De novo synthesis of brominated dioxins and furans

On the basis of laboratory experiments with model mixtures (active carbon + CuBr2 at different loads), this work studies the formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) by de novo synthesis. For the different samples, the temperature of the maximum carbon oxidation rate was determined by thermogravimetric analysis, and a kinetic model was proposed for the degradation of the materials in an oxidizing atmosphere (synthetic air). The effect of the addition of different amounts of CuBr2 was studied, finding that its presence accelerates the degradation of the carbonaceous structure in the presence of oxygen. The thermal degradation of the samples in air is satisfactorily described by a first-order single-reaction model. In addition, combustion runs of one of the mixtures (consisting of activated carbon + 50 wt % CuBr2, pyrolyzed at 700 °C) were performed in a quartz horizontal laboratory furnace. The analysis of the emissions and the solid residue proved the formation of brominated dioxins and furans at 300, 400, and 500 °C, with a maximum yield at 300 °C (91.7 ng/g of total PBDD/Fs) and a higher bromination degree with increasing temperature.

Using IR-n for information retrieval of Genomics Track

Nowadays there is a big amount of biomedical literature which uses complex nouns and acronyms of biological entities thus complicating the task of retrieval specific information. The Genomics Track works for this goal and this paper describes the approach we used to take part of this track of TREC 2007. As this is the first time we participate in this track, we configurated a new system consisting of the following diferenciated parts: preprocessing, passage generation, document retrieval and passage (with the answer) extraction. We want to call special attention to the textual retrieval system used, which was developed by the University of Alicante. Adapting the resources for the propouse, our system has obtained precision results over the mean and median average of the 66 official runs for the Document, Aspect and Passage2 MAP; and in the case of Passage MAP we get nearly the median and mean value. We want to emphasize we have obtained these results without incorporating specific information about the domain of the track. For the future, we would like to further develop our system in this direction.

Washcoated Pd/Al2O3 monoliths for the liquid phase hydrodechlorination of dioxins

The catalytic activity and durability of 2 wt.% Pd/Al2O3 in powder and washcoated on cordierite monoliths were examined for the liquid phase hydrodechlorination (LPHDC) of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs), also known as dioxins. NaOH was employed as a neutralizing agent, and 2-propanol was used as a hydrogen donor and a solvent. Fresh and spent powder and monolith samples were characterized by elemental analysis, surface area, hydrogen chemisorption, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and transmission electron microscopy/energy dispersive X-ray spectroscopy (TEM/EDX). Three reactor configurations were compared including the slurry and monolith batch reactors as well as the bubble loop column resulting in 100, 70, and 72% sample toxicity reduction, respectively, after 5 h of reaction. However, the slurry and monolith batch reactors lead to catalyst sample loss via a filtration process (slurry) and washcoat erosion (monolith batch), as well as rapid deactivation of the powder catalyst samples. The monolith employed in the bubble loop column remained stable and active after four reaction runs. Three preemptive regeneration methods were evaluated on spent monolith catalyst including 2-propanol washing, oxidation/reduction, and reduction. All three procedures reactivated the spent catalyst samples, but the combustion methods proved to be more efficient at eliminating the more stable poisons.

Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800 °C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants.

Decomposition of two types of electric wires considering the effect of the metal in the production of pollutants

Combustion runs at 700 °C in a horizontal laboratory furnace were carried out on two different electric wires (PVC and halogen-free wire). Tests were performed in the presence and in the absence of the metal conductor of the wires. The analyses of the polycyclic aromatic hydrocarbons (PAHs), chlorobenzenes (CBzs), chlorophenols (CPhs), mono- to octa-chlorodibenzo-p-dioxin and dibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, PAHs production decreases in the presence of metal, while a higher amount of chlorinated compounds are emitted. Respect to the PCDD/Fs, the PVC wire in the presence of metal presents the highest emission, with a much more emission of furans than dioxins. The maximum emission is with 2 or 3 chlorine atom PCDD/Fs. PCBs emission correlates with PCDD/F production and represents 3–4% of total toxicity, determined by using WHO2005 factors.

