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An Upflow Anaerobic Sludge Blanket reactor combined with a two-stage membrane bioreactor were operated for 193 days in order to evaluate the biological removal of carbamazepine (CBZ) from low-strength municipal wastewater. The system worked in three different organic load stages (0.7 ± 0.1 kg COD·m−3·d−1, 0.4 ± 0.1 kg COD·m−3·d−1 and 0.1 ± 0.0 kg COD·m−3·d−1) to assess the impact of the influent OLR on operational parameters such as anaerobic and aerobic sludge retention time (SRT), acidity, volatile fatty acids (VFAs), biomass activity or biogas production. The highest carbamazepine removals were achieved during the anaerobic stage (UASB reactor), reaching averages of 48.9%, 48.0% and 38.2% operating at high, medium and low OLR, respectively. The aerobic treatment (MBR) served as post-treatment, improving the removals, and the global UASB-MBR system reached averages of 70.0%, 59.6% and 49.8% when the influent was at medium and low OLR, respectively. The results demonstrate the potential of combined biological systems on the removal of recalcitrant pharmaceuticals. HIGHLIGHTS UASB-MBR was proposed for the removal of the anti-epileptic drug carbamazepine.; The CBZ removal rates of the UASB-MBR combined system were highly dependent on the organic loads of the influent.; UASB-MBR system proved to be particularly suitable for treating municipal wastewater containing CBZ at OLR above 0.7 kg COD·m−3·d−1.; UASB reactor was the main contributor to degradation of the pharmaceutical CBZ.

The composition of evolved slow pyrolysis products under inert and oxidising atmospheres of reference tobacco from the University of Kentucky and its mixture with an SBA-15 mesoporous silica have been measured using a multishot pyrolyser attached directly to a gas chromatography/mass spectrometer. The results obtained show that under an inert atmosphere, the main decomposition rate occurs between 200 and 400 °C, with the evolution of nicotine and the generation of compound's characteristic of the decomposition of cellulose, hemicellulose, lignin and other constituents. The addition of SBA-15 to tobacco produces a reduction in most evolved gases at temperatures below 300 °C, markedly decreasing the formation of quinic acid, neophytadiene, nicotyrine and so on. In contrast, at temperatures above 300 °C, the opposite effect occurs and the generation of compounds is higher, increasing mainly the formation of acetaldehyde, chloromethane and aromatics. Under an oxidising atmosphere, at temperatures below 300 °C, almost all compounds are reduced when SBA-15 is added to tobacco, such as glycerol, neophytadiene and nicotine. The combustion processes occur between 400 and 500 °C with the generation of mainly CO2 and H2O. At temperatures above 300 °C, there is also a significant reduction in the evolved gases like acid acetic, acetonitrile and some aromatics. The application of this type of material could be interesting for heat-not-burn tobaccos to further reduce their toxicity for the consumer. Financial support for this investigation has been provided by the “Ministerio de Economía, Industria y Competitividad” (Grant Number CTQ2015-70726/P); the “Conselleria d’Educació, Investigació, Cultura i Esport” (Grant Numbers PROMETEO2016/056 and IDIFEDER 2018/009) and the “Universidad de Alicante” (Grant Number UAFPU2018-013).

As valuable chemical materials, the heterocyclic nitrogen compounds are widely found in nature, and they are in common use. In this paper, the multiscale interaction mechanisms between 1-ethyl-3-methylimidazolium nitrate ([emim][NO3]) and representative heterocyclic nitrogen compounds (pyrrole and indole) during the extraction process are investigated. By combining theoretical and experimental research, first, the ionic liquid and its corresponding composite systems are studied with a multiscale microscopic method. With the help of quantum chemical calculation and molecular dynamics simulation, the polarity and the difference of the interactions of [emim][NO3] and nitrogen compounds as well as the mechanism of the separation process are explored. Additionally, the mechanism of the separation process and its effects are evaluated through phase equilibrium measurement and extraction experiment. The results reveal the highly selective separation of neutral pyrrole and indole and lay a solid foundation for the development of a new extraction process for complex systems containing neutral heterocyclic nitrogen compounds. The authors are grateful for the support of the National Natural Science Foundation of China (No. 21908131), the Natural Science Foundation of Shandong Province (ZR2019BB066), and the Shenzhen Supercomputer Center.

Polyvinyl chloride (PVC) waste generation has significantly increased in recent years and their disposal is considered a major environmental concern. Removal techniques of chlorine from PVC waste are being studied to minimize a negative environmental impact. In this work, the use of K2CO3 as an alkaline additive to improve the dechlorination efficiency (DE) in the hydrothermal degradation of PVC wires was studied. Different experiments were carried out varying both temperature (175, 200, 225, 235 and 250 °C) and K2CO3 concentration (0.025, 0.050 and 0.125 M), using a solid/liquid ratio of 1:5 in order to determine the evolution of the dechlorination efficiency with time. About 4.66, 21.1, 24.4, 45.7 and 92.6 wt% of chlorine in PVC wire was removed during hydrothermal dechlorination (HTD) with an additive/chlorine ratio of 1:25 (K2CO3 solution of 0.050 M) at 175, 200, 225, 235 and 250 °C, respectively. Optimal additive/chlorine ratio decreased to 1:50 (K2CO3 solution of 0.025 M) at 250 °C, obtaining a dechlorination degree of 99.1% after 4 h without the need of metallic catalysts. Concerning the solid phase behavior during dechlorination, a linear correlation between the DE reached and the weight loss of PVC was found. Support for this work was provided by the CTQ2016-76608-R project and the scholarship BES-2017-080382 from the Ministry of Economy Industry and Competitiveness (Spain).

For separating the azeotrope of dimethyl carbonate (DMC) and ethanol, four imidazolium-based ionic liquids were selected as extractants. The liquid-liquid equilibrium data for the ternary systems DMC + ethanol + ILs were determined at 298.15 K under pressure of 101.3 kPa. The effect of ILs anions and the alkyl chain length of the cations on the liquid-liquid phase behavior was investigated and discussed. Moreover, the distribution coefficient and selectivity were calculated and analyzed to evaluate the most suitable IL to separate the azeotrope of DMC and ethanol. Meanwhile, the interaction energies of ILs with DMC and ethanol were explored. The calculated results indicate that the adopted ILs have strong interactions with ethanol than with DMC. In addition, the NRTL activity coefficient model was adopted to correlate the measured experimental data and the optimum binary interaction parameters were obtained. This work was supported by the Shandong Provincial Key Research & Development Project (2018GGX107001), National Natural Science Foundation of China (Grant 21878178) and Project of Shandong Province Higher Educational Science and Technology Program (J18KA072).

The presence of different pollutants in recycled plastics is reviewed in this article. The desirable circular economy of plastics should be linked to the availability of clean recycled plastics with a non-significant and small to nil amount of substances of concern. Different researchers found polycyclic aromatic hydrocarbons (PAHs) and Persistent Organic Pollutants (POPs), such as brominated flame retardants (BFRs), pesticides, dioxins and furans (PCDD/Fs and PBDD/Fs) in plastic recyclates. This represents an added difficulty to the effective recycling process of plastics that reduces the demand for energy and materials, in addition to posing a great environmental danger since they represent a vector of accumulation of the contaminants that will finally appear in the most unexpected products. Life Cycle Analysis of the plastic wastes recycling process indicates a great saving of energy, water and CO2 emissions. This research was funded by Ministry of Science and Innovation (Spain), grant number PID2019‐105359RB‐I00.

In the present research, the effect of two hybrid treatments, ozone followed by powdered activated carbon (PAC) or PAC followed by ozone (O3), was studied for the removal of two drugs present in water: diclofenac and carbamazepine. In the study, two initial concentrations of each of the contaminants, 0.7 mg L−1 and 1.8 mg L−1, were used. Different doses of PAC between 4–20 mg L−1 were studied as variables, as well as different doses of O3 between 0.056–0.280 mg L−1. The evolution of the concentration of each contaminant over time was evaluated. From the results obtained, it was concluded that the combined treatment with ozone followed by PAC reduces between 50% and 75% the time required to achieve 90% removal of diclofenac when compared with the time required when only activated carbon was used. In the case of carbamazepine, the time required was 97% less. For carbamazepine, to achieve reduction percentages of up to 90%, O3 treatment followed by PAC acted faster than PAC followed by O3. In the case of diclofenac, PAC treatment followed by O3 was faster to reach concentrations of up to 90%. However, to reach yields below 80%, O3 treatment followed by PAC was more efficient.

