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This study employs a novel combined pilot plant consisting of an anaerobic reactor followed by a membrane electro-bioreactor (eMBR) to treat domestic water containing selected micro-pollutants of emerging concern (CECs) [ibuprofen (IB), carbamazepine, diclofenac (DCF) and 17α-ethinylestradiol (EE2)]. The first phase operated as a conventional membrane bioreactor to achieve the removal of organic matter [chemical oxygen demand (COD)], the CECs and phosphorus. A removal rate of 96.3% for COD, 94.5% for IB, 37.1% for CMZ, 87.1% for DCF and 96% for EE2 was obtained. In the three subsequent phases, current density (CD) of 5, 10 and 15 A/m2 was applied successively in the eMBR with the aim of investigating the effects on the removal of the former components and the fouling of the membrane. After the application of 5 and 10 A/m2 CD, the removal rate of COD decreased. Regarding phosphorus, a CD of 5 A/m2 was enough to achieve the rate of 97% and the membrane fouling suffered a substantial reduction too. Finally, the experimental results were subject to statistical analysis using the Kruskal–Wallis and Wilcoxon tests to validate the influence of each DC. The research was funded by the Ministry of Economy and Competitiveness of Spain through the project ‘Elimination of emerging pollutants through serial anaerobic and aerobic processes and complementary treatments: combined system UASB + eMBR + O3/AC CTM2016-76910-R, and by the Generalitat Valenciana through a Santiago Grisolía grant, ref GRISOLIAP/2017/173.

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 adequate correlation of experimental phase equilibrium data by using any thermodynamic model represents a key point for the rigorous design of the chemical processes. However, this data correlation process remains a challenging problem, due to the high nonlinearity of the models used and the consequent problems of convergence. The present work analyzes the NRTL model to check the relation between the values of the binary interaction parameters and the corresponding phase equilibria that the NRTL model can or cannot reproduce. Additionally, in the case of the LLE, empirical equations have been established as a function of the non-randomness parameter, to model the trajectory of the different miscibility boundaries observed. These functions can be used as constraints in the experimental data correlation procedure to reduce the search space and guarantee the consistency of the obtained binary interaction parameters with the experimental behavior of the system under study.

Póster presentado en META 2022: XIV Congreso de la Mesa Española de Tratamiento de Aguas, Sevilla, 1-3 junio 2022. En este trabajo se muestra la investigación llevada a cabo en la Universidad de Alicante sobre el efecto del equipo electromagnético TK3K, diseñado y patentado por la empresa Ecotecnica Energy Systems S.L., que se comercializa para evitar incrustaciones en tuberías. Se están realizando estudios experimentales para la precipitación de carbonato cálcico, a partir de aguas de diferentes calidades, según 2 métodos: (1) “ensayos de precipitación rápida controlada” (Mahmoud, B. et al. (2016) Separation and Purification Technology, 171, 88-92) donde se elimina el CO2 mediante agitación y (2) ensayos con incremento de concentraciones en disolución (Piyadasa, C. et al. (2017). Environmental Science Water Research & Technology, 3, 566-572) con Ca (NO3)2 y Na2CO3. El efecto del tratamiento se analizó midiendo diferencias en turbidez, absorbancia y tipo de cristalización: calcita (romboédrica, incrustante) y aragonito (ortorrómbica, no incrustante) con un microscopio óptico de luz polarizada (OPTIKA NP-400T) o mediante SEM (JEOL modelo JSM-840). Este estudio se ha realizado gracias a la financiación de la Generalitat Valenciana (FEDEGENT/2018/005) y la empresa ECOTÉCNICA ENERGY SYSTEMS S.L.

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. In this work, waste printed circuit boards (WCBs) containing tetrabromobisphenol A (TBBPA) as a brominated flame retardant (BFR) underwent debromination using a mechanochemical treatment (MCT) and marble sludge, another recoverable waste, as well as pure CaO as additives. All runs in this work were performed at an intermediate rotation speed of 450 rpm, using additive/WCB mass ratios (Rm) of 4:1 and 8:1, ball to powder ratios (BPR) of 20:1 and 50:1, treatment times from 2.5 h to 10 h, two WCB sizes (powder and 0.84 mm) and marble sludge, from original to precalcined conditioning. Stainless steel jars and balls were used to verify the effect of each parameter on the system and to seek an optimum process. Complete debromination of 0.84 mm WCBs was achieved at 450 rpm, using a Rm of 8:1, a BPR of 50:1, a residence time of 10 h (more than 95% in only 5 h), and a precalcined marble sludge as additive. The results revealed that when using a Rm of 4:1 instead of 8:1, more waste could be effectively treated, per batch with a lesser need for additives, at the expense of a slightly lower level of debromination efficiency. In the same way, an appropriate apparent ball diameter (with respect to the volume of the used jar) should be carefully studied in relation to WCB size in order to achieve a beneficial total amount of energy transfer during milling. This research was funded by the Ministry of Science and Innovation of Spain, grant numbers PID2019-105359RB-I00 (project) and BES-2017-080382 (scholarship). Support for this work was funded too by the University of Alicante, grant number UAUSTI20-05.

