Abstract: This paper analyzes the impact of urban land-use changes on farmers' livelihood around the city of Bahir Dar (Ethiopia). Rapid urban expansion in and around the city has resulted in massive land-use changes in its urban fringes, with land expropriation programs affecting communities' livelihood and the environment. A survey was conducted in three urbanizing villages near Bahir Dar, focusing on 150 farmers who were land-expropriated and 180 farmers who were non-land-expropriated. Regression models and propensity matching scoring are applied to examine the livelihood differences of farmers in terms of farm income, off-farm income, primary expenditure type, and perception of urban expansion benefits to farmers. The results reveal that land expropriation in the area has led to (a) a shift to off-farm income for land expropriated farmers; (b) an increase in their household expenditure on staple foods compared to other expenditure types, including farm inputs; and (c) diverging perceptions on whether and how city expansion benefits farmers in the neighboring villages. Our findings provide insight into the need for tighter and impactful policy actions to ensure the sustainability of urbanization through accommodating expropriated farmers' livelihood changes and protecting natural resources in the area.

Abstract: Recycling of end-of-life polyvinyl chloride (PVC) calls for solutions to deal with the vast amounts of harmful phthalate plasticizers that have historically been incorporated in PVC. Here, we report on the upcycling of such waste-extracted phthalate esters into analogues of the much safer diisononyl 1,2-cyclohexanedicarboxylate plasticizer (DINCH), via a catalytic one-pot (trans)esterification-hydrogenation process. For most of the virgin phthalates, Ru/Al2O3 is a highly effective hydrogenation catalyst, yielding >99% ring-hydrogenated products under mild reaction conditions (0.1 mol% Ru, 80 degrees C, 50 bar H-2). However, applying this reaction to PVC-extracted phthalates proved problematic, (1) as benzyl phthalates are hydrogenolyzed to benzoic acids that inhibit the Ru-catalyst, and (2) because impurities in the plasticizer extract (PVC, sulfur) further retard the hydrogenation. These complications were solved by coupling the hydrogenation to an in situ (trans)esterification with a higher alcohol, and by pretreating the extract with an activated carbon adsorbent. In this way, a real phthalate extract obtained from post-consumer PVC waste was eventually completely (>99%) hydrogenated to phthalate-free, cycloaliphatic plasticizers.

Abstract: Scanning electron microscopy coupled with microanalysis (SEM-EDX) is an important analytical tool for the morphological and chemical characterization of different types of materials. In many applications, SEM-EDX elemental maps are usually used and processed as images, thus flattening and reducing the spectroscopic information contained in EDX hyperspectral data cubes. The exploitation of the full hyperspectral dataset could be indeed very useful for the study of complex matrices like soil. In order to maximize the information attainable by SEM-EDX data cubes analysis, the software package “Datamuncher Gamma” was implemented and applied to study soil aggregates. By using this approach, different phases (silicates, aluminosilicates, Ca-carbonates, Ca-phosphates, organic matter, iron oxides) inside soil aggregates were successfully identified and segmented. The advantages of this method over the common ROI imaging approach are presented. Finally, this method was used to compare different aggregates in a Cr-polluted soil and understand their possible pedological history. The present method can be used for the analysis of every type of SEM-EDX data cubes, allowing its application to different types of samples and fields of study.

