Biodiesel production from sewage sludge using supported heteropolyacid as heterogeneous acid catalyst.

Phosphotungstic acid (HPW) and silicotungstic acid (HSiW) were tested as homogeneous and as heterogeneous catalysts (after immobilized on different supports as high surface area graphite -HSAG500-, montmorillonite -MMT- and alumina -Al2O3-) for the in situ transesterification of sewage sludge lipids. Both catalysts exhibited similar performance in homogeneous phase, with slightly higher biodiesel yield for HPW. When the different supports were tested with HPW, the maximum yield obtained follow the trend: MMT > HSAG500 > Al2O3, but a greater leaching of the heteropolyacid (HPA) was observed with MMT. Therefore, HSAG500 showed the best results with a good FAMEs profile. The percentage of active phase was optimized from 1 to 40%, reaching the optimum at 10%. A more heterogeneous surface is obtained with larger quantities, also favouring the HPA leaching. The reaction temperature and the use of sonication as pre-treatment were also optimized. The best results were obtained after sonication with HPW-HSAG500 (10%) as catalyst, catalyst/sludge ratio 1:2, MeOH/sludge ratio 33:1, 120 °C and 21 h of reaction time with a maximum biodiesel yield of 31.1 % (FAMEs/lipids). In view of the results obtained HPW supports on HSAG500 offers a novel alternative as heterogeneous acid catalyst for in situ transesterification using sewage sludge as raw material.

Effect of Water and Carbon Dioxide on the Performance of Basolite Metal-Organic Frameworks for Methane Adsorption.

MOFs are potential adsorbents for methane separation from nitrogen, including recovery in diluted streams. However, water and carbon dioxide can seriously affect the adsorption performance. Three commercial MOFs, basolite C300, F300, and A100, were studied under similar conditions to fugitive methane streams, such as water (75 and 100% relative humidity) and carbon dioxide (0.33%) presence in a fixed bed. The presence of available open metal sites of copper (Cu2+) and aluminum (Al3+) in the case of basolite C300 and A100, respectively, constitutes a clear drawback under humid conditions, since water adsorbs on them, leading to significant methane capacity losses. Surprisingly, basolite F300 is the most resistant material due to its amorphous structure, which hinders water access. The combination of carbon dioxide and water creates a synergy that seriously affects basolite A100, closely related to its breathing effect, but does not constitute an important issue for basolite C300 and F300.

Dolomite industrial by-products as active material for CO2 adsorption and catalyst for the acetone condensation.

The feasibility of using dolomite powders, by-product from the refractory industry, as a CO2 adsorbent and as a catalyst for the acetone liquid-phase self-condensation is demonstrated in this article. The performance of this material can be largely improved by combining physical pretreatments (hydrothermal ageing, sonication) and thermal activation at different temperatures (500-800 °C). The highest CO2 adsorption capacity was observed for the sample after sonication and activated at 500 °C (46 mg·g-1). As to the acetone condensation, the best results were obtained also with the sonicated dolomites, mainly after activation at 800 °C (17.4% of conversion after 5 h at 120 °C). The kinetic model reveals that this material optimizes the equilibrium between catalytic activity (proportional to the total basicity) and deactivation by water (specific adsorption process). These results demonstrate that the valorisation of dolomite fines is feasible, proposing attractive pretreatments for obtaining activated materials with promising results as adsorbents and basic catalysts.

Metal-Organic Frameworks (MOFs) as methane adsorbents: From storage to diluted coal mining streams concentration.

