This master's thesis deals with the analysis of organic substances, which are present in biochar. Biochar contains a number of organic compounds, that can be toxic and also carcinogenic to living organisms. In order for biochar to be used to improve soil quality or to be used for other applications, its safety must be declared by European or international certifications. Relevant European and international standards have been created for the determination of organic substances, that could be present in biochar. The theoretical part of the thesis was focused on selected organic substances, the process of pyrolysis and thermochemolysis, biochar characterisation and the used analytical methods. The experimental part of the thesis consisted of extraction with toluene and after that the determination of concentration of the 38 polycyclic aromatic hydrocarbons was performed. Qualitative analysis was performed by two-dimensional gas chromatography. Biochar samples were also subjected to thermochemolysis method and then they were analysed on GC-MS again. In both analytical methods, a large number of substances from groups such as PAHs, carboxylic acids, amines, substituted naphthalenes etc. was found, as well as smaller number of eg. polychlorinated biphenyls.

<p>Predmet&nbsp; istraživanja&nbsp; ove&nbsp; doktorske&nbsp; disertacije&nbsp; je&nbsp; procena&nbsp; potencijalno&nbsp; biodostupne&nbsp; frakcije odabranih&nbsp; prioritetnih&nbsp; organskih&nbsp; polutanata&nbsp;&nbsp; (pentahlorbenzena,&nbsp; heksahlorbenzena,&nbsp; lindana, trifluralina, 4-oktilfenola i 4-nonilfenola) u sedimentu, ispitivanje biodegradacionog potencijala ovih&nbsp; jedinjenja&nbsp; u&nbsp; sedimentu&nbsp; u&nbsp; različitim&nbsp; uslovima,&nbsp; kao&nbsp; i&nbsp; procena&nbsp; potencijala&nbsp; stabilizacije<br />sedimenta&nbsp; dodatkom&nbsp; ugljeničnih&nbsp; sorpcionih&nbsp; agenasa.&nbsp; U&nbsp; cilju&nbsp; razvoja&nbsp; metoda&nbsp; za&nbsp; određivanje biodostupnosti odabranih organskih polutanata ispitivane su i&nbsp; optimizovane metode vi&scaron;estepene i jednostepene parcijalne ekstrakcije primenom sledećih hemijskih agenasa:&nbsp; Tenaks&nbsp; smole, XAD-4&nbsp; smole&nbsp; i&nbsp; rastvora&nbsp; ciklodekstrina&nbsp; (2-hidroksipropil-&beta;-ciklodekstrina,&nbsp; &beta;-ciklodekstrina&nbsp; i&nbsp; metil-&beta;-ciklodekstrina).&nbsp; Optimalni&nbsp; agens&nbsp; za&nbsp; procenu&nbsp; biodostupne&nbsp; frakcije&nbsp; odabranih&nbsp; organskih zagađujućih&nbsp; materija&nbsp; sa&nbsp; sedimenta&nbsp; XAD-4&nbsp; smola,&nbsp; a&nbsp; optimalno&nbsp; vreme&nbsp; ekstrakcije&nbsp; primenom jednostepenih&nbsp; ekstrakcija&nbsp; je&nbsp; oko&nbsp; 8&nbsp; h.&nbsp; Procena&nbsp; biodegradacionog&nbsp; potencijala&nbsp; odabranih prioritetnih&nbsp; organskih&nbsp; zagađujućih&nbsp; materija&nbsp; u&nbsp; sedimentu&nbsp; ispitana&nbsp; je&nbsp; u&nbsp; različitim&nbsp; aerobnim&nbsp; i anaerobnim uslovima uz optimizaciju uslova putem biostimulacije i bioaugmentacije. Pokazano je&nbsp; da&nbsp; svih&nbsp; &scaron;est&nbsp; odabranih&nbsp; jedinjenja&nbsp; poseduju&nbsp; značajan&nbsp; potencijal&nbsp; biodegradacije&nbsp; u&nbsp; anaerobnoj sredini&nbsp; pri&nbsp; čemu&nbsp; u&nbsp; slučaju&nbsp; lindana&nbsp; i&nbsp; trifluralina&nbsp; dolazi&nbsp; do&nbsp; potpunog&nbsp; uklanjanja&nbsp; biodostupne količine&nbsp; jedinjenja&nbsp; primenom&nbsp; sva&nbsp; četiri&nbsp; ispitana&nbsp; inokuluma.&nbsp; Aerobni&nbsp; potencijal&nbsp; u&nbsp; ispitanim uslovima&nbsp; pokazali&nbsp; su&nbsp; samo&nbsp; alkil&nbsp; fenoli,&nbsp; gde&nbsp; je&nbsp; takođe&nbsp; uklonjena&nbsp; skoro&nbsp; celokupna&nbsp; količinabiodostupne&nbsp; frakcije&nbsp; jedinjenja&nbsp; u&nbsp; sedimentu&nbsp; (78-85%).