As of now, the environmental issue is very topical and there is also an underutilization of different biological material where these can be used in ways that are typically not thought of. One way to increase the degree of utilization is to convert various biomasses such as natural rubber, olive pits, wood chips, and reed pellets into biochar. These biochars can then be added to materials, such as polymers, to improve their reaction-to-fire properties with a low impact on the environment. The process to convert biomasses into biochars, takes place through so-called pyrolysis, i.e., heating under high temperatures and low oxygen concentrations. During pyrolysis, the volatile substances in the biomasses are released and a material is left behind where the compounds that can sustain fire are minimal and a carbon skeleton consisting of strong C-C covalent bonds is prevalent. This biochar then has significantly different material properties compared to its corresponding biomass, where one of the differences is its improved reaction-to-fire properties. This study aims to investigate whether it is possible to determine the final reaction-to-fire properties of different biochars based on the corresponding biomass and its chemical composition. The basis of this study consists of a literature review, laboratory experiments and an analysis. The literature review has been carried out to find the chemical composition of the various biomasses, the laboratory experiments has been carried out to obtain the reaction-to-fire properties of said biomasses and biochars, and the analysis to determine the possibility of predicting the final reaction-to-fire properties of various biochars. The results obtained in this study are that despite the unfavorable reaction-to-fire properties of natural rubber, biochar made from natural rubber had the most desirable reaction-to-fire properties (i.e., fire safe). Of the seven parameters assessed for its reaction-to-fire properties, natural rubber performed worst in five of these compared to the remaining biomasses. However, after conversion to biochar, rubber had the best parameters in three out of five cases where the two additional parameters could not be assessed as these are based on the specimen igniting, which they did not. The parameters in which biochar made from natural rubber obtained the best results were peak heat release rate (PHRR), total heat released per unit area (THRPUA), and maximum average rate of heat emission (MARHE). However, biochar made from natural rubber also obtained the worst results in terms of time to peak heat release rate (TTPHRR) and fire growth rate (FIGRA), where FIGRA is inversely proportional to TTPHRR. Although the lignocellulosic biomasses showed difference in their chemical composition, no major difference in PHRR, THRPUA, and MARHE could be detected between them when their corresponding biochars were tested in the cone calorimeter. The conclusions that can be drawn from this study are that it is possible to predict the final reaction-to-fire properties of the lignocellulosic biochars since they react almost equally when exposed to fire. However, more tests and studies are required to be able to predict the final reaction-to-fire properties of the non-lignocellulosic biochars. This is to understand the chemical compounds and bonds that are formed during pyrolysis, as well as how these affect the biochar’s reaction-to-fire properties.

No description available.

Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic compounds with unique properties, including chemical inertness, resistance to many degradation processes and amphiphilic structure. This makes them useful in a range of applications, but also very persistent and bioaccumulative in nature, where PFAS have been linked to adverse health effects in both animals and humans. There are regulations for PFAS, including the REACH regulation and Stockholm Convention, but for now PFAS are monitored individually. This poses a problem since many regulated, long-chain PFAS today are being replaced with unregulated, short-chain homologues with similar hazardous properties.For water remediation of PFAS, a popular and effective sorption technique for their removal is activated carbon (AC), with its close to 100% sorption efficiency. This study focuses on the efficiency of more sustainable materials like bark, steel slag and biochar to sorb eleven different PFAS (PFAS-11) from contaminated water. In this work, contaminated water passed through different constellations of sorbent materials by flow-through experiments, underwent solid-phase extraction (SPE) using a weak anion-exchange (WAX) adsorbent for sample clean-up, and was lastly prepared for analysis using an ultra-performance liquid chromatograph (UPLC) coupled to a quadrupole tandem mass spectrometer (MS/MS).For the different sorbent constellations tested, perfluorooctane sulfonic acid (PFOS) was removed to the highest degree, with an average removal of 70%. When studying the sum of PFAS-11 between the tested sorption constellations, the bark tests sorbed around 20%, the steel slag combinations sorbed between 30-40% and biochar sorbed 43% of the initial PFAS-11 concentration (1 750 ng/L) in the contaminated water. None of these materials achieved an efficient enough sorption to go below the Swedish PFAS-11 drinking water limit value of 90 ng/L, so the results are for the time being suggested more as complementary, low-cost sorption techniques. Further research is recommended to extensively be able to implement more sustainable sorbents with higher sorbing efficiencies.