Ventilation Air Methane emissions (VAM) from coal mines lead to environmental concern because their high global warming potential and the loss of methane resources. VAM upgrading requires pre-concentration processes dealing with high flow rates of very diluted streams (<1% methane). Therefore, methane separation and concentration is technically challenging and has important environmental and safety concerns. Among the alternatives, adsorption on Metal-Organic Frameworks (MOFs) could be an interesting option to methane selective separation, due to its tuneable character and outstanding physical properties. Most of the works devoted to the methane adsorption on MOFs deal with methane storage. Therefore, these works were reviewed to determine the properties governing methane-MOF interactions. In addition, the metallic ions and organic linkers roles have been identified. With these premises, decisive effects in the methane adsorption selectivity in nitrogen/methane lean mixtures have been discussed, since nitrogen is the most concentrated gas in the VAM stream, and it is very similar to methane molecule. In order to fulfill this overview, the effect of other aspects, such as the presence of polar compounds (moisture and carbon dioxide), was also considered. In addition, engineering considerations in the operation of fixed bed adsorption units and the main challenges associated to MOFs as adsorbents were also discussed.

Resistencia a la fractura de coronas dentales fabricadas análogamente vs tecnología cad-cam. Estudio In vitro / Fracture resistance of analogally made dental crowns vs cad-cam technology. In vitro study

Resumen Antecedentes. La resistencia a la fractura de las coronas puede tener influencia en su ocurrencia, de acuerdo con el método de fabricación usado, ya sea análogamente o por medio de tecnología Cad-Cam. Objetivo. Comparar la resistencia a la fractura de las coronas individuales realizadas por dos métodos de fabricación, bajo diseño asistido por ordenador y fabricación computarizada (CAD-CAM) e inyectadas. Método. Estudio in vitro. Tamaño de la muestra 20 coronas en dos grupos: 10 coronas bajo tecnología CAD-CAM y 10 coronas inyectadas. Fueron sometidas a cargas compresivas en una máquina de ensayos universal, con una velocidad de 1mm/min y una carga de celda de 5kN hasta obtener la fractura máxima de estas. Los datos se analizaron estadísticamente utilizando las pruebas Shapiro Wilk, Mann Whitney p=0,05. Resultados. Las coronas fabricadas por Cad-Cam obtuvieron un mínimo de 602,5 Newton y un máximo de 1093 Newton, mientras que las coronas fabricadas análogamente obtuvieron un mínimo de 525,2 Newton y un máximo de 1773 Newton en el experimento con la máquina de ensayo universal para lograr su fractura. Se obtuvo una diferencia significativa en la prueba de resistencia a la factura entre ambos métodos de fabricación (p <0,001). Conclusión. Las coronas de Disilicato de litio Prensadas obtuvieron una mayor resistencia a la fractura que las coronas fabricadas via CAD-CAM.

Abstract Background. The fracture resistance of the crowns may have an influence on their appearance, according to the method of making them, either analogously or by means of Cad-Cam technology. Objective. To compare the resistance to the fracture of the individual crowns made by two manufacturing methods, under computer-aided design and computerized manufacturing (CAD-CAM) and injected. Methods. In vitro study. Sample size 20 crowns in two groups: 10 crowns using CAD-CAM technology and 10 crowns injected. Crowns were subjected to compressive loads in a universal testing machine, with a speed of 1mm / min and a cell load of 5kN until obtaining the maximum bill for these. Data were statistically analyzed using the Shapiro Wilk tests, Mann Whitney p = 0.05. Results. Crowns manufactured by Cad-Cam obtained a minimum of 602.5 Newton and a maximum of 1093 Newton, while the crowns manufactured analogously obtained a minimum of 525.2 Newton and a maximum of 1773 Newton in the experiment with the machine Universal test to achieve their fracture. A significant difference was obtained in the invoice resistance test between both manufacturing methods (p <0.001). Conclusion. Pressed Lithium Disilicate crowns obtained higher fracture resistance than crowns under design and manufacturing by computer (CAD-CAM).

A review of the adsorption-biological hybrid processes for the abatement of emerging pollutants: Removal efficiencies, physicochemical analysis, and economic evaluation.