&nbsp; Potencijal&nbsp; remedijacije&nbsp; sedimenta dodatkom&nbsp; ugljeničnih&nbsp; materijala&nbsp; ispitan&nbsp; je&nbsp; sa&nbsp; aspekta&nbsp; odabira&nbsp; ugljeničnih&nbsp; sorpcionih&nbsp; agenasa (aktivni&nbsp; ugalj,&nbsp; biougalj&nbsp; i&nbsp; humus);&nbsp; određivanja&nbsp; optimalne&nbsp; količine&nbsp; materijala;&nbsp; isptivanja dugoročnih i kratkoročnih efekata dodatka ovih agenasa na biodostupnost organskih zagađujućih materija&nbsp; kako&nbsp; bi&nbsp; se&nbsp; ispitao&nbsp; efekat&nbsp; starenja &nbsp; i&nbsp; toksičnosti&nbsp; dobijenih&nbsp; sme&scaron;a.&nbsp; Rezultati&nbsp; stabilizacije zagađujućih&nbsp; supstanci&nbsp; u&nbsp; sedimentu&nbsp; pokazuju&nbsp; da:&nbsp; (1)&nbsp; povećanje&nbsp; doze&nbsp; sva&nbsp; tri&nbsp; sorpciona&nbsp; agensa dovodi&nbsp; do&nbsp; povećanja&nbsp; efikasnosti&nbsp; imobilizacije&nbsp; i&nbsp; smanjenja&nbsp; biodostupne&nbsp; frakcije&nbsp; odabranih organskih jedinjenja; (2) starenjem sme&scaron;a sedimenta i&nbsp; sorbenata u toku prvih 90 dana dolazi do daljeg smanjenja biodostupne frakcije svih jedinjenja, nakon čega se biodostupna koncentracija ispitivanih&nbsp; jedinjenja&nbsp; primenom&nbsp; aktivnog&nbsp; uglja&nbsp; ne&nbsp; menja,&nbsp; dok&nbsp; primenom&nbsp; biouglja&nbsp; i&nbsp; humusa&nbsp; dolazi&nbsp; do&nbsp; porasta&nbsp; biodostupne&nbsp; frakcije&nbsp; jedinjenja.&nbsp; Testovi&nbsp; fitotoksičnosti&nbsp; su&nbsp; pokazali&nbsp; da&nbsp; je&nbsp; <em>Zea mays&nbsp; </em>akumulirao&nbsp; značajno&nbsp; veće&nbsp; količine&nbsp; ispitivanih&nbsp; jedinjenja&nbsp; iz&nbsp; netretiranog&nbsp; sedimenta&nbsp; u poređenju sa&nbsp; <em>Cucurbita pepo</em>&nbsp; i&nbsp;<em> Lactuca sativa. </em>Toksičnost sme&scaron;a sedimenta sa aktivnim ugljom i humusom&nbsp; procenjena&nbsp; na&nbsp; osnovu&nbsp; inhibicije&nbsp; luminiscencije&nbsp; na&nbsp; <em>Vibrio&nbsp; fischeri</em>&nbsp; kao&nbsp; i&nbsp; ispitivanjem <em>Zea&nbsp; mays&nbsp; </em>germinacije&nbsp; i&nbsp; produkcije&nbsp; biomase&nbsp; je&nbsp; pokazala&nbsp; značajno&nbsp; smanjenje&nbsp; u&nbsp; odnosu&nbsp; na netretirani&nbsp; sediment.&nbsp; Akumulacija&nbsp; ispitivanih&nbsp; jedinjenja&nbsp; u&nbsp; biomasi&nbsp; <em>Zea&nbsp; mays&nbsp; </em>u&nbsp; netretiranom sedimentu je bila značajno veća u odnosu na sve sme&scaron;e sedimenta i aktivnog uglja i humusa. Sva tri&nbsp; sorbenta&nbsp; pokazala&nbsp; su&nbsp; veliki&nbsp; remedijacioni&nbsp; potencijal&nbsp; za&nbsp; sediment&nbsp; zagađen&nbsp; organskim zagađujućim supstancama, ali je aktivni ugalj pokazao najbolje performance.</p> / <p>The&nbsp; aim&nbsp; of&nbsp; the&nbsp; research&nbsp; in&nbsp; this&nbsp; PhD&nbsp; dissertation&nbsp; is&nbsp; the&nbsp; assessment&nbsp; of&nbsp; the&nbsp; potentially biodegradable&nbsp; fraction&nbsp; of&nbsp; selected&nbsp; organic&nbsp; pollutants&nbsp;&nbsp; (pentachlorbenzene,&nbsp; hexachlorobenzene, lindane,&nbsp; trifluraline,&nbsp; 4-octylphenol&nbsp; and&nbsp;&nbsp;&nbsp; 4-nonylphenol)&nbsp; in&nbsp; the&nbsp; sediment,&nbsp; estimation&nbsp; of&nbsp; the biodegradation potential of these compounds in sediment in different conditions, as well as the assessment&nbsp; of&nbsp; the&nbsp; stabilization&nbsp; potential&nbsp; sediment&nbsp; by&nbsp; the&nbsp; sediment&nbsp; amendment&nbsp; with&nbsp; of&nbsp; carbon rich sorption agents. In order to develop and optimise&nbsp; methods for the bioavailability assessment of&nbsp; the&nbsp; selected&nbsp; organic&nbsp; pollutants,&nbsp; methods&nbsp; of&nbsp; multistage&nbsp; and&nbsp; single-step&nbsp; non&nbsp; exhaustive extraction&nbsp; were&nbsp; studied&nbsp; using&nbsp; the&nbsp; following&nbsp; chemical&nbsp; agents:&nbsp; Tenax&nbsp; resin,&nbsp; XAD -4&nbsp; resin&nbsp; and&nbsp; a cyclodextrin&nbsp; solution&nbsp; (2-hydroxypropyl- &beta;-cyclodextrin,&nbsp; &beta;-cyclodextrin&nbsp; and&nbsp; methyl-&beta;-cyclodextrin).