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The authors acknowledge financial support to CESAM by FCT/MCTES (UIDP/50017/2020+UIDB/50017/2020+ LA/P/0094/2020), through national funds. Diogo Pereira thanks FCT for PhD grant (2020.05389.BD). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish State Research Agency and ESF.

This work was developed inside the scope of the project CICECO -Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020 & LA/P/0006/2020). We acknowledge financial support to CESAM by FCT/MCTES (UIDP/ 50017/2020+UIDB/50017/2020+LA/P/0094/2020), through national funds. Érika M.L. Sousa thanks to Fundação para a Ciência e Tecnologia (FCT) for her PhD grant (2020.05390.BD). Paula Ferreira is thankful to FCT for the Investigator Program (IF/00300/2015). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government and the Spanish State Research Agency, co-financed by the European Social Fund (ESF).

El biogás es un recurso biomásico sostenible debido a su naturaleza renovable que puede ser utilizado para la producción de biometano, como sustituto del metano de origen fósil, y de hidrógeno. El hidrógeno se considera uno de los futuros vectores energéticos más limpios si se genera a partir de fuentes renovables.

The use of bio-waste for the production of bio-based adsorbents not only has intrinsic benefits to the environment but is also a route for its valorization. Based on the concept of a circular economy, this book chapter aims to provide an overview of present trends and future potential in the conversion of bio-waste into bio-based adsorbents with particular emphasis on its application to carbon dioxide capture. Bio-based adsorbents have recently gained considerable attention as benign and cost-effective materials for CO2 capture applications. These adsorbents can be produced from cheap and widely available biomass feedstocks and bio-wastes from different industries (e.g., dairy manure, forestry, and agricultural). As a result, a carbon-rich material of hydrophobic nature is obtained, which is activated to gain high porosity development, and it requires mild regeneration conditions. However, large-scale deployment of bio-based adsorption processes remains challenging.

This work was funded by FEDER through COMPETE 2020 and national funds through Fundação para a Ciência e Tecnologia (FCT) by the research project WasteMAC (POCI-01- 0145-FEDER-028598). Thanks are also due to FCT/MCTES for the financial support to UIDP/50017/2020+UIDB/50017/2020, through national funds. Guilaine Jaria thanks to FCT for her PhD grant SFRH/BD/138388/2018. Vânia Calisto and Marta Otero are thankful to FCT for the Scientific Employment Stimulus Program (CEECIND/00007/2017) and Investigator Program (IF/00314/2015), respectively. María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government, co-financed by the European Social Fund (ESF).

This is the peer reviewed version of the following article: Querejeta, N. , Gil, M. V., Rubiera, F. and Pevida, C. (2018), Sustainable coffee‐based CO2 adsorbents: toward a greener production via hydrothermal carbonization. Greenhouse Gas Sci Technol, 8: 309-323. doi:10.1002/ghg.1740, which has been published in final form at https://doi.org/10.1002/ghg.1740. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions, Activated carbons for adsorption of CO2 under flue gas conditions were prepared by means of hydrothermal carbonization (HTC) and subsequent CO2 activation of spent coffee grounds. The HTC of the samples consisted of their heating at moderate temperature with a high water content in autoclave. A preliminary screening concluded that 1:2 biomass/water ratio (spent coffee grounds as received) and no chemicals added during HTC with further activation in CO2 at 800°C for 1 h are suitable conditions to produce the CO2 adsorbents. In addition, the response surface methodology (RSM) successfully evaluated the combined effect of HTC temperature and dwell time, to maximize the CO2 capture capacity within the experimental region. Both the lowest temperature and dwell time (120°C, 3 h) resulted in the maximum CO2 capture capacity (2.95 wt.%). Two activated carbons (ACs) were then produced: one via hydrothermal carbonization optimized by means of response surface methodology (RSM) followed by CO2 activation (HC‐Co) and the other one by single‐step CO2 activation as described in the Group's patent ES2526259 (AC‐Co). Analysis of the features and performances of the two ACs revealed superior chemical and textural characteristics on HC‐Co for CO2 adsorption under post‐combustion capture conditions; HTC process is the sole responsible of this enhancement. Moreover, the proposed methodology to produce CO2 adsorbents from spent coffee grounds represents a more energy‐efficient approach, This work was carried out with financial support from the Gobierno del Principado de Asturias (PCTI‐GRUPIN14‐079)