The limited efficiency of conventional wastewater treatment plants (WWTPs) in emerging pollutants (EPs) removal encourages the development of alternative technologies for the adequate treatment of wastewater, due to its adverse effects on human health and ecosystems. The biological, physical or chemical hybrid technologies to treat EPs results interesting since they can enhance the performance of WWTPs. Among them, hybrid adsorption/biological technology could offer different possibilities that are explored in this work (PAC-MBR, PACT/GAC-CAS, BAC configurations). In this way, different variations in the adsorption process have been considered: the form of the adsorbent, the feed to the system, and the type of biological process, either conventional activated sludge (CAS), membrane bioreactor (MBR) or biofilm systems. For each combination, the removal efficiency of micropollutants, classified according to their use into pharmaceuticals, personal care products (PCPs) and other micropollutants (mainly benzotriazoles) was analysed. From reported data, it was observed a beneficial synergistic effect of dipole moment and octanol-water partition coefficient on the removal efficiency of micropollutants by adsorption/biological hybrid technology. Finally, a preliminary economic evaluation of the powdered activated carbon in a conventional activated sludge reactor (PACT), powdered activated carbon-membrane bioreactor (PAC-MBR) and biological activated carbon (BAC) hybrid systems was carried out by analysing the capital expenditure (CAPEX) of plants for capacities up to 75,000 m3d-1. Likewise, estimations of adsorbent concentration for a hypothetical plant with a capacity of 10,000 m3d-1 is presented. Among these hybrid configurations, PAC-MBR achieved the highest micropollutant elimination percentages; however, it presents the highest CAPEX and activated carbon requirements.

Harnessing of Diluted Methane Emissions by Direct Partial Oxidation of Methane to Methanol over Cu/Mordenite.

The upgrading of diluted methane emissions into valuable products can be accomplished at low temperatures (200 °C) by the direct partial oxidation of methanol over copper-exchanged zeolite catalysts. The reaction has been studied in a continuous fixed-bed reactor loaded with a Cu-mordenite catalyst, according to a three-step cyclic process: adsorption of methane, desorption of methanol, and reactivation of the catalyst. The purpose of the work is the use of methane emissions as feedstocks, which is challenging due to their low methane concentration and the presence of oxygen. Methane concentration had a marked influence on methane adsorption and methanol production (decreased from 164 µmol/g Cu for pure methane to 19 µmol/g Cu for 5% methane). The presence of oxygen, even in low concentrations (2.5%), reduced methane adsorption drastically. However, methanol production was only affected slightly (average decrease of 9%), concluding that methane adsorbed on the active centers yielding methanol is not influenced by oxygen.

Influence of delignification and reaction conditions in the aqueous phase transformation of lignocellulosic biomass to platform molecules.

The effect of oxidative and reductive delignification processes on the hydrolysis of pine sawdust at mild conditions (200-1000 ppm of HCl and 140-220 °C) is studied in this work. Dimers and reduced sugars are the main products obtained with the fresh sawdust (>82%), reaching a maximum liquid phase yield of 17% after 8 h, at the strongest conditions. This conversion increases up to almost 40% with the pretreated sawdust, obtaining selectivities higher than 87% of levulinic acid and a well-defined distribution of the relevant platform molecules (sugars, HMF, furfural, levulinic acid) as function of the severity of the reaction, decreasing the humins formation and being possible to define different conditions to maximize each yield. These conclusions were corroborated by the kinetic analysis, obtaining a clear decrease in the energy activation for all the individual steps involved in this process.

Densification-Induced Structure Changes in Basolite MOFs: Effect on Low-Pressure CH4 Adsorption.

Metal-organic frameworks' (MOFs) adsorption potential is significantly reduced by turning the original powder into pellets or granules, a mandatory step for their use at industrial scale. Pelletization is commonly performed by mechanical compression, which often induces the amorphization or pressure-induced phase transformations. The objective of this work is the rigorous study of the impact of mechanical pressure (55.9, 111.8 and 186.3 MPa) onto three commercial materials (Basolite C300, F300 and A100). Phase transformations were determined by powder X-ray diffraction analysis, whereas morphological changes were followed by nitrogen physisorption. Methane adsorption was studied in an atmospheric fixed bed. Significant crystallinity losses were observed, even at low applied pressures (up to 69.9% for Basolite C300), whereas a structural change occurred to Basolite A100 from orthorhombic to monoclinic phases, with a high cell volume reduction (13.7%). Consequently, adsorption capacities for both methane and nitrogen were largely reduced (up to 53.6% for Basolite C300), being related to morphological changes (surface area losses). Likewise, the high concentration of metallic active centers (Basolite C300), the structural breathing (Basolite A100) and the mesopore-induced formation (Basolite F300) smooth the dramatic loss of capacity of these materials.