Graphite has important applications in several key industries, which has been listed as a “criticalraw material” considered to be supply-risk by European since 2020. Purification of engineered graphite is one of the essential processes for the manufacturing of high-quality graphite. In this work, the production process and the existing methods to purify the three major types of graphite are evaluated and compared. Then purification method focusing on acid washing to remove iron from bio-graphite is investigated. The results showed that the impurity removalefficiency of acid washing increases with the increase of temperature, but efficiency decreased because of HCl volatilization when the temperature reaches 100 ℃. High concentrations of hydrochloric acid and other strong acids can improve the ability of acid washing. The smaller the graphite particle size, the more iron impurities are removed. Finally, through multi-steps acid washing with hydrochloric acid and aqua regia at 80 °C, bio-graphite with a purity of 99.67 % was obtained. This meets the requirements of metallurgical electrodes and other applications. The acquisition of ultra-high-purity graphite still needs more further work. / Grafit har viktiga tillämpningar i flera nyckelindustrier, som har listats som en "kritisk råvara" som anses vara en försörjningsrisk av Europa sedan 2020. Rening av teknisk grafit är en av de väsentliga processerna för tillverkning av högkvalitativ grafit. I detta arbete utvärderas och jämförs produktionsprocessen och de befintliga metoderna för att rena de tre huvudtyperna av grafit. Därefter undersöks reningsmetod med fokus på syratvätt för att avlägsna järn från biografit. Resultaten visade att effektiviteten för avlägsnande av föroreningar vid syratvätt ökar med ökningen av temperaturen, men effektiviteten minskade på grund av HCl-förångning när temperaturen når 100 ℃. Höga koncentrationer av saltsyra och andra starka syror kan förbättra förmågan till syratvätt. Ju mindre grafitpartikelstorlek, desto mer järnföroreningar avlägsnas. Slutligen erhölls biografit med en renhet på 99,67 % genom syratvätt i flera steg med saltsyra och aqua regia vid 80 °C. Detta uppfyller kraven för metallurgiska elektroder och andra applikationer. Förvärvet av grafit med ultrahög renhet kräver fortfarande mer arbete.

Demand for high-quality graphite is expected to experience an extraordinary growth rate, in large part due to its wide range of industrial applications such as adsorbents, lubricants, electrodes, etc. This thesis developed a novel sustainable approach to produce green-graphite materials by applying biochar, acarbon-rich valuable by-product obtained from biomass, as a carbon precursor. Meanwhile, iron-based catalysts are applied to enable the graphitization at a relatively lower temperature. This study focuses on the different parameters which could affect the evolution of carbon structure. The samples were mixed with catalyst in two ways, dry mixing and wet impregnation. Aside from the addition method, several parameters including temperature, heating duration, and iron loading amount were varied from 800 to 1300 ℃, 1 to 6 hours, and 0 to 33.6% respectively, to figure out an optimum graphitization process. The samples were characterized by X-ray diffraction, Raman scattering, SEM and particle size distribution analysis. Based on the characterization results, it was confirmed that with the increase of the graphitization temperature, duration and amount of iron loading, synthetic graphite performs a better graphitization and a higher conversion rate. Meanwhile, a detailed dissolution-precipitation mechanism was introduced and discussed in the context of iron-carbon equilibrium phase diagram to explain this catalytic process. / Efterfrågan på högkvalitativ grafit förväntas uppleva en extraordinär tillväxttakt, till stor del på grund av dess breda utbud av industriella applikationer som adsorbenter, smörjmedel, elektroder etc.  Denna avhandling utvecklar ett nytt hållbart tillvägagångssätt för att producera grön-grafit genom att använda biokol, en kolrik värdefull biprodukt erhållen från biomassa, som en kolprekursor. Även järnbaserade katalysatorer används för att möjliggöra grafitisering vid relativt lägre temperaturer. Denna  studie fokuserar på  de olika  parametrar  som  kan  påverka  bildandet  av kolstrukturen. Proverna blandades med katalysatormaterialet på två sätt, torrblandning och våtimpregnering. Förutom tillsatsmetoden justeras flera andra parametrar, inklusive temperatur, uppvärmningstid och mängd järnbelastning för  att  få  en optimal  grafitiseringsprocess.  Proverna karakteriserades därefter genom röntgendiffraktion, Ramanspridning, SEM och  partikelstorleksfördelningsanalys. Baserat på karakteriseringsresultaten bekräftades det att med en ökande grafitiseringstemperatur, varaktighet och mängd av järnbelastning, får syntetisk grafit en bättre grafitisering och en högre omvandlingsgrad. Även en detaljerad upplösnings-utfällningsmekanism introducerades och diskuterades i sammanhanget av järn-kol jämviktsfasdiagrammet  för  att förklara den katalytiska processen.