This work was funded by FEDER through COMPETE 2020 and national funds through Fundação para a Ciência e a Tecnologia (FCT) by the research project POCI-01-0145-FEDER-028598. Guilaine Jaria, Marta Otero and Vânia Calisto thank FCT for the grant SFRH/BD/138388/2018, Investigator Program IF/00314/2015 and CEEC Program CEECIND/00007/2017, respectively. María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government.

This work is a contribution to the project WasteMAC (POCI-01-0145-FEDER-028598) funded by FCT – Fundação para a Ciência e a Tecnologia, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Thanks are also due for the financial support to CESAM (UID/AMB/50017/2019), to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Vânia Calisto is funded by national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Guilaine Jaria and Marta Otero thank FCT for the grant SFRH/BD/138388/2018 and Investigator Program IF/00314/2015, respectively.

Biomass cofiring is a promising technology to decrease the use of fossil fuels for energy generation and hence mitigate greenhouse gas emissions. Coal and biomass cofiring accounts for the relevant advantages of a relative ease of implementation and an effective reduction of CO2 and other pollutant (SOx, NOx) emissions to the atmosphere. Cofiring biomass with coal may record no loss in total boiler efficiency after adjusting combustion output for the new fuel mixture. However, the guarantee of a stable and cheap supply of biomass, together with an optimum delivery system, is a key parameter for the success of biomass cofiring. Standardization in the characterization and treatment of biomass is also lacking. Future research on thermal, chemical, and mechanical characteristics of biomass; technical problems in burning biomass; and optimum cofiring conditions have to be addressed. Finally, incentives and favorable regulatory and environmental policies will be the major factors encouraging the development of the cofiring technology., Authors are grateful to the Gobierno del Principado de Asturias (PCTI-GRUPIN14-079) and to the CSIC (PIE-201780E057) for funding.

This work was funded by FEDER through COMPETE 2020 and national funds through Fundação para a Ciência e Tecnologia (FCT) by the research project RemPharm - PTDC/AAG-TEC/1762/2014. The authors also thank FCT for funding through a PhD grant (SFRH/BD/138388/2018), Investigator Program (IF/00314/2015) and CEEC Program (CEECIND/00007/2017). M.V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government, co-financed by the European Social Fund (ESF).

This is the accepted version of the following article: Álvarez-Gutiérrez, N., Victoria Gil, M., Rubiera, F. and Pevida, C. (2015), Cherry-stones-based activated carbons as potential adsorbents for CO2/CH4 separation: effect of the activation parameters. Greenhouse Gas Sci Technol, 5: 812–825. doi: 10.1002/ghg.1534, which has been published in final form at http://dx.doi.org/10.1002/ghg.1534, A low-cost biomass, cherry stones (CS), was used as a carbon precursor to synthesize two activated carbons to be used for CO2/CH4 separation. Single-step activation with two activating agents, carbon dioxide and steam, was used. The activation conditions that maximize the CO2 adsorption capacity by the adsorbents at 25 ºC and atmospheric pressure were determined by response surface methodology (RSM). The optimum values were 885 ºC and 12% of solid yield when activating with carbon dioxide, but 850 ºC and 15.3% of solid yield when activating with steam. Heating rate did not show a significant effect on the CO2 uptake. CO2 adsorption capacity values up to 11.45 and 10.56 wt.% were achieved under such conditions using carbon dioxide and steam as activating agents, respectively. Carbon dioxide activation promoted the development of microporosity, whereas both micropores and mesopores were developed during steam activation. The CO2/CH4 separation performance at 3 bar of the optimum adsorbents indicated that both cherry-stones-based activated carbons could have great potential as CO2 adsorbents for CO2/CH4 separation. The adsorbent activated with carbon dioxide, CS-CO2, showed a slightly higher adsorption capacity, but the steam-activated sample, CS-H2O, had an enhanced selectivity to separate CO2 from CO2/CH4 binary mixtures., This work was carried out with financial support from the Spanish MINECO (Project ENE2011-23467), co-financed by the European Regional Development Fund (ERDF) and from the Gobierno del Principado de Asturias (PCTI-GRUPIN14-079)