Infecciones en Pie Diabético. Serie de Casos / Diabetic Foot Infections. Case Series

Introducción El objetivo de este trabajo es describir las características clínicas, gérmenes aislados en muestras tomadas en quirófano, tipo de procedimientos quirúrgicos y desenlaces en el tratamiento realizado a pacientes con pie diabético atendidos en nuestra institución. Materiales y Metodos Estudio descriptivo retrospectivo observacional tipo serie de casos, describiendo resultados obtenidos de los cultivos tomados en cirugía, características clínicas según la clasificación de Wagner, número y tipo de procedimientos entre Enero de 2012 y Diciembre de 2016 por complicaciones derivadas de pie diabético. Resultados Se obtuvieron 58 pacientes, con edad media de 65 años, 69% eran varones. El estadio clínico en la evaluación prequirúrgica fue de 39.7% Wagner III, 37.9% IV; en la evaluación intraquirúrgica fue 32.8% III, 50% IV. Los gérmenes aislados, en 1er lugar 15.5% Escherichia Coli, de estas 11.9% era BLEE positiva y 3.6% multisensible; otro 15.5% Pseudomona Aeruginosa, variantes multirresistentes 10.7% productoras de carbapenemasas 1.2%, y resistentes a meropenem 1.2% y multisensibles 2.4%. 77.5% de los pacientes requirió cambio de antibiótico. Un tercio de los pacientes requirieron amputaciones mayores de los cuales 46.6% presentaban infecciones por gérmenes de multirresistentes. Discusión Encontramos que los gérmenes predominantes son bacilos gram negativos en su mayoría multirresistente. Sugerimos la toma de muestras de manera intraquirúrgica previo al inicio de antibioticoterapia. Dado la flora bacteriana aislada en esta serie, al iniciar antibioticoterapia empírica se sugiere el uso de carbapenémicos.

Background The main purpose of the study is to describe the clinical characteristics, micro-organisms isolated in specimens taken in the operating room, types of surgical procedures, and outcomes in treatments performed on patients with diabetic foot. Methods A case series study is presented, describing results obtained from cultures taken in surgery, clinical characteristics according to Wagner's classification, and number and type of procedures performed between January 2012 and December 2016 due to complications derived from diabetic foot.. Results The study included 58 patients, with a mean age of 65 years, and 69% were men. The clinical stage in the pre-surgical evaluation was 39.7% and 37.9% Wagner III and IV, respectively, and during the operation it was 32.8% III, 50% IV. The isolated micro-organisms were 15.5% Escherichia Coli, of these 11.9% were ESBL positive and 3.6% multisensitive. Another 15.5% were Pseudomonas Aeruginosa, multiresistant variants 10.7%, producing carbapenemases 1.2%, resistant to meropenem 1.2%, and multiple sensitivity 2.4%. The large majority (77.5%) of the patients required a change of antibiotic. One third of the patients required major amputations, of which 46.6% had infections caused by multidrug-resistant germs. Discussion The predominant micro-organisms found were multi-resistant gram negative bacilli. It is suggested taking specimens intraoperative prior to the start of antibiotic therapy. Given the bacterial flora isolated in this series, when starting empirical antibiotic therapy, the use of carbapenems is suggested.

Carbon Materials as Phase-Transfer Promoters for Obtaining 5-Hydroxymethylfurfural from Cellulose in a Biphasic System.

