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Compósitos com biochar e carvão vegetal para camadas de pavimentos asfálticos / Composites with biochar and vegetable charcoal for asphalt pavement layersTorres, Alemar Pereira, 92981056447 18 June 2018 (has links)
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Previous issue date: 2018-06-18 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Biochar is a charcoal derived from the carbonization of biomass under a low oxygen atmosphere. Its origin is due to the study developed in the so-called "Indian black earth", which considerably improves the agricultural properties of a soil. In the work under study the influence of biochar as a participant of composites with soil and asphalt mixtures is analyzed by means of the four point bending test. We also compare these results regarding the responses of the formulations with the presence of native charcoal from the Amazon region. For this, prismatic formations of natural clay soil (SN), soil-charcoal (SCV), soil-biochar (SBC), asphalt concrete (CA), asphalt-charcoal concrete (CACV) and concrete asphalt-biochar (CABC). The results showed that the biomass, which participates in composites with the clay soil, improved the stiffness properties, with the purpose of its use in base and sub-base of pavements, culminating in higher values for complex module regarding the mixtures with charcoal . Allus asphaltic composites with biochar and charcoal were verified for both values of stiffness inferior to the standard asphalt concrete, considering average temperature of 25oC. However, for the 40oC temperature, representative of the surface of the pavements of the city of Manaus, these formulations proved to be more advantageous in comparison to the concrete reference, conceiving an alternative for the achievement of road systems with better performance in the Amazon region. / O biochar é um carvão vegetal oriundo da carbonização de biomassa sob baixa atmosfera de oxigênio. Sua origem deve-se ao estudo desenvolvido na chamada “terra preta de índio”, a qual melhora consideravelmente as propriedades agrícolas de um solo. No trabalho em pauta analisa-se a influência do biochar como partícipe de compósitos com solo e misturas asfálticas, por meio do ensaio de flexão a quatro pontos. Também se comparam tais resultados relativos as respostas das formulações com a presença do carvão vegetal nativo da região amazônica. Para tal moldaram-se os corpos de prova de formato prismático do solo argiloso natural (SN), solo-carvão vegetal (SCV), solo-biochar (SBC), concreto asfáltico (CA), concreto asfáltico-carvão vegetal (CACV) e concreto asfáltico-biochar (CABC). Os resultados registraram que o biocarvão, participante em compósitos com o solo argiloso, melhorou as propriedades de rigidez, com a finalidade de seu emprego em base e sub-base de pavimentos, culminando em maiores valores para módulo complexo respeitante as misturas com o carvão vegetal. Alusivo aos compósitos asfálticos com biochar e carvão vegetal, verificou-se para ambos valores de rigidez inferior ao concreto asfáltico padrão, considerando temperatura média de 25oC. No entanto, para a temperatura de 40oC, representativa da superfície dos pavimentos da cidade de Manaus, tais formulações se mostraram mais vantajosos frente ao concreto referência, concebendo uma alternativa para a consecução de sistemas viários com melhor desempenho na região Amazônica.