&nbsp; Results&nbsp; showed&nbsp; that&nbsp; optimal&nbsp; agent&nbsp; for&nbsp; estimating&nbsp; the&nbsp; bioavailable&nbsp; fraction&nbsp; of selected organic pollutants from the sediment is XAD-4 resins, and that the optimum extraction time using single-step extraction is about 8 h. The assessment of the biodegradation potential of selected&nbsp; priority&nbsp; organic&nbsp; pollutants&nbsp; in&nbsp; the&nbsp; sediment&nbsp; was&nbsp; examined&nbsp; in&nbsp;&nbsp; various&nbsp; aerobic&nbsp; and anaerobic&nbsp; conditions,&nbsp; with&nbsp; the&nbsp; optimization&nbsp; of&nbsp; conditions&nbsp; through&nbsp; biostimulation&nbsp; and bioaugmentation.&nbsp; It&nbsp; has&nbsp; been&nbsp; shown&nbsp; that&nbsp; all&nbsp; six&nbsp; selected&nbsp; compounds&nbsp; possess&nbsp; significant biodegradation&nbsp; potential&nbsp; in&nbsp; the&nbsp; anaerobic&nbsp; environment,&nbsp; where&nbsp; in&nbsp; the&nbsp; case&nbsp; of&nbsp; lindane&nbsp; and trifluraline there is complete removal of the bioavailable amount of the compound&nbsp;&nbsp; using all four inoculum tested. Aerobic potential under the applied conditions has been showen only for alkyl phenols,&nbsp; where&nbsp; almost&nbsp; all&nbsp; of&nbsp; the&nbsp; bioavailable&nbsp; fraction&nbsp; of&nbsp; the&nbsp; compound&nbsp; in&nbsp; the&nbsp; sediment&nbsp; was removed (78-85%). The potential of sediment remediation with the amendment of sediment withcarbon&nbsp; rich&nbsp; materials&nbsp; was&nbsp;&nbsp; examined&nbsp; from&nbsp; the&nbsp; aspect&nbsp; of&nbsp; selecting&nbsp; carbon&nbsp; sorption&nbsp; agents (activated carbon, biochar and humus); estimation the optimal material doses; the long -term and short-term effects of the addition&nbsp; of these agents on the bioavailability of organic pollutants&nbsp; in order to examine the effect of aging and the toxicity of the resulting mixtures. The results of the stabilization of pollutants in the sediment show that: (1)&nbsp; increasing the dose of all three&nbsp;&nbsp; sorption agents&nbsp; leads&nbsp; to&nbsp; an&nbsp; increase&nbsp; in&nbsp; the&nbsp; immobilization&nbsp; efficiency&nbsp; and&nbsp; reduction&nbsp; of&nbsp; the&nbsp; bioavailable fraction of the selected&nbsp; organic compounds; (2) aging of the amended sediment during the first 90 days results in a further reduction of the biodegradable fraction of all compounds, after which the&nbsp; biodegradable&nbsp; concentration&nbsp; of&nbsp; the&nbsp; selected&nbsp; compounds&nbsp; remain&nbsp; the&nbsp; same&nbsp; in&nbsp; the&nbsp; case&nbsp; of activated carbon amendment, while the bioavailable fraction of&nbsp; the compound increases with the use&nbsp; of&nbsp; biohar&nbsp; and&nbsp; humus.&nbsp; Phytotoxicity&nbsp; tests&nbsp; showed&nbsp; that&nbsp; <em>Zea&nbsp; mays&nbsp;</em> accumulated&nbsp; significantly higher amount of selected organic pollutants from unamended sediment, comparing to&nbsp; <em>Cucurbita pepo&nbsp;</em> and <em>Lactuca sativa</em>. Toxicity of activated carbon and humus amended sediment assessed by <em>Vibrio&nbsp; fischeri&nbsp;</em> luminescence&nbsp; inhibition&nbsp; test&nbsp; and&nbsp; by&nbsp; measuring&nbsp; <em>Zea&nbsp; mays&nbsp; </em>germination&nbsp; and biomass yield was significantly reduced in the amended sediment samples. Accumulation of the selected&nbsp; organic&nbsp; pollutants&nbsp; in&nbsp; the&nbsp; <em>Zea&nbsp; mays</em>&nbsp; biomass&nbsp; in&nbsp; the&nbsp; unamended&nbsp; sediment&nbsp; were&nbsp; a significantly&nbsp; higher&nbsp; than&nbsp; in&nbsp; the&nbsp; humus&nbsp; and&nbsp; activated&nbsp; carbon&nbsp; amended&nbsp; sediment.&nbsp; Both&nbsp; sorbents show&nbsp; potential&nbsp; to&nbsp; be&nbsp; used&nbsp; as&nbsp; remediation&nbsp; agents&nbsp; for&nbsp; organically&nbsp; contaminated&nbsp; sediment,&nbsp; but activated carbon exhibited the better performance.</p>