Different carbonaceous materials were tested as mass-transfer promoters for increasing the yield of 5-hydroxymethylfurfural (5-HMF) in biphasic cellulose hydrolysis. The benefits of working with a biphasic system (water/methyl isobutyl ketone) under soft acid conditions were taken as starting point (no humins or levulinic acid production), with slow extraction kinetics as the weakest point of this approach. Carbon nanotubes (CNTs) and activated carbon (AC) were proposed to improve 5-HMF liquid-liquid mass transfer. A kinetic analysis of the extraction process indicated the competition between 5-HMF and glucose adsorption as the main cause of the poor results obtained with AC. In contrast, very promising results were obtained with CNTs, mainly at 1.5 wt % loading, with complete transfer of HMF and a high global mass-transfer coefficient. The use of CNTs improved the amount of 5-HMF in the organic phase by more than 270 %.

Electrochemical degradation of naproxen from water by anodic oxidation with multiwall carbon nanotubes glassy carbon electrode.

Naproxen (NPX) degradation was investigated by anodic oxidation both at constant potential and by cyclic voltammetry, using this last technique for optimizing reaction conditions and catalyst properties. Three multiwall carbon nanotubes (MWCNTs)-promoted electrodes were used (MWCNT, MWCNT-COOH and MWCNT-NH2) and a two steps oxidation process was observed in all the cases. At the optimized conditions (volume of MWCNT = 15 µL), the influence of the scan rate indicates the diffusion-adsorption control of the process. Likewise, the kinetic study of NPX degradation at fix potential, considering two different stirring speeds (250 and 500 rpm), indicates that degradation rate increases with the stirring speed. After 20 h, NPX is degraded even an 82.5%, whereas the mineralization reaches almost 70%, as it was obtained from total organic carbon analysis. The pH effect was also analysed, in the range 5-11, observing a positive effect at low pH. Concerning the surface chemistry of the electrode, MWCNT-NH2, with the highest isoelectric point (4.70), is the most promising material due to the improved interactions with the reactant. From these observations, a pathway is proposed, which includes two steps of electrochemical oxidation followed by subsequent oxidation steps, until mineralization of the NPX, attributed mainly to active chlorine species and ·OH.

Effect of sewage sludge composition on the susceptibility to spontaneous combustion.

The different technologies applied to the sewage sludge management have in common a first step devoted to the storage. In the case of dried sludges, this storage leads to important safety concerns because of the explosive character of the resulting dusts. In order to ensure safety in the storage step, it is necessary to evaluate the spontaneous combustion trends on terms of measurable chemical and physical properties of the dried sludges. In order to accomplish this scope, twelve samples from different wastewater treatment plants were characterized, correlating the susceptibility to spontaneous combustion with both the sludge composition and the heating value. Equations traditionally used for coals were used to determine the higher heating value from the chemical composition, finding as main source of error the high oxygen content of the sludge samples. Concerning the thermal susceptibility, different parameters were obtained (Maciejasz Index, induction temperature, maximum weight loss temperature, characteristic temperature and activation energy), being in all cases the spontaneous combustions favored by high H/C and low O/C ratios. Likewise, the presence of sulphur in the dried sludge was found to increase the thermal susceptibility of the material. This effect is tentatively explained with the formation of pyrophoric iron sulfides.

Aqueous-Phase Transformation of Glucose into Hydroxymethylfurfural and Levulinic Acid by Combining Homogeneous and Heterogeneous Catalysis.

Homogeneous (HCl) and heterogeneous catalysts (various zeolites) were combined to enhance the upgrading of glucose into two different platform molecules: 5-hydroxymethylfurfural (HMF) and levulinic acid (LA). ß-Zeolite was the most active material for the glucose isomerization to fructose, improving also the activity of HCl for the subsequent steps. Reaction time, temperature, and pH were then modified, identifying 140 °C, 200 ppm of HCl, and 5 h as the optimum conditions for HMF formation (41 % selectivity; 0.06 mol L-1 ) and 140 °C, 400 ppm of HCl, and 24 h for LA formation (34 % selectivity; 0.12 mol L-1 ). This new approach is also relevant because of significant changes to the mechanism for humins formation. All results are successfully fitted to a kinetic model simultaneously considering both catalytic mechanisms.

