Thermal Decomposition of Bio-Based Plastic Materials.

This research delves into a detailed exploration of the thermal decomposition behavior of bio-based polymers, specifically thermoplastic starch (TPS) and polylactic acid (PLA), under varying heating rates in a nitrogen atmosphere. This study employs thermogravimetry (TG) to investigate, providing comprehensive insights into the thermal stability of these eco-friendly polymers. In particular, the TPS kinetic model is examined, encompassing the decomposition of three distinct fractions.

Analysis and removal of bisphenols in recycled plastics using polyethylene glycol.

This study examines the presence of bisphenol A (BPA), S (BPS), F (BPF), and M (BPM) in various recycled plastics readily available on the market (LDPE, HDPE, PET, and PP), in light of European Food Safety Authority (EFSA) limits. Twenty samples of different origin are analyzed, cleaning treatments are applied, and the migration potential of these bisphenols into food is studied. BPM is absent in all samples, but a post-consumer recycled LDPE sample reveals high bisphenol concentrations, raising concerns, reaching 8540 ng/g, 370 ng/g, and 29 ng/g of BPA, BPS, and BPF, respectively.

Debromination of Waste Circuit Boards by Reaction in Solid and Liquid Phases: Phenomenological Behavior and Kinetics.

The debromination of waste circuit boards (WCBs) used in computer motherboards and components has been studied with two different pieces of equipment. Firstly, the reaction of small particles (around one millimeter in diameter) and larger pieces obtained from WCBs was carried out with several solutions of KCO in small non-stirred batch reactors at 200-225 °C. The kinetics of this heterogeneous reaction has been studied considering both the mass transfer and chemical reaction steps, concluding that the chemical step is much slower than diffusion.

Debromination and Reusable Glass Fiber Recovery from Large Waste Circuit Board Pieces in Subcritical Water Treatment.

The great economic, social, and environmental interest that favors an effective management of the recycling of waste printed circuit boards (WCBs) encourages research on the improvement of processes capable of mitigating their harmful effects. In this work, the debromination of large WCBs was first performed through a hydrothermal process employing potassium carbonate as an additive. A total of 32 runs were carried out at 225 °C, various CO /Br anionic ratios of 1:1, 2:1, 4:1, and 6:1, treatment times from 30 to 360 min, proportion of submerged WCBs in the liquid of 100, 50, and 25% that corresponded with the use of three WCB sizes of 20 mm × 16.

Mechanochemical debromination of waste printed circuit boards with marble sludge in a planetary ball milling process.

An effective management of waste printed circuit board (WCB) recycling presents significant advantages of an economic, social, and environmental nature. This is particularly the case when a suitable valorisation is made of the non-metallic parts of the WCBs, well known for their "hidden" toxicological risks. Such benefits motivate research on techniques that could contribute to mitigating their adverse socio-environmental impacts.

Integration of steam gasification and catalytic reforming of lignocellulosic biomass as a strategy to improve syngas quality and pollutants removal.

Residual biomass gasification is a promising route for the production of H-rich syngas. However, the simultaneous formation of pollutants such as light hydrocarbons (HCs), benzene, toluene and xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during gasification must be controlled. As a result, this study evaluated the effect of temperature and catalytic reforming over a Rh-Pt/CeO-SiO catalyst during steam gasification of sugarcane residual biomass on syngas composition and pollutant removal.

Heavy metals, PAHs and POPs in recycled polyethylene samples of agricultural, post-commercial, post-industrial and post-consumer origin.

In the present work, recycled polyethylene (LDPE) samples of agricultural, post-commercial, post-industrial and post-consumer origin were selected and analysed. The analysis comprised the determination of different contaminants such as metals, polycyclic aromatic hydrocarbons (PAHs), dioxin-like biphenyl polychlorides (PCBs), and polychlorinated-dibenzo-p-dioxins and furans (PCDD/Fs). A comparison with one sample of virgin plastic (unrecycled) was performed.

Presence of microplastics in commercial canned tuna.

The present study aims to determine the presence of synthetic polymeric microparticles (MPs) in samples of canned tuna. An analysis procedure of these microparticles was developed and tested. Four brands of tuna marketed in Ecuador canned both in water and oil were analysed.