In order to keep global average temperature below 2°C it is necessary to accelerate climate change mitigation actions and reduce global greenhouse gas emissions. This can be achieved by carbon capture and storage methods such as the production of biochar. Especially its production from municipal sewage sludge could decrease emissions and disposal costs as well as act as a valuable material for different fields of application afterwards. In this quantitative study, the potential for a biochar production system was investigated for the case of the Swedish island, Gotland. Documents and grey literature were reviewed to collect the necessary information and data and experts were asked to fill in information gaps to evaluate the following: Calculate the energy and mass balance of a biochar production system from municipal sewage sludge in 2018, to find possible applications for the produced biochar by investigating the heavy metal content as well as to assess the direct carbon sequestration potential of the produced biochar. The results indicate that in 2018, 540 t of biochar could have been produced with a net heat demand of around 543 MWhth and electricity consumption of 231 MWhel. Heavy metal contents were found to be very high especially for copper and zinc, which means that the produced biochar would only qualify for the EBC-BasicMaterial certification class of the European Biochar Certificate. The annual carbon sequestration potential resulted in 97.2 t of carbon stored in the material or 356.4 t of CO2 emissions saved. Further research needs to be conducted on economic factors of a biochar production system from municipal sewage sludge.

Biochar can reduce the amount of CO2 in the atmosphere and is acknowledged as one feasible technology for negative carbon emissions. The stability of carbon in biochar is of major importance for the carbon sequestration value. A method for confident estimation of the stability is needed to make efficient priorities for the climate. The aim of this study is to identify the best available method that can be used to indicate the stability and quantify the carbon sequestration potential of biochar. The result builds on a literature review of the current state of scientific knowledge and the proposed method is tested with data from previous studies and then applied to the case of Stockholm Exergi. Biochar has a stable carbon structure, always more recalcitrant than the biomass that it derives from. However, estimations of how stable the carbon are varying a lot in the literature. Biochar is not unambiguously defined, there is rather a range of materials with different stability and the degradationis context dependent. Further discrepancy in the estimated stability derives from different experimental design and approaches to modeling the data. There is a challenge to do a proper estimation of the actual degradation, due to the long time perspective and the complexity of observation of behavior in a naturalsystem. A functional method to indicate the stability of carbon in biochar is needed because a biochar producer cannot conduct a long term trial to prove the carbon sequestration potential. Several methods have in theory the ability to indicate stability. However, the H/Corg model with the expression BC+100 emerging to be the best suited method due to its connection to measured degradation, accessibility and acceptance. The H/Corg model could be further improved by calibration and validation by collecting existing data from previous assessments. Communication of the carbon sequestration after hundred years compared to other carbon sinks should be improved to better reflect the long term carbon sequestration value of biochar. Stockholm Exergi is planning for a biochar production of 5 000 ton/year. The H/Corg method estimate that this corresponds to 9 000 – 11 500 ton CO2 per year, stable for at least hundred years. The widerange in the result derives from the different interpretations on the H/Corg method, where the different interpretations derive from the variation that previous research result shows. This is an incentive to support further development of