Carbon nanotube modified glassy carbon electrode for electrochemical oxidation of alkylphenol ethoxylate.

Electrochemical oxidation of an emerging pollutant, 2-(4-methylphenoxy)ethanol (MPET), from water has been studied by cyclic voltammetry (CV). Multiwall carbon nanotubes glassy carbon electrodes (MWCNT-GCE) were used as working electrode due to their extraordinary properties. The oxidation process is irreversible, since no reduction peaks were observed in the reverse scan. The electrocatalytic effect of MWCNT was confirmed as the oxidation peak intensity increases in comparison to bare-GCE. The effect of functional groups on MWCNT was also studied by MWCNT functionalized with NH2 (MWCNT-NH2) and COOH (MWCNT-COOH) groups. The oxidation peak current decreases in the following order: MWCNT > MWCNT-NH2 > MWCNT-COOH. Taking into account the normalized peak current, MWCNT-NH2 exhibits the best results due to its strong interaction with MPET. Under optimal conditions (pH = 5.0 and volume of MWCNT = 10 µL), degradation was studied for MWCNT-GCE and MWCNT-NH2-GCE. A complete MPET removal was observed using MWCNT-GCE after four CV cycles, for a volume/area (V/A) ratio equal to 19. In the case of MWCNT-NH2-GCE, the maximum MPET removal was close to 90% for V/A = 37, higher than that obtained for MWCNT-GCE at the same conditions (≈80%). In both cases, no organic by-products were detected.

Effect of sludge features and extraction-esterification technology on the synthesis of biodiesel from secondary wastewater treatment sludges.

Secondary sludge from municipal wastewater treatment plant is proposed as a promising alternative lipid feedstock for biodiesel production. A deep study combining different type of raw materials (sludge coming from the oxic, anoxic and anaerobic steps of the biological treatment) with different technologies (liquid-liquid and solid-liquid extractions followed by acid catalysed transesterification and in situ extraction-transesterification procedure) allows a complete comparison of available technologies. Different parameters - contact time, catalyst concentration, pretreatments - were considered, obtaining more than 17% FAMEs yield after 50min of sonication with the in situ procedure and 5% of H2SO4. This result corresponds to an increment of more than 65% respect to the best results reported at typical conditions. Experimental data were used to propose a mathematical model for this process, demonstrating that the mass transfer of lipids from the sludge to the liquid is the limiting step.

Photocatalytic degradation of 2-(4-methylphenoxy)ethanol over TiO2 spheres.

The photocatalytic TiO2-assisted decomposition of 2-(4-methylphenoxy)ethanol (MPET) in aqueous solution has been studied for the first time. The intermediate compounds of MPET photodegradation have been also determined. A toxic p-cresol is formed in significant quantities during the photocatalytic reaction. A solvent-exchange approach for a template-free preparation of spherical TiO2 particles has been described, which is based solely on precipitation of hydrous titania from aqueous titanium peroxo complex by using organic solvents. The proposed method favours the formation of spherical titania particles with a mean size varying from 50 to 260nm depending on the choice of solvent. The procedure for converting nonporous titania spheres into mesoporous material maintaining the same spherical morphology has been developed. The synthesized TiO2 spheres demonstrate a degree of MPET photo-degradation close to that of the commercial titania Aeroxide P25, besides being successfully recovered and reused for four reaction cycles without loss of photocatalytic activity. The effectiveness of the commercial Aeroxide P25 in MPET photodegradation, on the other hand, suffers 10-time drop during the third reaction cycle, which is attributed to its poor recoverability because the photocatalyst is composed of small particles of 20nm size.

Electrochemical reduction of nalidixic acid at glassy carbon electrode modified with multi-walled carbon nanotubes.

