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Inhalt: - Was ist das Problem? – Politikverdrossenheit und Entfremdung zwischen Bürger und Staat - Warum mehr Partizipation? – Eine kommunitaristische Diagnose - Warum reicht politische Partizipation nicht aus? – Das Beispiel der Bürgerkommune - Wo können sich Bürger als Koproduzenten beteiligen? – Lehren aus dem Neuen Steuerungsmodell - Wie kann bürgerschaftliche Koproduktion gesteuertwerden? – Die neuen Möglichkeiten des Internets - Fazit
Die Freiheit des Geldes
(2012)
Was wird unter „nachhaltiger Prävention“ in der Präventionsforschung verstanden? Welche guten Beispiele für nachhaltige Prävention gibt es in der Praxis? Und v. a.: Wie lässt sich Prävention in den verschiedenen Bereichen wie Kriminalität, Gewalt und Rechtsextremismus nachhaltig gestalten? Diesen Fragen will der vorliegende Sammelband nachgehen und damit der Präventionsdebatte neue Impulse verleihen. Der Band will insbesondere die nationale sowie internationale Fachdebatte konstruktiv aufgreifen, Theorie und Praxis verbinden, „good practice“ Beispiele darstellen sowie Perspektiven nachhaltiger Prävention aufzeigen. Mit diesem Themenspektrum richtet er sich sowohl an die Wissenschaft als auch an die Praxis sowie insgesamt an eine interessierte Öffentlichkeit.
Diverse Entwicklungen der letzten Jahrzehnte zeigten die Relevanz am Diskurs um eine sogenannte „nachhaltige Entwicklung“ auf. Nachhaltiger Entwicklung wird dabei eine immer größere Bedeutung zugesprochen und zudem wird die Bildung als eine der wichtigsten Kräfte, um eine nachhaltige Entwicklung voranzutreiben, angesehen. Im Rahmen der Bachelorarbeit soll deshalb untersucht werden, welches Verständnis Schülerinnen und Schüler vom Begriff Nachhaltigkeit haben. Zunächst wird der theoretische Hintergrund zu nachhaltiger Entwicklung und einer „Bildung für nachhaltige Entwicklung“ geklärt. Auf Basis dieser theoretischen Fundierung wird dann ein leitfadengestütztes Interview entwickelt. Aus den Ergebnissen sollen unter Verwendung der zusammenfassenden Inhaltsanalyse nach Mayring Rückschlüsse über das Verständnis der Schüler*innen gezogen werden. Auf der Basis der Ergebnisse und Interpretationen sollen abschließend Überlegungen gemacht werden, wie das Verständnis der Schüler*innen erweitert werden kann. Im Rahmen der Untersuchung wurden schließlich sechs Schülerinnen und Schüler der Jahrgangsstufe zehn einer Gesamtschule mit einem Interview befragt. Es wurde festgestellt, dass ein Verständnis von Nachhaltigkeit nur bei vier der sechs Befragten vorhanden war und auch dort größtenteils in Bezug auf ökologische und soziale Aspekte. Dabei konnten das persönliche Interesse, der Lebensweltbezug, und auch der Unterricht als Grund für beide Seiten ausgemacht werden.
Air pollution has been a persistent global problem in the past several hundred years. While some industrialized nations have shown improvements in their air quality through stricter regulation, others have experienced declines as they rapidly industrialize. The WHO’s 2021 update of their recommended air pollution limit values reflects the substantial impacts on human health of pollutants such as NO2 and O3, as recent epidemiological evidence suggests substantial long-term health impacts of air pollution even at low concentrations. Alongside developments in our understanding of air pollution's health impacts, the new technology of low-cost sensors (LCS) has been taken up by both academia and industry as a new method for measuring air pollution. Due primarily to their lower cost and smaller size, they can be used in a variety of different applications, including in the development of higher resolution measurement networks, in source identification, and in measurements of air pollution exposure. While significant efforts have been made to accurately calibrate LCS with reference instrumentation and various statistical models, accuracy and precision remain limited by variable sensor sensitivity. Furthermore, standard procedures for calibration still do not exist and most proprietary calibration algorithms are black-box, inaccessible to the public. This work seeks to expand the knowledge base on LCS in several different ways: 1) by developing an open-source calibration methodology; 2) by deploying LCS at high spatial resolution in urban environments to test their capability in measuring microscale changes in urban air pollution; 3) by connecting LCS deployments with the implementation of local mobility policies to provide policy advice on resultant changes in air quality.