A Win-Win Combination to Inhibit Persistent Organic Pollutant Formation via the Co-Incineration of Polyvinyl Chloride E-Waste and Sewage Sludge.

Persistent organic pollutant inhibition in the combustion process of polyvinyl chloride (PVC) by prior addition of an inhibitor is currently being studied, reducing the emission of pollutants, and thus reducing the large amount of waste PVC destined for landfill. In this work, the use of sewage sludge (SS) as an alternative to chemical inhibitors to improve the quality emissions of the incineration of polyvinyl chloride waste (PVC e-waste) was studied and optimized. Different combustion runs were carried out at 850 °C in a laboratory tubular reactor, varying both the molar ratio R (0.

Kinetics of the formation and destruction of PCDD/Fs in a laboratory tubular furnace.

A kinetic model has been developed for the formation of selected congeners of PCDD/Fs during the thermal decomposition of different wastes in a horizontal reactor. Previously published data on the decomposition of wastes have been correlated using a kinetic model that only considers process parameters, such as the presence of different amounts of oxygen in the atmosphere of reaction, chlorine and metals in the waste. The effect of both chlorine and metals is modelled through an equation assuming a "saturation effect", i.

Implications of Increasing College Attainment for Aging in General Equilibrium.

We develop an overlapping generations general equilibrium model of the U.S. economy with heterogeneous consumers who face idiosyncratic earnings and health risk to study the implications of increasing college attainment, decreasing fertility, and increasing longevity (2005-2100).

Estimation of Industrial Emissions during Pyrolysis and Combustion of Different Wastes Using Laboratory Data.

In our lab, we have been studying the emissions of different pollutants during pyrolysis and combustion of wastes under different conditions for the last three decades. These studies have focused on the effect of temperature and presence of oxygen on the production of different pollutants. Waste decomposition has been studied in a horizontal laboratory scale reactor, but no estimate has been made of the actual emissions in a conventional thermal decomposition system.

Photodecomposition properties of brominated flame retardants (BFRs).

This study investigates the geometric and electronic properties of selected BFRs in their ground (S) and first singlet excited (S) states deploying methods of the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). We estimate the effect of the S→ S transition on the elongations of the C-Br bond, identify the frontier molecular orbitals involved in the excitation process and compute partial atomic charges for the most photoreactive bromine atoms. The bromine atom attached to an ortho position in HBB (with regard to C-C bond; 2,2',4,4',6,6'-hexabromobiphenyl), TBBA (with respect to the hydroxyl group; 2,2',6,6'-tetrabromobisphenol A), HBDE and BTBPE (in reference to C-O linkage; 2,2',4,4',6,6'-hexabromodiphenylether and 1,2-bis(2,4,6-tribromophenoxy)ethane, respectively) bears the highest positive atomic charge.

Macroeconomic Effects of Medicare.

This paper develops an overlapping generations model to study the macroeconomic effects of an un-expected elimination of Medicare. We find that a large share of the elderly respond by substituting Medicaid for Medicare. Consequently, the government saves only 46 cents for every dollar cut in Medicare spending.

Recyclability of four types of plastics exposed to UV irradiation in a marine environment.

Plastics are the most abundant products in the world and therefore also represent the largest volume of materials found in the sea. Their resistance to degradation makes them dangerous for the marine environment. In this study, the degradation of the four main plastics (Nylon, Polyethylene (PE), Polypropylene (PP), Polyethylene terephthalate (PET)) found in the sea was observed for 6.

Inhibiting fly ash reactivity by adding N- and S- containing compounds.

The inhibitory effect of thiourea (TUA), ammonium thiosulfate (TSA) and amidosulfonic acid (ASA) on the reactivity of fly ash air was investigated using a thermobalance at different heating rates (5, 10 and 20 K min). A model fly ash (activated carbon + 50 wt% CuCl·2HO, pyrolyzed at 700 °C and washed) was used as carbonaceous material. Adding CuCl·2HO to the activated carbon led to an increased rate of decomposition with the air's oxygen.