Soil contamination is one of the main threats affecting food and water safety and ecosystem services on a global scale. Contamination of toxic inorganic and organic pollutants in soils and its remediation is closely related to the implementation of Sustainable Development Goals. With phytoremediation as a method and biochar as a tool, we used a common plant type Lupin Mexicanus  to remediate soil from arsenic contamination further,  we wanted to study how biochar affects the phytoremediation of contaminants. The combination of biochar made from reeds and L. mexicanus was in this study tested for its suitability for phytoremediation of arsenic (As) in soil. Seeds from L. mexicanus was grown in 18 different pots spiked with As (80 mg kg-1, dry weight) and different percentage of biochar amendment (0, 1, 2, 3, 4,5%). Two additional pots were planted with seeds but completely without any arsenic or biochar. The plants were grown for 5 weeks. The highest concentration in roots was 3094 mg kg-1 found in the pots with 2% biochar. The highest concentration of arsenic in the aerial parts was at a level of 168 mg kg-1 and found in the pots with 5 % biochar. L.mexicanus showed a potential of bioaccumulating arsenic from soil with a bioconcentration factor of 40,6 (2%) and 29,4 (5%), the concentration in leaves was 1-2 times higher compared to that in the soil. The results showed that biochar affected the translocation ratio and uptake of As in L. mexicanus, However, the biochar amended soil did not show anything major to the pH-value at these proportions (5% of biochar or less). This study was limited in explaining the mechanisms responsible for the increase in As uptake but shows a promising application for potential remediation of soils contaminated with high As levels. / Markföroreningar och föroreningar har visat sig vara ett av de största hoten som påverkar mark- och ekosystemtjänster på global nivå. Arbetet med förebyggande av föroreningar i marken och reningsarbeten, såsom marksanering har en stark koppling till nästan alla mål för hållbar utveckling. Med fytoremediering som metod och biokol som medel använde vi växter för att extrahera arsenikförorening från jord. I ett försök att minska kunskapsklyftan  kring hur biokol påverkar fytoremidering av föroreningar kombinerades dessa  två. Kombinationen  av biokol tillverkad av vass och  L.mexicanus testades  i denna studie  för dess lämplighet  för  fytoremediering av  As  i  jord. Frön  från  L.mexicanus odlades  i 18 olika  krukor spetsade med  As (80 mg kg-1  torrsubstans) och i en variation av andelen biokol ändring  (0,1,2,3,4,5%). Två ytterligare krukor planterades med frön men helt utan arsenik  eller  biokol. Dessa krukor fungerade  som  kontroll för att  säkerställa grobarheten hos   fröerna  eller de förhållanden som  växterna  odlades  i. Efter 5 veckor skördades växterna och den högsta koncentrationen av arsenik i rötter var på 3094 mg kg-1  och fanns i krukorna som hade 2% biokol. Den högsta koncentrationen av arsenik i plantdelar ovanjord var på 168 mg kg-1  och var i krukorna med 5% biokol. L. mexicanus visade sig kunna bioackumulera, och resultatet visade att bioconcentrations faktorn uppmätte 40,6 (2%) och 29,4 (5%), varav koncentrationen i löv och skälk var 1-2 gånger högre än vad som återfanns i jorden. Resultaten  visade även att biokol påverkade   translokeringsförhållandet  och  upptaget av arsenik i L. mexicanus, tillsättningen av biokol i  jord gav inga stora förändringar i pH-värdet med tillsatt koncentration  (5%  av biokol  eller mindre). Studien  var begränsad  i  att förklara  de mekanismer som är ansvarig  för  ökningen  av As  upptag men visar en lovande  applikationspotential i arbetet med  sanering av jordar från As.