The aqueous phase electrochemical degradation of nalidixic acid (NAL) is studied in this work, using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) as instrumental techniques. The promotional effect of multi-walled carbon nanotubes (MWCNT) on the performance of glassy carbon electrodes is demonstrated, being observed that these materials catalyze the NAL reduction. The effect of surface functional groups on MWCNT -MWCNT-COOH and MWCNT-NH2-was also studied. The modification of glassy carbon electrode (GCE) with MWCNT leads to an improved performance for NAL reduction following the order of MWCNT>MWCNT-NH2>MWCNT-COOH. The best behavior at MWCNT-GCE is mainly due to both the increased electrode active area and the enhanced MWCNT adsorption properties. The NAL degradation was carried out under optimal conditions (pH=5.0, deposition time=20s and volume of MWCNT=10µL) using MWCNT-GCE obtaining an irreversible reduction of NAL to less toxic products. Paramaters as the number of DPV cycles and the volume/area (V/A) ratio were optimized for maximize pollutant degradation. It was observed that after 15 DPV scans and V/A=8, a complete reduction was obtained, obtaining two sub-products identified by liquid chromatography-mass spectrometry (LC-MS).

Evaluation of the potential of different high calorific waste fractions for the preparation of solid recovered fuels.

Solid recovered fuels constitute a valuable alternative for the management of those non-hazardous waste fractions that cannot be recycled. The main purpose of this research is to assess the suitability of three different wastes from the landfill of the local waste management company (COGERSA), to be used as solid recovered fuels in a cement kiln near their facilities. The wastes analyzed were: End of life vehicles waste, packaging and bulky wastes. The study was carried out in two different periods of the year: November 2013 and April 2014. In order to characterize and classify these wastes as solid recovered fuels, they were separated into homogeneous fractions in order to determine different element components, such as plastics, cellulosic materials, packagings or textile compounds, and the elemental analysis (including chlorine content), heavy metal content and the heating value of each fraction were determined. The lower heating value of the waste fractions on wet basis varies between 10 MJ kg(-1) and 42 MJ kg(-1). One of the packaging wastes presents a very high chlorine content (6.3 wt.%) due to the presence of polyvinylchloride from pipe fragments, being the other wastes below the established limits. Most of the wastes analyzed meet the heavy metals restrictions, except the fine fraction of the end of life vehicles waste. In addition, none of the wastes exceed the mercury limit content, which is one of the parameters considered for the solid recovered fuels classification. A comparison among the experimental higher heating values and empirical models that predict the heating value from the elemental analysis data was carried out. Finally, from the three wastes measured, the fine fraction of the end of life vehicles waste was discarded for its use as solid recovered fuels due to the lower heating value and its high heavy metals content. From the point of view of the heating value, the end of life vehicles waste was the most suitable residue with a lower heating value of 35.89 MJ kg(-1), followed by the packaging waste and the bulky waste, respectively. When mixing the wastes studied a global waste was obtained, whose classification as solid recovered fuels was NCV 1 Cl 3 Hg 3. From the empirical models used for calculating higher heating value from elemental content, Scheurer-Kestner was the model that best fit the experimental data corresponding to the wastes collected in November 2013, whereas Chang equation was the most approximate to the experimental heating values for April 2014 fractions. This difference is due to higher chlorine content of the second batch of wastes, since Chang equation is the only one that incorporates the chlorine content.

Adsorption of emerging pollutants on functionalized multiwall carbon nanotubes.

Adsorption of three representative emerging pollutants - 1,8-dichlorooctane, nalidixic acid and 2-(4-methylphenoxy)ethanol- on different carbon nanotubes was studied in order to determine the influence of the morphological and chemical properties of the materials on their adsorption properties. As adsorbents, multiwall carbon nanotubes (MWCNTs) without functionalization and with oxygen or nitrogen surface groups, as well as carbon nanotubes doped with nitrogen were used. The adsorption was studied in aqueous phase using batch adsorption experiments, results being fitted to both Langmuir and Freundlich models. The adsorption capacity is strongly dependent on both the hydrophobicity of the adsorbates and the morphology of the adsorbents. Thermodynamic parameters were determined observing strong interactions between the aromatic rings of the emerging pollutant and the nitrogen modified adsorbents.