In a first step, it was found that LCS can be consistently calibrated with good performance against reference instrumentation using seven general steps: 1) assessing raw data distribution, 2) cleaning data, 3) flagging data, 4) model selection and tuning, 5) model validation, 6) exporting final predictions, and 7) calculating associated uncertainty. By emphasizing the need for consistent reporting of details at each step, most crucially on model selection, validation, and performance, this work pushed forward with the effort towards standardization of calibration methodologies. In addition, with the open-source publication of code and data for the seven-step methodology, advances were made towards reforming the largely black-box nature of LCS calibrations.
With a transparent and reliable calibration methodology established, LCS were then deployed in various street canyons between 2017 and 2020. Using two types of LCS, metal oxide (MOS) and electrochemical (EC), their performance in capturing expected patterns of urban NO2 and O3 pollution was evaluated. Results showed that calibrated concentrations from MOS and EC sensors matched general diurnal patterns in NO2 and O3 pollution measured using reference instruments. While MOS proved to be unreliable for discerning differences among measured locations within the urban environment, the concentrations measured with calibrated EC sensors matched expectations from modelling studies on NO2 and O3 pollution distribution in street canyons. As such, it was concluded that LCS are appropriate for measuring urban air quality, including for assisting urban-scale air pollution model development, and can reveal new insights into air pollution in urban environments.
To achieve the last goal of this work, two measurement campaigns were conducted in connection with the implementation of three mobility policies in Berlin. The first involved the construction of a pop-up bike lane on Kottbusser Damm in response to the COVID-19 pandemic, the second surrounded the temporary implementation of a community space on Böckhstrasse, and the last was focused on the closure of a portion of Friedrichstrasse to all motorized traffic. In all cases, measurements of NO2 were collected before and after the measure was implemented to assess changes in air quality resultant from these policies. Results from the Kottbusser Damm experiment showed that the bike-lane reduced NO2 concentrations that cyclists were exposed to by 22 ± 19%. On Friedrichstrasse, the street closure reduced NO2 concentrations to the level of the urban background without worsening the air quality on side streets. These valuable results were communicated swiftly to partners in the city administration responsible for evaluating the policies’ success and future, highlighting the ability of LCS to provide policy-relevant results.
As a new technology, much is still to be learned about LCS and their value to academic research in the atmospheric sciences. Nevertheless, this work has advanced the state of the art in several ways. First, it contributed a novel open-source calibration methodology that can be used by a LCS end-users for various air pollutants. Second, it strengthened the evidence base on the reliability of LCS for measuring urban air quality, finding through novel deployments in street canyons that LCS can be used at high spatial resolution to understand microscale air pollution dynamics. Last, it is the first of its kind to connect LCS measurements directly with mobility policies to understand their influences on local air quality, resulting in policy-relevant findings valuable for decisionmakers. It serves as an example of the potential for LCS to expand our understanding of air pollution at various scales, as well as their ability to serve as valuable tools in transdisciplinary research.
Wir schrumpfen!
(2012)
1. Einleitung
2. Wer definiert die Gewalt?
3. Gewalt als Beziehungstat
4. Schulkultur und Gewaltprävention
5. Ebenen der Gewaltprävention in der Schule
6. Gewaltprävention und Schulentwicklung
7. Gewaltprävention und pädagogisches Handeln
8. Gewaltprävention und außerschulische Aktivitäten
9. Zusammenfassung
Anlage: Vorschlag für ein Szenario zum Thema: Gewaltprävention und Schulentwicklung