The ignition behavior of coal and biomass blends was assessed in air and oxy-firing conditions in an entrained flow reactor. Four coals of different rank, an anthracite, a semi-anthracite, and two high-volatile bituminous coals, were tested in air and O2/CO2 (21–35% O2) environments. For all the coals, deterioration in ignition properties was observed in the 21%O2/79%CO2 atmosphere in comparison with air. However, the ignition properties were enhanced when the oxygen concentration in the O2/CO2 mixture was increased. Coal and biomass blends of a semi-anthracite and a high-volatile bituminous coal with 10 and 20 wt% of olive residue were also used in the ignition experiments under air and oxy-firing conditions. The ignition behavior of the coals improved as the additions of biomass increased both in air and oxy-firing conditions. In particular, the effect of biomass blending was more noticeable in the ignition of the high rank coal. Since industrial oxy-coal combustion with a wet recycle would result in higher concentrations of H2O(v), the effect of steam addition on ignition behavior was also studied. A worsening in ignition behavior was observed when steam was added to the oxy-fuel combustion atmospheres, although an increase in the steam concentration from 10 to 20% did not produce any significant difference in the ignition characteristics of the fuels., This work was carried out with financial support from the Spanish MICINN (Project PS-120000-2005-2) co-financed by the European Regional Development Fund. L.A. and M.V.G. acknowledge funding from the CSIC JAE programs, co-financed by the European Social Fund. J.R. acknowledges funding from the Government of the Principado de Asturias (Severo Ochoa program), respectively. Support from the CSIC (PIE 201080E09) is gratefully acknowledged.

An activated carbon was produced from paper mill sludge (AC-P) and functionalized with thiol groups (AC-MPTMS) for the adsorptive removal of the antibiotic sulfamethoxazole (SMX) from buffered solutions prepared in ultrapure water (pH 8) and real wastewater samples. The physicochemical properties of the two materials (AC-P and AC-MPTMS) showed differences mainly in specific surface area (SBET), in the type of oxygen functional groups and in the relative percentage of sulphur groups. The adsorption results showed a decrease in the Langmuir adsorption capacity (qm) upon an increase on temperature (15, 25 and 35 °C), varying between 113 ± 7 and 42.5 ± 0.6 mg g−1 for AC-P and between 140 ± 20 and 28.0 ± 1.5 mg g−1 for AC-MPTMS. Pseudo-second order model presented the best fit for the kinetic studies, with rate constants (k2) increasing with temperature and varying from 0.005 ± 0.002 to 0.013 ± 0.004 g mg−1 min−1 for AC-P and from 0.006 ± 0.002 to 0.03 ± 0.01 g mg−1 min−1 for AC-MPTMS. Both adsorbents showed very similar thermodynamic parameters, with the adsorption process being spontaneous (−26 kJ mol−1 ≤ ΔG° ≤ −40 kJ mol−1), endothermic (69 kJ mol−1 ≤ ΔH° ≤ 78 kJ mol−1), and entropically favorable (356 ≤ ΔS° ≤ 365 J mol−1 K−1). The performance of AC-MPTMS in the removal of SMX was tested in wastewater, where the material displayed lower SMX adsorption velocity and capacity than in buffered aqueous solution (pH 8) due to competitive matrix effects., Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020+ UIDB/50017/2020) and CICECO-Aveiro Institute of Materials, (UIDB/50011/2020 & UIDP/50011/2020), through national funds. Guilaine Jaria thanks her PhD grant (SFRH/BD/138388/2018) supported by national funds and FSE through Fundação para a Ciência e a Tecnologia (FCT), POCH (Programa Operacional Capital Humano) and European Union. Marta Otero, Paula Ferreira and Sérgio Santos thank FCT for the Investigator Program (IF/00314/2015, IF/00300/2015 and IF/00973/2014, respectively). Vânia Calisto is thankful to FCT for Scientific Employment Stimulus (CEECIND/00007/2017). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) by the Spanish Government, co-financed by the European Social Fund (ESF). The authors thank to the project RemPharm (PTDC/AAG-TEC/1762/2014) funded by FCT, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Milton Fontes and workers of Aveiro's WWTP (Águas do Centro Litoral) are gratefully acknowledged for assistance on the effluent sampling campaigns.