<div>Thermochemical processing using fast-pyrolysis technology has been used to upgrade feedstocks like biomass and natural gas and more recently studied for plastic recycling. This work aims to improve the selectivity to desired products from a pyrolysis process through better catalysts and reactor design.</div><div>Fast-pyrolysis of biomass to fuels is considered a promising technology due to the higher yields to liquid fuel products. However, the process suffers from low carbon efficiency to hydrocarbon products due to carbon losses to biochar, accounting for 25-40 wt.% of the product stream depending on the biomass type. Using a combination of inorganic free-model compounds, biomass pretreatments and mass spectrometric analyses coupled with lab-scale reactor experiments, the char contribution from the lignocellulosic components (cellulose, hemicellulose, and lignin) and mineral content was investigated. The lignocellulosic components were found to follow the order: Lignin > Hemicellulose > Cellulose. Addition of inorganic salts (K, Na and Ca) to cellobiose, a model compound for cellulose, was found to catalyze additional dehydration reactions on primary pyrolysis products (e.g., levoglucosan) to yield secondary products (e.g., 5-HMF), and produce more char. This knowledge of char formation contributors can enable optimization of the bio-refining process sequencing using process system engineering tools and thus achieve higher carbon efficiency for biomass conversion.</div><div>While biomass has been viewed as a future energy source, there is a need for a transition fuel with the lowest possible greenhouse gas (GHG) footprint. Shale gas, consisting primarily of methane, is a potential candidate due to its large availability and high hydrogen to carbon ratio. Recently, single-atom catalysts have been studied as stable and non-coking catalysts for the non-oxidative coupling of methane (NOCM) to higher hydrocarbons (like ethylene). However, lack of post reaction catalyst characterization and rigorous kinetic testing have raised questions on the stability of these materials. This work combines homogenous (Chemkin simulations, gas phase kinetics) and heterogeneous reaction kinetic studies (reaction orders, steady state kinetics), coupled with microscopy (Scanning and Transmission Electron Microscopy (SEM, TEM)) and surface characterization tools (BET, TGA, Raman spectroscopy, CO-IR spectroscopy) to understand the role of the solid materials during NOCM. Post reaction catalyst characterization using transmission electron microscopy (TEM) analysis on the spent samples (CH4 treated at 975 deg C for 3 hours) reveals that the materials containing Pt single atoms (SA) and Pt nanoparticles (NP) are found to sinter to particles approximately 5-7 nm in size. Ethylene hydrogenation experiments, a kinetic probe for surface Pt, shows initial ethane formation rates that are four orders of magnitude lower on the isolated Pt+2 sites, found on Pt SAs, when compared to the rates obtained if all the surface Pt were assumed to be metallic. These results suggest that single atoms are not the active sites. However, under same reaction conditions (50 mL min-1 CH4 flow and 975 deg C), the ethylene formation rates (in mol h-1) on the solid materials are 2-7 times higher than the empty tube rates, indicating that the surface plays a role during NOCM. Addition of incremental amounts of the solid material increases methane conversion, extrapolating to the bare tube conversion at zero loading. This indicates that the solid materials improve the NOCM performance.