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Efeito da temperatura final de pir?lise na estabilidade de biocarv?o produzido a partir de madeira de Pinus sp e Eucalyptus sp. / Pyrolysis final temperature effects on the stability of biochar produced from Pinus sp and Eucalyptus sp.ALHO, Carlos Francisco Braz?o Vieira 28 May 2012 (has links)
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Previous issue date: 2012-05-28 / CAPES / Biochar is composed not only of stable carbon, certain portion of this material is relatively easily degraded and this condition is not only dependent on the characteristics of the feedstock, but also on the pyrolysis conditions, especially the final temperature. Thus, the aim of this study was to evaluate the effects of pyrolysis final temperature on the stability of biochar produced from residues of softwoods (Pinus caribaea and Pinus taeda) and hardwoods (Eucalyptus dunnii and Eucalyptus urophylla). For in natura feedstocks, the content of Klason lignin was quantified, it was proceeded elemental analysis, thermogravimetric analysis (TGA/DTA) and solid-state nuclear magnetic resonance 13C (13C NMR). For biochars, which were produced at a heating rate of 10?C.min-1 for 60 min at 5 different temperatures (350, 400, 450, 500 and 550?C) it was proceeded proximate analysis s and to the materials produced 350, 450 and 550 ? C, elemental analysis, TGA / DTA and 13C NMR. In order to evaluate the stability of biochar, the stable carbon fraction was quantified (Tce) by thermochemical oxidation with a 5% H2O2 solution at 80?C for 48h, the materials produced at 350, 450 and 550 ?C, before and after oxidation, were analyzed by 13C NMR technique. The contents of Klason lignin did not differ statistically by Tukey test at 5%. As higher the pyrolysis final temperature was, lower was the yield of biochar, higher was the content of fixed carbon (Tcf), lower was the O/C and H/C ratios, higher was the thermogravimetric index (ITG) and higher was the Tce, indicating the increase in stability of these materials after pyrolysis, and this effect was more evident as higher was pyrolysis final temperature. The Rcf and Rce varied little in all the treatments, indicating that no significant gain or loss independent of the feedstock and/or pyrolysis final temperature. High Pearson correlation (0.96) between Rcf and Rce suggests that both approaches could be used to estimate the stable fraction of biochar. From 13C NMR spectra it was observed that biochars produced at 350?C, signals relating to lignin were still present. For 450 and 550?C, the spectra were very similar, indicating that there is no need to produce biochar above these temperatures, since the structure of the materials slightly altered, with a predominance of aromatic structures. For biochars produced at 350?C, it was observed that thermochemical oxidation was responsible for removing the labile structures still present as well as aromatic structures less resistant to degradation. For 450 and 550?C, as they already had the predominance of aromatic structures, thermochemical oxidation has been mainly active in these structures, however much milder. The thermochemical oxidation was responsible for the functionalization of biochars, this effect being milder, as higher was pyrolysis final temperature. Thus, biochars produced at pyrolysis final temperatures up to 450?C, were more stable and therefore more resistant to degradation. / O biocarv?o n?o ? composto somente de carbono est?vel. Certa por??o do material ? degradada com certa facilidade, sendo esta condi??o dependente n?o somente das caracter?sticas da mat?ria-prima, mas tamb?m das condi??es de pir?lise, principalmente a temperatura final de produ??o. Dessa forma, o objetivo geral deste estudo foi avaliar os efeitos da temperatura final de pir?lise na estabilidade de biocarv?o produzido a partir de res?duos florestais de esp?cies de (Pinus caribaea e Pinus taeda) e folhosas (Eucalyptus dunnii e Eucalyptus urophylla). Para as mat?rias-primas in natura, quantificou-se o teor de lignina de Klason, procedeu-se a an?lise elementar, an?lise termogravim?trica (TGA/DTA) e resson?ncia magn?tica do 13C no estado s?lido (RMN 13C). Para os biocarv?es, os quais foram produzidos a uma taxa de aquecimento de 10?C.min-1 por 60 min em 5 diferentes temperaturas (350, 400, 450, 500 e 550?C) procedeu-se a an?lise imediata e para os materiais produzidos a 350, 450 e 550?C, a an?lise elementar, TGA/DTA e RMN 13C. A fim de avaliar a estabilidade do biocarv?o, quantificou-se o teor de carbono est?vel (Tce) atrav?s da oxida??o termoqu?mica com solu??o de H2O2 5 %, a 80?C por 48h, sendo os materiais produzidos a 350, 450 e 550?C, antes e ap?s a oxida??o, analisados atrav?s da t?cnica de