Three pyridinium-based ionic liquids (ILs) were adopted to extract isopropanol (IPA) from its aqueous mixture for investigating the potential of these ILs in the separation of a (water + IPA) azeotropic mixture. The liquid–liquid equilibrium values for the mixtures (water + IPA + ILs) was determined at 298.15 K. The selectivity and distribution coefficient were computed, which indicates that the IL n-hexylpyridinium bis(trifluoromethyl sulfonyl)imide displays a better extraction effect to separate the mixture of IPA and water. Besides, the NRTL model was applied to regress the determined tie-line values, and the coherence of the optimized binary parameters was examined using the Gibbs energy surfaces analysis. This work was supported by the National Natural Science Foundation of China (No. 21878178) and Natural Science Foundation of Shandong Province (No. ZR2019BB066).

The aerobic granular sludge (AGS) process is an effective wastewater treatment technology for organic matter and nutrient removal that has been introduced in the market rapidly. Until now, limited information is available on AGS regarding the removal of bacterial and viral pathogenic organisms present in sewage. This study focussed on determining the relation between reactor operational conditions (plug flow feeding, turbulent aeration and settling) and physical and biological mechanisms on removing two faecal surrogates, Escherichia coli and MS2 bacteriophages. Two AGS laboratory-scale systems were separately fed with influent spiked with 1.0 × 106 CFU/100 mL of E. coli and 1.3 × 108 PFU/100 mL of MS2 bacteriophages and followed during the different operational phases. The reactors contained only granular sludge and no flocculent sludge. Both systems showed reductions in the liquid phase of 0.3 Log10 during anaerobic feeding caused by a dilution factor and attachment of the organisms on the granules. Higher removal efficiencies were achieved during aeration, approximately 1 Log10 for E. coli and 0.6 Log10 for the MS2 bacteriophages caused mainly by predation. The 18S sequencing analysis revealed high operational taxonomic units (OTUs) of free-living protozoa genera Rhogostoma and Telotrochidium concerning the whole eukaryotic community. Attached ciliates propagated after the addition of the E. coli, an active contribution of the genera Epistylis, Vorticella, and Pseudovorticella was found when the reactor reached stability. In contrast, no significant growth of predators occurred when spiking the system with MS2 bacteriophages, indicating a low contribution of protozoa on the phage removal. Settling did not contribute to the removal of the studied bacterial and viral surrogates. M.L. Barrios-Hernández acknowledges the Technological Institute of Costa Rica for providing the fellowship (Grant Number 007-2014-M) to pursue her PhD programme (2016-2020) at IHE-Delft, the Netherlands. K. Mora-Cabrera acknowledges the Generalitat Valenciana (GRISOLIAP/2017/173) and the European Social Funds (BEFPI/2019/065) for their financial support.

Liquid-liquid equilibrium (LLE) data correlation of multicomponent mixtures is frequently carried out without using any procedure to ensure that the model parameters obtained for the totally miscible binary mixtures are consistent with such behavior (i.e. they do not lead to two liquid phases in equilibrium). In other words, the behavior of the model beyond the LLE region fitted (experimental tie-lines) is not usually considered in LLE correlations. It seems to be wrongly assumed that the mere absence of tie-lines data in totally miscible regions should guarantee that the parameters resulting from the LLE correlation lead to total miscibility in such homogeneous regions. We have checked that for the correlation of certain type 1 ternary systems (Treybal classification) a high probability exists of obtaining inconsistent model parameters, which lead to type 2 instead type 1 ternary behavior, unless specific restrictions for such parameters are imposed during the correlation. Commercial tools to carry out this type of data fitting, which are frequently included in process simulation packages such as Aspen Plus, do not include the possibility of applying such restrictions and consequently they could provide this type of misleading correlation results with serious consequences in equipment design. In the present paper, LLE data correlation for certain type 1 ternary systems has been carried out using Aspen Plus resulting in inconsistent type 2 results. These same systems have been satisfactorily correlated using our own correlation tools including restrictions to ensure the required miscibility behavior, and thus obtaining consistent parameters. A similar problem could occur in the correlation of the less frequent island (or zero) type ternary systems. Some examples are also presented for such type of systems. The authors would like to thank “Generalitat Valencia: Consellería de Educación, Investigación, Cultura y Deporte” for the PhD grant (ACIF/2019/040).

Research abounds in the literature on kinetic analyses using thermogravimetric (TG) runs. Many of these studies use approximations of integral or derivative forms of the kinetic law and all of them use programmed temperature, not the actual temperature measured by thermocouples close to the sample. In addition, it is common to conduct a single run in order to perform the calculation. Nevertheless, many authors consider that numerical methods should be used to analyse the kinetics of decomposition. In such cases, the actual temperature is used and, generally, several runs are fitted using the same kinetic parameters, giving robustness to the results. In the present work, a numerical integration procedure was discussed and applied to different examples. We focused on materials presenting a single decomposition curve as well as other materials with more complex processes. Different examples were explored, and the methodology was applied to a number of wastes such as coffee husks, polystyrene and polyethylene.

In this study, the reduction of the emerging organic contaminant atrazine in water, was investigated by adsorption, oxidation and a combination of both technologies. Adsorption tests were performed using method ASTM D3860-98 with two types of activated carbon: powdered activated carbon and granular activated carbon. For the oxidation tests, advanced ozone oxidation technology was used. Finally, in the combined tests, firstly adsorption treatment was applied followed by oxidation and then the order was reversed. We studied the contaminant removal percentage using different treatments at various reaction times. Results for the different treatments under study showed that, for an initial atrazine concentration of 0.7 mg L−1 and a dose of 16 mg L−1 of powdered activated carbon, with contact times of 60 min, 24 h and 48 h, percentage reductions of the contaminant of 81%, 92% and 94% respectively were obtained. For the same concentration of contaminant, but instead using granular activated carbon, the percentage reduction of atrazine at 60 min was 2%, this percentage rising to 34% and 35% after 24 and 48 h of contact time, respectively. For the same initial contaminant concentration, when ozone was applied at a dose of 19.7 mg L−1, and with a reaction time of 18 min, a reduction of atrazine of 93% was obtained, but oxidation by-products were also produced. For the combined treatments, with the same initial concentration of contaminant and the same doses of carbon and ozone as previously indicated, better contaminant reductions were obtained when the treatment started with activated carbon followed by ozone, achieving a 90% reduction of atrazine observing a 17 minute contact time with powdered activated carbon and a 3 day contact time using the granulated carbon. When the order was reversed by starting with ozone, the contact time was 52 min and 4 days, respectively. This research is part of the project of the Ministry of Economy and Competitiveness “Elimination of emerging contaminants through anaerobic and aerobic processes in series and complementary combined treatment systems UASB SMEBR O3/AC” ref. CTM2016 76910 R.

Dimethyl carbonate (DMC) has recently gained popularity due to its environmentally friendly status and multiple applications in which it is able to replace more toxic chemicals. Among its several commercial synthesis production routes, the ethylene carbonate (EC) transesterification shines as a CO2 consuming process. However, other factors such as the high emitting synthesis of EC precursors hinder its environmental capabilities. Methanol oxycarbonylation is a mature DMC non-CO2 consuming synthesis route with the potential to indirectly utilize the greenhouse gas throughout the synthesis of its intermediates. In this work, we propose a DMC production superstructure using the methanol oxycarbonylation route with the aim of consuming CO2 in both the synthesis gas (syngas) and methanol synthesis stages. Results show that the integration of methanol and syngas synthesis with the DMC production process vastly decreases both the cost and emission with respect to the unintegrated case. However, the addition of a Reverse Water Gas Shift (RWGS) reactor further decreases the emission down to a minimum of 1.019. kg CO2-eq/kg DMC, resulting in a 54 % decrease in the indicator compared with the direct CO2 utilization route. In comparison with other routes, utilization of this DMC in blends with gasoline manages to reduce the GWP of using the fuel mix to a potential 16 %. The authors gratefully acknowledge financial support from the project PROMETEO2020/064. The authors would also like to thank «Generalitat Valenciana: Conselleria de Educación, Investigación, Cultura y Deporte» for the Ph.D grant (ACIF/2016/ 062).