</div><div>Experiments with pure methane feeds indicate that the solid materials are found to deactivate due to coking on the surface, evidenced by the coke buildup observed using thermogravimetric analysis (TGA) and the initial time-on-stream kinetic results showing rapid methane deactivation. Raman spectroscopy on the spent catalysts indicate at the development of a similar graphite-like surface intermediate under steady state conditions on all the materials. When compared under the same reaction conditions (975 deg C, 60 mL min-1 Pure CH4 with 10% UHP N2 feed, space velocity = 39.6 L h-1 gcat-1), these coked surfaces show a linear dependence for the ethylene formation rate (in mol h-1 gcat-1) with the spent surface area of the material (in m2 gcat-1). This observation is irrespective of the type of the material studied (alpha Al2O3, Davisil SiO2, 1 wt.% Pt/CeO2, Graphene, Graphite, etc.). In conclusion, these results prove that the spent surface area is critical for NOCM.</div><div>Similar experimental setup was used to study the dehydrogenation of methane, ethane, and propane mixture in the gas phase. Initial experiments at 1 bar pressure and reaction temperatures ranging from 650-850 deg C revealed that ethylene and hydrogen are the main gas phase products, with methane acting as a diluting agent under these reaction conditions. These results could enable direct processing of the shale gas without the use of a conventional ethane/propane separation step. These results were further studied by the system engineers using ANSYS ChemkinPro. For practical applications, these experiments were suggested to be performed at much higher operating pressures (~30 bar) and low residence time (~0.2 s), with a quick quenching step added after the reactor to prevent change in the exit stream compositions. A new reaction system was built to experimentally validate these recommendations.</div>

The concept of sludge management at the level of sludge treating technology of sewage treatment plants, as well as at national, continental or world level, requires fundamental improvement in the interest of sustainable development. Sewage sludge production is continuously increasing. Sewage sludge contains a number of pollutants but also a significant renewable resource for material transformation and / or energy recovery. Sewage sludge is composed of an inorganic mineral part and organic components. Its organic part is a source of energy and nutrients, but also contains harmful pollutants for exapmple heavy metals. However, there are technologies that offer the possibility of neutralizing pollutants while using other sludge components in terms of recycling energy, nutrients and other attractive sludge components. The mentioned technologies include mainly thermal methods of sewage sludge treatment and one of them is pyrolysis. Thessis focuses on sewage sludge prepartation for pyrolysis process, which includes mixing with additives and peletization of prepared mixture for purposes of agricultural or energetical utilisation. Technology for material transformation and energy utilization of sewage sludge, in particular the mentioned pyrolysis or torrefaction, require an insignificant degree of detailed research in order to expand it in the field of sludge management. Indeed, it is not only research that will enable direct correct use of this technology in practice. The results of such research are the basis for the drafting of the relevant legislation, which will subsequently enable the deployment of pyrolysis technologies in practice.

