Chimia最新文献

Food and beverage production generates enormous amounts of spent residues in the form of pomaces, pulps, grains, skins, seeds, etc. Although these sidestreams remain nutritious, their conversion to foods can be complicated by issues of digestibility and processing, particularly when the residues are wet and therefore highly susceptible to microbial degradation. Ideally, these sidestreams could be stabilized and then re-circulated into food, instead of being diverted to waste, animal feed, or biofuels. Indeed, the end-of-life of our food crops is increasingly important to consider in the context of circularity, ensuring that land, water, and chemical inputs to agriculture are sustainable. In the context of wet byproducts from the food industry, we discuss two separate case studies that look at how to valorize and extend the longevity of nutritionally-rich but underutilized sidestreams. The first study examines the fermentation of okara into an edible tempeh-like cake, while the second investigates ProSeed's approach to drying and valorizing brewer's spent grain. We conclude with some words on the nuance and challenges involved in saving from waste the highly perishable but nutritious side products of current food and beverage production.

In this article, we provide an overview of hydrogen storage materials, taking our previous results as examples. Towards the end of the paper, we present a case study in order to highlight the effects of substitutional alloying, compositional additives, and nanostructuring on the hydrogen sorption properties of magnesium-based intermetallics. Specifically, partial substitution of Mg by Li and d-elements by p-elements leads to structural changes, inducing disorder and the formation of high-entropy alloys. Our approach showcases the methodology to enhance the H2-capacity and to provide a positive boost to the H2-storage performance, including lower temperatures of H2 desorption, better thermodynamics and kinetics, lower temperatures of hydrogen uptake/ release for Metal-Hydride Hydrogen Storage (MHHS) systems and higher capacity of anodes for Metal-Hydride batteries (MHB) together with lower prices of raw materials.

Atmospheric aerosols can be emitted directly as particles or formed in the atmosphere from phase transitions of gaseous compounds with low enough vapor pressure. During their lifecycle in the atmosphere, aerosols undergo multiphase changes, altering chemical composition, reactivity, physical and optical properties, ultimately influencing how they impact climate, human health and ecosystems. The understanding of the chemical processes in the atmosphere is crucial to assess these effects. Here we provide a brief overview on relevant aerosol chemical processes and measurement techniques with no claim to completeness and describe the Swiss contribution to the European infrastructure ACTRIS for long-term monitoring and its relevance for the research field.

Arctic coasts cover more than 101,000 km and emulsify terrestrial, marine and socio-economic ecosystems. All three components produce specific emissions that contribute to the mix of atmospheric constituents, which are processed and dispersed in the coastal atmosphere to contribute to cloud formation through cloud condensation nuclei and ice nucleating particles. Clouds strongly influence the coastal energy balance. Importantly, Arctic coastal ecosystems are exposed to multiple pressures such as the warming atmosphere and ocean, the thawing cryosphere and the expanding anthropogenic activities. This means that coastal emissions and atmospheric processes are in constant evolution. Given the large area covered by coasts and the mix of emission sources, coastal aerosol processes deserve quantification to better understand their role in accelerated Arctic climate change.

Ammonia (NH3) is an important atmospheric pollutant due to its contribution to secondary inorganic aerosol formation and its deposition and impacts on (semi-)natural ecosystems. Therefore various efforts have been made to limit emissions to the atmosphere. The predominant emission source in Switzerland is livestock agriculture, wherein NH3 is volatilised from ammonium contained in animal manure. While modelled NH3 emissions based on agricultural activity data indicate a minor decrease since 2000, concentration measurements do not reflect this trend. This can at least partly be attributed to a decline in the transformation of NH3 to particulate ammonium due to significantly decreased emission of oxidised nitrogen and sulfur compounds in the past decade. The partitioning between the gaseous and the particulate phase also determines the deposition pathway (dry or wet deposition) and thus the average lifetime and transport distance in the atmosphere. Gaseous NH3 is subject to fast dry deposition and is deposited preferentially to ecosystems close to the source. Once deposited into an ecosystem, NH3 leads to eutrophication and acidification of water and soils, which change the plant community composition and microbial functioning, especially in N-sensitive ecosystems. Although NH3 can also cause direct toxicity to plants, assessments of ecosystem impacts are generally collated using the critical load approach, which includes the input of all N compounds. These reveal that in 2020, 87% of forests, 94% of raised bogs, 74% of fens, and 42% of dry mountain grasslands likely experienced adverse impacts from N exceedances in Switzerland. To improve this situation, considerable NH3 emission abatement efforts are needed in the future.

Particulate Matter (PM) is the most toxic component in polluted air causing over 6 million deaths per year worldwide according to World Health Organisation estimates. Due to the highly complex composition of PM in the atmosphere, with thousands of inorganic and especially organic components, it is unknown which particle sources are responsible for their toxicity. In recent years it emerged that overall oxidising particle properties might directly link particle composition with health effects. This review summarises contributions of Swiss research groups to the chemical and biological characterisation of PM oxidising properties and identification of biological responses such as oxidative stress due to PM exposure.

Awareness of atmospheric air quality in Switzerland became a concern in the 1960s, as a result of which the Swiss National Air Pollution Monitoring Network (Nationales Beobachtungsnetz für Luftfremdstoffe - NABEL) was created in the 1970s. This paper describes the establishment and evolution of NABEL, emphasizing its important role in monitoring air quality in Switzerland, and its contribution to international observation networks and research. The network's history, legal framework, and measurement program are described, and exemplary time-series of air quality parameters are given. NABEL is an excellent example for reliable, long-term air quality monitoring and demonstrates the importance of such monitoring for air pollution control at both national and international levels.

Atmospheric aerosol particles contribute to over four million premature deaths annually and play a critical role in modulating Earth's climate. Most atmospheric particles and more than 50% of the cloud condensation nuclei are formed through a secondary process named new particle formation involving unique precursor vapors. This article summarizes current knowledge of how new atmospheric particles form, based on experiments at the CERN CLOUD chamber. While the role of sulfuric acid has long been known, other vapors like highly oxygenated organic molecules and iodine oxoacids are also important, along with stabilizers like ammonia, amines, and ions from cosmic rays. We explain how findings from CLOUD experiments help us understand particle formation in various atmospheric conditions and improve air quality and climate models.

Earth's atmosphere comprises a complex mix of gas and condensed phases, where condensed phases facilitate multiphase chemical reactions that would not occur in the gas phase alone. These reactions drive dynamic physical and chemical processes across various spatial and temporal scales, playing a crucial role in the cycling of atmospheric trace constituents. Multiphase chemistry significantly influences geochemical cycles, human health, and climate. This review focuses on the chemical steps governing the cycling of important species, such as halogens, reactive nitrogen, and organics, within aerosol particles, a key type of atmospheric condensed phases, and at condensed phase-air interfaces. These interfaces include mineral oxides, ice, and aqueous solutions found in particulate matter, clouds, snow, and on oceanic and terrestrial surfaces. This review also discusses the important role of redox chemical cycling, the hydrogen bonding network and water activity in these processes.