the method. The sequestered carbon in biochar must be protected in its application to ensure the carbon sink in a trade system. Biochar in soil, green areas and concrete face the risk of being dis/re-located. However, that is not a threat to the carbon sequestration value. Biochar and biochar in a soil product sold in bags cannot account for the biochar sequestration value detached from the product, because of the risk of incineration. The future development of biochar stability assessment should in a short term assemble the existing knowledge of conducted trials and use that with knowledge of what approaches that best corresponds to the real stability of biochar. This could decrease the observed variations in the stability assessments and be used to calibrate and validate methods that could indicate stability. In the long perspective field trials and incubation trials should be done in a standardized way to assess the degradation, designed according to best practice with long trial times and consciously extrapolated data. / Biokol kan minska halten av CO2 i atmosfären och är identifierad som en möjlig teknologi för negativa CO2 utsläpp. Biokolets stabilitet har stor betydelse för dess potential. Målet med denna studie är att identifiera den bästa tillgängliga metoden för att indikera kolets stabilitet. Resultatet bygger på en litteraturgenomgång av befintligt kunskapsläge. Den föreslagna metoden testas med biokolsdata ifrån tidigare gjorda mätningar. Kolinbindningspotentialen i Stockholm Exergi’s biokolsprojekt beräknas genom att applicera metoden på förväntad biokolsproduktion. Biokol har en stabil kolstruktur, alltid mer stabil än den biomassa den härstammar ifrån. Uppskattningar av hur stabilt biokol är varierar mycket i litteraturen. Biokol är inte entydigt definierat utan är ett spann av olika material och dessutom är stabiliteten kontext beroende. Ytterligare variationer härstammar ifrån varierande experimentdesign och olika metoder som används för extrapolation av mätdata. För att beräkna kolinbindning i biokol som produceras behövs en metod som kan visa hur stabilt kolet är.Mätmetoden är resurskrävande och därför behövs istället ett samband mellan kolets innehåll/struktur och uppvisad stabilitet som kan användas i kombination med en enklare analys av det producerade biokolet för att indikera stabilitet. I teorin finns det många metoder som kan vara funktionella men enligt denna studie är H/Corg metoden i kombination med BC+100 index mest lämpligt att använda pågrund av metodens uppvisade koppling till uppmätt stabilitet, tillgänglighet och acceptans. Stockholm Exergi planerar för en biokolsproduktion på 5000 ton/år och H/Corg metoden uppskattar att detta årligen motsvarar 9 000 – 11 500 ton CO2 stabilt i minst 100 år. Spannet som resultatet uppvisar beror av den variation av uppskattad stabilitet i litteraturen och är ett incitament för att stödja en vidareutveckling av metoden. I applikationen av biokol måste kolsänkan skyddas för att kunna ingå i ett handelssystem. För biokol till jordförbättring, grönområden i staden samt biokol i betong föreligger en möjlighet att biokolet blir omflyttat eller förloras ifrån den ursprungliga applikationen, detta medför dock inte att kolsänkan går förlorad och är därför inte ett problem för värdet av kolsänkan. Däremot bör värdet av kolsänkan av biokol som säljs i konsumentförpackningar inte frikopplas ifrån biokolsprodukten eftersom det då saknas kontroll över att kolet inte bränns. Vidare studier av stabilitet av biokol bör på kort sikt innefatta insamling av befintlig data ifrån genomförda försök. Genom kunskap om hur olika faktorer inverkar på verklig och uppskattad stabilitet kan spannet av variation bättre accepteras och minska. Vidare kan insamlad data användas för att kalibrera och validera indikationsmetoder. Kommunikationen av kolsänkan av biokol och det långsiktiga värde som skiljer biokol ifrån andra mer kortsiktiga kolsänkor bör förbättras. Långsiktiga fält och inkubationsförsök bör etableras enligt kunskap om experimentell design och hantering av data för att på ett så korrekt sätt som möjligt spegla verklig stabilitet och kolsänka.