Introduction: Post-hospital syndrome (PHS) is defined as a period of vulnerability during the first 30 days after a patient is discharged from hospital, in which multiple factors come into play. Hyponatremia is the most frequent hydroelectrolytic disorder in hospitalized patients and may be related to the appearance of PHS. Objective: The objective is to estimate the prevalence of PHS that is assessed as the rate of readmissions in the first 30 days after discharge, in patients with hyponatremia. Material and Methods: It is a descriptive observational study of patients with hyponatremia who were discharged from 1 September 2010 to 2 February 2020 at the Internal Medicine Service of the Hospital University of San Juan (Alicante, Spain). Results: Of the 25 included patients, 5 (20%) were readmitted within a month of discharge, after a mean of 11.4 days (standard deviation [SD] 5.1). The overall mortality of the study was 20% (n = 5), with one case of death in the first 30 days post-hospitalization (4%). In 12 patients (48%) the origin of the hyponatremia was undetermined. The most frequently recorded etiology for the condition was pharmacological (n = 7, 28%), and there was pronounced variability in its clinical and laboratory study. The most widely used corrective measure was drug withdrawal, in 16 patients (64%). Water intake restriction was the most common treatment after discharge (5 patients, 20%), followed by urea (2 patients, 8%), while tolvaptan was not used. Conclusion: Hyponatremia may be the cause of PHS, which could increase the rate of early readmission. Hyponatremia is an underdiagnosed and undertreated entity, so it is necessary to apply an appropriate system to optimize its management and, in future studies, to assess its impact on PHS.

Highlights • How to integrate environmental concerns into Chemical Engineering education. • University education in Sustainable Developent through two case studies. • Human waste can be managed to obtain energy, fertilizer and improve sanitation. • Mathematical Optimization is used in this context and explained for non-specialists., Given the damage that the natural environment suffers from human activities, it is relevant to provide ecological literacy to all Chemical Engineering students. Sometimes, this information is offered through elective courses and/or seminars and consequently it might not reach the whole class. Some courses have more obvious connections to environmental issues, while others do not appear to. In this paper, we aim to show through some solved examples how to introduce an environmental topic in the subject Mathematical Optimization. The problems goal is to decide on the best logistics for the transport and management of human waste that will be used in the production of sustainable energy. The context is that of improving the sanitation and hygiene in areas of the developing world, while simultaneously creating job opportunities within the communities. The research that we have conducted for finding the proper way to address the environmental analysis in class, led us first to the Sustainable Development Goals (SDGs), but later on, other theories such as the Cradle-to-Cradle (C2C) have proven to be more comprehensive and therefore, better. We believe that this multidisciplinary paper shows how to integrate environmental concerns and understanding in the Chemical Engineering curricula.

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).

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 CO32–/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 × 16.5 mm, 20 mm × 33 mm, and 80 mm × 33 mm, respectively, and solid/liquid ratios of 1:2 and 1:1 g/mL without other metallic catalysts. A debromination efficiency of 50 wt % was reached at only 225 °C (limited by mechanical reasons) and 360 min, using a CO32–/Br– anionic ratio of 4:1 and a solid/liquid ratio of 1:2 for a large WCB with only 25% of its volume submerged in the liquid. This means conservation of water and energy compared to previous studies. A muffle furnace was used later to thermally treat a total of 101 debrominated samples, at constant temperature or following a temperature scaling program. An estimated decrease in resistance to rupture of glass fibers of only around 50% was accomplished by following a temperature scaling program up to 475 °C, obtaining clean glass fibers of large size. The simple techniques proposed to obtain reusable glass fibers from WCBs as large as the size of the reactor allows (as it might be in their original size) could significantly improve interest in the industry. Support for this work was granted by the PID2019-105359RB-I00 project and the scholarship BES-2017-080382 from the Ministry of Science and Innovation of Spain and project UAUSTI20-05 from the University of Alicante.

Examples of applications of equilibrium-based methods for multicomponent separations usually require the use of simulation packages, which do not allow students to follow the involved algorithms step by step. Excel spreadsheets with examples of six such rigorous methods have been used with MSc students of Chemical Engineering of the University of Alicante (Spain), showing a significant enhancement of their ability to apply these methods.

Póster presentado en II Symposium on Chemical and Physical Sciences for Young Researchers, Murcia, 24-25 marzo 2022. The formation of scale in systems that work with hot water is a problem that can generate economic losses in domestic and industrial installations. A great variety of techniques soften the water, but modify the chemical composition and generate waste streams. An alternative is the use of the electromagnetic techniques, which prevent scale formation without altering the quality of the water, however, the mechanism is not entirely clear. One of the theories proposed is that the precipitation of calcium carbonate such as aragonite (less encrusting) is favoured compared to calcite (encrusting). In this study, the rapid controlled precipitation test has been used to precipitate calcium carbonate from synthetic waters, which are previously prepared by dissolving calcium carbonate in distilled water, treated with the TK3K equipment (Ecotécnica Energy Systems, S.L.), and bubbling with CO2 until complete dissolution. These studies were compared with others without electromagnetic treatment of the distilled water. The controlled rapid precipitation tests were carried at 600 rpm and the obtained crystals were analysed with a polarized light optical microscope (OPTIKA NP-400T). Untreated samples were found to be calcite (rhombohedral), with no other mineral phases and the treated samples had presence of aragonite (orthorhombic), together with calcite. The authors acknowledge the financial support of the Generalitat Valenciana (FEDEGENT/2018/005) and the company ECOTÉCNICA ENERGY SYSTEMS S.L.

Several physical properties and the isobaric vapour-liquid equilibria at 101.32, 50, and 30 kPa were measured for the binary system consisting of acetone and the ionic liquid 1-ethyl-3-methyl-imidazolium acetate. Liquid-liquid equilibrium data were also measured at temperatures from 298.15 up to 328.35 K and atmospheric pressure. An hourglass-shaped miscibility gap was found. The simultaneous correlation of both VLE and LLE regions at 101.32 kPa was addressed. The NRTL model, considering different options to formulate the temperature dependence of the parameters, was tested and found unable to correlate the whole set of equilibrium data. A detailed analysis of the excess Gibbs energy demonstrated the limitations of the classical equation and allowed the definition of a new model with a correction term. A unique set of parameters were used to simultaneously correlate both sets of equilibrium data with very low deviations from experimental data. Moreover, the corrected NRTL function overcomes some uncertainty problems that may occur in liquid-liquid equilibrium calculations. The authors would like to thank “Generalitat Valencia: Consellería de Educación, Investigación, Cultura y Deporte” for the PhD grant (ACIF/2019/040) and Xunta de Galicia for support through project ED431B 2020/021. M.K.W. is grateful to the Erasmus + programme of the European Union for the award of a mobility traineeship.