Abstract: Clathrate hydrates gained significant attention as a viable option for large-scale storage of natural gas, primarily methane (CH4). Unlike employing the nanoconfinement for enhancing the nucleation sites and hydrate growth as in the porous materials, whose synthesis is often associated with high costs and poor batch reproducibility, a new approach for promoting CH4 hydrates using pure water (H2O) in an unstirred reactor packed with stainless steel beads (SSB) was proposed in this fundamental work, where the interstitial space between the beads was exploited for enhanced hydrate growth. SSB of two diameters, 5 mm and 2 mm, were used as. a packed bed to investigate their effects on CH4 hydrate formation at 273.65 K, 275.65 K, and 277.65 K with an initial pressure of 6 MPa. The thermal conductivity of SSB packing potentially aided hydrate growth by expelling the hydration heat, while, the results also revealed that driving force has a substantial impact on the rate of CH4 hydrate formation and gas uptake. The experiments conducted in both 5 mm and 2 mm SSB packed bed reactors showed a maximum gas uptake of 0.147 mol CH4/mol H2O at 273.65 K with water to hydrate conversion of 84.42% with no significant variation. The results established the promotion effect on the kinetics of CH4 hydrate formation in the unstirred reactor packed with 2 mm SSB due to the availability of more interstitial space offering multiple nucleation sites for CH4 hydrate by providing a larger specific surface area for H2O-CH4 reaction. Experiments with varying H2O content were also performed and the results showed that the water to hydrate conversion and rate of hydrate formation could be enhanced at a lower H2O content in a packed bed reactor. This study demonstrates that the use of costly or intricate porous materials can be made redundant, by exploiting the interstitial voids in packing of cheap and widely available SSB as a promising alternative material for enhancing the kinetics of artificial CH4 hydrate synthesis.

Abstract: Cadmium red is the name used for denoting a class of twentieth century artists' pigments described by the general formula CdS1-xSex. For their vibrant hues and excellent covering power, a number of renowned modern and contemporary painters, including Jackson Pollock, often used cadmium reds. As direct band gap semiconductors, CdS1-xSex compounds undergo direct radiative recombination (with emissions from the green to orange region) and radiative deactivation from intragap trapping states due to crystal defects, which give rise to two peculiar red-NIR emissions, known as deep level emissions (DLEs). The positions of the DLEs mainly depend on the Se content of CdS1-xSex; thus, photoluminescence and diffuse reflectance vis-NIR spectroscopy have been profitably used for the non-invasive identification of different cadmium red varieties in artworks over the last decade. Systematic knowledge is however currently lacking on what are the parameters related to intrinsic crystal defects of CdS1-xSex and environmental factors influencing the spectral properties of DLEs as well as on the overall (photo)chemical reactivity of cadmium reds in paint matrixes. Here, we present the application of a novel multi-length scale and multi-method approach to deepen insights into the photoluminescence properties and (photo)chemical reactivity of cadmium reds in oil paintings by combining both well established and new non-invasive/non-destructive analytical techniques, including macro-scale vis-NIR and vibrational spectroscopies and micro-/nano-scale advanced electron microscopy mapping and X-ray methods employing synchrotron radiation and conventional sources. Macro-scale vis-NIR spectroscopy data obtained from the in situ non-invasive analysis of nine masterpieces by Gerardo Dottori, Jackson Pollock and Nicolas de Stael allowed classifying the CdS1-xSex-paints in three groups, according to the relative intensity of the two DLE bands. These outcomes, combined with results from micro-/nano-scale electron microscopy mapping and X-ray analysis of a set of CdS1-xSex powders and artificially aged paint mock-ups, indicated that the relative intensity of DLEs is not affected by the morphology, microstructure and local atomic environment of the pigment particles but it is influenced by the presence of moisture. Furthermore, the extensive study of artificially aged oil paint mock-ups permitted us to provide first evidence of the tendency of cadmium reds toward photo-degradation and to establish that the conversion of CdS1-xSex to CdSO4 and/or oxalates is triggered by the oil binding medium and moisture level and depends on the Se content. Based on these findings, we could interpret the localized presence of CdSO4 and cadmium oxalate as alteration products of the original cadmium red paints in two paintings by Pollock.