While the annual European demand for polyolefins is 25 million tonnes, only 3 million tonnes of recycled polyolefins find their place in the market, despite collecting 15 million tonnes of post-consumer polyolefins every year. Brand owners of care products are showing their interest in using post-consumer recycled plastics for their packaging. However, there is a general concern in using these materials, as recycled polymers can contain unwanted substances that may expose the consumer to health risks or make the packaging unattractive. Accordingly, the presence of these contaminants narrows the market opportunity of recycled plastics to applications with low-quality requirements and in which the product is not in direct contact with the consumer. Though mechanical recycling is the most widespread solution presents limitations in terms of decontamination, as only superficial substances are removed. Thereby, the volatile organic compounds (VOCs) migrated to the polymer matrix remain inside. Consequently, there is a need to find a solution to purify recycled plastics and increase their market share. This study focuses on removing VOCs from post-consumer recycled HDPE through two innovative methods applied for the first time in this field, steam stripping and polyethylene glycol (PEG) extraction. The methodology implemented to analyze the volatile organic compounds in HDPE was HS-SPME-GC/MS. Both methods showed a decrease above 70% in the VOCs content compared to extrusion-degassing. Moreover, these were compared to hot air stripping, a new technology developed at an industrial scale for the removal of VOCs. As a result, steam stripping improved efficiency in reducing the overall VOCs compared to hot air stripping. The PEG extraction method lowered the volatile polar compounds further than using hot air stripping. Additionally, none of these technologies modified the HDPE melting flow index. This work was supported by a grant from the University of Alicante as part of the InnoUA Transfer of Knowledge program and co-financed by Cadel Deinking (Industrial Doctorate).

The main objective of this work was to quantify the impact of handling of bulk materials on PM10 levels measured at the port-city border of Alicante (Spain), located on the western Mediterranean coast. To achieve that goal, 355 PM10 samples were collected at the perimeter of the harbor of Alicante from March 2017 to February 2018. A 181 sample subgroup was chemically characterized in order to perform a source apportionment study with the EPA PMF 5.0 model. Eight factors were identified, two of them directly related to the handling of bulk materials (Limestone + gypsum and Clinker), accounting jointly for 35% of the average PM10 concentration. A Road traffic factor was the second highest contributor to PM10 levels (17%) while the Shipping emissions factor accounted for only 6% of the average PM10 mass. Other factors such as Biomass burning+ secondary nitrate and Aged sea salt represented a joint contribution of 25% of the PM10 mass. Results indicate that emission abatement strategies should primarily focus on the reduction of fugitive emissions caused by the handling of bulk materials at the docks. Moreover, scenarios including reductions of more than 50% in bulk handling sources and 10% in other anthropogenic sources would help to reduce anthropogenic exceedances of the daily PM10 limit (50 μg·m−3) and to approach to WHO daily PM10 standard (20 μg m−3). This work was supported by the Spanish Ministry of Science, Innovation and Universities through the projects CGL2017-90884-REDT (ACTRIS) and RTI2018-098639-B-I00 (COSMOS) (AEI/FEDER,UE) and through an FPU Grant (FPU18/00081).

The synthesis of SBA-15 has been optimized using sodium silicate, an inexpensive precursor of SBA-15. In this work, the influence of synthesis times of the precipitation and the hydrothermal treatment steps, on the textural properties developed as well as for reducing the toxic compounds generated in tobacco smoking, has been studied. The hydrothermal treatment has been proved to be necessary to obtain materials with adequate performance in this particular application. Twenty-four hours of hydrothermal treatment provide materials with the best properties. Although the reaction stage usually involves the mixing of reagents during 24 h, 40 min is enough to obtain a material with stick-like morphology and typical textural properties. Moreover, between 1 and 2 h of reaction time, the material proved to have the best performance for the purpose of reducing the toxicity of the products generated during the tobacco smoking process. These results are of great significance for an eventual scaling up to industrial scale of the SBA-15 manufacturing process. Results of a pilot plant experiment in a batch of 4 kg of SBA-15 are reported. This research was funded by the Spanish “Secretaría de Estado de Investigación” of the Ministerio de Ciencia e Innovación (CTQ2015-70726-P), Generalitat Valenciana (PROMETEO/2016/056, PROMETEO 2020/093 and IDIFEDER 2018/009).

The Ni/SiO2 system is one of the most interesting to produce COx-free H2 and valuable carbon nanofibers (CNFs) by the catalytic decomposition of CH4. SiO2 is one of the most effective support while Ni catalyst displays long life and high activity. We studied the catalytic chemical vapor deposition (CCVD) process of CH4 within Ni/glass system at relatively low temperature (600 °C) during long times (3 h), varying the amount of the catalyst (2.3–17.8% Ni(%)) and the carbon source (100:200 to 100:0, CH4:N2). As the amount of Ni and CH4 increases, the formation of CNFs is enhanced giving as a result CNFs/glass materials with more amount, longer and thicker CNFs. The initial microstructure of the glass support and the way of Ni catalyst is deposited play a decisive role. Pristine porous glass displays a microstructe of interconnected mesopores which are progressively filled with Ni, producing ink-bottle pores with open ends. After the CCVD process as the amount of Ni or CH4 increases, the porosity of the Ni-doped glass is reduced due to the progressively filling of the mesopores (4 nm) with CNFs. Furthermore, due to the formation of large entanglements of CNFs new pores appear (20–70 nm) depending on the processing conditions. Fish-bone with hollow core and bamboo-like CNFs are found over the surface and also inside the porous glass support. It is observed a base-growth mechanism due to the strong interaction between the catalyst and the support, which prevents the Ni deactivation enhancing its activity for long times. This work was supported by project MAT2016-78700-R financed by Spanish Research Agency and European Regional Development Fund (AEI/FEDER, EU).

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.e., that a certain amount of each substance produces the maximum rate, and that higher amounts do not increase the rate. The presence of oxygen is modelled by a destruction reaction over part of the PCDD/Fs produced. The model, which uses data from more than 64 experiments, correlated the emissions of three selected congeners: 1,2,3,6,7,8-HxCDD, OCDF and 2,3,7,8-TCDF, which are enough to estimate the total amount and toxicity of an emission.

Thermochemical processes for biomass conversion are promising to produce renewable hydrogen-rich syngas. In the present study, model fitting methods were used to propose thermal degradation kinetics during catalytic and non-catalytic pyrolysis (in N2) and combustion (in synthetic air) of sugarcane residual biomass. Catalytic processes were performed over a Rh-Pt/CeO2-SiO2 catalyst and the models were proposed based on the Thermogravimetric (TG) analysis, TG coupled to Fourier Transformed Infrared Spectrometry (TG-FTIR) and TG coupled to mass spectrometry (TG-MS). Results showed three different degradation stages and a catalyst effect on product distribution. In pyrolysis, Rh-Pt/CeO2-SiO2 catalyst promoted reforming reactions which increased the presence of H2. Meanwhile, during catalytic combustion, oxidation of the carbon and hydrogen present in biomass favored the release of H2O, CO and CO2. Furthermore, the catalyst decreased the overall activation energies of pyrolysis and combustion from 120.9 and 154.9 kJ mol−1 to 107.0 and 138.0 kJ mol−1, respectively. Considering the positive effect of the Rh-Pt/CeO2-SiO2 catalyst during pyrolysis of sugarcane residual biomass, it could be considered as a potential catalyst to improve the thermal degradation of biomass for syngas production. Moreover, the proposed kinetic parameters are useful to design an appropriate thermochemical unit for H2-rich syngas production as a non-conventional energy technology. This research was funded by Colciencias (Francisco Jose de Caldas Fund) and Universidad de La Sabana through the Project ING-221 (Colciencias contract 548–2019) and The International Relations Department of University of Alicante for the financial support through the program named “University Development Cooperation 2018”.

