Continuous population growth and rapid industrial advancement and development have paved the way for ever increasing environmental pollution. At present, water pollution is a serious global issue that threatens environmental sustainability. The contamination of aquatic bodies with potentially toxic organic and inorganic substances are the result of world-wide anthropogenic activities. These pollutants can have detrimental health consequences on humans and ecosystems. Over the past decades, techniques such as chemical precipitation, ion-exchange, adsorption, membrane filtration, and electrocoagulation-flocculation have been developed and employed for the treatment of drinking and wastewater. Among the currently available techniques, pollutant removal by adsorption is most promising due to its cost-effectiveness, simplicity in operation, environmental friendliness, and abundance of adsorbents. This study emphasized the utilization of biochar (BC), after appropriate surface modification, for the removal of potentially toxic contaminants. In the first study, a base activated biochar was synthesized by treating the biochar with potassium hydroxide (KOH) at 700 ℃ in a muffle furnace for 1 h. The resulting high surface area biochar (KOHBC) was used for the removal of Cr(VI), Pb(II) and Cd(II). In the second study, a biochar-supported polyaniline hybrid was synthesized for aqueous chromium and nitrate adsorption. Introduction of amine and imine groups to the biochar facilitated the removal of these contaminants. In the final study, a composite containing Fe-Ti oxide/biochar (Fe2TiO5/BC) was synthesized for sorptive removal of metal cations, oxy anions, inorganics, and organic contaminants from aqueous solutions. Additionally, this composite was used as a photocatalyst towards aqueous methylene blue (MB) degradation. The surface chemistry and composition of these adsorbents were examined by PZC SEM, TEM, XPS, FTIR, TGA, elemental analysis, and surface area measurements.

Phosphorus (P) in stormwater runoff has detrimental effects on water quality and ecosystem health when it reaches surface waters and promotes algal blooms. Constructed wetlands (CWs) have been utilized to combat this problem by containing stormwater and removing excess nutrients. Including filter materials in the design of CWs has shown promise for increasing their capacity for nutrient removal. This mesocosm scale study was conducted outdoors over a 12-month period to evaluate the effectiveness of three filter materials in their ability to adsorb phosphorus, retain water, and support plant life. The filter materials examined were electric arc furnace (EAF) slag, engineered biochar, and sand. All treatments demonstrated positive plant response and the ability to retain water. The EAF slag and biochar removed significant amounts of P from effluent and appear to be suitable materials for integrating into CW design. Sand was found to be ineffective as a P filter.

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Accumulation of heavy metals in different environmental compartments and their toxicity even at trace level concentration necessitates the study of their efficient removal. Furthermore, metals could co-exist in the environment which is a complex scenario as there would be competition among the metals in terms of removal efficiency. This study presents the effective removal of trace level toxic metals (Hg2+, Cd2+, Pb2+) in both single and ternary metal solutions through adsorption on the successfully synthesized composite (SC) of pinewood-derived biochar (BC) and graphene oxide (GO) nanomaterials. Moreover, different linear regression tools (Gaussian Process (GP), Random Forest (RF), and Feed Forward Back Propagation (FFBP)) from the machine learning (ML) toolbox were used to make the comparison between actual and their predicted adsorption. The structural and morphological analysis of the SC showed that GO was successfully coated on the surface of the BC. GO coating increased the surface area, porosity, functional groups, and adsorption efficiency of these toxic metals on the SC as compared to the unmodified BC. The factors affecting adsorption efficiency were metal concentration, pH, and the ratio of BC and GO in the SC. The adsorption efficiency in single metal solution was found 94-98% for Hg2+, 92-94% for Cd2+, and 96-99% for Pb2+ and for ternary metal solutions 94-96% for Hg2+, 95-97% for Cd2+, and 97-99% for Pb2+ at pH 6 and SC with BC/GO (w/w) ratio as 1:10. However, for unmodified BC, the adsorption efficiency was less in both single and ternary solutions. Thus, results indicate that modification of BC with GO increases adsorption efficiency as compared to unmodified BC. Furthermore, for all three metals, Freundlich's adsorption isotherm was followed in both single and ternary solutions. Regeneration of the SC was also attained by adsorbate desorption, producing a competent and cost-effective adsorbent for the removal of toxic metals from our environment. Furthermore, from the ML toolbox mean squared error (MSE) values between the actual efficiency and predicted efficiency were calculated which was negligible in the case of GP, with regression coefficient (R2) equal to 1. This implied that GP was the most suitable linear regression model among other models (RF, FFBP) for the available data sets. These predicted values through different ML models could significantly reduce the experimental workload for various parameters in predicting the removal efficiency of the synthesized composite for the target toxic metals. Thus, these models help in reducing experimental time and predicting the most appropriate combination for the best result in the future.