The proposal aims to build on Eskilstuna municipality's work with circular ideas about sustainability to create a lively community house with focus on cultivation and creativity. By utilizing garden waste and processing it into biochar used in both large- and small-scale cultivation, carbon dioxide is bound in the soil for thousands of years.  The biochar binds nutrients and water and provides an improved harvest. The design takes inspiration from the character of the place with it’s traditional red colored cultivation boxes and the red cycle bridge across the creek. The idea of a historic warehouse building (magasin) as a flexible basic structure emerged and has led to an exploration of how to give the typology a public character. The goal was to create a place where young and old could cultivate their interest in agriculture and culture, and in the long run encourage own food production as a driving factor in achieving a more climate-smart and resilient society. / Förslaget syftar till att bygga vidare på Eskilstuna kommuns arbete med cirkulära idéer om hållbarhet för att skapa ett levande folkets hus med fokus på odling och kreativitet. Genom att ta tillvara på trädgårdsavfall och förädla detta till biokol, som används i både stor- och småskalig odling, binds koldioxid i marken i tusentals år samtidigt som kolet binder näring och vatten och ger en förbättrad skörd. Gestaltningen tar avstamp i de faluröda odlingslådorna och platsens karaktär. Idén om en magasinsbyggnad som en flexibel grundstruktur dök upp och har lett vidare till ett utforskande av hur man ger typologin en offentlig karaktär. Målet är att skapa en plats för stora och små med fokus på växande och odling som ska uppmuntra till egen produktion av livsmedel, som en drivande faktor för att uppnå ett mer klimatsmart och motståndskraftigt samhälle.

Der anhaltende Anstieg der anthropogenen Treibhausgasemissionen führt zu einer erheblichen Verschärfung des Klimawandels und bedroht damit zunehmend die Integrität der Biosphäre und Gesellschaften weltweit. Negative Emissions-Technologien (NETs) wie die Pyrogene Kohlenstoffbindung und -speicherung (PyCCS) bieten potenzielle Lösungsansätze zur Minderung dieser Bedrohung. Diese Dissertation umfasst drei Studien, in denen das Vegetationsmodell LPJmL angewendet wird, um die globalen biogeochemischen Potenziale von PyCCS unter verschiedenen Implementierungsszenarien zu analysieren und die damit verbundenen Landnutzungsdynamiken zu evaluieren, die zu den kritischsten Zielkonflikten gehören. Zunächst zeigt die erste Studie mithilfe einer bedarfsorientierten Analyse, dass die Speicherung von Pflanzenkohle im Boden das Potenzial aufweist, NE von einem Umfang zu liefern, der laut klima-ökonomischen Szenarien zur Begrenzung der globalen Klimaerwärmung auf 1,5°C erforderlich wäre, was als besonders schwer vereinbar mit Naturschutz identifiziert wird. Die zweite Studie untersucht darauffolgend einen PyCCS-Ansatz, der den Landnutzungsdruck reduziert, indem Ackerflächen für PyCCS freigegeben werden, während die Kalorienversorgung auf den verbleibenden Anbauflächen durch Ertragssteigerungen mittels Pflanzenkohlezuführung aufrechterhalten wird. Dieser Ansatz könnte NE aus Bioenergie mit CO2-Abscheidung und -Speicherung—eine wichtige NET in ökonomischen Mitigationsszenarien—ersetzen und Flächen freigeben, die alternativ die Kalorienproduktion oder Naturschutzflächen fördern könnten. Im Rahmen der dritten Studie baut die Dissertation das Verständnis über das Potenzial von LCN-PyCCS als Instrument zur Klimastabilisierung durch die zusätzliche Darstellung der sich verbreitenden Praxis der Pflanzenkohle-basierten Düngung und Sensitivitätsanalysen der angenommenen Pyrolyseparameter und Bewirtschaftungsintensitäten weiter aus. / The ongoing rise in anthropogenic greenhouse gas emissions is significantly exacerbating climate change, which poses an increasing threat to the integrity of the biosphere and societies worldwide. Negative emission technologies (NETs) like Pyrogenic carbon capture and storage (PyCCS) offer potential mitigation solutions. This dissertation comprises three studies that apply the Dynamic Global Vegetation Model LPJmL to estimate global biogeochemical potentials of PyCCS under different deployment scenarios and evaluate the associated land use dynamics, which are among the most critical potential trade-offs. The first study is a demand-driven analysis aiming to achieve NEs projected to be required for limiting global warming to 1.5°C by PyCCS deployment. It finds that that biochar application has the potential to deliver these NEs — yet only under significant land use expansion, posing a significant threat to areas identified as particularly relevant for conservation. Subsequently, a novel approach to PyCCS deployment was assessed that reduces land pressure by releasing cropland to PyCCS feedstock production while maintaining calorie supply through biochar-mediated yield increases on remaining cropland. Based on this allocation scheme and LPJmL-computed biomass yields, a sequestration potential of 0.44–2.62 Gt CO2 yr−1 was quantified alongside calculating the potential benefits of replacing NE from BECCS (bioenergy with carbon capture and storage — a prominent NET in stabilization scenarios of climate economics) with PyCCS for nature restoration and calorie production. The understanding of the potential for LCN-PyCCS as a strategy for climate stabilization was further expanded by the representation of the emerging practice of biochar-based fertilization (i.e., biochar applied as mixtures with fertilizer at lower rates than the previously evaluated soil amendment) and sensitivity analyses of assumed pyrolysis parameters and management intensities in the third study.