Thermogravimetric study of the decomposition of printed circuit boards from mobile phones

Thermal decomposition of printed circuits boards (PCB) is studied, using thermogravimetric analysis to compare the thermal behavior of PCB of mobile phones before and after the removal of the metallic fraction by acid washing. Several dynamic and dynamic + isothermal runs have been carried out at different heating rates (5, 10 and 20 K min−1), from room temperature to more than 1100 K. Also runs in the presence and in the absence of oxygen were performed (combustion and pyrolysis runs). Moreover, TG–MS experiments were performed (both in inert and oxidizing atmosphere) in order to better understand the thermal decomposition of these wastes and identify some compounds emitted during the controlled heating of these materials. Different reaction models are proposed, one for pyrolysis and one for combustion of the two kinds of wastes studied, which proved to simulate appropriately the experimental results at all the heating rates simultaneously.

Gas production during the pyrolysis and gasification of biological and physico-chemical sludges from oil refinery

Pyrolysis and gasification of two different sludges coming from a Spanish refinery have been performed at different experimental conditions. A physico-chemical (PC) and a biological (BIO) sludge have been studied. Runs at different heating rates (approx. 4 and 10 K/s) and with different contact time between gases and decomposed sludge have been performed. In general, the ratio H2/CO is higher in pyrolytic runs. The highest ratio is obtained in the pyrolysis at low heating rate and parallel flow, using both sludges. The maximum emission of CO, i.e. the worst combustion conditions, is given in the runs where contact time is minimized and at high heating rates.

Kinetic Analysis and Pollutant Evolution During Thermal Degradation of Printed Circuit Boards Considering the Effect of Metals

Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013.

Pollutant Formation During the Thermal Decomposition of Electrical and Electronic Wastes

Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013.

Pyrolysis and combustion study of flexible polyurethane foam

The thermal degradation of flexible polyurethane foam has been studied under different conditions by thermogravimetric analysis (TG), thermogravimetric analysis-infrared spectrometry (TG-IR) and thermogravimetric analysis-mass spectrometry (TG-MS). For the kinetic study, dynamic and dynamic+isothermal runs were performed at different heating rates (5, 10 and 20 °C min−1) in three different atmospheres (N2, N2:O2 4:1 and N2:O2 9:1). Two reaction models were obtained, one for the pyrolysis and another for the combustion degradation (N2:O2 4:1 and N2:O2 9:1), simultaneously correlating the experimental data from the dynamic and dynamic+isothermal runs at different heating rates. The pyrolytic model considered consisted of two consecutive reactions with activation energies of 142 and 217.5 kJ mol−1 and reaction orders of 0.805 and 1.246. Nevertheless, to simulate the experimental data from the combustion runs, three consecutive reactions were employed with activation energies of 237.9, 103.5 and 120.1 kJ mol−1, and reaction orders of 2.003, 0.778 and 1.025. From the characterization of the sample employing TG-IR and TG-MS, the results obtained showed that the FPUF, under an inert atmosphere, started the decomposition breaking the urethane bond to produce long chains of ethers which were degraded immediately in the next step. However, under an oxidative atmosphere, at the first step not only the urethane bonds were broken but also some ether polyols started their degradation which finished at the second step producing a char that was degraded at the last stage.

Gold Nanoparticles Supported on Polyacrylamide Containing a Phosphorus Ligand as an Efficient Heterogeneous Catalyst for Three-Component Synthesis of Propargylamines in Water

Gold nanoparticles supported on a polyacrylamide containing a phosphinite ligand have been synthesized and characterized using different techniques such as TEM, SEM, EDX, XPS, and solid UV analyses. The new material was successfully applied as a heterogeneous catalyst for the three-component A3 coupling of amines, aldehydes, and alkynes to give propargylamines. Reactions are performed in neat water at 80 °C with only 0.05 mol% catalyst loading. The heterogeneous catalyst is recyclable during seven consecutive runs with small decrease in activity.