Literatur
1. Eine kritische Vorbemerkung zum Thema Nachhaltigkeit
2. Gewalt ist alltäglich – aber …
3. Was macht nun Gewaltprävention an Schulen nachhaltig?
4. Schulische Prävention in Brandenburg
5. Was verhindert Nachhaltigkeit in der Präventionsarbeit?
6. Die Prävention von Rechtsextremismus und Rassismus in Brandenburg – Was kann Gewaltprävention davon lernen?
LiteraturAlfred
Anthropogenic activities have transformed the Earth's environment, not only on local level, but on the planetary-scale causing global change. Besides industrialization, agriculture is a major driver of global change. This change in turn impairs the agriculture sector, reducing crop yields namely due to soil degradation, water scarcity, and climate change. However, this is a more complex issue than it appears. Crop yields can be increased by use of agrochemicals and fertilizers which are mainly produced by fossil energy. This is important to meet the increasing food demand driven by global demographic change, which is further accelerated by changes in regional lifestyles. In this dissertation, we attempt to address this complex problem exploring agricultural potential globally but on a local scale. For this, we considered the influence of lifestyle changes (dietary patterns) as well as technological progress and their effects on climate change, mainly greenhouse gas (GHG) emissions. Furthermore, we examined options for optimizing crop yields in the current cultivated land with the current cropping patterns by closing yield gaps. Using this, we investigated in a five-minute resolution the extent to which food demand can be met locally, and/or by regional and/or global trade. Globally, food consumption habits are shifting towards calorie rich diets. Due to dietary shifts combined with population growth, the global food demand is expected to increase by 60-110% between 2005 and 2050. Hence, one of the challenges to global sustainability is to meet the growing food demand, while at the same time, reducing agricultural inputs and environmental consequences. In order to address the above problem, we used several freely available datasets and applied multiple interconnected analytical approaches that include artificial neural network, scenario analysis, data aggregation and harmonization, downscaling algorithm, and cross-scale analysis.
Globally, we identified sixteen dietary patterns between 1961 and 2007 with food intakes ranging from 1,870 to 3,400 kcal/cap/day. These dietary patterns also reflected changing dietary habits to meat rich diets worldwide. Due to the large share of animal products, very high calorie diets that are common in the developed world, exhibit high total per capita emissions of 3.7-6.1 kg CO2eq./day. This is higher than total per capita emissions of 1.4-4.5 kg CO2eq./day associated with low and moderate calorie diets that are common in developing countries. Currently, 40% of the global crop calories are fed to livestock and the feed calorie use is four times the produced animal calories. However, these values vary from less than 1 kcal to greater 10 kcal around the world. On the local and national scale, we found that the local and national food production could meet demand of 1.9 and 4.4 billion people in 2000, respectively. However, 1 billion people from Asia and Africa require intercontinental agricultural trade to meet their food demand. Nevertheless, these regions can become food self-sufficient by closing yield gaps that require location specific inputs and agricultural management strategies. Such strategies include: fertilizers, pesticides, soil and land improvement, management targeted on mitigating climate induced yield variability, and improving market accessibility. However, closing yield gaps in particular requires global N-fertilizer application to increase by 45-73%, P2O5 by 22-46%, and K2O by 2-3 times compare to 2010. Considering population growth, we found that the global agricultural GHG emissions will approach 7 Gt CO2eq./yr by 2050, while the global livestock feed demand will remain similar to 2000. This changes tremendously when diet shifts are also taken into account, resulting in GHG emissions of 20 Gt CO2eq./yr and an increase of 1.3 times in the crop-based feed demand between 2000 and 2050. However, when population growth, diet shifts, and technological progress by 2050 were considered, GHG emissions can be reduced to 14 Gt CO2eq./yr and the feed demand to nearly 1.8 times compare to that in 2000. Additionally, our findings shows that based on the progress made in closing yield gaps, the number of people depending on international trade can vary between 1.5 and 6 billion by 2050. In medium term, this requires additional fossil energy. Furthermore, climate change, affecting crop yields, will increase the need for international agricultural trade by 4% to 16%.
In summary, three general conclusions are drawn from this dissertation. First, changing dietary patterns will significantly increase crop demand, agricultural GHG emissions, and international food trade in the future when compared to population growth only. Second, such increments can be reduced by technology transfer and technological progress that will enhance crop yields, decrease agricultural emission intensities, and increase livestock feed conversion efficiencies. Moreover, international trade dependency can be lowered by consuming local and regional food products, by producing diverse types of food, and by closing yield gaps. Third, location specific inputs and management options are required to close yield gaps. Sustainability of such inputs and management largely depends on which options are chosen and how they are implemented. However, while every cultivated land may not need to attain its potential yields to enable food security, closing yield gaps only may not be enough to achieve food self-sufficiency in some regions. Hence, a combination of sustainable implementations of agricultural intensification, expansion, and trade as well as shifting dietary habits towards a lower share of animal products is required to feed the growing population.