Pellets for industrial use were produced from blends of pine sawdust (PIN) and alternative residual biomasses in a pilot-scale pelletizer. The effect of the pelletization temperature (T = 50–80 °C) and biomass moisture content (MC = 14–20%) on pine sawdust pellet quality was studied by using response surface methodology (RSM). Pelletization performance was evaluated on the basis of the durability, bulk density, moisture content, lower heating value (LHV), energy density, diameter, length and density of the pellets. From the RSM analysis, a maximum durability value of 99.4% was obtained at T = 80 °C and MC = 16.6%. Under these conditions, all the parameters showed values within the required range of industrial pellet qualities, i.e., a bulk density of 616 kg/m3, a pellet moisture content of 7.6%, a lower heating value (as received) of 18 MJ/kg, a diameter of 6.2 mm and a length of 23.4 mm. Blends of pine sawdust with eleven unconventional biomass samples were then pelletized under the optimum conditions to obtain pellets for industrial use according to the categories of quality defined by ISO 17225-2. Blends of pine sawdust with almond shells (AS) and olive stones (OS) contents of up to 30 wt%, as well as with pine cone leafs (PCL) contents of up to 15 wt%, produced I1 pellets. Blends of pine sawdust with coffee dregs (CD), coffee husks (CH) and grape pomace (GP) proportions of up to 10 wt%, as well as with hazelnut shells (HS), miscanthus (MIS), pine kernel shells (PKS) and switchgrass (SG) contents of up to 15 wt%, and also with a PCL content of between 15 and 30 wt%, generated I3 class pellets. Classification was not possible for cocoa shells (CS) mixed with pine sawdust due to the low bulk density of the pellets. Energy consumption resulting from the pelletization of the blends was evaluated with values ranging from 0.09 to 0.33 kWh/kg, while the pelletization of pine sawdust required 0.18 kWh/kg. The addition of alternative biomass feedstocks to pine sawdust may therefore serve to reduce energy consumption in industrial pelletization., Financial support from the CSIC (Spain) (Project PIE 201780E057) and from the Gobierno del Principado de Asturias (PCTI, Ref. IDI/2018/000115) with co-funding from the European Regional Development Fund (ERDF) is gratefully acknowledged.

Multivariate analysis was used to study the influence of the biomass characteristics on the gasification process. Ten lignocellulosic biomass samples (almond shells –AS–, chestnut sawdust –CHE–, torrefied chestnut sawdust –CHET–, cocoa shells –CS–, grape pomace –GP–, olive stones –OS–, pine cone leafs –PCL–, pine sawdust –PIN–, torrefied pine sawdust –PINT–, and pine kernel shells –PKS–) were gasified in a bubbling fluidized bed gasifier under an air-steam atmosphere. Statistical analysis was applied to the variables that described the results of the gasification process, i.e., gas concentration, gas production (moles), calorific value of the product gas, energy density, and cold gas efficiency, together with the main biomass properties, such as those derived from the elemental and proximate analyses, the higher heating value (HHV), the particle density, and the elemental composition of the ashes. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were applied to the data of biomass properties and gasification parameters in order to elucidate which feedstock features had a more determinant influence on the gasification process. Both HCA and PCA revealed a clear separation of the biomass samples into two main groups on the basis of the gasification results. The results indicated that PKS, PCL, PINT, OS and PIN biomasses were characterized by high production of combustible gases, such as CO and CH4, high conversion and cold gas efficiency during gasification. This indicated that the most important biomass properties for promoting the gas production, calorific value of the product gas, gasification conversion and energy efficiency were the C and H contents and the HHV of the biomass. However, biomasses CS and GP were mainly characterized by high H2 concentration and H2/CO molar ratio in the gas product, which was mainly related to the higher H/O ratio and K2O ash content of the biomass. The H2 concentration in the product gas was negatively related to the O and VM contents of the biomass. Therefore, it can be concluded that the use of multivariate statistical techniques for analyzing gasification data facilitated to draw valuable conclusions about the influence of the biomass properties on the gasification results., This work has received financial support from CSIC, Spain (Project PIE 201780E057). M.P. González-Vázquez acknowledges a fellowship awarded by the Spanish MINECO (FPI program), cofinanced by the European Social Fund.

