun, olefinen eskaria handituz doa: etilenoaren eskariak urteko % 3-5eko igoera izan du, eta propilenoak, aldiz, % 5-7koa. Etilenoaren eskaria bermatuta dago etanoaren ur-lurrun bidezko cracking termiko (SC) prozesuaren bitartez, baina propilenoaren eskaria betetzeko, ohiko prozesuek (SC eta cracking katalitikoa ohantze fluidizatuan (FCC)) eskaintzen duten hautakortasuna hobetu beharra dago. Gainera, industria-mailan ezarritako teknologiek erregai fosilen mendekotasun eta energia-kontsumo handia dute. Beraz, ohiko teknologiak hobetzea eta iturri berriztagarriak erabiltzen dituzten prozesuak garatzea dira gaur egungo findegiaren et

Light olefins (especially, ethylene and propylene) are the key building blocks of the petrochemical industry and they are mainly used to produce polyolefins (polyethylene and polypropylene). Nowadays, light olefin demand is continuosly increasing, where ethylene demand shows an annual average rate of 3-5% and propylene of 5-7%. Ethylene demand is satisfied by ethane steam cracking (SC) process. However, in order to fulfill the propylene demand, the selectivity achieved by conventional technologies (SC and fluid catalytic cracking (FCC)) should be improved. Furthermore, these industrial technologies show a great dependence on fossil fuels and a high energy consumption.Thus, improving these conventional technologies, as well as developing alternative processes based on rewenable sources are the main challenges for the refineries and the petrochemical industries. In this work, the main applications of light olefins and their worldwide demand are firstly analyzed. Then, the conventional technologies (from fossil fuels) are described; and, finally, other sustainable techonologies are discussed, which are based on the valorization of biomass and wastes.; Olefina arinak (bereziki, etilenoa eta propilenoa) industria petrokimikoko oinarrizko lehengaiak dira eta poliolefinak (polietilenoa eta polipropilenoa) ekoizteko erabiltzen dira nagusiki. Gaur egun, olefinen eskaria handituz doa: etilenoaren eskariak urteko % 3-5eko igoera izan du, eta propilenoak, aldiz, % 5-7koa. Etilenoaren eskaria bermatuta dago etanoaren ur-lurrun bidezko cracking termiko (SC) prozesuaren bitartez, baina propilenoaren eskaria betetzeko, ohiko prozesuek (SC eta cracking katalitikoa ohantze fluidizatuan (FCC)) eskaintzen duten hautakortasuna hobetu beharra dago. Gainera, industria-mailan ezarritako teknologiek erregai fosilen mendekotasun eta energia-kontsumo handia dute. Beraz, ohiko teknologiak hobetzea eta iturri berriztagarriak erabiltzen dituzten prozesuak garatzea dira gaur egungo findegiaren et

[EN] Bimetallic Pt-Co catalysts derived from cobalt aluminate spinel were investigated in the liquid-phase water–gas shift (WGS) reaction and CO hydrogenation. Liquid-phase WGS is a key reaction in the aqueous-phase reforming (APR) of polyols; thus, WGS activity is essential to formulate good APR catalysts. In this work, catalysts with different Pt/Co molar ratios were synthesized together with a reference Pt/alumina. All the synthesized catalysts were characterized by various techniques in order to gain knowledge on their structural and surface characteristics. WGS activity was tested with a feedstream of CO/H2O = 1/15 (space-time of 76.8 kg·s/molCO), isothermal operation at 260 ºC and 50 bar, for 10 TOS. Bimetallic Pt-Co catalysts showed improved activity in liquid-phase WGS in comparison to bare Co or Pt catalysts, which was ascribed to the synergistic effect. Despite being subjected to an increased hydrogen concentration in the feedstream (H2/CO between 0 and 12/3), these catalysts maintained a preferential selectivity towards WGS activity. In addition, the effect of temperature (220–260 ºC) and pressure (25–50 bar) was investigated over a catalyst with 0.3Pt/CoAl. CO conversion and CO2 yield were more sensitive to temperature, while a higher pressure favored methane production. The measured activation energy in the 220–260 ºC temperature range was 51.5 kJ/mol.

Bulk nickel aluminate (NiAl2O4) was synthesised by co-precipitation at a Ni/Al mole ratio of 1:2 (stoichiometric ratio). The prepared sample was reduced at different temperatures, in the 300 to 850 ºC range, and obtained assays were analysed by a wide range of analytical techniques (XFR, XRD, H2-chemisoprtion, H2-TPR, DRS UV-vis NIR, FTIR, 27Al MAS NMR, NH3-TPD, CO2-TPD, TPO) and tested for the APR of glycerol. The spinel precursor allowed the formation of small and stable Ni particles (< 14 nm) upon reduction with good performance in the APR of glycerol (NiAl-850 93% conversion, 57% conversion to gas, at 250 ºC/45 bar and WHSV 24.5 h-1). Hydrogen was the main gaseous product and the activation temperature did not substantially alter selectivity to gaseous products; however, selectivity to intermediate oxygenated liquid compounds was substantially modified. Overall, glycerol dehydrogenation route was dominant at high reduction temperature. The good stability of the spinel led to stable H2 yield in the long-term runs (50 hours) and proved potential to be used in the APR of glycerol.

Carbon-based adsorbents were prepared by the physical activation of sewage sludge with CO2 through an integrated method (without a precarbonization stage). The activation was conducted at different temperatures (600e1000 ºC), and the effect of the acid washing, performed either before or after the physical activation, was investigated. From the standpoint of textural properties, the optimum activation temperature is between 800 and 900 ºC; higher temperatures cause an important reduction in porosity. The acid post-washing significantly increases the porosity in the whole pore size range due to the removal of the inorganic fraction and pore unblocking. Both the activation temperature and the acid treatment strongly affect the surface chemistry. The uptake of methylene blue correlates significantly with textural properties (such as BET surface area), but also with surface chemistry (carbonyl groups). The combination of a moderate activation temperature (600 ºC) and acid post-washing results in a cost-effective material with a suitable methylene blue removal ability. On the contrary, the adsorption of phenol, favoured by materials with a high degree of microporosity, is maximized by acid pretreatment prior to activation at 900 ºC.

Ur edangarrietan aurkitzen diren mikrokutsatzaileen ezabapena animali hezurretatik eta EDAR lokatzetatik eratorritako karbono aktibatuaren bidez.

Duración (en horas): De 31 a 40 horas Nivel educativo:Grado, El problema ABP propuesto pretende impulsar la capacidad del alumno a la hora de plantear y resolver adecuadamente balances de energía entálpicos en sistemas de intercambio de calor. El problema se centra en el diseño de un dispositivo de enfriamiento instantáneo comercializado bajo el nombre de “bolsa de frío”. Este problema permite que el alumno se pregunte cómo es posible enfriar una sustancia sin necesidad de un aparato eléctrico. La resolución del problema implica que los alumnos identifiquen, en primer lugar, la información necesaria; conceptos tales como calor específico, calor de reacción y, posteriormente, resuelvan el balance de energía para el conjunto bolsa de frío y producto enfriado; cerveza en este caso.