This paper introduces a comprehensive study of the Life Cycle Impact Assessment (LCIA) of water management in shale gas exploitation. First, we present a comprehensive study of wastewater treatment in the shale gas extraction, including the most common technologies for the pretreatment and three different desalination technologies of recent interest: Single and Multiple-Effect Evaporation with Mechanical Vapor Recompression and Membrane Distillation. The analysis has been carried out through a generic Life Cycle Assessment (LCA) and the ReCiPe metric (at midpoint and endpoint levels), considering a wide range of environmental impacts. The results show that among these technologies Multiple-Effect Evaporation with Mechanical Vapor Recompression (MEE-MVR) is the most suitable technology for the wastewater treatment in shale gas extraction, taking into account its reduced environmental impact, the high water recovery compared to other alternatives as well as the lower cost of this technology. We also use a comprehensive water management model that includes previous results that takes the form of a new Mixed-Integer Linear Programming (MILP) bi-criterion optimization model to address the profit maximization and the minimization Life Cycle Impact Assessment (LCIA), based on its results we discuss the main tradeoffs between optimal operation from the economic and environmental points of view. This project has received funding from the Spanish «Ministerio de Economía, Industria y Competitividad» under the projects CTQ2016-77968-C3-1-P and CTQ2016-77968-C3-2-P (FEDER, UE).

En esta investigación se evaluó la eficiencia de un biorreactor de membrana (MBR, por sus siglas en inglés), para eliminar pesticidas. Además, se comprobó que la presencia de pesticidas no influyera en la eficiencia de eliminación de materia orgánica. Se estudió un total de 16 pesticidas, con los que se dopó agua residual urbana sintética. La investigación se llevó a cabo en una planta MBR a escala piloto, operada a tiempos de retención celular (TRC) de 30 y 60 días, carga másica de 0.23 kgDQO∙kgSSV-1·d-1 y flujo promedio de 5.44 l∙m-2h-1. Los resultados demostraron que las triazinas y el linurón presentan menor grado de eliminación, siendo los mejores resultados a TRC de 60 días con valores entre 73 y 82%; los organoclorados se reducen en el orden de 90 y 99%. Esta tecnología puede alcanzar una calidad óptima del efluente, permitiendo su reutilización, o bien puede contribuir en el mantenimiento del estado ecológico adecuado del medio receptor. This research evaluated the efficiency of a membrane bioreactor (MBR) to eliminate pesticides. It also demonstrated that the presence of pesticides did not influence the efficiency of elimination of organic matter. Sixteen pesticides were studied, which were used to dope a synthetic urban residual water. The research was carried out in a pilot scale MBR plant, operated at a sludge retention time (SRT) of 30 and 60 days, with a mass loading of 0.23 kgCOD∙kgVSS-1·d-1 and average flow of 5.44 L∙m-2h-1. The results showed that triazines and linuron have a lower degree of elimination, with the best results being 60 days TRC with values between 73% and 82%, while organochlorines were reduced in the order of 90% and 99%. This technology can result in an excellent effluent quality, allowing it to be reused and contributing to maintain the good ecological state of the receiving environment. Esta investigación ha sido desarrollada en el Instituto del Agua y las Ciencias Ambientales de la Universidad de Alicante, en el marco del Proyecto “CTM 2013-46669: eliminación y/o degradación de contaminantes emergentes en aguas mediante tratamientos combinados”, del Ministerio de Economía y Competitividad de España, y también con la ayuda del Subprograma de Ayuda Económica Complementaria N° 08-2014-074 del Instituto para la Formación y Aprovechamiento de Recursos Humanos (IFARHU)-Universidad Tecnológica de Panamá, República de Panamá.

The quality of coatings is continuously improving due in part to the irruption of nanotechnology in material science, which has made it possible to manufacture novel nanocomposites. Similarly, the methodologies to measure the mechanical properties of polymer-based nanocomposite coatings are changing. However, a real standard to measure, for example, anti-scratch resistance using equipment such an Atomic Force Microscope (AFM), does not exist due to the strong influence of operational conditions on the final results. This means it is impossible to compare the results of different authors. Moreover, traditional methodologies used in industry, like the Wolf-Wilburn Test, are not able to measure the hardness of novel composites since they can go out of scale. In this work, an AFM is used to make nano-scratches in urethane-acrylate coating surfaces with known Wolf-Wilburn scale values, calculating the anti-scratch resistance. These data are correlated through linear regression. This correlation could be used to obtain the Wolf-Wilburn values from the width of groove made on the polymer surface by the AFM tip. Thus, this work present a potential way to extend the Wolf-Wilburn scale using AFM for those coatings that could not be measurable with Wolf-Wilburn Test. The authors gratefully acknowledge the financial support of the Ministerio de Economía y Competitividad of Spain, MINECO (Project CTQ2014-54772-P and CTQ2013-44213-R) and Generalitat Valenciana (Project PROMETEOII/2014/007).

Experimental equilibrium data of the systems water + NaCl or KCl+ 2-methyl 2-propanol are determined experimentally at boiling conditions and 101.3 kPa. The results obtained permit a study of the shape and different regions of their equilibrium diagrams. A comparison with similar diagrams of other alcohols is made, demonstrating that the ability of NaCl and KCl to split the water + alcohol mixture into two liquid phases increases with temperature and that NaCl splits the alcohols from water in the following order: 2-methyl 2-propanol > 1-propanol > 2-propanol. DGICYT of Spain (project CTQ2014-59496).

The SLLV phase equilibria of the water + NaCl + 2-propanol mixture have been determined experimentally at 101.3 kPa by means of a modified recirculating still. The results obtained allow us to study the shape of the phase diagram of the system, to analyze the evolution with temperature of this equilibrium diagram and to show the differences with a similar system such as water + NaCl + 1-propanol. Moreover, the experimental data obtained have been compared with previously published data showing their important inconsistencies and presenting the rules that must be met by the experimental equilibrium data of water + non-volatile salt + organic solvent type systems in each one of the different SLLV, LLV and SLV equilibrium regions. The authors wish to thank the DGICYT of Spain for the financial support of project CTQ2014-59496.

Plastic flexible films are increasingly used in many applications due to their lightness and versatility. In 2014, the amount of plastic films represented 34% of total plastic packaging produced in UK. The flexible film waste generation rises according to the increase in number of applications. Currently, in developed countries, about 50% of plastics in domestic waste are films. Moreover, about 615,000 tonnes of agricultural flexible waste are generated in the EU every year. A review of plastic films recycling has been conducted in order to detect the shortcomings and establish guidelines for future research. This paper reviews plastic films waste management technologies from two different sources: post-industrial and post-consumer. Clean and homogeneous post-industrial waste is recycled through closed-loop or open-loop mechanical processes. The main differences between these methods are the quality and the application of the recycled materials. Further research should be focused on closing the loops to obtain the highest environmental benefits of recycling. This could be accomplished through minimizing the material degradation during mechanical processes. Regarding post-consumer waste, flexible films from agricultural and packaging sectors have been assessed. The agricultural films and commercial and industrial flexible packaging are recycled through open-loop mechanical recycling due to existing selective waste collection routes. Nevertheless, the contamination from the use phase adversely affects the quality of recycled plastics. Therefore, upgrading of current washing lines is required. On the other hand, household flexible packaging shows the lowest recycling rates mainly because of inefficient sorting technologies. Delamination and compatibilization methods should be further developed to ensure the recycling of multilayer films. Finally, Life Cycle Assessment (LCA) studies on waste management have been reviewed. A lack of thorough LCA on plastic films waste management systems was identified. This work was supported with a Grant from the University of Alicante as part of the InnoUA Transfer of Knowledge programme (Industrial Doctorate).