The design of a pressure swing adsorption (PSA) system requires the development of a complex model that can describe the dynamics of adsorption in a fixed-bed, which means a labor intensive and time consuming work, especially when several adsorbents are going to be compared. Therefore, it would be very useful to establish a simple procedure to quickly assess the performance during the early stages of PSA systems design. The aim of this work is to develop a simplistic approach that drives the decision-making process on the adsorbent in a shorter time. A combined experimental and numerical study of CO2/CH4 adsorption is presented. Thus, three commercial activated carbons are compared in their performance to separate CO2 from biogas under PSA conditions by means of equilibrium adsorption data. A straightaway model, developed to approach PSA systems in a very simple way, where the only input is equilibrium of adsorption data, has been adopted. The Adsorption Figure of Merit (AFM), CO2 purity and CO2 recovery were selected as performance indicators and they have pointed out one of the activated carbons, MC27, as the most promising adsorbent candidate to separate CO2/CH4 by means of PSA. A sensitivity analysis of the process performance as a function of the bed dimensions has been addressed using the developed short-cut model.

The main goal of this work was to produce an easily recoverable waste-based magnetic activated carbon (MAC) for an efficient removal of the antiepileptic pharmaceutical carbamazepine (CBZ) from wastewater. For this purpose, the synthesis procedure was optimized and a material (MAC4) providing immediate recuperation from solution, remarkable adsorptive performance and relevant properties (specific surface area of 551 m g and saturation magnetization of 39.84 emu g) was selected for further CBZ kinetic and equilibrium adsorption studies. MAC4 presented fast CBZ adsorption rates and short equilibrium times (< 30–45 min) in both ultrapure water and wastewater. Equilibrium studies showed that MAC4 attained maximum adsorption capacities (q) of 68 ± 4 mg g in ultrapure water and 60 ± 3 mg g in wastewater, suggesting no significant interference of the aqueous matrix in the adsorption process. Overall, this work provides evidence of potential application of a waste-based MAC in the tertiary treatment of wastewaters. [Figure not available: see fulltext.]., This work is a contribution to the project WasteMAC (POCI-01-0145-FEDER-028598) funded by FCT – Fundação para a Ciência e a Tecnologia, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Thanks are also due for the financial support to CESAM (UID/AMB/50017/2019), to FCT/MCTES through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Marta Otero and Diogo Pereira thank FCT funding through IF Program (IF/00314/2015). Vânia Calisto is thankful to FCT for the Scientific Employment Stimulus support (CEECIND/00007/2017). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government, co-financed by the European Social Fund (ESF).

H2 production from biogas (60%CH4 + 40%CO2) by sorption enhanced steam reforming (SESR) was thermodynamically and experimentally studied in a fluidized bed reactor. Biogas is an interesting renewable biomass resource for hydrogen production due to its sustainable nature. SESR combines the catalytic reforming reaction of biogas with simultaneous CO2 removal in a single step. A Pd/Ni–Co hydrotalcite-like material (HT) was used as catalyst and dolomite as CO2 sorbent. The effects of temperature (550–800 °C), steam/CH4 molar ratio (2–6) and gas hourly space velocity (GHSV) (492–3937 mL CH4 gcat−1 h−1) on the process performance were evaluated. CO2 in biogas was effectively removed by the sorbent from the gas phase at 550–700 °C, without influencing the reforming process. H2 yield increased with temperature from 550 to 650 °C, but H2 concentration decreased at temperatures higher than 600 °C, requiring a tradeoff between both parameters to select an optimum operating temperature. H2 purity of 98.4 vol% was obtained at 550–600 °C and H2 yield of 92.7% was reached at 650 °C. Higher steam/CH4 ratios enhance the process, whereas higher space velocities decrease H2 yield. Results demonstrate that high-purity high-yield biohydrogen can be produced by the SESR of a renewable biomass resource as biogas., The authors thank Franefoss Miljøkalk A/S (Norway) for supplying Arctic dolomite. This work was carried out with financial support from the Spanish MICINN (Project ENE2017-83530-R) and from the Gobierno del Principado de Asturias (PCTI, Ref. IDI/2018/000115), both co-financed by the European Regional Development Fund (ERDF). M.V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish Government, co-financed by the European Social Fund (ESF).