Abstract: A combination of synchrotron radiation-based elementalimaging, in vivo redox status analysis, histology, and toxic responses was usedto investigate the uptake, biodistribution, and adverse effects of Cenanoparticles (CeO2NP; 10 nm; 0.5-34.96 mg Ce L-1) or Ce(NO3)3(2.3-26 mg Ce L-1)inCaenorhabditis elegans. Elemental mapping of theexposed nematodes revealed Ce uptake in the alimentary canal prior todepuration. Retention of CeO2NPs was low compared to that of Ce(NO3)3in depurated individuals. X-rayfluorescence (XRF) mapping showed that Cetranslocation was confined to the pharyngeal valve and foregut. Ce(NO3)3exposure significantly decreased growth, fertility, and reproduction, causedslightly reduced fecundity. XRF mapping and histological analysis revealedsevere tissue deformities colocalized with retained Ce surrounding thepharyngeal valve. Both forms of Ce activated the sod-1 antioxidant defense,particularly in the pharynx, whereas no significant effects on the cellular redox balance were identified. The CeO2NP-induceddeformities did not appear to impair the pharyngeal function or feeding ability as growth effects were restricted to Ce(NO3)3exposure. The results demonstrate the utility of integrated submicron-resolution SR-based XRF elemental mapping of tissue-specificdistribution and adverse effect analysis to obtain robust toxicological evaluations of metal-containing contaminants.

Abstract: The Covid era has made us aware of the need for resilient, self-sufficient, and local production. We are likely willing to pay an extra price for that quality. Ammonia (NH3) synthesis accounts for 2 % of global energy production and is an important point of attention for the development of green energy technologies. Therefore, we propose a thermally integrated process for H2 production and NH3 synthesis using plasma technology, and we evaluate its techno-economic performance and CO2 footprint by life cycle assessment (LCA). The key is to integrate energy-wise a high-temperature plasma (HTP) process, with a (low-temperature) non-thermal plasma (NTP) process and to envision their joint economic potential. This particularly means raising the temperature of the NTP process, which is typically below 100 ◦ C, taking advantage of the heat released from the HTP process. For that purpose, we proposed the integrated process and conducted chemical kinetics simulations in the NTP section to determine the thermodynamically feasible operating window of this novel combined plasma process. The results suggest that an NH3 yield of 2.2 mol% can be attained at 302 ◦ C at an energy yield of 1.1 g NH3/kWh. Cost calculations show that the economic performance is far from commercial, mainly because of the too low energy yield of the NTP process. However, when we base our costs on the best literature value and plausible future scenarios for the NTP energy yield, we reach a cost prediction below 452 $/tonne NH3, which is competitive with conventional small-scale Haber-Bosch NH3 synthesis for distributed production. In addition, we demonstrate that biogas can be used as feed, thus allowing the proposed integrated reactor concept to be part of a biogas-to-ammonia circular concept. Moreover, by LCA we demonstrate the environmental benefits of the pro­posed plant, which could cut by half the carbon emissions when supplied by photovoltaic electricity, and even invert the carbon balance when supplied by wind power due to the avoided emissions of the carbon black credits.

Abstract: Being confronted with increasing and expanding urbanisation and the loss of natural green spaces, our living environment is threatened more and more by the effects of global climate change. Green infrastructure is often thought of as the solution to increase climate resilience and reinforce the quality of the lived environment simultaneously. While the benefits, or ecosystem services, that are generated through green infrastructure have been studied intensively, forces that influence green infrastructure decision-making have been far less subjected to thorough research. In this study a discrete choice experiment was conducted with local decision makers in Flemish municipalities to reveal crucial factors in the decision process applied to green infrastructure projects. Flanders is one of the most densely built regions in Europe, stressing the urgency to understand local spatial decision factors to guarantee green space. 568 decision makers active in the local administration of 235 Flemish municipalities participated in the experiment, set in a hypothetical neighbourhood park. Every choice alternative exists of five attributes: investment cost, maintenance cost, deferred investment, recreational value, and climate impact. We find that barriers hampering Flemish munipalities' GI implementation, differ over size of the municipality: smallers municipalities are more affected by knowledge gaps, while larger municipalities are experiencing prioritization issues. Results from hierarchical Bayes choice models indicate that municipal decisions on green infrastructure are highly – almost solely -cost-driven, rarely consider the full range of benefits, and centre around short-term and immediate arguments. Moreover, interaction models reveal that a municipalities' financial result is a key determinant of its willingness to invest in public greening and consider long term benefits, suggesting that GI is a luxury good. The results expose some of the heuristics in GI decision making and can be used to inform higher authorities on ways to overcome barriers towards informed decision-making and to facilitate GI investment.