RMN 13C. Os teores de lignina de Klason n?o diferiram estatisticamente pelo Teste de Tukey a 5%. Quanto maior a temperatura final de pir?lise, menor o rendimento em biocarv?o, maior o teor de carbono fixo (Tcf), menores as raz?es O/C e H/C, maior o ?ndice termogravim?trico (ITG) e maior o Tce, indicando o aumento da estabilidade dos materiais ap?s a pir?lise, sendo este efeito mais evidente, quanto maior a temperatura final de pir?lise. O Rcf e o Rce variaram pouco para todos os tratamentos, indicando que n?o foram observados ganhos ou perdas expressivos, independente da mat?ria-prima e/ou da temperatura final de pir?lise. A alta correla??o de Pearson (0,96) entre Rcf e Rce sugere que ambas as metodologias poderiam ser utilizadas para estimar a fra??o est?vel do biocarv?o. A partir dos espectros de RMN 13C ? poss?vel observar que em biocarv?es produzidos a 350?C, sinais referentes ? lignina ainda est?o presentes. Em 450 e 550?C, os espectros s?o bem semelhantes, evidenciando que n?o h? necessidade de se produzir biocarv?o acima dessas temperaturas, uma vez que a estrutura qu?mica dos materiais pouco se altera, com o predom?nio de estruturas arom?ticas. Para os biocarv?es produzidos a 350?C, observa-se que a oxida??o termoqu?mica foi respons?vel por remover parte das estruturas l?beis ainda presentes, bem como estruturas arom?ticas menos resistentes ? degrada??o. Em 450 e 550?C, como j? havia o predom?nio de estruturas arom?ticas, a oxida??o termoqu?mica atuou principalmente nestas estruturas; no entanto, de uma forma mais branda. A oxida??o termoqu?mica foi respons?vel pela funcionaliza??o dos biocarv?es, sendo este efeito mais brando, quanto maior a temperatura final de pir?lise. Dessa forma, biocarv?es produzidos em temperaturas finais de pir?lise acima de 450?C, mostraram-se mais est?veis, logo, mais resistentes ? degrada??o.
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Estudo experimental da pirólise lenta de bambu (Dendrocalamous giganteus Munro) e caracterização do carvão vegetal gerado / Experimental study of the slow pyrolysis of bamboo (Dendrocalamus giganteus Munro) and chraracterization of the produced charHernández Mena, Laidy Esperanza, 1986- 26 August 2018 (has links)
Orientador: Araí Augusta Bernárdez Pécora / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-26T02:49:16Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: O decréscimo da oferta de recursos florestais nativos tem chamado a atenção de pesquisadores do mundo todo para a busca de matérias-primas renováveis e o desenvolvimento de processos sustentáveis. O bambu apresenta-se como uma matéria-prima de alta produtividade, rápido crescimento e maturidade, e que está tornando-se importante como um excelente substituto em processos onde a madeira é utilizada. Suas propriedades o tornam atrativo para ser utilizado em processos de termoconversão de biomassa, como a pirólise. O objetivo deste projeto é contribuir com novos conhecimentos para a valorização do bambu como matéria prima sustentável, através do estudo experimental da pirólise lenta de partículas de bambu da espécie Dendrocalamus giganteus Munro para a produção de carvão vegetal. Este estudo apresenta a determinação da influência da temperatura sobre o processo de degradação térmica e sobre as propriedades do produto solido. O estudo envolveu a caracterização físico-química das partículas de biomassa in natura moídas e a realização de testes experimentais conduzidos em reator de pirólise com leito mecanicamente agitado em temperaturas finais na faixa de 300 a 500 °C. A caracterização do produto sólido gerado nas diferentes condições operacionais testadas envolveu análise elementar e imediata, determinação do poder calorífico, analises BET e microscopia eletrônica de varredura (MEV),e do pH. Adicionalmente o bio-óleo gerado foi caracterizado, visando aplicação como combustível ou matéria prima química, e a sustentabilidade econômica do processo. Os resultados indicam que a temperatura final do processo de pirólise tem grande influência sobre a produção e composição dos produtos. O rendimento de carvão diminui com o aumento da temperatura de pirólise, no entanto, seu teor de carbono fixo e seu poder calorífico aumentam. Os resultados mostram que o bambu estudado apresenta potencial de utilização como matéria-prima para pirólise apresentando propriedades similares a de outras biomassas como a madeira. Os produtos gerados podem ser utilizados para diversas finalidades, o carvão tem aplicações energéticas e agrícolas e o bio-óleo pode ser considerado uma fonte valiosa de produtos químicos / Abstract: The decrease of the supply of native forest resources has drawn attention from researchers around the world in the search for renewable raw materials