Flexible and low-cost binderless capacitors based on p- and n-containing fibrous activated carbons from denim cloth wastes

Activated carbon cloths have been prepared from denim cloth wastes (DCWs) through chemical activation with H3PO4. The effect of the H3PO4/DCWs impregnation ratio and the carbonization temperature on the porous texture, the chemical composition, the fibers morphology, and the electrochemical performance has been studied. Low H3PO4/DCWs impregnation ratios lead to flexible and microporous activated carbons cloths, whereas more fragile and rigid activated carbon cloths with higher external surface area are produced upon increasing the amount of H3PO4. The increase in the carbonization temperature allows for obtaining a more ordered and conductive carbon structure. The activated carbon prepared at 900 ºC with a H3PO4/DCWs impregnation ratio of 0.5 (w/w) exhibits the best performance as electric double layer capacitor. This electrode shows a specific surface area of 2016 m2 g-1 and the highest registered gravimetric capacitance (227 F g-1). Moreover, its flexibility minimizes the ohmic resistance of the electrode, thus increasing the feasibility of working at higher current densities than the other synthesized electrodes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech; MINECO CTQ2015-68654-

Methanol dehydration over ZrO2 supported-activated carbons

Resumen comunicación congreso internacionalDME is playing an important role due to its potential use as an alternative fuel in diesel engines. The use of this fuel produces lower NOx emissions, and less engine noise compared to traditional diesel fuels. Moreover, this compound is used as building block for many value-added chemicals such as lower olefins. DME is usually produced via catalytic dehydration of methanol over a solid acid. The use of activated carbons in catalytic processes, acting directly as catalyst and as catalyst support, is focussing much attention. They can be obtained from different types of lignocellulosic waste, producing not only an environmental but an economical profit. In this sense, the preparation of activated carbons with phosphoric acid produces catalytic supports with certain surface acidity, which have shown high activity for alcohol dehydration. In this study, ZrO2 supported activated carbons were prepared from an industrial byproduct as lignin for the methanol dehydration to DME. The activated carbon was prepared by chemical activation with H3PO4, using Alcell® lignin as precursor. The impregnation ratio value (H3PO4/lignin) used was 3. The impregnated sample was activated under N2 flow at 500 ºC for 2h, washed and dried. The activated carbon was loaded with different amounts of ZrO(NO3)2, dried at 120ºC for 24h, and calcined in air at 250ºC for 2h, obtaining ZrO2 loadings of 5 and 10%, respectively. For the sake of comparison, pure ZrO2 was also used. Catalytic tests were performed at atmospheric pressure in a fixed bed reactor, at different space times and partial pressures. The activated carbon (ACP) prepared shows a well-developed porous structure, with an apparent surface area higher than 2000 m2/g, and a high contribution of mesoporosity. After metal loading, a maximum decrease of 20% in all structural parameters of the ACP was observed.The results show that ZrO2 loading produces an enhancing in the catalytic activity of the carbon materials compared to the parent activated carbon (0.1 g·s/μmol, PCH3OH= 0.02 atm in helium and 350 ºC). In this sense, a methanol conversion of 25% was observed with the addition of 10% w/w ZrO2 (ACP-10Zr), at steady state conditions (Figure 1). ACP shows negligible conversion, at the same conditions and for pure ZrO2 the methanol conversion was of 10%. Very high selectivity to DME (~100%) was found at temperatures lower than 350 ºC. The methanol conversion increases with temperature, reaching a value of 67% at 475ºC, but a slight decrease in DME selectivity is observed, resulting in a higher production of light hydrocarbons, mainly CH4. The results suggest that the addition of only a 10% of ZrO2 over an activated carbon prepared by chemical activation with H3PO4 enhances significantly the performance of the catalyst, compared to pure ZrO2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Inference of mixed information in Formal Concept Analysis

Negative information can be considered twofold: by means of a negation operator or by capturing the absence of information. In this second approach, a new framework have to be developed: from the syntax to the semantics, including the management of such generalized knowledge representation. In this work we traverse all these issues in the framework of formal concept analysis, introducing a new set of inference rules to manage mixed (positive and negative) attributes.TIN2014-59471-P of the Science and Innovation Ministry of Spain, co-funded by the European Regional Development Fund (ERDF). UNIVERSIDAD DE MÁLAGA. Campus de Excelencia Internacional Andalucía Tech