Residual biomass gasification is a promising route for the production of H2-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/CeO2-SiO2 catalyst during steam gasification of sugarcane residual biomass on syngas composition and pollutant removal. The above was carried out in a horizontal moving reactor, an Amberlite XAD-2 polyaromatic resin was used to collect the contaminants and characterization of the catalyst was performed. In this study, a concentration of up to 37 mol% of H2, a yield of 23.1 g H2 kg−1biomass, and a H2/CO ratio ≥2 were achieved when gasification and reforming were integrated. In addition, the catalyst characterization showed that Rh-Pt/CeO2-SiO2 was not susceptible to sintering and favored the formation of hydroxyl groups that promoted CO oxidation, thereby increasing the H2/CO ratio, as confirmed by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). At 800 °C, where a high H2 yield was obtained, 209 g Nm−3 of light HCs and BTEX, 10.9 g Nm−3 of PAHs, and 32.5 ng WHO-TEQ Nm−3 of PCDD/Fs were formed after gasification. Interestingly, after catalytic reforming, 62% of light HCs and BTEX, 60% of PAHs, and 94% of PCDD/Fs were removed, leading to cleaner syngas with properties that allow it to be used in a wide range of energy applications. The authors are grateful to Universidad de La Sabana (Project code ING-203-2018), the Spanish Ministry of Science and Innovation (State Investigation Agency, project code PID2019-108632RB-I00), and The International Relations Department of the University of Alicante (program named “University Development Cooperation 2019”) for their financial support toward this work. The GC-MS/QQQ used in the analysis was supported by Project IDIFEDER/2018/004 by the Generalitat Valenciana (Spain).

Water treatment generally does not specifically address the removal of microplastics (MPs). Nevertheless, treatment plants process water effectively, and the number of synthetic microparticles in effluents is usually very low. Still, discharge volumes from water-treatment plants are often elevated (reaching around 108 L/day), leading to the daily discharge of a substantial number of MPs and microfibers. Furthermore, MPs accumulate in the primary and secondary sludge, which in the end results in another environmental problem as they are currently used to amend soils, both for cultivation and forestry, leading to their dispersion. Something similar occurs with the treatment of water intended for human consumption, which has a much lower but still significant number of MPs. The amount of these pollutants being released into the environment depends on the processes that the water undergoes. One of the most-used treatment processes is rapid sand filtration, which is reviewed in this article. During the filtration process, MPs can break into smaller pieces, resulting in a greater number of plastic particles which mainly accumulate in sewage sludge. Thermal processes, such as incineration, carried out in facilities with the best available techniques in practice, could guarantee the safe disposal of highly MP-contaminated sewage sludges. This research was funded by MINISTRY OF SCIENCE AND INNOVATION (Spain), grant number PID2019-105359RB-I00, and by the UNIVERSITY OF ALICANTE, grant number UAUSTI20-05.

Actualmente, la correlación de datos experimentales de equilibrio resulta una tarea de elevada necesidad en el diseño de procesos industriales. A pesar de la importancia de la correlación de datos experimentales, la fuerte no linealidad y complejidad de los modelos termodinámicos de ajuste, así como la naturaleza iterativa de este proceso de cálculo hacen que este proceso resulte de elevada dificultad y alto consumo de tiempo. Respecto a los modelos de equilibrio, no siempre van a tener la suficiente flexibilidad para ajustar los datos experimentales. De modo, que la primera de las preocupaciones consiste en establecer qué modelo, o grupo de modelos, se va a emplear en la correlación de un determinado sistema. Además, la naturaleza iterativa inherente del propio proceso de correlación implica una gran dependencia con la dispersión de los datos experimentales originales, los valores supuestos de partida para la inicialización del cálculo, la función objetivo o la condición de equilibrio seleccionada, así como la robustez del propio algoritmo de optimización empleado para tratar de garantizar la convergencia. Al depender en gran medida la calidad y consistencia del resultado final con los valores iniciales proporcionados a los parámetros de interacción binaria del modelo escogido en la etapa de inicialización, resulta de vital importancia establecer una forma sistemática de seleccionar estos valores de partida. Debido al reciente, y muy acusado, desarrollo de las redes neuronales, la inteligencia artificial y los distintos algoritmos de Machine Learning, surge la oportunidad de realizar, en una primera aproximación, una herramienta que permita clasificar un determinado sistema experimental de ELL isotermo, que se pretende correlacionar con el modelo termodinámico NRTL utilizando inteligencia artificial capaz de aprender a clasificar sistemas en función de una serie de características definidas y de un conjunto sistemas de referencia, y proporcionar unos parámetros de interacción binaria de partida adecuados para inicializar la correlación de los datos experimentales de ELL de un sistema sobre el cual no se tiene información. Proporcionando unos parámetros de partida relativamente cercanos al resultado final y coherentes con la tipología Treybal y características del sistema estudiado. Referencias relacionadas: *Labarta, J.A; Olaya, M.M.; Marcilla, A. GMcal_TieLinesLL v.2.2. Graphical User Interface (GUI) for the representation of GM surfaces and curves (for binary and ternary systems), including tie-lines, Hessian Matrix analysis, Plait Point location, etc. 2015-2022. Institutional Repository RUA: http://hdl.handle.net/10045/51725. (Including a Thermodynamic Review). *Labarta, J.A.; Olaya, M.M.; Marcilla, A. Boundaries_LL_NRTL Graphical User Interface (GUI) for the characterization of the NRTL model: Binary Spinodal Surfaces (in the Ti,j-Tj,i-xi space), LLE maps and Miscibility Boundaries. Institutional Repository of the University of Alicante (RUA) 2022 (http://hdl.handle.net/10045/121471). *Marcilla, A.; Labarta, J.A.; Olaya, M.M. Should we trust all the published LLE correlation parameters in phase equilibria? Necessity of their Assessment Prior to Publication. Fluid Phase Equilibria. 2017, 433, 243-252 (http://dx.doi.org/10.1016/j.fluid.2016.11.009) (RUA: http://rua.ua.es/dspace/handle/10045/66521). Vicerrectorado de Investigación y Transferencia de Conocimiento, y grupo de investigación CONCEPT (Computer Optimization of Chemical Engineering Processes and Technologies) del Dpto. de Ingeniería Química e Instituto de Ingeniería de los Procesos Químicos. Universidad de Alicante (Ayudas para estudios de Máster oficial e iniciación a la investigación 2020, Referencia: AII20-23).