and for the development of sustainable processes. The bamboo as a raw material presents high productivity, easy propagation, fast growth and maturation, and it is becoming increasingly important as an excellent substitute for wood. These properties make it attractive for energy conversion processes like pyrolysis. The aim of this project is to contribute to the knowledge and valorization of the bamboo as a sustainable feedstock, through experimental research of the slow pyrolysis of bamboo specie Dendrocalamus giganteus Munro aiming biochar production. In this study the effect of temperature on the slow pyrolysis process of bamboo and the properties of pyrolysis solid products were determined.The research included the physicochemical characterization of biomass particles and the experimental pyrolysis tests conducted in a pyrolysis reactor mechanically agitatedat a final temperature ranging from 300 to 500 °C. The characterization of the solid product involved proximate and CHN-elemental analysis, heating value, density, BET and scanning electron microscopy (SEM) analysis and pH. Furthermore, the bio-oil was characterized considering its utilization as a liquid fuel or chemical feedstock as well as the economical sustainability of the slow pyrolysis process of bamboo. The results indicate that the final temperature of the pyrolysis process has important influence over products distribution and composition: when the temperature increased char yield decreased and its fixed carbon content and high heating value increased. The results show that bamboo has potential as feedstock in pyrolysis process because it has similar properties with others biomass as wood. The pyrolysis products can be evaluated in different applications, the char has energetic and agricultural applications and the bio-oil can be considered as a source of valuable chemicals / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
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Effets des amendements organiques exogènes sur la composition de la matière organique et le stockage du carbone d'un sol dégradé par l'érosion dans le Nord du Vietnam / Effects of exogenous organic amendments on carbon storage and soil organic matter composition in erosion-degraded soil in Northern VietnamNgo, Thi Phuong 06 May 2014 (has links)
Une stratégie pour améliorer durablement la fertilité des sols dégradés par érosion au Nord du Vietnam consiste à apporter des amendements organiques exogènes (AOEs). L'application du lisier de buffle, son compost et lombricompost, ainsi que le biochar permettraient à faible coût d’améliorer la qualité des sols et la croissance des plantes en réduisant l'utilisation d'engrais, mais également de séquestrer du carbone. L’objective de cette thèse est d’évaluer (1) l’utilité des quatre AOEs seuls ou en association pour séquestrer du carbone, et (2) l’effet de l’apport des quatre substrats organiques seuls ou en association sur la quantité et qualité des matières organiques d’un sol agricole tropical dégradé typique du Nord du Vietnam. Pour répondre à cet objectif, nous avons effectué des incubations au laboratoire, en sachet de litière dans des conditions de terrain et suivi pendant trois ans une expérience en mesocosme avec ajouts des AOEs au sol cultivé en conditions de terrain.Nos résultats montrent que le compostage en présence de vers de terre conduit à une plus forte transformation de la matière organique issue du lisier de buffle par rapport au compostage traditionel. Le lombricompost était enrichi en composés azotés et appauvri en polysaccharides, et se caractérisait par une altération plus importante des lignines en comparaison avec le compost. La stabilité biologique de ces AOEs a été liée à leur teneur en carbone soluble, diminuant suivant l’ordre : lisier de buffle > compost > lombricompost, alors que leur réactivité chimique était similaire. Le biochar, constitué de carbone aromatique, se caractérisait par une très forte stabilité biologique et chimique. L’association du biochar avec les autres AOEs a influencé leur stabilité chimique et biologique, en protégeant la matière organique labile contre l'oxydation chimique et la dégradation biologique.Notre expérience de trois ans en mésocosmes en conditions naturelles a montré que tous les AOEs ont un effet positif sur le stockage du carbone dans le sol ainsi que sur la qualité de la matière organique de sol. L’association de biochar et de lombricompost en augmenttant l’abondance des composés dérivés de la lignine ainsi que la teneur en sucre provenant des plantes et des microorganismes, semble montrer un effet synergique de cette association sur la fertilité des sols (activité microbienne, prospection racinaire). Comparé aux résultats d’incubation