Conventional farming practices and land-use conversions drive carbon out of soil and into the atmosphere, where it contributes to climate change. Biochar, a soil amendment produced by pyrolyzing organic feedstocks under low-oxygen conditions, is a promising tool to restore soil carbon and draw down atmospheric carbon dioxide. Biochar has received considerable attention from scientists, growers, and environmentalists in the last 20 years, but there is still a gap between academic research and practical recommendations on biochar production and application that are relevant to small-scale growers. Here I present the results from two complementary studies that demonstrate the utility of local-scale biochar systems and provide some recommendations for those looking to work with biochar. The first study sought to determine the impact of biochar amendments on soil carbon and nutrient retention on three working farms across a variety of soil types, cropping systems, and climates in the United States. The effect of biochar amendment depended on initial soil characteristics and the properties of the biochar applied. Biochar amendments increased soil carbon in all three sites and increased soil nitrogen at two of the three. In this study pyrolysis conditions appeared to be as important as local soils and climate influences on the efficacy of biochar treatments. The second study was a life cycle assessment using SimaPro software to quantify the carbon balance and global warming potential of biochar produced from three local feedstocks (softwood, hardwood, and hay) applied to pasture soils in Southwest Virginia. Feedstock type, pyrolysis gas yield, and transportation distance significantly contributed to variation in the carbon balance of each agro-ecosystem. Biochar made from softwood lumber scraps performed best, with the highest net carbon storage and lowest global warming potential, followed by biochar made from hardwood scraps. Hay biochar performed worst, with positive carbon emissions (i.e., more carbon released than stored over its life cycle) in most scenarios tested, mainly because of its low biochar yield and the carbon emissions associated with agronomic production and transportation. Together these studies demonstrate the potential of local biochar systems to improve both soil health and carbon sequestration, and reinforce how important it is to know the characteristics of the soil and the production history and properties of the biochar being applied in order to meet soil health and carbon sequestration goals. / Master of Science / Conventional farming practices break down organic material in the soil, which decreases the capacity of soils to sustain crop growth and contributes to climate change as the soil releases carbon dioxide and other greenhouse gasses into the atmosphere. Biochar, or charcoal that is deliberately incorporated into soil, is gaining popularity among farmers, gardeners, and climate scientists for its ability to improve soil health and draw carbon out of the atmosphere to create stable long-term pools of carbon underground. Unfortunately, much of the research on biochar does not translate easily into recommendations for growers and land-managers to make and use biochar. Here I discuss the results from two studies examining the effect of biochar on soil health and carbon sequestration on local scales. In the first experiment I analyzed soil samples shared by farmers in New Mexico, Minnesota and Virginia who applied locally-sourced biochar to their soils. I found that the initial characteristics of the soil and of the biochar affected how the biochar application changed agriculturally-relevant soil properties. In general, biochar improved soil carbon and nitrogen levels, had mixed effects on soil pH depending on the biochar's pH, and had no effect on electrical conductivity (a measure of soil salinity). The second study was a life cycle assessment that quantified and compared greenhouse gas emissions of three different types of biochar, from feedstock harvest to biochar application to soil. I found that the type of feedstock used to make biochar, the amount of gas emitted during the conversion process, and the distance the feedstocks and biochar were transported all played a role in the overall carbon balance of the life cycle. The biochar made from softwood scraps performed best from a carbon storage perspective, followed by biochar made from hardwood. These two biochars tended to return more carbon to the soil than they emitted over their life cycle. The biochar made from hay performed worst, and emitted more carbon than it stored in most of the scenarios I tested. Together these studies show the potential of local biochar systems to improve both soil health and carbon sequestration and reinforce how important it is to be familiar with the soil and the production history and properties of the biochar being applied in order to meet soil health and carbon sequestration goals.