Gas-permeable membranes coupled with low-rate aeration is useful to recover ammonia (NH4+) from livestock effluents. In this study, the role of inorganic carbon (bicarbonate, HCO3−) to enhance the N recovery process was evaluated using synthetic effluents with various NH4+ to HCO3− molar ratios of 0.5, 1.0, 1.5 and 2.0. The study also evaluated the effect of increased organic matter on the NH4+ recovery using humic acids (3000–6000 mg L−1), and the N recovery from high-strength swine manure. The release of hydroxide from the HCO3− with aeration increased the wastewater pH and promoted gaseous ammonia formation and membrane uptake. At the same time, the recovery of gaseous ammonia (NH3) through the membrane acidified the wastewater. Therefore, an abundant inorganic carbon supply in balance with the NH4+ is needed for a successful operation of the technology. NH4+ removal efficiencies >96% were obtained with NH4+ to HCO3− ratios ≤1. However, higher molar ratios inhibited the N recovery process resulting in lower efficiencies (

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 CO2; the high level of CO found in the pyrolytic runs was easily transformed into CO2 by reaction with oxygen. The total amount of light hydrocarbons emitted was higher in the samples containing WEEE, methane being the most abundant light hydrocarbon in all the runs. However, the presence of WEEE reduced the emission of PAHs which decreased with the increase of the oxygen. The total amount of BrPhs increased in the decomposition of the samples containing WEEE, reaching its maximum in pyrolysis runs. Emission of PCDD/Fs was enhanced in pyrolytic conditions and easily decreased in the presence of oxygen. This work was supported by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain), the PROMETEOII/2014/007 project of the Valencian Community regional Government (Spain) and the UAUSTI17-07 grant from University of Alicante (Spain).

The recovery and purification of methanol from its mixtures is of great importance; to this end, liquid-liquid extraction is an effective method for the separation of azeotropes. In this work, three imidazolium-based ionic liquids were used to separate a hexane-methanol azeotropic mixture, and the ternary liquid-liquid equilibria (LLE) data for the systems of hexane + methanol + [MIM][HSO4] (1-methylmidazole hydrogen sulfate), [BMIM][HSO4] (1-Butyl-3-methylimidazolium hydrogen sulfate), [BMIM][OTf] (1-Butyl-3-methylimidazolium trifluoromethansulfonate) were measured at 298.15 K and atmospheric pressure. The separation factor and distribution coefficient were calculated from the experimental LLE data to evaluate the separation performance. The influence of the anions and mono-/di-substituted hydrocarbon chains on the imidazolium cation ring of the LLE was investigated. The experimental LLE data were successfully correlated by non-random two liquid (NRTL) and universal quasi-chemical (UNIQUAC) models, and the binary interaction parameters were obtained. This work is supported by the National Natural Science Foundation of China (Project 21776145 and Project 21306093).

Composting of sewage sludge is a common practice for sludge disposal. Some previous studies found high levels of polychorodibenzo-p-dioxins and polychorodibenzofurans (PCDD/Fs) after composting, especially octachlorodibenzo-p-dioxin (OCDD) but also 1234678-heptachlorodibenzo-p-dioxin (1234678-HpCDD) to a lesser extent. In this work, the concentrations of OCDD, 1234678-HpCDD and the rest of the 17 toxic congeners of PCDD/Fs were determined in compost obtained under different conditions. Although the toxicity of the two compounds mentioned above is small, their generation may reach undesirable levels. The PCDD/F content was analyzed in a composting plant and in a laboratory test. In both cases, the composted material was a mixture of sewage sludge, straw and sawdust. The composting plant was a tunnel with air turbine aeration and with a turner to homogenize and move the mixture upwards. The laboratory tests were carried out with Dewar vessels (with air dispersion at the bottom and controlled temperature) and with small vessels inside a controlled oven with non-forced aeration. The laboratory runs were also carried out with the addition of pentachlorophenol in some runs, as a dioxin precursor. The highest OCDD levels were found in three samples of the composting plant (30000–90000 pg/g dry matter or dm), with toxicity values surpassing the limit level for soil amendment (17 pg I-TEQ/g dm). Their formation was analyzed considering their concentration vs. that of octachorodibenzofuran (OCDF), which is not formed during composting. In the laboratory, in experiments carried out in a vessel with non-forced aeration conditions and with the addition of pentachlorophenol, the formation of OCDD was significant (e.g. from 80 to 1500 pg/g dm). That means that these two factors, non-forced aeration and the presence of pentachlorophenol, can cause the OCDD formation. Support for this work was provided by Research project GRE 13-14 from the University of Alicante, Research project PROMETEOII/2014/007 from the Generalitat Valenciana (Spain) and Research project CTQ2013-41006-R from the Ministry of Economy and Competitiveness (Spain).

Coastal areas submitted to seawater intrusion and with discharges from urban and industrial wastewaters, municipal landfill leachates, rivers, recreational waters and other sources are sensitive to be polluted with parabens. Understanding the fate of these compounds in environmental studies, it requires previously the knowledge of the reactive processes in controlled conditions. In this research, laboratory columns experiments were carried out with a group of parabens (methyl-, ethyl-, propyl- and butylparaben) and their main degradation compound (4-hydroxybenzoic acid) to study mainly the dynamic sorption processes in different aquifer materials (100% sand and heterogeneous: 81% sand, 9% silt and 10% clay) and with fresh and sea waters, the end members of seawater intrusions. To the column hydrodynamic characterization, tracer assays with increase and decrease of salinity were performed, to obtain the mean residence time of each column and other transport parameters which allow us to compare parabens’ sorption in different conditions. The results of the adsorption and desorption of parabens in the sand column demonstrated be fast and simultaneous, with a short delay and without influence of the water salinity. Very different results were found in the column experiments with heterogeneous material, where the presence of clay and organic matter increase the time of adsorption/desorption as the length of the alkyl chain paraben increased, according with their hydrophobicity. It should be noted that despite the quick desorption of the major quantities of parabens, the elution of their trace concentrations was very slow (for the seawater, the buthylparaben required a dimensionless time of 800). Planning the restoration of a coastal aquifer with freshwater, and in the conditions of the studied sand column experiment, it will need a dimensionless time of 160. However, it is necessary to take into account that the studied parabens and 4-hydroxybenzoic acid are biodegradable substances, as can be seen in long term experiments, when bacterial proliferation could occur, despite starting the experiment under sterile conditions. This study was partially financed by the Ministry of Economy and Competitiveness via the project “Combined treatments for degradation and removal of emerging pollutants in water” (CTM2013-46669-R).

Isobaric vapor-liquid-liquid-solid equilibria for the ternary system water + sodium chloride + 1-propanol have been determined at 101.3 kPa by means of a modified recirculating still. The addition of sodium chloride to the solvent mixture results in the appearance of different equilibrium regions. A detailed quantitative analysis of the evolution with temperature of the phase diagram has been carried out. The experimental data obtained in this way have been compared, on the one hand, with previously published data containing important inconsistencies and, on the other hand, with data calculated by the extended UNIQUAC model. We would like to thank the DGICYT of Spain for the financial support of project CTQ2014-59496.

A series of resorcinol formaldehyde based carbon xerogels were synthesized under identical conditions using different graphene oxide loads. The gelification reaction was carried out using a stable aqueous suspension of graphene oxide, yielding organic gels with graphene oxide concentrations ranging from 1.2–2.5%. After the carbonization, xerogels with medium surface area (650 m2/g) and a highly improved electrical conductivity were obtained. Specific capacitance of 120 F/g of one electrode at very high scan rate of 500 mV/s were achieved, as well as power densities above 30 kW/kg, which is a significant improvement of 180% with respect to the pristine xerogels. Carbonized xerogels were further steam activated to yield activated carbon xerogels with surface areas of up to 1800 m2/g. The use of activated xerogels improves slightly the specific capacitance at low scan rates only, and there is a sharp decrease above 20 mV/s, resulting in a worse performance than graphene oxide doped carbonized xerogels. The electrical conductivity of the graphene oxide-doped carbon xerogels decreases upon activation, which means that the influence of the electrical conductivity on a carbon xerogel is greater than its specific surface area, which it is the first time it is observed for porous carbons, The authors gratefully acknowledge the financial support of the Ministerio de Economía y Competitividad of Spain, MINECO (Project CTQ2014-54772-P and CTQ2013-44213-R), and Generalitat Valenciana (project PROMETEOII/2014/007)

The present study deals with the influence of graphene oxide functional groups on their ability to reinforce an epoxy resin when forming carbon fiber composites. Composites were processed through the direct vacuum infusion of the doped resin into carbon fiber fabrics. We used graphene oxide nanosheets with two different chemical characters: as‐produced graphene oxide, with a high oxygen content and acid character, and a simple ammonia base‐washed graphene oxide, which to a great extent removes the oxidative debris or highly oxidized fulvic‐like entities, resulting in an average lower oxygen content and cleaner surface sheets than as‐produced graphene oxide. Base‐washed graphene oxide performed considerably better in both tensile and mode‐I interlaminar properties of carbon fiber composites. The fracture energy required for the onset of mode I interlaminar fracture toughness was enhanced 31% when using as‐produced graphene oxide and 60% when using base‐washed graphene oxide by adding 0.2 wt% only. More interestingly, base‐washed graphene oxide produces a higher delamination resistance along the entire range of crack growth. The effect of adding graphene oxide with a cleaner surface and lower oxygen surface chemistry allows direct chemical bonding matrix‐graphene when the resin is curing, promoting a better interface fiber‐resin and consequently, improving the reinforcement efficiency. Government of Spain and the Ministry of Economy and Competitiveness; contract grant number: CTQ2013-44213-R; contract grant sponsor: Generalitat Valenciana; contract grant number: PROMETEOII/2014/007.