No description available.

Utilizing biomass such as lignin, bamboo, soybean, corn stalk, rice husk, etc., as a carbon source to produce graphene-based nanomaterials has been reported recently. However, the potential of using such nanomaterials for engineering and environmental applications has not been realized. This dissertation investigates the use of graphene-based nanomaterials synthesized from using biomass as a carbon source for water remediation and cement-based composites’ (CBCs) property enhancement. The first chapter introduces graphene and graphene-based nanomaterials, as well as the synthesis and application of graphene-based nanomaterials for removing heavy metals in an aqueous solution and for property enhancement in CBCs. The experimental investigation on the pyrolytic synthesis of graphene-encapsulated iron nanoparticles from biochar (BC) as the carbon source (BC-G@Fe0) was covered in the second chapter. Two synthetic routes for producing BC-G@Fe0, i.e., impregnation-carbonization (route-I) and pyrolysis-impregnation-carbonization (route-II) processes, were investigated experimentally using different characterization techniques and heavy metal removal methods. The third chapter reports the experimental performances of the heavy metal removal of Pb2+, Cu2+, and Ag+ from an aqueous solution using BC-G@Fe0. The effectivenesses of various adsorption benchmarks, such as pH, kinetics, and isotherms were assessed. Additionally, the removal efficiency of BC-G@Fe0 was evaluated. BC-G@Fe0 sample made from route II, in particular, FeCl2-impregnated-BC with 15% wt% iron loading carbonized at 1000 ℃ for 1h showed promising Pb2+, Cu2+, and Ag+ removal capacities of 0.30, 1.58, and 1.91 mmol/g, respectively. The fourth chapter experimentally investigated the reinforcement effect of commercially sourced, industrial graphene nanoplates (IG) on the mechanical properties of CBCs. This investigation was based on a hypothesis that the uniform dispersion of IG would significantly enhance the compressive strength of CBC. The main outcome of this research was that, while the wet dispersion mixing process of IG into CBC did not consistently yield significant increases in the composite compressive strength, but the newly proposed dry dispersion process demonstrated significant increases (22%) in the composite compressive strength. Chapter Five investigated the synthesis of lignin-based graphene nanoplatelets (LG) and their application in CBC reinforcement. The main findings were that LG did not show impressive increases compared to IG, even when dry dispersion was introduced. This was attributed to LG's lack of effective surface area compared to IG. Finally, a general conclusion and outlook for the future of research into biomass-based graphene nanomaterials were discussed in chapter six.

Biochar application as a soil additive is gaining global acceptance. In this era of climate change, biochar use for improved soil productivity is not just a sustainable eco-friendly substitute to synthetic fertilizer, but a noble contributor to the fight against climate change. Although biochar has been accredited with some environmental and agricultural benefits, most studies concentrated on agricultural and biowaste products as feedstocks. This research was designed to explore P-enriched modified-Douglas fir biochar potential as a soil additive. Using corn as a test crop, greenhouse studies were performed on acidic sandy soil, comparing phosphorus enriched modified-Douglas fir biochar efficacy to a commercial synthetic triple superphosphate fertilizer and a control treatment. Incubation studies were also performed to evaluate the liming and heavy metal immobilization efficacies. Firstly, P-enriched modified-Douglas fir biochar’s ability to release plant soluble P was investigated. At various P enrichment concentration, soil plant availability P from P enriched modified-Douglas fir biochar treatments differed insignificantly from superphosphate fertilizer treatment. The direct correlations between both K and Mg recoveries with available soil P, suggested P enriched modified-Douglas fir biochar potential to supply multiple plant nutrients. Secondly, the influence of P uptake on plant growth and P use efficiency was examined. The greater agronomic P use efficiency obtained in P enriched modified-Douglas fir biochar (~32 kg kg-1) than the triple supper phosphate fertilizer (~17 kg kg-1) treatment confirmed P enriched modified-Douglas fir biochar potential as a multiple nutrient released soil additive. Thirdly, biochar-supported phosphate (BP) effectively reduced Pb2+ mobility in simulated contaminated soil. Pb2+reacted with phosphate from Ca10(PO4)6(OH)2 embedded in the biochar supported phosphate at pHPb10(PO4)6(OH)2. Finally, the amendment of acidic soils with modified P-enriched modified-biochar improved soil buffering capacity because of its enhanced ash contents, alkalinity, and surface functional groups. Spectroscopic methods were used to analyze biochar, soil, and plant materials extracts. Several other analytical methods including BET and thermogravimetric analyses were used to characterized biochar. These findings suggest that the use of phosphorus enriched modified-Douglas fir biochar in agricultural soil is a feasible relatively low-cost, effective, and environmentally sustainable soil management and P recycling strategy