Water availability is presently under risk owing to the increased discharge of pollutants from both industrial and residential properties. A distinct category of pollutants known as "emerging contaminants" (ECs), whose hazards were either unknown before they were noticed, e.g., antibiotics, dyes, PFAS, etc. Most of the ECs are unregulated and pose a threat to aquatic and human life at even low doses. Our water treatment facilities are not designed to efficiently eliminate these toxic substances. Therefore, we need an economical tertiary treatment approach. Adsorptionis a sustainable, cost effective and simple technique, making it a viable technique for pollutants elimination on a worldwide scale. The removal of these ECs has been made possible by several commercially available adsorbents, however most of them are expensive. Adsorbents fabrication using, agricultural wastes is an effective waste management technique that helps reduce greenhouse gas emissions via carbon sequestration. The adsorption capability of adsorbents can be enhanced by further modification of its properties. This research study focuses on conversion of biomass into environmentally friendly adsorbents including biochar and nanocellulose aerogel. In the first study, a natural mineral dolomite (CaMg(CO3)2) modified biochar was fabricated from rice husk and used to remove anionic reactive dyes, Remazol Brilliant Blue (RBB) and Reactive Black 5 (RB-5) from synthetic wastewater. In the second study, a sustainable aminated/TEMPO cellulose nanofiber (Am/TEMPO-CNF) aerogel was fabricated and used to treat oxytetracycline (OTC) and chloramphenicol (CAP) contaminated water. The physiochemical properties of all adsorbents were studied using FTIR, SEM, TGA, elemental analyzer and N2 adsorption-desorption isothermal analyses. The contaminants were quantified using Ultraviolet–visible spectroscopy (UV-Vis) before and after the experiments. Kinetics, isothermal and thermodynamics modeling was applied to analyze the adsorption behavior and mechanism. In the third investigation, a novel In-situ UiO-66-NH2/TOCNF adsorbent was employed to remove the anionic azo dyes Orange II (ORII) and Congo Red (CR) from synthetic wastewater. We also looked at how pH, time, and initial concentration impacted CR and ORII adsorption. Research was conducted to assess the stability and adsorption potential under various situations by thermodynamics and regeneration.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-03-07T13:36:31Z No. of bitstreams: 1 Wendson de Moraes Silva.pdf: 987908 bytes, checksum: 4fcf02e96752efd0c4080412468aca99 (MD5) / Made available in DSpace on 2017-03-07T13:36:31Z (GMT). No. of bitstreams: 1 Wendson de Moraes Silva.pdf: 987908 bytes, checksum: 4fcf02e96752efd0c4080412468aca99 (MD5) Previous issue date: 2016-07-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The use of biochar in agriculture is a practice widely used, in order to improve soil characteristics, being of great importance and contributing to soil structure, increase the carbon content in the soil, it is becoming an increasingly important tool in soil conditioning. Several studies are being conducted throughout in Brazil and in the world using the application of biochar in order to find management alternatives to increase the content of soil organic matter. Thus, this study aimed to characterize two biochars produced from two types of waste (peel and coffee grounds), and to evaluate the effect of these in the chemical and biological characteristics of an Entisol cultivated with corn and beans. The work was conducted in the experimental area of the Academic Unit of Garanhuns Federal Rural University of Pernambuco (UAG/UFRPE). Initially it was conducted to produce the two biochar a coffee pods (CC) and other coffee grounds (BC), which was carried out by means of combustion heat in a small home oven. After production of these were determined specific surface area (SSA), the adsorption capacity and desorption of phosphorus by colorimetric and performed the analysis of chemical composition of each biochar. For implementation of the experiment in greenhouse was collected soil at 0-20 cm in an area from native forest, the farm Riacho kite in mesoregion South Agreste of Pernambuco, São João, which is classified as Entisol typical eutrophic. Also analyzes were performed to characterize the chemical and physical properties of the soil. The experiment was conducted in a completely randomized design (CRD) at random. Treatments consisted of soil with mineral fertilizers (NPK) and organic fertilization with cattle manure, both according to the recommendations indicated for each crop, and two types of Biochar, with 4 repetitions. Four seeds of maize and beans were placed on vessels, five days after emergence (DAE) was carried out thinning, leaving one plant per pot. The pH and conductivity were measured (EC) soil water drainage and held