This work aimed at the microwave-assisted production of activated carbon (AC) from primary paper mill sludge (PS) for the adsorption of antibiotics from water. Production conditions, namely pyrolysis temperature, pyrolysis time and activating agent (KOH):PS ratio, were optimized as a function of product yield, specific surface area (SBET), total organic carbon (TOC) content and adsorptive removal percentage of two target antibiotics (amoxicillin (AMX) and sulfamethoxazole (SMX)). Under the optimized conditions (pyrolysis at 800 °C during 20 min and a KOH:PS ratio of 1:5), a microporous AC (MW800-20-1:5, with SBET = 1196 m2 g-1, TOC = 56.2% and removal of AMX and SMX = 85% and 72%, respectively) was produced and selected for further kinetic and equilibrium adsorption studies. The obtained results were properly described by the Elovich reaction-based kinetic model and the Langmuir equilibrium isotherm, with maximum adsorption capacities of 204 ± 5 mg g-1 and 217 ± 8 mg g-1 for AMX and SMX, respectively. Considering the satisfactory comparison of these results with the performance of commercial and alternative AC produced by conventional pyrolysis, this work demonstrated the feasibility of the microwave-assisted production of environmentally and energetically sustainable waste-based AC to be applied in the efficient removal of antibiotics from water., This work is a contribution to the project WasteMAC (POCI-01-0145-FEDER-028598) funded by FCT – Fundação para a Ciência e a Tecnologia, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Thanks are also due for the financial support to CESAM (UIDB/50017/2020+UIDP/50017/2020), to FCT/MEC through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. Marta Otero, Vânia Calisto and Guilaine Jaria are thankful to FCT for the Investigator Program (IF/00314/2015), the Scientific Employment Stimulus (CEECIND/00007/2017) and a PhD grant (SFRH/BD/138388/2018), respectively. María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government, co-financed by the European Social Fund (ESF).

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy and Fuels, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/ef200411j, The effect of devolatilization conditions (pressure and temperature) on the steam gasification kinetics and reactivity of coal chars was investigated. For this purpose, five different rank coals were selected: a lignite (LT), two high-volatile bituminous coals (DT and SA), a low-volatile bituminous coal (DI), and a semianthracite (HV). The coal chars were obtained by devolatilization in a novel pressurized fixed-bed reactor at temperatures of 800, 900, and 1000 °C and pressures of 1, 5, 10, and 20 atm. The reactivity of the chars was studied by isothermal thermogravimetric analysis in a kinetically controlled regime at different temperatures under a steam atmosphere. The reactive behavior of the chars was evaluated by means of the random pore model (RPM), which satisfactorily described the steam gasification of the coal chars. The gasification apparent reaction rate increased as the devolatilization pressure increased, whereas this parameter decreased as the devolatilization temperature increased., M.V. Gil acknowledges funding from the CSIC JAE Program co-financed by the European Social Fund.