<p>   </p> <p>Biochar and charcoal cannot properly be discussed without understanding the diverse technologies available for their production. This is because approximately 70% of wood harvested worldwide is burned for energy and this, in addition to unstainable agricultural activities, has caused a massive increase in deforestation and contributed to climate change. Due to this, current global interventions are focused on promoting sustainable approaches through the expansion of agricultural technologies in countries where the deforestation rate keeps increasing due to overdependency on unsustainable and inefficient conversion technologies. It is therefore obvious that African regions cannot be left out when talking about the impact of global agriculture and charcoal production. Not only is 95% of all household energy used in Africa derived from burning wood in the form of charcoal and firewood, but sub-Saharan Africa regions also contribute 62% to global charcoal production. Since sustainability approaches are of global concern and must be understood from different perspectives and regions, this work analyzed sustainable agriculture and climate mitigation strategies using charcoal and biochar production as indicators. From a sustainability point of view, the study categorized this assessment into three chapters to help understand the preferences of local producers in relation to technologies used and the necessary actions or interventions needed for future improvements.</p> <p><br></p> <p>In the first chapter, 492 charcoal producers from Ghana were interviewed with semi-structured questionnaires to understand the demographics of charcoal producers, species used for charcoal, and how these producers intend to sustain the charcoal industry in terms of acquisition of wood resources/raw materials. This helped to analyze how the demographics of charcoal producers influence the charcoal production industry, characterize some wood species suitable and acceptable for sustainable charcoal production, and to recommend some necessary interventions toward sustainability.</p> <p><br></p> <p>In the second chapter, the heating characteristics of the most common indigenous species and exotic species identified in the first chapter were examined for their charcoal production properties (yield and calorific values) using the most common conversion technology available in the study area (earth mound). The heating/calorific values of these species were also determined using a ballistic bomb calorimeter. This also helped in examining the impact of the common charcoal production technologies on the qualities of charcoal produced and their corresponding impacts on the environment. Additionally, this chapter identified that most charcoal production species have longer rotation times with added values other than being used for charcoal. Furthermore, inappropriate conversion technologies minimize charcoal yield and quality; therefore, developing more efficient and affordable conversion kilns would increase charcoal production efficiency and improve the sustainable production of charcoal.</p> <p><br></p> <p>Based on the recommendation from chapter two, chapter three focused on building transferable skills and knowledge to help smallholder farmers and charcoal producers to fabricate cost-effective retorts/kilns for biochar and charcoal production. Through the process, we reviewed, selected, redesigned, and manufactured three common global conversion technologies and tested their potential for sustainable biochar and charcoal production using wood and crop stubbles (corn husk, corn cob, and sorghum residues). This helped in proposing best techniques and technologies suitable for biochar and charcoal production based on their production and use variables. It was therefore concluded that when farmers gain more knowledge and skills in manufacturing relevant and cheap technologies at their convenience, they could make the right subsequent choices towards sustainable agricultural practices.</p> <p>  </p>