Póster presentado en META 2022: XIV Congreso de la Mesa Española de Tratamiento de Aguas, Sevilla, 1-3 junio 2022. El equipo electromagnético TK3K, diseñado y patentado por la empresa Ecotecnica Energy Systems S.L., que se comercializa para evitar incrustaciones en tuberías y pretende aplicarse en la mejora de la calidad del agua, con estudios en organismos acuáticos y microbiología. En este trabajo se muestran la investigación llevada a cabo en la Universidad de Alicante sobre este tema. Para el estudio del efecto del tratamiento electromagnético sobre microorganismos como Pseudomona spp y Escherichia coli (Piyadasa, et al. (2018) Journal of Chemical Technology & Biotechnology, 93, 871–877), se realizaron cultivos microbiológicos realizando el conteo con una lupa binocular (LEICA GZ-4). En el caso de las algas tomadas de aguas de diferente procedencia, se identificaron con el microscopio Carl Zeiss Axioskop 2 plus. Se cultivaron en depósitos de 10 L con y sin tratamiento electromagnético, en una sala termostatizada a 24°C. Este estudio se ha realizado gracias a la financiación de la Generalitat Valenciana (FEDEGENT/2018/005) y la empresa ECOTÉCNICA ENERGY SYSTEMS S.L.

Esta tesis estudia el impacto que tienen los COV presentes en los plásticos reciclados para la economía circular. Actualmente, la industria del reciclaje actual no puede cubrir la creciente demanda de plásticos reciclados de alta calidad en los últimos años. Hasta ahora, el reciclaje mecánico es la solución más utilizada a nivel mundial, y su eficacia y fiabilidad han sido demostradas para el tratamiento del residuo plástico post-industrial. Sin embargo, el mismo reciclaje mecánico aplicado a los residuos plásticos post-consumo da lugar a un material reciclado de menor calidad que solamente es apto para aplicaciones de bajo valor añadido, como son las tuberías de riego o cubos de basura. Por ello, esta tesis evalúa la influencia que tienen las sustancias orgánicas que aparecen en los plásticos reciclados post-consumo dentro el sector del plástico. Investigación cofinanciada por el Vicerrectorado de Investigación y Transferencia de Conocimiento para el fomento de la I+D+i de la Universidad de Alicante y Cadel Deinking, S.L.

To improve the efficiency of the water treatment system, a plastic deinking company has decided to implement a lamellar decanter in its process. This work will try to design, model, simulate and test different operating conditions to try to maximize the benefits of the equipment. The simulations will be carried out with a CFD program based on finite volume methods called Ansys, which will be combined with MATLAB in order to study the results obtained and to be able to perform a sensitivity analysis. In addition, a surrogated model will be obtained to calculate the settling efficiency without having to perform the simulations and to reach the result in a faster way. As a complement, the Navier-Stokes equations used by the program to predict the fluid flow will be developed.

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. The study aimed at stressing the importance of this type of analysis in recycled plastics. Indeed, such an examination will determine the material’s final destination, and the possible origin of the pollutants analysed is investigated. Black post-industrial and post-consumer samples presented the highest concentration of PCBs and PCDD/Fs, attaining a maximum value of 2.40 pg WHO-TEQ/g, while the least toxic sample (post-commercial) presented a toxicity of 0.38 pg WHO-TEQ/g. PAHs content was also much higher in black samples, reaching 514.41 ng/g, while the lowest concentrations were obtained for the post-commercial plastic sample, which did not exceed 38.98 ng/g. The higher PAHs concentrations in the black samples were related to the carbon black content of the black samples, which was 2.00% for black post-industrial sample and 1.51% for post-consumer sample. The PCDD/Fs congener profile observed in almost all samples was very similar to the profile found in the literature on urban air samples, indicating that the plastic is mainly influenced by the environment. The presence of some metals (mainly copper) showed a slight correlation with PCDD/Fs content. The pollutants analysed were found to be significantly reduced during the cleaning processes that are generally carried out in recycling companies. This work was supported by the Ministry of Science and Innovation (Spain) [grant number PID2019-105359RB-I00], and by the University of Alicante [grant number UAUSTI21-03].