Rehabilitating, repairing and restoring against demolishing, tearing down and destroying: the recovery of the military fort for the Santa Pola town museum

This communication develops the process of interventions of the Renaissance fortress of a new plant built in 1554–57 in Santa Pola. It is one of the earliest examples built with reference to military architecture theoretical treaties (XV–XVI) and best preserved. The study runs its own story from its initial military use, through the use of civil equipment until the final cultural and Museum Center. First, the project of Italian origin is examined and its use as barracks for troops for a duration of three centuries (1557–1850), pointing out the architectural constants of war machinery in a defense position and its origin as a rainwater collector and cistern: a perfect square with two bastions in which a plan of the uprising is preserved (1778). Secondly, we study the changes in the mentioned architecture throughout a century and a half (1850–1990) after its change of ownership (from the state to the municipality), and as a result of the new use as a city hall and public endowment: a market and health and leisure centre, which meant the demolition of defensive elements and the opening up to the outside of the inner parade ground. And thirdly, the new transfer of the municipal offices brings in the beginning of a project of transformations (1990–2015) that retrieves the demolished elements at the same time as it assigns the entire fort for a cultural centre: exhibition, research and history museum, promoting the identity between the citizens and the building which stands in the foundations of their city. The conclusions take us through an interesting route that goes from the approach of defensive tactics, its use as administrative headquarters to the current cultural policy of preservation. In addition, all the known plans of the fort are recovered (of military, civil and cultural use), some unpublished, as well as the project of the North wing that has guided the last operation and which has been set as a pattern of reference.

Pollutant emissions during the pyrolysis and combustion of flexible polyurethane foam

Thermal decomposition of flexible polyurethane foam (FPUF) was studied under nitrogen and air atmospheres at 550 °C and 850 °C using a laboratory scale reactor to analyse the evolved products. Ammonia, hydrogen cyanide and nitrile compounds were obtained in high yields in pyrolysis at the lower temperature, whereas at 850 °C polycyclic aromatic hydrocarbons (PAHs) and other semivolatile compounds, especially compounds containing nitrogen (benzonitrile, aniline, quinolone and indene) were the most abundant products. Different behaviour was observed in the evolution of polychlorodibenzo-p-dioxins and furans (PCDD/Fs) at 550 °C and 850 °C. At 550 °C, the less chlorinated congeners, mainly PCDF, were more abundant. Contrarily, at 850 °C the most chlorinated PCDD were dominant. In addition, the total yields of PCDD/Fs in the pyrolysis and combustion runs at 850 °C were low and quite similar.

Kinetic study and thermal decomposition behavior of viscoelastic memory foam

A systematic investigation of the thermal decomposition of viscoelastic memory foam (VMF) was performed using thermogravimetric analysis (TGA) to obtain the kinetic parameters, and thermogravimetric analysis coupled to Fourier Transformed Infrared Spectrometry (TGA-FTIR) and thermogravimetric analysis coupled to Mass Spectrometry (TGA-MS) to obtain detailed information of evolved products on pyrolysis and oxidative degradations. Two consecutive nth-order reactions were employed to correlate the experimental data from dynamic and isothermal runs performed at three different heating rates (5, 10 and 20 K/min) under an inert atmosphere. On the other hand, for the kinetic study of the oxidative decomposition, the data from combustion (synthetic air) and poor oxygen combustion (N2:O2 = 9:1) runs, at three heating rates and under dynamic and isothermal conditions, were correlated simultaneously. A kinetic model consisting of three consecutive reactions presented a really good correlation in all runs. TGA-FTIR analysis showed that the main gases released during the pyrolysis of VMF were determined as ether and aliphatic hydrocarbons, whereas in combustion apart from the previous gases, aldehydes, amines and CO2 have also been detected as the main gases. These results were confirmed by the TGA-MS.

Dimeric assemblies of lanthanide-stabilised dilacunary Keggin tungstogermanates: A new class of catalysts for the selective oxidation of aniline

In this work we demonstrate the efficiency of some dimeric [Ln4(H2O)6(β-GeW10O38)2]12− anions composed of lanthanide-stabilised dilacunary Keggin tungstogermanate fragments (ββ-Ln4, Ln = Dy, Ho, Er, Tm) as heterogeneous catalysts for the organic phase oxidation of aniline with hydrogen peroxide. The results obtained evidence total conversion of aniline at room temperature, as well as full selectivity towards nitrosobenzene, and the catalysts are able to retain both their activity and selectivity after several runs. Peroxopolyoxometalate intermediaries have been identified as the catalytically active species during the aniline-to-nitrosobenzene oxidation process.