Was isst die Zukunft?
(2012)
Inhalt - Gegenwärtige Situation und Prognosen für den Zugang zu Nahrung: Globale Fleisch- und Getreideverteilung - Chronische Unterernährung und steigender Nahrungspreis - Zukunftsmodell 1: »land grabbing« - Zukunftsmodell 2: Insekten essen - Zukunftsmodell 3: »Vertical Farming« - Zukunftsmodell 4: Verringerung von Essensverschwendung
1. Einführung
2. Kriminalität, Gewalt und Rechtsextremismus: Begriffsgenese und Modell „nachhaltiger Prävention“
2.1 Entwicklungsorientierung
2.2 Kommunale Netzwerkarbeit
2.3 Evaluation und Qualität
3. Kriminal- und Gewaltprävention im Land Brandenburg
3.1 Gewaltprävention an einer Brennpunkt-Schule am Beispiel von „Wir für uns“
3.2 Regionale Netzwerkarbeit am Beispiel von „Mit-Ein-Ander in Kita und Schule“
3.3 Rechtsextremismusprävention am Beispiel des Handlungskonzepts „Tolerantes Brandenburg“
4. Folgerungen und Empfehlungen
Literatur
Fünf Finger hat die Hand …
(2012)
Recycling
(2012)
Mehr Demokratie wagen!
(2012)
Umweltschutz und nachhaltige Lebensweise sind die globalen Herausforderungen der heutigen Zeit. Diese Arbeit wird zu den derzeit geführten Debatten einen Beitrag aus altsprachlicher Perspektive leisten, indem sie das Thema Holzwirtschaft in den Blick nimmt und dem Lateinunterricht zugänglich macht. Dabei geht die Autorin auf die antike Forstwirtschaft ein, beleuchtet den vielfältigen Einsatz der Ressource Holz und vergleicht die damals herrschenden Vorstellungen vom Nachwachsen natürlicher Rohstoffe mit dem heutigen Kenntnisstand.
Digitalisation in industry – also called “Industry 4.0” – is seen by numerous actors as an opportunity to reduce the environmental impact of the industrial sector. The scientific assessments of the effects of digitalisation in industry on environmental sustainability, however, are ambivalent. This cumulative dissertation uses three empirical studies to examine the expected and observed effects of digitalisation in industry on environmental sustainability. The aim of this dissertation is to identify opportunities and risks of digitalisation at different system levels and to derive options for action in politics and industry for a more sustainable design of digitalisation in industry. I use an interdisciplinary, socio-technical approach and look at selected countries of the Global South (Study 1) and the example of China (all studies). In the first study (section 2, joint work with Marcel Matthess), I use qualitative content analysis to examine digital and industrial policies from seven different countries in Africa and Asia for expectations regarding the impact of digitalisation on sustainability and compare these with the potentials of digitalisation for sustainability in the respective country contexts. The analysis reveals that the documents express a wide range of vague expectations that relate more to positive indirect impacts of information and communication technology (ICT) use, such as improved energy efficiency and resource management, and less to negative direct impacts of ICT, such as electricity consumption through ICT. In the second study (section 3, joint work with Marcel Matthess, Grischa Beier and Bing Xue), I conduct and analyse interviews with 18 industry representatives of the electronics industry from Europe, Japan and China on digitalisation measures in supply chains using qualitative content analysis. I find that while there are positive expectations regarding the effects of digital technologies on supply chain sustainability, their actual use and observable effects are still limited. Interview partners can only provide few examples from their own companies which show that sustainability goals have already been pursued through digitalisation of the supply chain or where sustainability effects, such as resource savings, have been demonstrably achieved. In the third study (section 4, joint work with Peter Neuhäusler, Melissa Dachrodt and Marcel Matthess), I conduct an econometric panel data analysis. I examine the relationship between the degree of Industry 4.0, energy consumption and energy intensity in ten manufacturing sectors in China between 2006 and 2019. The results suggest