Studies show that nanoscale zero-valent iron (nZVI) particles enhance the formation of chlorinated compounds such as polychlorinated dioxins and furans (PCDD/Fs) during thermal processes. However, it is unclear whether nZVI acts as a catalyst for the formation of these compounds or contains impurities, such as PCDD/Fs, within its structure. We analyzed the presence of PCDD/Fs in nZVI particles synthesized through various production methods to elucidate this uncertainty. None of the 2,3,7,8-substituted congeners were found in the commercially-produced nZVI, but they were present in the laboratory-synthesized nZVI produced through the borohydride method, particularly in particles synthesized from iron (III) chloride rather than from iron sulfate. Total PCDD/F WHO-TEQ concentrations of up to 35 pg/g were observed in nZVI particles, with hepta- and octa-chlorinated congeners being the most abundant. The reagents used in the borohydride method were also analyzed, and our findings suggest that FeCl3 effectively contains PCDD/Fs at concentrations that could explain the concentrations observed in the nZVI product. Both FeCl3 and nZVI showed a similar PCDD/F patterns with slight differences. These results suggest that PCDD/Fs might transfer from FeCl3 to nZVI during the production method, and thus, care should be taken when employing certain nZVI for environmental remediation. We would like to acknowledge the University of Alicante (EEBB-UA2013) for financing this study.

In this study, the reduction of the pesticide simazine at an initial concentration of 0.7 mg L&minus, 1 in water has been investigated using two different technologies: adsorption with powdered and granulated activated carbon, advanced oxidation processes with ozone and finally, the combination of both technologies. The results obtained for a carbon dose of 16 mg L&minus, 1 show that powdered activated carbon, with contact times of 60 min, obtained 81% of reduction and in 24 h 92%, while granulated activated carbon at 60 min obtained a reduction of 2%, rising to 34% after 24 h of contact time. Therefore, powdered activated carbon achieves better reductions compared to granulated, when ozone was applied at a dose of 19.7 mg L&minus, 1, with a reaction time of 18 min, a reduction of 93% was obtained, achieving a better reduction in less time than with adsorption treatments, however, during oxidation, by-products of simazine were produced. In the combined treatments, with the same doses of carbon and ozone mentioned above, the treatment that starts with ozone followed by activated carbon powder is recommended due to the adsorption in the last phase reaching a 90% reduction of the simazine and its by-products in 38 min of time.

Plastic demand is continuously growing and, with it, the amount of plastic waste. The packaging industry is by far the largest source of single-use plastic products that, after use, end up in landfills and oceans. Mechanical recycling is the solution most widely implemented in the global industry and its effectiveness and reliability have been demonstrated for processing post-industrial plastic scrap. The recycling of post-consumer plastic waste, however, requires an upgrade in the current technology to achieve complete decontamination and removal of malodorous substances embedded in the polymer. This review explores the state-of-the-art technology currently employed in the mechanical recycling of plastic waste, focusing on the progress made for the removal of volatile organic compounds emitted from recycled materials. Followed by a review of the analytical techniques that have been applied for the identification of volatile organic compounds, including, in particular, the techniques used for the identification of odor-active substances. Finally, this review gathers from literature all the volatile organic compounds and odor-active substances identified in virgin and recycled polymers, aiming to evaluate whether there is a notable difference between them based on the chemical structure of the emitted VOCs. As a result, 437 volatiles were gathered, which show the difference between post-consumer recycled plastics and the other plastic waste sources. A larger number of volatile organic compounds, especially flavor and fragrances-based substances as well as oxygenates, appear in post-consumer plastic waste compared to virgin and post-industrial plastic scrap. This work was supported by a grant from the University of Alicante as part of the InnoUA Transfer of Knowledge program and co-financed by Cadel Deinking (Industrial Doctorate).

Dicationic ionic liquids (ILs) generally possess higher thermal and electrochemical stability than the analogous monocationic ILs, which makes them more suitable for high-temperature applications as solvents for organic reactions, lubricants or stationary phase in gas chromatography. However, knowledge on dicationic IL cytotoxicity is still scarce. Here we explore the cytotoxicity of twelve mono- and dicationic pyridinium-based ILs on HeLa, MCF-7, BGM and EA.hy926 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle arrest assays, apoptosis experiments and orange staining were carried out. The results showed that dicationic ILs are generally less cytotoxic than their monocationic counterparts. In monocationic ILs, cytotoxicity was stronger when they contain long alkyl chains, because of their higher lipophilicity. However, the full effect of the length of the linkage alkyl chain of dicationic ILs on cytotoxicity is not clear probably because the chain is “trapped” between both cationic moieties. IL cytotoxicity is highly dependent on the cell type, and HeLa cells exposed to [C12Pyr]Br die via apoptosis. The present study increases our knowledge of IL cytotoxicity on human and monkey cells and clarifies the cell death mechanism. The results suggest that dicationic ILs offer the potential to replace some monocationic ILs because of their lower cytotoxicity. This work was partially supported by the European Commission (FEDER/ERDF) and the Spanish MINECO (Ref. CTQ2017-87708-R) and the research support programme of the Seneca Foundation of Science and Technology of Murcia, Spain (Ref. 20977/PI/18). M. G. Montalbán acknowledges support from MINECO (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081), P. Licence acknowledges EPSRC and BBSRC for support (EP/S005080/1, EP/P013341/1, BB/L013940/1).

Elucidating the essential details of the structure of graphene oxide (GO) is still a challenge. There is no consensus in the increasingly abundant literature, especially relating to the epoxy groups as the main surface complexes in the basal plane, as well as the simultaneous presence of GO sheets and oxidative debris (OD), with a large difference in their oxygen content. In the present work we characterized the base-washed GO (bwGO) sheets, the OD and the humic fraction of the OD obtained by base digestion, when the parent GO was dispersed by applying sonication, a routine procedure when starting from dried graphite oxide. When sonication is not applied, the amount of OD detected is considerably lower, indicative of its formation before base digestion. The presence of lactols and carboxylic anhydrides as the dominant surface complexes at graphene edges is consistent with all the characterization results, as well as with the general knowledge of surface chemistry of carbon materials ranging from coal to graphite. These findings suggest that the Hummers-Offeman reaction produces a chemical scissor effect during the water/hydrogen peroxide quenching step, yielding a broad size distribution of GO sheets, with little in-plane oxidation and the vast majority of edges being oxidized to form oxepinone-type functionalities. The authors gratefully acknowledge the financial support of the Ministerio de Economía y Competitividad of Spain (Project CTQ2013-44213-R), and Generalitat Valenciana (project PROMETEOII/2014/007). LRR is grateful for the support of CONICYT-Chile (project Fondecyt 1160949).