measuring evapotranspiration (ET). And at the end of the experiment, 45 DAE was held to determine the production of fresh biomass (BF) and dry (BS) of the shoot. On the ground it was determined carbon analysis of soil microbial biomass (CBM), the basal respiration (RBS), total organic carbon (TOC), soil organic matter (OM), metabolic quotient (qCO2) and the quotient microbial (QMIC). Data were submitted to analysis of variance (ANOVA) by F test and means were compared by Tukey test at 5% probability, and the data were subjected to multivariate principal component analysis (PCA). The biochar BC was more effective in releasing the CC P, which may be related to the lower ASE BC with respect to DC, since higher SEA can cause the P becomes adsorbed to the particles of CC. Whatever type of biochar (CC or BC), the highest dose (16 Mg ha-1) promoted changes in the microbiological properties of the soil, increasing the CBM, TOC and qMIC and decreasing qCO2. Treatment with coffee grounds of biochar (16 Mg ha-1 dose) promoted greater efficiency in water use, consuming 45.6 and 47% less water in crops of corn and beans, respectively. The use of biochar coffee waste (CC and BC) promoted changes in soil properties, increasing pH, P and K levels. / Vários estudos estão sendo realizados em todo no brasil e no mundo utilizando a aplicação de biochar, com a finalidade de se encontrar alternativas de manejo para aumentar o teor de matéria orgânica do solo. Dentre essas alternativas, o uso do biochar na agricultura vem se tornando cada vez mais uma técnica bastante interessante para mitigar os efeitos das mudanças climáticas, sendo uma importante ferramenta no sequestro de carbono que também tem potencial de proporcionar diversas melhorias nas propriedades físicas, químicas e biológicas do solo. Assim, o presente trabalho teve o objetivo de caracterizar dois biochars, produzidos a partir de dois tipos de resíduos (casca e borra de café), além de avaliar o efeito destes nas características químicas e biológicas de um Neossolo Regolítico cultivado com milho e feijão. O trabalho foi conduzido na área experimental da Unidade Acadêmica de Garanhuns da Universidade Federal Rural de Pernambuco (UAG/UFRPE). Inicialmente foi realizado a produção dos dois biochar um de casca de café (CC) e outro da borra de café (BC), que foi realizada por meio da combustão em um pequeno forno térmico caseiro. Após a produção destes, foram determinadas a superfície específica (ASE), a capacidade de adsorção e dessorção do fósforo por colorimetria, e realizada a análise da composição química de cada biochar. Para implantação do experimento em casa de vegetação foi coletado solo na camada de 0-20 cm numa área proveniente de mata nativa, na fazenda Riacho do Papagaio, na mesorregião do Agreste Meridional do Estado de Pernambuco, município de São João, sendo este classificado como Neossolo Regolítico eutrófico típico. Também foram realizadas análises para caracterizar as propriedades químicas e físicas do solo. O experimento foi conduzido no delineamento inteiramente casualizado (DIC) ao acaso. Os tratamentos consistiram de solo com adubação mineral (NPK) e adubação orgânica com esterco de curral, ambas segundo a recomendação indicada para cada cultura, e dois tipos de Biochar, com 4 repetições. Quatro sementes de milho e de feijão, foram colocadas por vasos, sendo que cinco dias após a emergência (DAE) foi realizado um desbaste, deixando-se uma planta por vaso. Foram medidos os valores de pH e de condutividade elétrica (CE) da água de drenagem do solo, e realizada a medição da evapotranspiração (ET). E no final do experimento, 45 DAE, realizou-se a determinação da produção de biomassa fresca (BF) e seca (BS) da parte aérea. No solo foram determinadas as análises do carbono da biomassa microbiana do solo (CBM), da respiração basal (RBS), do carbono orgânico total (COT), da matéria orgânica do solo (MO), do quociente metabólico (qCO2) e do quociente microbiano (qmic). Os dados foram submetidos à análise de variância (ANOVA) por meio do teste F e as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade, e os dados foram submetidos à análise multivariada de componentes principais (ACP). O biochar de BC foi mais efetivo em liberar P que o CC, o que pode estar relacionado com a menor ASE do BC em relação ao CC, uma vez que maior ASE pode fazer com que o P fique adsorvido às partículas do CC. Independentemente do tipo de biochar (CC ou BC), as maiores doses (16 Mg ha-1) promoveram alterações nas propriedades microbiológicas do solo, aumentando o CBM, o COT e o qMIC e diminuindo o qCO2. O tratamento com biochar de borra de café (dose de 16 Mg ha-1) promoveu maior eficiência no uso de água, consumindo 45,6 e 47% menos água nas culturas do milho e feijão, respectivamente. O uso de biochar de resíduos de café (CC e BC) promoveram mudanças nas propriedades químicas do solo, aumentando o pH e os teores de P e K.