that overall, there is no significant relationship between the degree of Industry 4.0 and energy consumption or energy intensity in manufacturing sectors in China. However, differences can be found in subgroups of sectors. I find a negative correlation of Industry 4.0 and energy intensity in highly digitalised sectors, indicating an efficiency-enhancing effect of Industry 4.0 in these sectors. On the other hand, there is a positive correlation of Industry 4.0 and energy consumption for sectors with low energy consumption, which could be explained by the fact that digitalisation, such as the automation of previously mainly labour-intensive sectors, requires energy and also induces growth effects. In the discussion section (section 6) of this dissertation, I use the classification scheme of the three levels macro, meso and micro, as well as of direct and indirect environmental effects to classify the empirical observations into opportunities and risks, for example, with regard to the probability of rebound effects of digitalisation at the three levels. I link the investigated actor perspectives (policy makers, industry representatives), statistical data and additional literature across the system levels and consider political economy aspects to suggest fields of action for more sustainable (digitalised) industries. The dissertation thus makes two overarching contributions to the academic and societal discourse. First, my three empirical studies expand the limited state of research at the interface between digitalisation in industry and sustainability, especially by considering selected countries in the Global South and the example of China. Secondly, exploring the topic through data and methods from different disciplinary contexts and taking a socio-technical point of view, enables an analysis of (path) dependencies, uncertainties, and interactions in the socio-technical system across different system levels, which have often not been sufficiently considered in previous studies. The dissertation thus aims to create a scientifically and practically relevant knowledge basis for a value-guided, sustainability-oriented design of digitalisation in industry.
1. Einleitung
2. Präventionspraxis und -forschung
3. Qualitätskriterien für die Beschaffenheit von Präventionsarbeit bzw. gezielter Präventionsprojekte
4. Selbstevaluation des Projekts „Eltern-Medien-Beratung“ der Aktion Kinder- und Jugendschutz Brandenburg e. V. (AKJS)
4.1 Problemanalyse und Zielbestimmung
4.2 Zielgruppen und Methodenwahl
4.3 Ausgewählte Ergebnisse der Selbstevaluation zur Zufriedenheit der Beteiligten mit den Veranstaltungen sowie zur Wirksamkeit
5. Anforderungen an die Evaluation von Präventionsprojekten und deren Realisierung im Praxisalltag
Literatur
"Tolerantes Brandenburg"
(2014)
1. Einleitung
2. Kriminalitätsprävention und Rechtsextremismusprävention
3. Ausgewählte Strukturelemente des Kooperationsverbundes TBB
3.1 Aufgabendefinition zwischen Rechtsextremismusbekämpfung und Demokratieförderung
3.2 Status der landesweiten Zentralstelle
3.3 Ressortübergreifende Aufgaben im Verhältnis zu den Fachressorts
3.4 Vernetzung und Hierarchie
3.5 Verhältnis zur Zivilgesellschaft
3.6 Evaluation
4. Fazit
1. Einleitung: … Prozesse nachhaltig gestalten?
2. Konzeptioneller Ansatz: Positive Entwicklung junger Menschen fördern
3. Impulse des DFK zur Weiterentwicklung der Gewaltprävention in Deutschland im Zeitraum 2001 bis 2011
3.1 Projekt „Primäre Prävention von Gewalt gegen Gruppenangehörige“ (2001–2006)
3.2 Unterrichtung der Ministerpräsidentenkonferenz über den Stand der Gewaltprävention sowie über zentrale Handlungserfordernisse zu ihrer nachhaltigen Gestaltung (2003–2006)
3.3 Bericht des Deutschen Jugendinstituts (DJI): Strategien der Gewaltprävention im Kindes und Jugendalter – Eine Zwischenbilanz in sechs Handlungsfeldern (2007)
3.4 Expertise „Gelingensbedingungen für die Prävention von interpersonaler Gewalt im Kindes- und Jugendalter“ (2008)
3.5 Förderung der Evaluation gewaltpräventiver Programme (seit 2009)
3.6 Kooperationsprojekt von Deutscher Bahn AG (DB), DFK und FU Berlin zur Verbreitung entwicklungsorientierter Programme (seit 2010)