Rigorous black-box simulations are useful to describe complex systems. However, it cannot be directly integrated into mathematical programming models in some algebraic modeling environments because of the lack of symbolic formulation. In the present paper, a framework is proposed to embed the Aspen HYSYS process simulator in GAMS using kriging surrogate models to replace the simulator-dependent, black-box objective, and constraints functions. The approach is applied to the energy-efficient C3MR natural gas liquefaction process simulation optimization using multi-start nonlinear programming and the local solver CONOPT in GAMS. Results were compared with two other meta-heuristic approaches, Particle Swarm Optimization (PSO) and Genetic Algorithm (GA), and with the literature. In a small simulation evaluation budget of 20 times the number of decision variables, the proposed optimization approach resulted in 0.2538 kW of compression work per kg of natural gas and surpassed those of the PSO and GA and the previous literature from 2.45 to 15.3 %. The authors acknowledge the National Council for Scientific and Technological Development – CNPq (Brazil), processes 148184/2019-7, 440047/2019-6, 311807/2018-6, 428650/2018-0, and Coordination for the Improvement of Higher Education Personnel – CAPES (Brazil) for the financial support.

In this work, the role of phenolic compounds in the hydrothermal synthesis of carbon-encapsulated iron nanoparticles (CEINs) was studied. To model phenolic compounds, gallic acid (GA) was selected, with glucose as the carbon source. Iron was found as α-Fe2O3, γ-Fe2O3, Fe3O4, and zero-valent iron (ZVI) depending on the synthesis pH and GA/Fe molar ratio. For GA/Fe = 1, the CEINs' yield increased significantly. In the samples with phenolics, increasing the initial pH increased the amount of γ-Fe2O3 and Fe3O4 and enhanced the iron oxide encapsulation due to enhanced chelating ability. Reducing the GA/Fe ratio to 0.2 resulted in CEINs with stronger magnetization due to the presence of Fe3O4. Ash weight, HCl digestion, and Raman spectroscopy were used in conjunction to characterize the composition of the CEINs. The magnetization of the samples was compared using a simple magnetic weight setup. A scheme for the reactions occurring during the hydrothermal carbonization of GA-Fe complexes was proposed.

With the objective of suppressing dioxins and furans (PCDD/Fs) emission in municipal solid waste incineration plants (MSWI), different chemical inhibitors have been tested. Among these inhibitors, nitrogen and sulphur compounds can significantly suppress PCDD/Fs formation via de novo synthesis, which gives very interesting results with very little capital investment. In recent years, the possibility of using waste rich in nitrogen and/or sulphur as a source of inhibitor compounds has been considered, and thus has reduced the emissions of pollutants while the waste is treated. The effect of adding sludge from urban sewage treatment plants in three variants has been specially studied: directly mixing the waste, using the decomposition gas of the previously dried sludge, and using the decomposition gas of the sludge together with other inhibitors such as thiourea. Reduction of emissions in laboratory tests using model samples indicated the efficiency to be higher than 99%, using sewage sludge (SS) as an inhibitor whereas, in actual MSWI plants, the efficiency can be as high as 90%. This research was funded by MINISTRY OF SCIENCE AND INNOVATION (SPAIN), grant number PID2019-105359RB-I00.

Thermal and catalytic pyrolysis of a tobacco blend were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The Py-GC/MS experiments were carried out in helium and air atmosphere at 300, 500 and 700 °C. SBA-15 mesoporous silica has been used as a catalyst blended with the tobacco at 5%, 15% and 50%. The results obtained show that under inert atmosphere and at high pyrolysis temperatures, the catalyst addition did not significantly modify the formation of pyrolysis products, while under oxidising atmosphere and at low temperatures, the formation of pyrolysis products decrease considerably. It was found that components linked to tobacco use responsible of the most severe health effects are generated from 500 °C on. Catalyst selectivity has been observed, maintaining nicotine release while decreasing the generation of other pyrolysis products. It was found that the concentration of the catalyst modifies the formation of the selected pyrolysis products significantly, although 5% of the catalyst is enough to obtain significant results. 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 IDIFEDER 2018/009 and PROMETEO2020/093) and the “Universidad de Alicante” (grant number UAFPU2018-013).

To reduce the environmental impact of desalination plants, a good dilution of the brine is needed. Brine dilution may be carried out using diffusers, by mixing the concentrate with other effluents, or with seawater bypassing. Seawater bypassing increases the energy consumption of the plant but, thus far, this energy consumption has not been estimated. The environmental impact statement (EIS) of desalination plants in Alicante establishes a system of seawater bypassing for diluting brine and protecting the Posidonia oceanica seagrass meadows. The aim of this paper is to quantify the energy consumption of brine dilution, which was necessary for meeting the environmental requirements from 2012 to 2018. During the research period, the plants’ operation was variable, as it depended on the supply needs. The results indicate that the energy consumption of the dilution systems fluctuated between 2,135,315 kWh in 2012 and 685,988 kWh in 2013, with an average consumption of 1,205,952 kWh for the selected period. The energy cost in 2012 was EUR 179,556, while that for 2013 was EUR 60,787, with an average annual cost of EUR 91,690. This interannual variability is due to the difference in the production values of the plants and in the dilution ratio, which oscillated between 2.5 and 7.5 seawater:brine. In addition, the dilution showed an additional cost of the energy consumed by the desalination plants of around 1.7% on average. However, it also allowed the fulfillment of the established requirements in the EIS and the protection of the Posidonia oceanica seagrass from the discharge of the desalination plants.