Abstract: KBiNb2O7 was prepared from RbBiNb2O7 by a sequence of cation exchange reactions which first convert RbBiNb2O7 to LiBiNb2O7, before KBiNb2O7 is formed by a further K-for-Li cation exchange. A combination of neutron, synchrotron X-ray and electron diffraction data reveal that KBiNb2O7 adopts a polar, layered, perovskite structure (space group A11m) in which the BiNb2O7 layers are stacked in a (0, ½, z) arrangement, with the K+ cations located in half of the available 10-coordinate interlayer cation sites. The inversion symmetry of the phase is broken by a large displacement of the Bi3+ cations parallel to the y-axis. HAADF-STEM images reveal that KBiNb2O7 exhibits frequent stacking faults which convert the (0. ½, z) layer stacking to (½, 0, z) stacking and vice versa, essentially switching the x- and y-axes of the material. By fitting the complex diffraction peak shape of the SXRD data collected from KBiNb2O7 it is estimated that each layer has approximately an ~11% chance of being defective – a high level which is attributed to the lack of cooperative NbO6 tilting in the material, which limits the lattice strain associated with each fault.

Abstract: The deployment of CCUS plants does not match the enormous requirements to meet the CO2 emission reductions fixed during the Paris agreement, and we must ask ourselves what is refraining the technology deployment, especially in light of the recent high CO2 prices. Owing to the higher costs than their fossil counterparts, Carbon Capture & Utilization represents a long-term solution. In addition to a gigantic scale-up effort even for the most mature Carbon Capture & Storage (CCS) technologies, various factors are responsible for the slow roll-out of CCS projects. Luckily, the financial sector and governments are playing their role. Support from the public is however key, and an open communication is required to convert social tolerance into social acceptance.

Abstract: It is a generally accepted idea that the particle size distribution strongly affects the optical spectra of colloidal plasmonic nanoparticles. It is often quoted as one of the main reasons while explaining the mismatch between the theoretical and experimental optical spectra of such nanoparticles. In this work, these aspects are critically analyzed by means of a bottom up statistical approach that considers variables such as mean, standard deviation and skewness of the nanoparticle size distribution independently from one another. By assuming normal and log-normal distributions of the particle size, the effect of the statistical parameters on the Mie analytical optical spectra of colloidal nanoparticles was studied. The effect of morphology was also studied numerically in order to understand to what extent it can play a role. It is our finding that the particle polydispersity, skewness and surface morphology in fact only weakly impact the optical spectra. While, the selection of suitable optical constants with regard to the crystallinity of the nanoparticles is a far more influential factor for correctly predicting both the plasmon band position and the plasmon bandwidth in theoretical simulations of the optical spectra. It is shown that the mean particle size can be correctly estimated directly from the plasmon band position, as it is the mean that determines the resonance wavelength. The standard deviation can on the other hand be estimated from the intensity distribution data obtained from dynamic light scattering experiments. The results reported herein clear the ambiguity around particle size distribution and optical response of colloidal plasmonic nanoparticles.

Abstract: Industrial ammonia production without CO2 emission and with low energy consumption is one of the technological grand challenges of this age. Current Haber-Bosch ammonia mass production processes work with a thermally activated iron catalyst needing high pressure. The need for large volumes of hydrogen gas and the continuous operation mode render electrification of Haber-Bosch plants difficult to achieve. Electrochemical solutions at low pressure and temperature are faced with the problematic inertness of the nitrogen molecule on electrodes. Direct reduction of N2 to ammonia is only possible with very reactive chemicals such as lithium metal, the regeneration of which is energy intensive. Here, the attractiveness of an oxidative route for N2 activation was presented. N2 conversion to NOx in a plasma reactor followed by reduction with H2 on a heterogeneous catalyst at low pressure could be an energy-efficient option for small-scale distributed ammonia production with renewable electricity and without intrinsic CO2 footprint.