en sachet de litières, ces résultats indiquent un effet significatif et contrasté des AOEs sur la croissance des plantes en particulier sur l’apport racinaire. En conclusion, l’association de biochar et de lombricompost semble la meilleure solution pour améliorer la qualité de sol dégradé par l'érosion dans le Nord du Vietnam. Ces résultats devront être confirmés par des études à long terme, tant du point de vue de la qualité physicochimique que biologique des sols amendés par ces AOEs. / Intensification of agricultural use of tropical soils in Northern Vietnam leads to acidification associated with organic matter loss, rapid decline of their fertility and high erosion rates. Such negative effects may be counteracted by exogenous organic amendments (EOMs). The application of buffalo manure, its compost and vermicompost and biochar alone or in mixture with other EOMs is promising to improve at low cost soil quality, plant growth and carbon sequestration. The aims of this study were to evaluate (1) the usefulness of the four EOM alone or in mixture to sequester carbon and (2) the effect of these amendments on quantity and quality of soil organic matter of a tropical soil degraded by erosion. To anwer to this objective we carried out incubations in the laboratory, in litterbags under field conditions and we monitored a mesocom experiment, where the EOM were added and subjected during three years to cultivation and natural rainfall conditions. Our results showed that composting in the presence of earthworms led to stronger transformation of buffalo manure than regular composting. Vermicompost was enriched in N-containing compounds and depleted in polysaccharides. It further contained stronger modified lignin compared to regular compost. Biological reactivity of these AOEs was related to their soluble organic matter content, which decreased in the order buffalo manure > compost > vermicompost, whereas their chemical reactivity was similar. Bamboo biochar was enriched in aromatic carbon and characterized by a high biological and chemical recalcitrance. The presence of biochar influenced the biological as well as chemical reactivity of the other organic amendments. It led to a protection of organic matter against chemical oxidation and changed their susceptibility to biological degradation. Our experience with mesocosmes during 3 year under the natural conditions showed that all organic amendments had a positive effect on soil carbon storage and significantly influences soil organic matter quality. Biochar could increase the soil carbon sequestration potential, when applied in mixture with vermicompost. The presence of biochar increased lignin derived compounds abundance as well as both plant and microbial sugar content of soil amended with vermicompost but it had no effect in the case of control soil. Compared to our litterbag experiment these results show that EOM have a strong contrasting effect on plant growth, in particular root litter input. In conclusion, the incorporation of biochar and vermicompost seems to be the best solution to improuve the quality of degraded soil in Northem Vietnam. More studies about the impacts of this amendment on soil physico-chemical and biological properties in long-term are needed to comfirm these results.
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Biokolsanvändningen i Sverige : Vad krävs för att svenska lantbruk, kommuner och trädgårdsindustrin ska börja använda eller utöka sin användning av biokol?Agnesson, Sara January 2021 (has links)
The amount of carbon dioxide, CO2, in the atmosphere is continuously rising due to human emissions caused by combustion of fossil fuels and changing of land use. In a very short time several measures need to be taken in order to reduce the amount of CO2 in the atmosphere and thereby slowing down climate change as much as possible. The land use has changed considerably the last century with the biggest change in recent decades. This has led to that arable land all over the world has been depleted of nutrients with up to 75% in some regions. With a growing population worldwide and increased climate changes that threatens the arable land, something needs to be done to make sure we use the arable land in the most effective way. Biochar is one of the solutions to both these problems. By producing char out of biomass in high temperatures with minimized access to oxygen in a pyrolysis process you get biochar. This process releases less CO2 than a normal combustion process and the biochar becomes a carbon sink when it is put in the soil. With its porous structure biochar has a great ability to keep water and nutrients in the soil for a very long time and it also makes the soil porous with a great amount of