Carbonate scale is one of the main problems in hot water systems, and therefore, interest in this subject has grown since 2000s. Water treatments, based on magnetic and electromagnetic (EM) techniques to prevent scale, are being commercialized, but their effectiveness is not clearly demonstrated because it depends on temperature, pressure, dissolved CO2, pH, field intensity, water flow, etc. In this paper, a review of these techniques, together with other classical techniques, such as chemical softening, the use of inhibitors, ion exchange, electrochemical and membrane treatments is presented. The latter alter the composition of the water and generate hazardous waste for health and the environment, unlike magnetic and EM treatments, which are considered non-invasive techniques. Different hypotheses are used to explain the effect of these treatments, such as the formation of aragonite instead of calcite or crystal nuclei formation within the fluid. Analysis of salts formed with SEM, X-ray diffraction, or colorimetric tests seem to support the efficiency of these treatments since study in the fluid is not easy. Dissolution of the formed scale or its prevention endorse the commercialization of these techniques, but their effectiveness must be verified in each installation. This research was funded by the Generalitat Valenciana (FEDEGENT/2018/005), the company ECOTÉCNICA ENERGY SYSTEMS S.L (ECOTECNICA1-18Y) and the facilities of the University Institute of Chemical Process Engineering and the University Institute of Water and Environmental Sciences of the University of Alicante.

This paper presents a new algorithm for the design of heat exchanger networks (HEN) that tries to take advantage of the strengths of the sequential and simultaneous approaches. It is divided into two sequential parts. The first one is an adaptation of the transportation model (TransHEN). It maintains the concept of temperature intervals and considers the possibility of heat transfer between all the hot and cold streams inside those intervals, and at the same time it allows the a priori calculation of the logarithmic mean temperature difference between all possible heat exchanges, and therefore it maintains the area estimation linear in the model. The second step (HENDesign model), uses a superstructure that contains all the possible alternatives in which the matches predicted by the first stage model can exchange heat to design the final heat exchanger network. Unlike the sequential approach, in this model, all heat flows, temperatures, areas, etc. are reoptimized maintaining the set of matches predicted in the first stage. The model is highly nonlinear and nonconvex, however, it is relatively easy to get good results, because the model starts with the values predicted by the TransHEN model. The algorithm has been tested using fifteen benchmark problems commonly used in literature to compare the performance of heat exchanger network algorithms. In eleven out of the fifteen cases present better or equal results than the best ones reported in the open literature. In three the results presented only marginal differences in total annualized cost (lower than 0.5%) and only a difference of 2.4% in the largest one. The authors gratefully acknowledge financial support from the «Generalitat Valenciana: Conselleria de Educación, Investigación, Cultura y Deporte-Spain» under project PROMETEO 2020/064 and from the “Conselho Nacional de Desenvovimento Científico e Tecnológico-CNPq–Brazil, under projects 428650/2018-0 and 311807/2018-6.”

Water distribution networks (WDNs) are the main component of industrial and urban water distribution systems and are currently formed by pipes, nodes and loops. In this article, a deterministic mathematical programming approach is proposed, aiming to minimize the cost of looped WDNs, considering known pipe lengths and a discrete set of commercially available diameters. The optimization model constraints are mass balances in nodes, energy balances in loops and hydraulic equations, in such a way that no additional software is needed to find the appropriate pressure drops and water velocities. Generalized disjunctive programming is used to reformulate the discrete optimization problem to a mixed-integer nonlinear programming (MINLP) problem. The GAMS (General Algebraic Modeling System) environment is used to solve the problem. Four cases are studied to test the applicability of the model and the results show compatibility with the literature. This study was financially supported by the Coordination for the Improvement of Higher Education Personnel (CAPES) (Brazil) [processes 88887.217374/2018-00 and 88881.171419/2018-01] and the National Council for Scientific and Technological Development (CNPq) (Brazil) [processes 428650/2018-0 and 440047/2019-6]; and by the Conselho Nacional de Desenvolvimento Científico e Tecnológico and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

The existence of multiplicity in steady-state separation problems based on the use of equilibrium stage cascades has been known since the second half of the 20th century. Nevertheless, there are few textbooks -among those usually accessible to Chemical Engineering students- explaining this behavior and even when it is considered it is not deeply treated. In this work, we propose a distillation problem whose resolution allows the instructor the opportunity to introduce some specific characteristics and behavior that may otherwise pass unnoticed. Thus, the simulation of a column for the heterogeneous azeotropic distillation of ethanol using benzene as an entrainer is suggested, and the results obtained do not seem to be compatible with the distillation boundaries of the ternary system. The apparent contradictions can be explained by means of the representation of mass balances on the residue curve map, and allow the students to actually understand the requirements for the feasibility of the separation. The obtainment of two different solutions depending on the initial composition profiles used for starting the calculations allows the instructor to introduce the steady-state multiplicity concept. Errors associated with bad checking of the thermodynamic model are also pointed out.

Starch films are gaining attention as substitutes of synthetic polymers due to their biodegradability and low cost. Some ionic liquids have been postulated as alternatives to glycerol, one of the best starch plasticizers, due to their great capacity to form hydrogen bonds with starch and hence great ability of preventing starch retrogradation and increasing film stability. In this work, [emim+][Ac−]-plasticized starch films were prepared from potato, corn and wheat starch. The effect of starch molecular structure in terms of granular composition (amylose and phosphate monoester contents) and molecular weight (Mw) on film properties was evaluated. Potato starch films were the most amorphous because of the higher Mw and phosphate monoester content of potato starch, both contributing to a lower rearrangement of the starch chains making the crystallization process difficult. In contrast, corn and wheat starches lead to more crystalline films because of their lower Mw, which may imply higher mobility and crystal growth rate, and lower phosphate monoester content. This more crystalline structure could be the responsible of their better mechanical properties. [emim+][Ac−] can be considered suitable for manufacturing starch films showing corn and wheat starch films similar properties to synthetic low-density polyethylene, but involving a simple and environmentally-friendly process. This work was partially supported from the European Commission, European-Union and Ministerio de Economía y Competitividad (MINECO), Spain (Ref. CTQ2016-78246-R) and Generalitat Valenciana (Project PROMETEOII/2014/007). M.G. Montalbán acknowledges support from Ministerio de Economía y Competitividad (MINECO) (Juan de la Cierva-Formación contract, Ref. FJCI-2016-28081).