Abstract: Co-digestion of organic waste and wastewater is receiving increased attention as a plausible waste management approach toward energy recovery. However, traditional anaerobic processes for co-digestion are particularly susceptible to severe organic loading rates (OLRs) under long-term treatment. To enhance technological feasi-bility, this work presented a two-stage Anaerobic Membrane Bioreactor (2 S-AnMBR) composed of a hydrolysis reactor (HR) followed by an anaerobic membrane bioreactor (AnMBR) for long-term co-digestion of food waste and kitchen wastewater. The OLRs were expanded from 4.5, 5.6, and 6.9 kg COD m- 3 d-1 to optimize biogas yield, nitrogen recovery, and membrane fouling at ambient temperatures of 25-32 degrees C. Results showed that specific methane production of UASB was 249 +/- 7 L CH4 kg-1 CODremoved at the OLR of 6.9 kg TCOD m- 3 d-1. Total Chemical Oxygen Demand (TCOD) loss by hydrolysis was 21.6% of the input TCOD load at the hydraulic retention time (HRT) of 2 days. However, low total volatile fatty acid concentrations were found in the AnMBR, indicating that a sufficiently high hydrolysis efficiency could be accomplished with a short HRT. Furthermore, using AnMBR structure consisting of an Upflow Anaerobic Sludge Blanket Reactor (UASB) followed by a side -stream ultrafiltration membrane alleviated cake membrane fouling. The wasted digestate from the AnMBR comprised 42-47% Total Kjeldahl Nitrogen (TKN) and 57-68% total phosphorous loading, making it suitable for use in soil amendments or fertilizers. Finally, the predominance of fine particles (D10 = 0.8 mu m) in the ultra -filtration membrane housing (UFMH) could lead to a faster increase in trans-membrane pressure during the filtration process.

Abstract: The Stöber method is one of the most important and fundamental processes for the synthesis of inorganic (nano)materials but has the drawback of using a large amount of organic solvent. Herein, ethanol was used as an example to explore if the organic solvent in a typical Stöber method can be omitted. It was found that ethanol increases the particle size of the obtained silica spheres and aids the formation of uniform silica particles rather than forming a gel. Nevertheless, the results indicated that an organic solvent in the initial synthesis mixture is not indispensable. An initially immiscible synthesis method was discovered, which can replace the organic solvent-based Stöber method to successfully synthesize silica particles with the same size ranges as the original Stöber process without addition of organic solvents. Moreover, this process can be of further value for the extension to synthesis processes of other materials based on the Stöber process.

Abstract: CO2 conversion by plasma technology is gaining increasing interest. We present a carbon (charcoal) bed placed after a Gliding Arc Plasmatron (GAP) reactor, to enhance the CO2 conversion, promote O/O2 removal and in­ crease the CO fraction in the exhaust mixture. By means of an innovative (silo) system, the carbon is constantly supplied, to avoid carbon depletion upon reaction with O/O2. Using this carbon bed, the CO2 conversion is enhanced by almost a factor of two (from 7.6 to 12.6%), while the CO concentration even increases by a factor of three (from 7.2 to 21.9%), and O2 is completely removed from the exhaust mixture. Moreover, the energy ef­ ficiency of the conversion process drastically increases from 27.9 to 45.4%, and the energy cost significantly drops from 41.9 to 25.4 kJ.L− 1. We also present the temperature as a function of distance from the reactor outlet, as well as the CO2, CO and O2 concentrations and the temperature in the carbon bed as a function of time, which is important for understanding the underlying mechanisms. Indeed, these time-resolved measurements reveal that the initial enhancements in CO2 conversion and in CO concentration are not maintained in our current setup. Therefore, we present a model to study the gasification of carbon with different feed gases (i.e., O2, CO and CO2 separately), from which we can conclude that the oxygen coverage at the surface plays a key role in determining the product composition and the rate of carbon consumption. Indeed, our model insights indicate that the drop in CO2 conversion and in CO concentration after a few minutes is attributed to deactivation of the carbon bed, due to rapid formation of oxygen complexes at the surface.