Alcohol decomposition on basic/acid lignin-derived submicron diameter carbon fibers

The use of lignin, the second most abundant polymer in nature, along with a simple and versatile technique, electrospinning, represents an advantageous and promising approach for the preparation of carbon fibers. In previous studies, we have demonstrated that the incorporation of H3PO4 to the initial lignin solution allows for shortening the carbon fibers preparation process and that the resulting carbon fibers present P-surface groups that are of great interest for heterogeneous catalysis. Different carbon fibers catalysts have been prepared by electropinning of Alcell lignin in the absence or presence of H3PO4 as chemical activating agent. Carbonization at different temperatures between 500 and 1600 ºC allows for preparing carbon fibers with a high variety of porosity and chemical surface properties. Diverse oxygen surface groups are presented on the carbon catalysts surface. The isopropanol decomposition has been used as a catalytic test to study the acid or basic character of the prepared carbon fibers. Carbon fibers without phosphorus surface groups generate acetone as the main product of the isopropanol decomposition reaction, from 400 to 600 ºC, suggesting the basic character of these catalysts. On the contrary, phosphorus-containing carbon fibers show high acid character, producing selectivity to propylene of 100 % at temperatures between 250 and 350 ºC. The most acid carbon fiber catalyst produced a high selectivity to ethylene and dimethyl ether for the decomposition of ethanol and methanol, respectively. The conversion enhancement that the presence of oxygen in the gas phase produced for all these reactions was also studied.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO (CTQ2015-68654-R). MINECO (PTA2015-11464-I)

Analysis of the budget impact of fractional exhaled nitric oxide monitoring in the management of childhood asthma: the Colombian National Health System perspective

Background: Fractional exhaled nitric oxide (FeNO) testing is a simple, noninvasive approach to assessing airway inflammation with minimal discomfort that provides results within a few minutes. For policy makers, the economic impact of this technology is the main concern, especially in developing countries. We evaluated the budget impact of asthma management using FeNO monitoring in patients aged between 4 and 18 years in Colombia. Methods: A budget impact analysis was performed to evaluate the potential cost of FeNO monitoring. The analysis was based on a 5-year time horizon and performed from the perspective of the Colombian National Health System. The incremental budget impact was calculated by subtracting the cost of the new treatment, in which FeNO is reimbursed, from the cost of conventional treatment without FeNO (management based on clinical symptoms [with or without spirometry/peak flow] or asthma guidelines [or both] for asthma-related cases). Univariate 1-way sensitivity analyses were performed. Results: In the base case analysis the 5-year costs associated with FeNO and non-FeNO were estimated to be €469 904 130 and €480 485 149, respectively, indicating savings for the Colombian National Health System of €10 581 019 if FeNO is adopted for the routine management of patients with persistent asthma. This result proved to be robust in the univariate 1-way sensitivity analysis. Conclusion: FeNO monitoring generated cost savings in emergency settings for infants with persistent asthma. This evidence can be used by decision makers in Colombia to improve clinical practice guidelines and should be replicated to validate the results in other middle-income countries

Removing redundancy for attribute implications in data with grades

Reasoning with if-then rules –in particular, with those taking from of implications between conjunctions of attributes– is crucial in many disciplines ranging from theoretical computer science to applications. One of the most important problems regarding the rules is to remove redundancies in order to obtain equivalent implicational sets with lower size.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Kinetic study of methanol dehydration over Zro2 supported-activated carbons

The growing concerns about climate change and energy consumption have been the driving force in seek of alternative fuels such as DME, mainly produced via methanol dehydration over a solid acid catalyst. The use of activated carbons for this aim has been little studied up to date. Only a few studies can be found in the literature, reporting all of them materials with a low thermal stability of the acid surface groups, which results into a fast deactivation of the catalyst. In this work, the preparation of activated carbons via chemical activation with phosphoric acid, their modification with different ZrO2 loads, and their application as methanol dehydration catalysts have been studied. The catalytic results showed that the best methanol conversion and selectivity towards DME were achieved with the activated carbon prepared with an impregnation mass ratio value (H3PO4 /precursor) of 2 and an activation temperature of 800 ºC, loaded with a 7 % (wt) of ZrO2 . This catalyst exhibits high steady state methanol conversion values even at temperatures as high as 400 ºC (XCH3OH= 80%, 0.1 g·s/μmol, PCH3OH= 0.08 atm in helium), keeping a selectivity to DME higher than 96%. The effect of oxygen in the reaction atmosphere was also analysed. In this sense, an increase of 15 % in the DME yield was obtained when using air instead of helium as reaction atmosphere (350 ºC, 0.1 g·s/μmol, PCH3OH= 0.04 atm). A kinetic study has been carried out on this catalyst in which two mechanisms (Eley Rideal and Langmuir Hinshelwood) for methanol dehydration have been analysed. The models proposed also consider the presence of oxygen in the reaction media.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO (CTQ2015-68654-R). MECD (FPU13/02413)