3.7 Wissensmanagement zu Entwicklungsförderung und Gewaltprävention (seit 2008)
4. DFK-Projekt „Entwicklungsförderung und Gewaltprävention für jungen Menschen (E & G)“ (seit 2011)
4.1 DFK Sachverständigenrat und Leitfaden „Entwicklungsförderung und Gewaltprävention für junge Menschen“ (2012/2013)
4.2 Weitführenden Perspektiven: Memorandum „Qualität, Struktur und Kooperation fördern“ (2013)
4.3 Projektfortsetzung und Webportal „wegweiser prävention“ (2014)
5. Fazit: … und am Ende nachhaltige Prozesse?
Literatur
Nachhaltige Grundsicherung
(2015)
»Human Security«
(2012)
Hat Alexander von Humboldt vor den dramatischen Folgen des vom Menschen verursachten Klimawandels gewarnt? Ausgehend von dieser Frage befasst sich der Beitrag mit seinen Klimastudien und zeigt dabei, welch enorme Wirkung diese für viele Länder der Welt hatten. Zahlreiche Aufforstungsmaßnahmen wurden im 19. Jahrhundert durch Humboldts Studien angeregt. Humboldt hat zudem – wohl als erster – die klimaverändernde Wirkung von „großen Dampf- und Gasmassen an den Mittelpunkten der Industrie“ erkannt und außerdem im 3. Band des Kosmos auch den Treibhauseffekt beschrieben. Die Bedrohungen des stetig zunehmenden anthropogenen Klimawandels jedoch konnte er nicht ahnen. Seine und auch die Erkenntnisse der anderen Klimaforscher des 19. Jhds. gerieten Anfang des 20. Jhds. in Vergessenheit. Der gerissene Rezeptionsfaden wurde erst mit der Umweltbewegung in den 1970er Jahren wieder aufgenommen und Alexander von Humboldt als Klimaforscher und „erster Ökologe“ neu bewertet.
Einführung
(2015)
Seit dem UN-Gipfel 1992 in Rio de Janeiro ist die Aufmerksamkeit in Politik und Öffentlichkeit für das Thema „Nachhaltigkeit“ gestiegen. In fast allen Ländern dieser Welt wurden Programme und Maßnahmen zum Schutz und Erhalt der Umwelt und der sozialen Lebensbedingungen umgesetzt. Trotz beachtenswerter Fortschritte sind die bisherigen Effekte jedoch völlig unzureichend. Umso interessanter ist daher der Blick auf einen erfolgreichen Akteur im Bereich der Umwelt- und Nachhaltigkeitspolitik: Kuba. Über diese Erfahrungen des Karibik-Staates wird im deutschen Sprachraum kaum berichtet. Die Autoren leisten hierzu mit ihrer Studie einen Beitrag und analysieren die entsprechenden Politiken, Strategien und Maßnahmen, die in Kuba trotz vielfältiger Probleme zu einer gelungenen Nachhaltigkeitspolitik geführt haben.