A long-held practice is to mix agricultural soil with a soil amendment to improve growing conditions in crops. A common soil amendment is biosolids produced from both municipal and dairy wastewater due to the macro- and micronutrients within it. Both the agricultural and wastewater industries are participating in the Circular Economy concept (CEC). Two experiments explored using expended bioelectrochemical systems (BES) that treated either synthetic dairy wastewater (DWW) or synthetic municipal wastewater (SWW) as soil amendments to improve corn plant growth when treated with three different nutrient treatments: 100%- 50%- and 0% Hoagland Nutrient Solutions. Biochar and used terracotta clay were used as soil amendments too. Additionally, the DWW and SWW soil amendments are being invested to see if soil moisture can be retained during simulated drought conditions. The experiments took place in the late fall and winter of 2021 and summer of 2022 in Starkville, Mississippi.

In  Kenya, lack of clean cooking services affect around 80 % of the population. A range of improved cookstoves (ICS) have been produced to address this. This study aims to investigate the long-term usage of an improved stove, the biochar producing gasifier. The stove was distributed to 150 rural households divided between three regions in Kenya, in a research project in 2016. This follow-up study looked at areas of stove satisfaction and dissatisfaction among participants, as well as identifying key factors which separate users from non-users. All 150 were asked a few questions over the phone and 30 were visited for in-depth, survey-based interviews. Most households used the traditional three stone open fire stove for everyday purposes, sometimes complemented by the gasifier or other ICSs[CS1] [CS2] . 60 % of households used the gasifier at least monthly. Users and non-users rated the gasifier stove similarly. They varied in terms of stove ownership with users owning on average half a stove more than non-users. User households were generally larger. The gasifier was a fuel efficient stove and created little smoke, but was considered too small and required tiresome fuel preparation. The reported problems cannot be fixed unless thoroughly changing the stove design and possibly the gasification process itself, and without addressing them the gasifier is unlikely to replace the three stone stove. The study recognizes the potential of the gasifier as an improved stove, but calls for creative redesign in order to achieve mass adoption. / I Kenya påverkar bristen på matlagningsutrustning som är säker ur hälso- och miljösynpunkt runt 80 % av befolkningen. Traditionellt lagas mat över öppen  eld. En mängd spisar har producerats i syfte att förändra detta. I denna studie undersöktes långtidsanvändningen av en spis, en biokolsproducerande förgasningsspis. Spisen delades ut till 150 hushåll på landsbygden, jämnt fördelade på tre regioner i landet i ett forskningsprojekt år 2016-7. Denna uppföljningsstudie tittar på vilka aspekter hos spisen som forskningsdeltagarna tyckt om respektive funnit utmanande, samt vad som skiljde användare från de som slutat använda spisen. En kort telefonintervju gjordes med alla, och med 30 gjordes djupgående, enkätbaserade intervjuer. Resultaten visade att de flesta hushåll lagade mat över öppen eld till vardags, ibland kompletterat med förgasningsspisen eller andra spisar. 60 % av hushållen använde förgasningsspisen  minst en gång i månaden. Användare och icke-användare hade liknande åsikter om förgasningsspisen. Användare ägde i genomsnitt en halv spis mer än icke-användare. Hushåll som använde förgasningsspisen var generellt sett större. Förgasningsspisen ansågs vara en bränslesnål spis och bara skapa en liten mängd rök, men ansågs vara för liten. Den krävde också mer ansträngande bränsleförberedning. De rapporterade problemen går inte att åtgärda utan att ändra förgasningsspisens design i grunden och eventuellt själva förgasningprocessen, och utan att åtgärda dem kommer förgasningsspisen sannolikt inte att ersätta matlagning över öppen eld. Studien understryker förgasningsspisen potential, men kräver kreativ omdesign för att uppnå massanvändning.