On the deactivation of Zr-loading P-containing mesoporous carbon catalyst during methanol dehydration

Dimethyl ether (DME) has received much attention in the last few years due to its potential use as a diesel substitute and it can be obtained from dehydration of biomass-based methanol. γ-Alumina, ZSM-5 and HPAs were tested as catalysts. A carbon-supported zirconium phosphate catalyst was synthesized and tested for methanol dehydration reaction in a high temperature range. Carbon matrix was produced by olive stone waste activated with phosphoric acid (mass acid to olive stone ratio of 2:1) at 800ºC for 2 h. Then, after washing with distilled water and sieving between 100-300μm, the obtained carbon was impregnated with ZrO(NO3)2 and thermal treated at 250ºC for 2 h. Reaction was performed in a fixed-bed reactor at a space time of 75 gcat·s/mmolCH3OH, a partial pressure of 0.04 atm of methanol and temperatures between 450-600ºC. Deactivated samples were exposed to air at 350ºC for 100 min to study the catalyst regeneration. The catalyst showed a high selectivity to DME (≥95%) and an acceptable conversion at Tª lower than 400ºC without noticeable deactivation. At T>400 ºC, deactivation was detected, due to coke deposition, whose rate increases with operating temperature. However, a high selectivity to DME was observed (above 65%) even at very long times on stream (tos). N2 adsorption results pointed out that deposition of coke took place mainly on the surface of the narrow micropores of the catalyst, blocking much of this narrow porosity at long tos. According to XPS analysis, superficial concentration of phosphorus and zirconium were also diminished with coke deposition, although zirconium was decreased to a larger extend. A kinetic model was developed for the catalyst deactivation during methanol dehydration under different reaction conditions, based on coke deposition.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Strategic situation, design and simulation of a biorefinery in Andalusia

In a lignocellulosic feedstock based biorefinery, biomass can be transformed in several products, with different chemical and/or agro-industrial applications, and energy (biofuels). The use of biomass waste is strongly advocated under European Union (EU) legislation in order to help achieve the climate and energy targets of the EU for 2020 and beyond. In this context, this study was focussed on the design and simulation of a biorefinery to mainly obtain ethanol and DME. These biofuels were obtained from waste forestry and agricultural waste biomass collected near the area where the biorefinery plant was proposed to be installed, to minimize the transportation costs and to promote the valorization of the biomass waste generated in this region. Moreover, the industrial applications of the possible obtained by-products were evaluated to minimize the environmental impacts and to make the biorefinery more sustainable. The central area of Andalusia was selected as the most adequate area to develop the installation of the biorefinery plant. Two commercial simulation software, such as Aspen HYSYS® and UniSim®, were used to design and size the equipments and to simulate both production lines. One of the most important achievements of this biorefinery is the possibility of obtaining 42,700 T y-1 of ethanol with a purity of 96%, which supposes a 16.5% of the Spanish national production in 2016, and 137,850 T y-1 of DME, with a purity of 99.99%. from these biomass waste Both compounds can be used as alternative fuels or energy sources. A techno-economic analysis was performed, obtaining a minimum selling price of 0.58 $/L for bioethanol, 1.15$/kg for DME and 0.65 $/kg for HMF and LA, respectively. These prices are comparable to those found in the literature. Furthermore, the implementation of the biorefinery in this strategic area promotes its economic and social development, improving the use of the natural resources to obtain competitive products to fossil fuels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work was supported by the Spanish MINECO under CTQ2015-68654-R project. MCGM gratefully acknowledges the assistance of Spanish Ministry of Economy and Competitiveness through a “Juan de la Cierva – Formación” fellowship (FJCI-2015-25788)