oxygen, which the roots prefer. The purpose of this essay is to find out what the use of biochar looks like in Sweden and how the use could increase within the agriculture, the municipalities and within horticulture. With qualitative interviews and a quantitaive and qualitative survey this essay has come to the conclusion that four things are needed to increase the use of biochar in Sweden. First of all, more scientific research is needed on biochar and how this can be used in the best way since it is a new product and there are still much to learn. Secondly, an increased production in Sweden is needed since today´s demand is bigger than the supply. Thirdly, it is needed to be able to certify ones carbon sink in order to be able to sell carbon-sink-ceritficates to companies who would like to reduce their climate impact. Finally, more information on biochar is needed, in all stages. Producers need information to be able to start producing biochar and consumers need information in order to increase the demand and the interest of biochar. / Koldioxidhalten i atmosfären ökar ständigt till följd av människans utsläpp i samband med förbränning av främst fossila bränslen och förändrat markanvändande. På mycket kort tid behöver flera åtgärder vidtas för att minska koldioxidhalten i atmosfären och därmed bromsa klimatförändringarna i största möjliga mån. Markanvändningen har förändrats kraftigt det senaste århundradet med den största förändringen de senaste decennierna, vilket har lett till att åkermark över världen har utarmats näringsmässigt med upp till 75% på vissa platser. Med en växande befolkning i världen och ökade klimatförändringar som hotar jordbruksmarken behöver något göras för att effektivisera den jordbruksmark som finns. Biokol är en av lösningarna på båda de här problemen. Genom att producera kol av biomassa under hög värme utan syretillgång i en s.k. pyrolysprocess skapar man biokol. Denna produktionsprocess avger mindre koldioxid än en vanlig förbränning hade gjort, samtidigt som biokolen binder kol i marken när man lägger det i jorden och därmed bildar en kolsänka. Med sin porösa struktur har biokolet stor förmåga att hålla näring och vatten kvar i jorden under lång tid och bidrar även till en porös markstruktur med mycket syre där rötter trivs. Biokol bidrar därmed både till att minska koldioxidhalten i atmosfären och till att skördarna på våra åkrar ökar och att våra stadsplanterade träd trivs bättre. Uppsatsens syfte är att ta reda på hur biokolsanvändningen ser ut i Sverige idag och att även komma fram till vad som skulle krävas för att öka biokolsanvändningen inom det svenska lantbruket, kommunerna och trädgårdsnäringen. Genom kvalitativa intervjuer och en kvalitativ och kvantitativ enkät har den här uppsatsen kommit fram till att det som krävs för att öka användningen av biokol i Sverige är främst fyra saker. Först och främst att mer forskning på biokol och dess användningsområden görs eftersom det är en ny produkt där mer kunskap behövs för att användningen av biokol ska göras på bästa sätt. Det behövs även en ökad produktion av biokol i Sverige eftersom efterfrågan idag är större än utbudet. Vidare krävs att det blir enkelt att få sin kolsänka certifierad så att den kan säljas på en marknad där företag som vill klimatkompensera kan köpa ”kolsänkecertifikat” samtidigt som certifikatet blir ett ekonomiskt incitament till att producera biokol. Slutligen krävs mer information om biokol i alla led. Producenter behöver få mer information för att vilja starta produktion av biokol och konsumenter behöver information så att intresset och marknaden för biokol ökar.
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Ekotoxikologické posouzení biouhlu z čistírenského kalu / Ecotoxicological assessment of biochar from sewage sludgeKotzurová, Iveta January 2019 (has links)
The aim of this diploma thesis is to assess the ecotoxicological effect of biochar produced from sewage sludge. In case of application of biochar to agricultural land, both the soil and aquatic ecosystem may be affected therefore contact and aquatic tests were chosen to assess the ecotoxicological effects. Representatives of soil invertebrates were earthworms Eisenia fetida; Daphnia magna and Artemia salina were chosen from aquatic animals and terrestrial plants were represented by Lactuca sativa, Sinapis alba and Allium cepa. The results of contact tests point out how ecosystem could be negatively affected by biochar dose. Through aqueous extract were shown differences in sensitivity of individual organisms in aquatic tests. Dried sewage sludge was found to be the biggest burden for all tested organisms. The pelletized biochar with the addition of an additive showed the lowest negative effect on tested organisms.