In this work, we present the modeling, optimization, and conceptual design of a dividing wall column for the separation of four products, commonly referred to in the literature as a Kaibel column, by implementing three different formulations: an NLP, an MINLP, and a GDP formulation. For its solution, we propose a rigorous tray-by-tray model and compared it to results from a commercial software, followed by its reformulation to include a mixed-integer nonlinear programming and a general disjunctive programming formulation to respond to the conceptual design problem attached to these complex configurations. Considering the proposed rigorous model and the two formulations, the Kaibel column is solved, obtaining four high-purity products and new optimal tray locations for the feed and two side product streams, when the mixed-integer nonlinear programming formulation is applied. The use of these optimally located side streams showed reductions in the energy consumption when compared to cases were non-optimal fixed tray locations are used. When the general disjunctive programming problem was solved, the minimum number of trays needed in the main column and dividing wall are obtained, showing a great reduction of the remixing effects in the Kaibel column, and with that, a more energy efficient configuration. The models were coded in Pyomo using the solver IPOPT for the solution of the nonlinear programming problem, the solver Bonmin for the solution of the mixed-integer nonlinear programming problem, and GDPopt for the solution of the general disjunctive programming optimization problem. Edna Soraya Rawlings is grateful for partial support by the Center of Advanced Decision-making at Carnegie Mellon and CONACyT, Mexico.

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 analysis of thermal behaviour of materials has been commonly used for their characterization and identification. This work aims to analyse the thermal decomposition and the pyrolytic products from leather of different animal species and tanning processes in order to discriminate them. The animal species studied were bovine hide, horsehide, pigskin, sheepskin and goatskin. Three different tanning agents were selected in this study (chromium salts, glutaraldehyde and vegetable tannins) at three different stages of the tanning process (pickled, tanned and crust leather). The thermal decomposition of all samples was studied by means of thermogravimetric analysis while the pyrolytic products were analysed using a pyrolyser connected online to a Gas Chromatograph-Mass Spectrometer (Py-GC/MS). Significant differences in the results obtained by both techniques can be observed depending on the treatments and animal species. Multivariate statistical analysis (MVA) based on principal component analysis confirm differences observed between leather samples, thus allowing the discrimination of both the animal origin and the tanning treatment. Co-financial support for this investigation has been provided by IVACE, Generalitat Valenciana, and FEDER for research within the field of flash pyrolysis of leather.

La crisis climática sigue siendo el desafío que caracteriza nuestra era. Los últimos 5 años han sido los más calurosos que se hayan registrado. La generación de gases de efecto invernadero (GEI), principalmente constituidos por CO2, CH4, N2O y gases fluorados han experimentado un aumento exponencial provocando un incremento de la temperatura media mundial de 1.1ºC en comparación con los niveles registrados en el periodo pre-industrial. Teniendo en cuenta la situación actual, es casi imposible reducir las emisiones sin depender de las tecnologías de captura, secuestro y utilización de CO2. Las técnicas de programación matemática se han convertido en una herramienta muy valiosa para abordar el desarrollo de una infraestructura de captura, transporte, almacenamiento y uso del CO2 (CCUS) a nivel europeo. En el presente trabajo, se propone un modelo de programación lineal mixta entera (MILP) para la optimización económica de una cadena de suministro multiperiodo. El territorio europeo se encuentra discretizado, permitiendo la definición espacial de las grandes fuentes estacionarias de emisiones de CO2. La red general de CCUS se optimiza en un horizonte temporal de 5 años para proporcionar la ubicación geográfica de las regiones de captura y secuestro, las rutas de transporte más convenientes y la ubicación de las plantas de conversión de los productos químicos (PPP y MeOH). Diferentes estudios son analizados y comentados. Los resultados demuestran el potencial europeo para el secuestro del CO2. El coste total de instalación de la red depende mayoritariamente de los costes totales de captura, mientras que los costes de transporte y secuestro no superan el 10%. Los costes generales de una CCUS a nivel europeo se estimaron en el rango de 15-17 [€/tCO2].

La captura y almacenamiento de carbono (CCS) se ha convertido en una de las opciones más prometedoras para disminuir las emisiones de los gases de efecto invernadero (GEI). Además, el uso de este carbono se ha considerado como un beneficio tanto para el medio ambiente, como para la reducción del coste total de instalación de los sistemas de CCS. Cuando se trata del diseño y optimización de una infraestructura de captura, almacenamiento y uso de CO2 («Carbon Capture, Usage and Storage», CCUS) a gran escala, es necesario emplear herramientas matemáticas para tratar la complejidad de esta red. En el presente trabajo, se propone un modelo de programación lineal mixta entera (MILP) para la optimización económica de una cadena de suministro a pequeña y gran escala de una CCUS. El territorio europeo ha sido discretizado con el fin de obtener una definición espacial de las grandes fuentes de emisiones estacionarias. En cuanto a la captura de CO2, la postcombustión, la oxicombustión y la precombustión han sido consideras como posibles tecnologías de captura, mientras que a nivel de transporte se ha diferenciado entre oleoducto tierra, oleoducto mar y barco. En base a los datos existentes en la literatura, la conversión del CO2 a PPP y MeOH fue seleccionada como una de las tecnologías prometedoras en la utilización del carbono. Diferentes escenarios (capturando hasta el 90% de las emisiones europeas de CO2 de grandes fuentes estacionarias) han sido analizados y comentados. Los resultados demuestran el potencial de las tecnologías de captura y almacenamiento de carbono; mientras que, según nuestras suposiciones, la utilización del carbono en términos de reducción del impacto ambiental no es suficiente teniendo en cuenta que actualmente sólo el 2.4% del CO2 capturado es eliminado mediante la conversión a productos químicos. Los costes de captura son la principal contribución al coste total, mientras que los costes de transporte y secuestro no superan el 10% de la inversión inicial necesaria. Sin embargo, se pueden obtener importantes beneficios en términos de reducción del coste total debido a los ingresos derivados de los productos químicos que se producen.