Pollutant formation in the pyrolysis and combustion of materials combining biomass and e-waste.

Combustion and pyrolysis runs at 850°C were carried out in a laboratory scale horizontal reactor with different materials combining biomass and waste electrical and electronic equipment (WEEE). Analyses are presented of the carbon oxides, light hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Results showed that gas emissions were mainly composed of CO and CO; the high level of CO found in the pyrolytic runs was easily transformed into CO by reaction with oxygen.

Author Correction: Microplastics in Spanish Table Salt.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Emissions of toxic pollutants from co-combustion of demolition and construction wood and household waste fuel blends.

Four different types of fuel blends containing demolition and construction wood and household waste were combusted in a small-scale experimental set-up to study the effect of fuel composition on the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), chlorobenzenes (PCBzs), chlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Two woody materials, commercial stemwood (ST) and demolition and construction wood (DC) were selected because of the differences in their persistent organic pollutants (POPs), ash and metals content. For household waste, we used a municipal solid waste (MSW) and a refuse-derived fuel (RDF) from MSW with 5-20 wt% and up to 5 wt% food waste content respectively.

Microplastics in Spanish Table Salt.

Marine debris is widely recognized as a global environmental problem. One of its main components, microplastics, has been found in several sea salt samples from different countries, indicating that sea products are irremediably contaminated by microplastics. Previous studies show very confusing results, reporting amounts of microparticles (MPs) in salt ranging from zero to 680 MPs/kg, with no mention of the possible causes of such differences.

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water.

Degradation of brominated flame retardants present in printed circuit boards (PCBs) was tested using subcritical water in a high pressure reactor. Debromination experiments were carried out in a batch stirred reactor at three different temperatures (225 °C, 250 °C and 275 °C) keeping a solid to liquid (S/L) ratio of PCB:water = 1:5 during 180 min. Results indicated that debromination efficiency was increased with temperature (18.

Isocyanate emissions from pyrolysis of mattresses containing polyurethane foam.

This study examined the emissions of powerful asthmatic agents called isocyanates from small-scale pyrolysis experiments of two common foams employed in mattress production such as flexible polyurethane foam (FPUF) and viscoelastic memory foam (VMF). A nitrogen atmosphere and five different temperatures, 300, 350, 400, 450 and 850 °C, were selected to carry out the experiments in order to evaluate the worst possible conditions for thermal degradation. A similar trend for both materials was found.

Pollutant emissions from the pyrolysis and combustion of viscoelastic memory foam.

Thermal degradation of viscoelastic memory foam (VMF) in a horizontal laboratory scale reactor has been studied. Pyrolysis and combustion experiments under sub-stoichiometric conditions were performed at four different temperatures (550°C, 650°C, 750°C and 850°C) for the determination of pollutants. Analyses of gas and semivolatile compounds, including polychlorodibenzo-p-dioxins and furans (PCDD/Fs) and dioxin-like polychlorobiphenyls (dl-PCBs) are shown.

Characterization of gaseous emissions and ashes from the combustion of furniture waste.

Gaseous emissions and ash obtained in the combustion of furniture waste have been studied, with particular emphasis on the emissions of hazardous pollutants, such as PCDD/Fs and dl-PCBS. Two different combustion procedures were carried out, one of them in a conventional residential stove (without an automatic control of combustion air and bad mixing of combustion gases with air), and the other in a laboratory-scale reactor (operating under substoichiometric conditions). Three different experiments were carried out in the residential stove, in which the gaseous emissions and ashes obtained were analysed.

Pollutant formation in the pyrolysis and combustion of Automotive Shredder Residue.

The present work has been carried out to verify the feasibility of thermal valorization of an automobile shredder residue (ASR). With this aim, the thermal decomposition of this waste has been studied in a laboratory scale reactor, analyzing the pollutants emitted under different operating conditions. The emission factors of carbon oxides, light hydrocarbons, PAHs, PCPhs, PCBzs, PBPhs, PCDD/Fs, dioxin-like PCBs and PBDD/Fs were determined at two temperatures, 600 and 850°C, and under different oxygen ratios ranging from 0 (pure pyrolysis) to 1.