In this study, carbon nanoparticles (CNP) have been synthetized by the method of hydrothermal carbonization (HTC), which entails low cost, minimum equipment requirement, and less synthesis time. In order to improve the characteristics and the mass yield of CNP, a variation in the HTC process has been developed; which consists in introducing a blend of organic solvent with water into the reactor, instead of only water. The precursor is the glucose and three organic solvents were tested: hexane, toluene, and butyl acetate at different reaction times: 1, 2 and 4 h. The size distribution of the CNP doesn't depend on the synthesis conditions. But, the mass yields of the CNP has an incredibly increase with the variation of process, this phenomenon is observed with all organic solvents at only 1 h of reaction time. With butyl acetate the highest degree of dehydration was achieved according to the Ven Krevelen diagram and the FT-IR spectra. Besides, with this organic solvent, the highest Photoluminescence Quantum Yield was reached. This work has been carried out with the financial support of Universidad Central del Ecuador.

Ionic liquids (ILs) can be recycled as extractants for their low vapor pressure and volatility. More and more applications are applied to the separation of industrial organic matter. The industrial production of ILs has gradually been realized, which also widens the way for the application of ILs. In this work, the liquid-liquid extraction of cyclohexane-acetone azeotropic mixture with different ILs {1-butyl-3-methylimidazolium bis(trifluormethylsulfonyl), 1-butyl-3-methylimidazolium trifluoromethansulfonate and 1-butyl-3-methylimidazolium dicyanamide} is studied. The extraction mechanism is discussed based on the molecular scale. The relationship between hydrogen bond donor and acceptor between ILs and acetone is analyzed by COSMO-SAC. The interaction between molecules is optimized and calculated by Materials Studio 7.0. The extraction ability of ILs is analyzed by radial distribution function, and the experimental results are verified. The liquid-liquid equilibrium test is carried out at 298.15 K. Distribution and selectivity are indices used to judge the extraction efficiency of ILs. The NRTL model and UNIQUAC model are adopted to correlate the liquid-liquid equilibrium data. The results show that all of the two models can well correlate the experimental. This work is supported by the National Natural Science Foundation of China (No. 21776145), National Natural Science Foundation of China (No. 21676152).

In this work, the liquid-liquid equilibrium data of the system water + 1-butanol + 2-butanol was studied at 303.15 and 313.15 K. In addition, the vapor-liquid and vapor-liquid-liquid equilibrium at 101.3 kPa was also determined experimentally. The effect of the temperature on the binary water + 2-butanol system and on the ternary system was analysed. Several correlations were tested using the experimental data. The viability of using LLE correlations to calculate LLE on the one side and VLE on the other side and the viability of using the VLE correlation to calculate VLE and LLE were studied using UNIQUAC and NRTL models. A comparison of these result with the UNIFAC predictive model was performed. The authors wish to thank the Conselleria d'Educació, Investigació, Cultura i Esport (Generalitat Valenciana) of Spain for the financial support of project AICO/2015/052.

The massive use of petroleum-based polymers and their improper waste treatment has brought on significant global environmental problems due to their non-biodegradable nature. Starch/poly(vinyl alcohol) (PVA) bioplastics are suitable substitutes for conventional polymers, such as polyethylene, due to their full biodegradability and excellent mechanical properties. Knowledge of the pollutant emissions during pyrolysis and combustion of starch/PVA films is important because they can arrive at landfills mixed with conventional polymers and be thermally degraded in uncontrolled fires. On the other hand, controlled thermal treatments could result in thermal valorization of the waste. Pyrolysis and combustion experiments were carried out at 650, 750, 850 and 950 °C in a laboratory furnace. The analysis of carbon oxides, light hydrocarbons, and semivolatile compounds, including polycyclic aromatic hydrocarbons (PAHs), is shown. Experiments showed lower pollutant emissions than those found with conventional polymers, such as polyethylene and polyester, in the same equipment. Nevertheless, the pyrolysis run at 950 °C showed the highest light hydrocarbon yield (123013 mg kg−1), but this is considerably lower than the values found for polyethylene. The main semivolatile compounds (not PAHs) emitted, with maximum yields ranging from 1351 to 4694 mg kg−1, were benzaldehyde, phenol, indene, and acetophenone. Specifically, the total semivolatile compounds emitted after pyrolysis and combustion of starch/PVA samples represent only 38 and 50%, respectively, of those emitted with polyethylene. Further, the main PAHs were naphthalene, acenaphthylene, and phenanthrene with maximum values of 4694, 2704 and 1496 mg kg−1, respectively. The PAH yield was considerably higher in experiments with low oxygen content. This work was partially supported from the European Commission (FEDER/ERDF) and the Spanish MINECO (Ref. CTQ2016-78246-R and CTQ2016-76608-R). M.G. Montalbán acknowledges support from MINECO (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081).

The demand for high quality recycled polymers in the European plastic industry is on the increase, likely due to the EU’s Plastic Strategy intended to implement the circular economy model in this sector. The problem is that there is not enough recycled plastic in the market. In terms of volume, post-consumer plastic waste could be key to meet the current and future demand. Nevertheless, a high level of contamination originated during the product’s life cycle restricts its use. The first step to change this must be identifying the undesired substances in post-consumer plastics and performing an effective risk assessment. The acquired knowledge will be fundamental for the development of innovative decontamination technologies. In this study, 134 substances including volatile and semi-volatile compounds have been identified in recycled LDPE and HDPE from domestic waste. Headspace and solvent extraction followed by GC/MS were used. The possible origin of each substance was studied. The main groups were additives, polymer and additives breakdown products, and contamination from external sources. The results suggest that recycled LDPE contains a broader number of additives and their degradation products. Some of them may cause safety concerns if reused in higher added value applications. Regarding recycled HDPE, the contaminants from the use phase are predominant creating problems such as intense odors. To reduce the number of undesired substances, it is proposed to narrow the variety of additives used in plastic manufacturing and to opt for separate waste collection systems to prevent cross-contamination with organic waste. This work was supported by a grant from the University of Alicante as part of the InnoUA Transfer of Knowledge program and cofinanced by Cadel Deinking (Industrial Doctorate).

For separating azeotropic mixture 2,2,3,3-tetrafluoro-1-propanol (TFP) and water, two kinds of imidazolium-based ionic liquids 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ([HMIM][OTf]) and 1-octyl-3-methylimidazolium trifluoromethanesulfonate ([OMIM][OTf]) were adopted to separate TFP and water. The liquid-liquid equilibrium behavior for the mixtures (water + TFP + [HMIM][OTf]) and (water + TFP + [OMIM][OTf]) were measured at temperature of 298.15 K and pressure of 101.3 kPa. The extraction ability of [HMIM][OTf] and [OMIM][OTf] was explored with partition ratio and selectivity. In the meantime, the hydrogen bond lengths, total electron density, interaction energies and deformation electron density were calculated to analyze the interactions between the [HMIM][OTf]/[OMIM][OTf] and (TFP/water). Also, the liquid-liquid equilibrium data was fitted by the NRTL model. This work was supported by National Natural Science Foundation of China (Grant 21978155), Shandong Provincial Key Research & Development Project (2018GGX107001).

In order to reduce the calculation effort during the simulation of the emission of polychlorinated dibenzo-p-dioxins and furans (PCDD/F) during municipal solid waste incineration, minimizing the number of simulated components is mandatory. For this purpose, two new multilinear regression models capable of determining the dioxins total amount and toxicity of an atmospheric emission have been adjusted based on previously published ones. The new source of data used (almost 200 PCDD/F analyses) provides a wider range of application to the models, increasing also the diversity of the emission sources, from industrial and laboratory scale thermal processes. Only three of the 17 toxic congeners (1,2,3,6,7,8-HxCDD, 2,3,7,8-TCDF and OCDF), whose formation was found to be linearly independent, were necessary as inputs for the models. All model parameters have been statistically validated and their confidence intervals have been calculated using the Bootstrap method. The resulting coefficients of determination (R2) for the models are 0.9711 ± 0.0056 and 0.9583 ± 0.0085; its root mean square errors (RMSE) are 0.2115 and 0.2424, and its mean absolute errors (MAE) are 0.1541 and 0.1733 respectively. Juan A. Conesa and Nuria Ortuño acknowledge the support for this work by the CTQ2016-76608-R project from the Ministry of Economy, Industry and Competitiveness (Spain). Damià Palmer thanks IQS—Universitat Ramon Llull for its financial support.