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Účinnost odstranění vybraných léčiv z vody různými sorpčními materiály / Removal efficiency of selected drugs by various sorptive materials from waterŠtofko, Jakub January 2019 (has links)
This thesis deals with sorption of selected drugs from model water by various sorption materials. Contamination of water resources by the pharmaceutical industry is a major problem today. Wastewater treatment plants, whose technological processes are unable to completely remove them, have a significant share in the penetration of these substances into the environment. At present, attention is paid to alternative materials that are capable of eliminating these substances. One of the potential sorption materials is biochar as one of the main pyrolysis products. This work focused on the assessment of the sorption properties of the different types of biochar and commercially used active charcoal. The sorption properties of the individual materials were compared with respect to the non-steroidal anti-inflammatory substance ibuprofen and the sulphonamide antibiotic sulfamethoxazole. The results of vial experiments were analysed on a liquid chromatograph with mass detection.
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Studium sorpčních vlastností biouhlí / Study of sorption properties of biocharKocinger, Oskar January 2020 (has links)
This diploma thesis deals with sorption properties of biochar produced from wood biomass treated with concentrated hydrochloric acid and activated carbon with respect to the triazine pesticide propazine. Although pesticides are widely used in both agriculture and the private sector worldwide, they pose a significant risk to ecosystems and human health. Propazine belongs to the group of chlorinated triazine herbicides, which pose a risk mainly as endocrine disruptors. The sorption of organic pollutants using pyrogenic carbonaceous materials promises an efficient and economically affordable solution, which has recently received increasing attention from the scientific community. In this work, we used isotherms to describe the equilibria of propazine sorption to given sorbents during vial experiments. Analysis of the propazine content in the model water solutions after reaching equilibrium was performed using high-performance liquid chromatography with mass detection.
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Nitrate and phosphate removal from aqueous solution by biochar and agroforestry residuesGara Ramos, Rodriguez January 2012 (has links)
No description available.
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Specific Phosphate Sorption Mechanisms of Unaltered and Altered BiocharSzerlag, Kathryn D 07 November 2016 (has links)
Biochar has been shown to act as an effective sorbent for many organic and inorganic contaminants (including phosphate) and can help to improve the quality of our fresh water resources by preventing eutrophication. Most of the high efficiency biochar phosphate-adsorbent feedstocks are modified with chemical pretreatment, phytoremediation or anaerobic digestion to accumulate desired elements. The main objectives of this project were to first engineer magnesium (Mg) and calcium (Ca) altered biochar by chemical pretreatment followed by pyrolysis at either 350 or 550°C and evaluate their phosphate adsorption rate and potential as compared to their unaltered counterparts. Determination of surface physiochemical characteristics of the unaltered (U350 and U550), Mg-altered (Mg350 and Mg550), and Ca-altered (Ca350 and Ca550) hardwood biochars was also completed. The unaltered biochars did not adsorb any phosphate which was likely due to a lack of Mg or Ca and crystalline structures as confirmed by ICP-AES and XRD. Adsorption kinetics revealed that both the Ca-altered and Mg-altered biochars took about 10 days to reach equilibrium. The Langmuir isotherm model was the best fitting model for all altered biochars and Mg550 adsorbed the most phosphate with a Langmuir maximum capacity (Q) of 135.8 mg/g at pH 9. XRD spectra confirmed crystallinity for both the Ca-altered and Mg-altered biochars for calcite (CaCO3) on the Ca-altered biochar and both periclase (MgO) and brucite (Mg(OH)2)on the Mg-altered biochars. SEM images of Mg550 followed by EDS confirmed the presence of nano-sized flakes on the biochar surface and identified them as the primary phosphate adsorption sites. SEM images of Ca550 identified globular, rather than flakey structures on the biochar surface and EDS offered further confirmation that these were calcite minerals. Although Ca350 and Ca550 adsorbed phosphate from solution, Mg350 and Mg550 exhibited a much greater phosphate sorption potential with Q at 18.91, 16.34, 39.59 and 135.8 mg/g (pH 9), respectively. This may be attributed to the morphological differences between the highly crystalline flake-like structures of the Mg altered biochars and the globular structures on the surface of the Ca altered biochars. The mechanisms revealed for phosphate sorption include electrostatic interactions, precipitation, and ligand exchange.
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