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.

This paper presents a surrogate-assisted framework to solve constrained black-box optimization problems, which is applied to the optimal single-mixed refrigerant natural gas liquefaction processes design. This approach uses kriging models as cheap-to-evaluate, reliable surrogates of the process-simulator-dependent black-box functions of the optimization problem. From kriging prediction and estimated error, the probability of feasible improvement acquisition function is derived and optimized to search forfeasible and improving candidates to perform local search in the penalized simulation. The kriging-assisted global search scheme is efficient to find promising candidates for local refinement, and it improves previous results that used only local optimization by 3.36 and 5.32 %. The surrogate model reduces the time to evaluate the functions from 0.9933 ± 0.0815 to 3.515e-4 ± 8.353e-5 seconds. The kriging approximation mean squared errors assessed in a k-fold cross-validation is 7.271e-7 ± 1.297e-7 for the objective function and 0.3099 ± 0.0856 for the constraint. The authors acknowledge the National Council for Scientific and Technological Development–CNPq (Brazil), processes 148184/2019-7, 440047/2019-6, 311807/2018-6, 428650/2018-0, 305055/2017-8, and Coordination for the Improvement of Higher Education Personnel–CAPES (Brazil) for the financial support.

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.

In this work, different alternatives for locating the optimal feed stage in a distillation column as well as the effect of the feed temperature are studied, by solving a classroom problem. The results obtained permit us to select the best way to optimize the feed stage location as well as to detect what thermal feed phase conditions should be avoided.

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).

Leather tanned with different agents was pyrolyzed in the presence of CoCl2 and MnCl2 catalysts. A bovine leather sample tanned with two inorganic tanning agents (chromium and titanium salts) and two organic tanning agents (glutaraldehyde and methylacrylic resin) has been used in this study. The samples were soaked in solutions of CoCl2 or MnCl2 of known concentration. The influence on decomposition temperature and the resultant pyrolysis compounds has been evaluated by using thermogravimetric analysis (TG/DTG) and flash pyrolysis (Py-GC/MS). A multivariate analysis has been applied to the pyrolysis products obtained confirming the effect of the catalyst treatment on leather, specifically on samples tanned with organic agents. According to the results, CoCi2 (higher Lewis acidity) shows a greater influence than the MnCI2 (lower Lewis acidity). The results indicate that the presence of chlorides affects the nature of the pyrolysis products, increasing the yield of the aromatic compounds in all the samples, thus improving the added-value of the volatiles. These catalysts reduced slightly the decomposition temperature. Co-financial support for this investigation has been provided by IMPIVA, Generalitat Valenciana, and FEDER for research within the field of pyrolysis flash of leather waste.

En la actualidad es importante contar con sistemas informáticos competentes capaces de abarcar un amplio abanico de problemas, operar muchas ecuaciones simultáneamente, optimizando objetivos que en muchos casos son opuestos, y al mismo tiempo que estos sistemas informáticos sean capaces de dar una respuesta inmediata o en el menor tiempo posible. Cada vez se escucha más el concepto de sostenibilidad, la capacidad de aprovechar los recursos de la mejor manera, por lo que ahora, más que nunca, es necesario un sistema competente que sea capaz de gestionar todos estos requisitos y los futuros retos que se puedan presentar debido, principalmente, a la escasez de recursos. En este trabajo se pretende hacer una introducción general al simulador EMSO, un simulador orientado a ecuaciones, que es muy útil en el ámbito académico gracias a su versatilidad, facilidad de uso, y que no requiere una gran capacidad de almacenamiento, además es gratuito para las instituciones académicas. Con el objetivo de dar a conocer el programa y una mejor comprensión de su funcionamiento se realizarán varios casos de estudio orientados, principalmente, a la simulación y optimización. Finalmente, se expondrán las ventajas e inconvenientes del simulador de procesos EMSO con respecto a otros simuladores que hay en el mercado.

Waste printed circuit boards (WCBs) were debrominated under hydrothermal treatment, using potassium carbonate as an alkaline additive to improve debromination efficiency (DE). Two different high-pressure reactors were used: a 1-L stirred reactor, where the evolution of the DE was followed over time at a low CO32−/Br− ratio (1:25), and an elementary 0.1-L non-stirred reactor, used to find the optimal parameters and to simplify the hydrothermal debromination (HTD) process. Considering both reactors, experiments were conducted changing the temperature (200 °C, 225 °C, 250 °C, 275 °C), and also the CO32−/Br− anionic ratio (1:50, 1:25, 1:10, 1:5, 1:2.5, 1:1, 2:1, 4:1) and the solid/liquid ratio (1:10, 1:5, 1:2) in the case of the 0.1-L reactor. No metallic catalyst was required. A maximum DE of about 98.9 wt % was reached in the agitated vessel at 275 °C after 4 h, with an additive/bromine ratio of 1:25. Similar DE (99.6 wt %) was also achieved in the non-stirred reactor at only 225 °C and after 2 h, using an additive/bromine ratio of 4:1 and a solid/liquid ratio of only 1:2. Concerning the solid phase behaviour during debromination, only 5 % of the net calorific value (NCV) was lost after a complete HTD treatment of WCB. Support for this work was granted by CTQ2016-76608-R project and the scholarship BES-2017-080382 from the Ministry of Economy, Industry and Competitiveness (Spain).