This study investigates the geometric and electronic properties of selected BFRs in their ground (S0) and first singlet excited (S1) states deploying methods of the density functional theory (DFT) and the time-dependent density functional theory (TDDFT). We estimate the effect of the S0 → S1 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; 2,2ʹ,4,4ʹ,6,6ʹ-hexabromobiphenyl), TBBA (with respect to the hydroxyl group; 2,2ʹ,6,6ʹ-tetrabromobisphenol A), HBDE and BTBPE (in reference to C–O linkage; 2,2ʹ,4,4ʹ,6,6ʹ-hexabromodiphenylether and 1,2-bis(2,4,6-tribromophenoxy)ethane, respectively) bears the highest positive atomic charge. This suggests that, these positions undergo reductive debromination reactions to produce lower brominated molecules. Debromination reactions ensue primarily in the aromatic compounds substituted with the highest number of bromine atoms owing to the largest stretching of the C–Br bond in the first excited state. The analysis of the frontier molecular orbitals indicates that, excitations of BFRs proceed via π→π*, or π→σ* or n→σ* electronic transitions. The orbital analysis reveals that, the HOMO-LUMO energy gap (EH−L) for all investigated bromine-substituted aromatic molecules falls lower (1.85–4.91 eV) than for their non-brominated analogues (3.39–8.07 eV), in both aqueous and gaseous media. The excitation energies correlate with the EH−L values. The excitation energies and EH−L values display a linear negative correlation with the number of bromine atoms attached to the molecule. Spectral analysis of the gaseous-phase systems reveals that, the highly brominated aromatics endure lower excitation energies and exhibit red shifts of their absorption bands in comparison to their lower brominated congeners. We attained a satisfactory agreement between the experimentally measured absorption peak (λmax) and the theoretically predicted oscillator strength (λmax) for the UV–Vis spectra. This study further confirms that, halogenated aromatics only absorb light in the UV spectral region and that effective photodegradation of these pollutants requires the presence of photocatalysts. This study has been supported by the Australian Research Council (ARC), and grants of computing time from the National Computational Infrastructure (NCI), Australia as well as the Pawsey Supercomputing Centre. A.S. and K.S. thanks Murdoch University, Australia, for a postgraduate research scholarship.

The establishment of recycling systems aiming at high-quality recyclates from post-consumer plastic waste are essential to avoid the waste of resources. One main impediment for introducing recyclates into the market is their unwanted odor. For this reason, this study aimed at determining if the collection strategy affects the odor profile of post-consumer LDPE bags. Furthermore, the effect of hot water washing, inspired by the conventional mechanical recycling procedure, on the odor of post-consumer LDPE bags was screened. More than 60 odorants were detected in LDPE bags collected in a separate plastic fraction as well as in LDPE bags from the non-separated collection by means of gas chromatography-olfactometry, and 37 of them were unequivocally identified using two-dimensional gas chromatography-mass spectrometry/olfactometry. The sensory results revealed that the type of collection affects the overall odor intensity, the hedonic tone of the odor and the odor profile. Namely, cheesy and fecal smelling odorants were predominant in the waste that had not been separated at source, whereas odorants with earthy and moldy smells showed mostly higher intensity ratings in the waste separated at source. Short chain carboxylic acids, likely originating from microbial spoilage of organic waste, were found with higher dilution factors in the mixed fraction, and could, accordingly, contribute to the observed differences. Additionally, we could show that the hot washing procedure, applied to the LDPE sample from the separate collection system, significantly reduced the overall odor intensity from 8 to 6.3 (0–10 scale). However, the washed waste still showed high smell intensity ratings. Miriam Strangl has been supported by a PhD scholarship provided by the Studienstiftung des Deutschen Volkes. Andrea Cabanes has been supported by a PhD scholarship provided by the University of Alicante and Cadel Deinking as part of the InnoUA Transfer of Knowledge program (Industrial Doctorate).

Methylparaben (MeP) and Propylparaben (PrP) are widely used in consumer products and their presence in surface, ground and waste water is a source of concern. They belong to category 1 of the Endocrine Disrupter Priority List for wildlife and human health and hence, these compounds should be completely removed from drinking water in Water Treatment Plants (WTP). Adsorption with powdered activated carbon (PAC) is a solution to eliminate emerging pollutants (ECs), as occurs in Benidorm WTP; however, it is necessary to know the conditions for the removal of these compounds and to optimize its application achieving lower economic costs. With this aim, the process has been characterized studying the adsorption equilibrium and kinetics in single and bicomponent batch experiments, using the commercial carbon Pulsorb PWX HA. The individual adsorption of MeP and PrP by PAC suits an “L” isotherm, according to Giles’ classification. The Langmuir and Freundlich models properly described the adsorption of MeP and PrP in monocomponent experiments. On the other hand, the results from bicomponent experiments suggested the existence of competitive adsorption with lower adsorption capacities for MeP. The multicomponent model Ideal Adsorbed Solution (IAS)-Freundlich predicted with more accuracy the competitive adsorption. For both compounds, the kinetic studies fit the pseudo-second order model. Differences between the removal efficiencies of similar compounds, MeP and PrP, were observed with ultrapure and real water, regarding the PAC dose and the contact time. The removal by adsorption in WTP could be optimized considering the parameters determined in this research. This study was partially financed by the Ministry of Economy and Competitiveness via the project “Combined treatments for degradation and removal of emerging pollutants in water” (CTM2013-46669-R). The authors are grateful to project “LIFE EMPORE” (LIFE15 ENV/ES/000598).

The objective of this work was to study the possibilities to manage and recycle dog faeces (DF) using biological processes, using two approaches: composting (C) and anaerobic digestion (AD). Thus, different experiments have been carried out: i) two laboratory/pilot scale experiments (self-heating and composting tests) and one, on a commercial scale; ii) two AD experiments. In both approaches, municipal waste such as the organic fraction of municipal solid waste (OMSW) and urban pruning waste (GW) were used as co-substrates. The results obtained regarding the optimization of the composting process indicated that the best strategy was the use of a 1:2 ratio of DF, a 1:4 ratio of OMSW, and a 1:4 ratio of GW, according to the thermal parameters studied (temperature and cumulative quadratic exothermic index (EXI2)), and the quality of the compost obtained. A potentially limiting factor of the process was the high salinity of the DF waste. In addition, AD experiments were performed on DF, OMSW, and GW wastes in controlled anaerobic systems at a laboratory scale. In these experiments, the biogas production obtained was 229 mL biogas/g total solids for the DF residue, 248 mL biogas/g total solids for GW, and 263 mL biogas/g total solids for OMSW. The co-digestion yields a clear improvement in the efficiency of the process against the use of a single residue, increasing the production of biogas by up to 27% with respect to that of the DF waste alone during the first 25 days of AD. The results obtained with these procedures have shown the possibilities to add value to this waste in an urban context where the circular economy represents an increasingly favourable scenario, including the generation of fertilisers and/or energy at a local scale, provided that the collection of dog faeces is optimized.

Hydrothermal liquefaction (HTL) of Animal By-Products (ABP) is a promising technology for their recycling and disposal. Different operating parameters have been studied to determine their influence on the process. Higher heating values of biocrudes ranging between 35 and 39 MJ/kg have been obtained showing a maximum yield of 61% at 225 °C. At low HTL temperature, the products are similar to those of rendering process and the biocrude is mainly formed by triglycerides and fatty acids in a 90:10 ratio, approximately. By increasing temperature, the free fatty acid yield increases, as well as amides and heterocyclic compounds as a result of the triglycerides and protein reactions. Between 250 and 290 °C a great difference in the composition of the biocrude obtained is observed. Water content also showed significant effects on the product yields. Large amounts of foams were obtained at low water contents that were minimised when it is increased. This is a very important feature to be considered for scaling up the phase separation process. Glycerine amount in the aqueous phase was remarkable, as a consequence of fat hydrolysis. Increasing pH to 9 increases the extraction of organics into the aqueous phase, whereas operating at pH 5 yields similar amounts of biocrude as compared with neutral pH, with a higher percentage of fatty acids. Reusing of the aqueous phase is necessary for the viability of the process and leads to increasing amounts of dissolved organics in the aqueous phase with the number of cycles, reaching a saturation level after three-four recycling rounds. The research leading to these results has received funding from the European Community’s 7th Framework Programme (FP7-2007-2013) under Grant Agreement No. 603986.