1. Notwendigkeit nachhaltiger Kriminalprävention
2. Das 1. Jugendgerichtsgesetz (JGGÄndG) 1990
3. Das 2. JGGÄndG 2008
4. Nationale Entwicklungen
5. Internationale Entwicklungen
5.1 Prävention in Europa
5.2 Jugendkriminalprävention im europäischen Vergleich
5.2.1 European Crime Prevention Network (EUCPN)
5.2.2 WHO-Bericht zur Jugendgewaltprävention in Europa (2010)
5.3 Jugendkriminalprävention USA
5.4 Reformbestrebungen, Präventionskoordination und -initiativen in den USA
6. Implementationswissenschaft: Effekte durch Einführung nachgewiesen wirksamer Programme
7. Ausblick
Literatur
Die "Grüne Liste Prävention"
(2014)
Tiger, Regenwald, Sprache
(2012)
Inhalt: - Verschiedene Dimensionen der Nachhaltigkeit - Das Gemeinsame der verschiedenen Dimensionen - Das Streben nach einem besseren Verständnis der Welt - Nachhaltigkeit - Ein allgemeines Modell der Nachhaltigkeit: Das »Existenzraum-Modell« - Das Metasystem Erde - Die Zukunftsfähigkeit der Gesellschaft
The need to reduce humankind reliance on fossil fuels by exploiting sustainably the planet renewable resources is a major driving force determining the focus of modern material research. For this reason great interest is nowadays focused on finding alternatives to fossil fuels derived products/materials. For the short term the most promising substitute is undoubtedly biomass, since it is the only renewable and sustainable alternative to fossil fuels as carbon source. As a consequence efforts, aimed at finding new synthetic approaches to convert biomass and its derivatives into carbon-based materials, are constantly increasing. In this regard, hydrothermal carbonisation (HTC) has shown to be an effective means of conversion of biomass-derived precursors into functional carbon materials. However the attempts to convert raw biomass, in particular lignocellulosic one, directly into such products have certainly been rarer. Unlocking the direct use of these raw materials as carbon precursors would definitely be beneficial in terms of HTC sustainability. For this reason, in this thesis the HTC of carbohydrate and protein-rich biomass was systematically investigated, in order to obtain more insights on the potentials of this thermochemical processing technique in relation to the production of functional carbon materials from crude biomass. First a detailed investigation on the HTC conversion mechanism of lignocellulosic biomass and its single components (i.e. cellulose, lignin) was developed based on a comparison with glucose HTC, which was adopted as a reference model. In the glucose case it was demonstrated that varying the HTC temperature allowed tuning the chemical structure of the synthesised carbon materials from a highly cross-linked furan-based structure (T = 180oC) to a carbon framework composed of polyaromatic arene-like domains. When cellulose or lignocellulosic biomass was used as carbon precursor, the furan rich structure could not be isolated at any of the investigated processing conditions. These evidences were indicative of a different HTC conversion mechanism for cellulose, involving reactions that are commonly observed during pyrolytic processes. The evolution of glucose-derived HTC carbon chemical structure upon pyrolysis was also investigated. These studies revealed that upon heat treatment (Investigated temperatures 350 – 900 oC) the furan-based structure was progressively converted into highly curved aromatic pre-graphenic domains. This thermal degradation process was observed to produce an increasingly more hydrophobic surface and considerable microporosity within the HTC carbon structure. In order to introduce porosity in the HTC carbons derived from lignocellulosic biomass, KOH chemical activation was investigated as an HTC post-synthesis functionalisation step. These studies demonstrated that HTC carbons are excellent precursors for the production of highly microporous activated carbons (ACs) and that the porosity development upon KOH chemical activation is dependent on the chemical structure of the HTC carbon, tuned by employing different HTC temperatures. Preliminary testing of the ACs for CO2 capture or high pressure CH4 storage yielded very promising results, since the measured uptakes of both adsorbates (i.e. CO2 and CH4) were comparable to top-performing and commercially available adsorbents, usually employed for these end-applications. The combined use of HTC and KOH chemical activation was also employed to produce highly microporous N-doped ACs from microalgae. The hydrothermal treatment of the microalgae substrate was observed to cause the depletion of the protein and carbohydrate fractions and the near complete loss (i.e. 90%) of the microalgae N-content, as liquid hydrolysis/degradation products. The obtained carbonaceous product showed a predominantly aliphatic character indicating the presence of alkyl chains presumably derived from the lipid fractions. Addition of glucose to the initial reaction mixture was found out to be extremely beneficial, because it allowed the fixation of a higher N amount, in the algae derived HTC carbons (i.e. 60%), and the attainment of higher product yields (50%). Both positive effects were attributed to Maillard type cascade reactions taking place between the monosaccharides and the microalgae derived liquid hydrolysis/degradation products, which were in this way recovered from the liquid phase. KOH chemical activation of the microalgae/glucose mixture derived HTC carbons produced highly microporous N-doped carbons. Although the activation process led to a major reduction of the N-content, the retained N-amount in the ACs was still considerable. These features render these materials ideal candidates for supercapacitors electrodes, since they provide extremely high surface areas, for the formation of electric double-layer, coupled to abundant heteroatom doping (i.e. N and O) necessary to obtain a pseudocapacitance contribution.
Prognosen
(2012)