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy and Fuels, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/ef100877t, The effect of operating conditions (pressure and temperature) on char morphology and structure during coal devolatilization was studied. For this purpose, five different rank coals were selected: a lignite, three bituminous coals, and a semi-anthracite. The coal chars were prepared by devolatilization in a novel pressurized fixed-bed reactor. The pyrolysis experiments were carried out isothermally at temperatures of 800, 900, and 1000 °C and pressures of 1, 5, 10, and 20 atm. The chars obtained from the bituminous coals at elevated pressure experienced a high degree of swelling, whereas those from the lignite and semi-anthracite were hardly affected at all by pressure. The devolatilization temperature did not appear to have any significant effect on char morphology below 1000 °C. The reactivity of the char samples prepared under different pyrolysis conditions was studied by isothermal thermogravimetric analysis at 1000 °C under a steam atmosphere. The chars obtained at elevated pressure were found to be more reactive than those produced at atmospheric pressure. An increase in the pyrolysis temperature led to a decrease in char reactivity.

In this study, a waste-based magnetic activated carbon (MAC) was used for the first time in a continuous-flow stirred tank reactor (CSTR). The aim was to evaluate the dynamic removal of diclofenac (DCF) from water and wastewater. Firstly, the breakthrough curves corresponding to DCF adsorption from distilled water at different feed flow rates and doses of MAC were determined. After selecting the most favourable conditions, namely 0.18 h L-1 flow rate and 400 mg L-1 of MAC, the effect of different aqueous matrices was studied, with the breakthrough curves evidencing a performance decline in wastewater in comparison with distilled water. Finally, the exhausted MAC was magnetically recovered, regenerated by microwave-assisted heating and applied in two subsequent adsorption cycles. The regeneration studies pointed to a decrease of the specific surface area and an improvement of the magnetic retrievability of MAC. After the first regeneration step, just mild effects were observed in the dynamic adsorptive performance of MAC. However, after a second regeneration step, the performance declined ca. 50%. Overall, the results highlight the feasibility of producing waste-based magnetic composites that simultaneously combine high adsorption efficiency under dynamic operation in a CSTR, with easy retrievability and successful one-stage regeneration for further reutilization., This work is a contribution to the project WasteMAC (POCI-01-0145-FEDER-028598) funded by FCT – Fundação para a Ciência e a Tecnologia, I.P., through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. The authors acknowledge financial support to CESAM by FCT/MCTES (UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020), through national funds. Érika M.L. Sousa thanks to FCT for a PhD grant (2020.05390.BD). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government and the Spanish State Research Agency, co-financed by the European Social Fund (ESF).

This study aimed at optimizing the one-step chemical activation and microwave pyrolysis of an agro-industrial waste to obtain a microporous activated carbon (AC) with superior textural and adsorptive properties by a fast, low-reagent and low-energy process. Spent brewery grains were used as precursor, and the antibiotics sulfamethoxazole (SMX), trimethoprim (TMP) and ciprofloxacin (CIP) were considered as target adsorbates. A fractional factorial design was applied to evaluate the effect of the main factors affecting the preparation of AC (activating agent, activating agent:precursor ratio, pyrolysis temperature and residence time) on relevant responses. Under optimized conditions (K2CO3 activation, pyrolysis at 800 °C during 20 min and a K2CO3:precursor ratio of 1:2), a microporous AC with specific surface area of 1405 m2 g-1 and large adsorption of target antibiotics (82-94%) was obtained and selected for further studies. Equilibrium times up to 60 min and maximum Langmuir adsorption capacities of 859 µmol g-1 (SMX), 790 µmol g-1 (TMP) and 621 µmol g-1 (CIP) were obtained. The excellent textural and adsorptive properties of the selected material were achieved with a very fast pyrolysis and low load of activating agent, highlighting the importance of optimization studies to decrease the environmental and economic impact of waste-based AC., This work was developed within the scope of the project CICECO - Aveiro Institute of Materials (UIDB/50011/2020 & UIDP/50011/2020). We acknowledge financial support to CESAM by FCT/MCTES (UIDP/50017/2020+UIDB/50017/2020+LA/P/0094/2020), through national funds. Érika M.L. Sousa thanks to Fundação para a Ciência e Tecnologia (FCT) for her PhD grant (2020.05390. BD). Paula Ferreira is thankful to FCT for the Investigator Program (IF/00300/2015). María V. Gil acknowledges support from a Ramón y Cajal grant (RYC-2017-21937) of the Spanish government and the Spanish State Research Agency, co-financed by the European Social Fund (ESF).