Pollution et agriculture urbaine (AU) sont deux mondes interconnectés soumettant les villes au défi de la durabilité, dans un contexte où la pollution aux metalloïdes augmente au moins autant que l'intérêt pour l'agriculture urbaine. Les biofertilisants / bioamendements utilisés en AU (champignons mycorhiziens à arbuscules, compost, biochar) peuvent influencer la mobilité des polluants du sol. Cette étude vise à mieux comprendre le devenir de contaminants inorganiques géogéniques et anthropiques, majeurs (Cd, Pb) ou émergents (Sb), dans des systèmes sol-plante-biofertilisant et leur bioaccessibilité pour l'homme. Si la mobilité des polluants est modifiée par les biofertilisants, le type de source influence aussi leur bioaccessibilité. La communauté fongique semble cruciale dans ces phénomènes mais est impactée par l'ajout de compost. Ainsi, l'utilisation de ces biofertilisants sur sol pollué est à raisonner du fait des interactions multiples affectant la phytodisponibilité des polluants. / Urban agriculture (UA) and pollution are two worlds more inter-connected every day, creating one of the main challenges of sustainable cities as persistent metal(loid) contamination increases as much as the interest for urban agriculture. Biofertilizers and bioamendments used in UA (arbuscular mycorrhizal fungi, compost, and biochar) can influence the mobility of contaminants in soil. This study aims to better understand the fate of anthropic or geogenic, major (Cd, Pb) and emerging (Sb), inorganic contaminants in soil-plant-biofertilizer systems and their human bioaccessibility. While contaminant mobility in soil is affected by biofertilizers, their origin influences also their bioaccessibility. The fungal community seems crucial in this phenomenon but is impacted by compost addition. Hence, using these biofertilizers in contaminated soils has to be thought wisely because of the multiple interactions affecting contaminant's phytoavailability.

Dans le contexte économique de la plupart des pays en voie de développement, la gazéification sous vapeur d’eau de résidus agricoles lignocellulosiques pourrait être un procédé intéressant, à la fois pour la génération d’énergie dans des régions isolées et pour la production des produits à valeur ajoutée. Étant donné que la disponibilité des résidus agricoles est souvent saisonnière, différents types de biomasse doivent être utilisés pour assurer le fonctionnement des installations de gazéification. A cet égard, ce travail est axé sur la compréhension de l'impact des caractéristiques de la biomasse sur le procédé de gazéification et les propriétés des sous-produits gazeux et solides. Trois biomasses lignocellulosiques à composition macromoléculaire et inorganique différentes ont été sélectionnées pour cette étude : coques de noix de coco (CS), bambou guadua (BG) et coques de palmier à huile (OPS). La cinétique de décomposition thermique des biomasses a été étudiée sur une échelle thermogravimétrique sous atmosphère inerte et sous vapeur d’eau. Malgré les différences dans la structure macromoléculaire des échantillons, la composition inorganique s’est avérée être le paramètre le plus important influençant la réactivité et la cinétique de gazéification. L'impact bénéfique des métaux alcalins et alcalino-terreux a été confirmé, ainsi que l'effet inhibiteur du Si et du P. Plus précisément, le ratio K/(Si+P) est considéré approprié pour décrire et comparer le comportement des biomasses pendant la gazéification sous vapeur d’eau. En conséquence, une nouvelle approche pour la modélisation de la cinétique de gazéification à partir de la composition inorganique de l’échantillon a été proposée. La validité du ratio K/(Si+P) pour classifier et prédire le comportement des biomasses a également été confirmée par des expériences dans un réacteur à lit fluidisé à l’échelle laboratoire. Les échantillons avec un ratio K/(Si+P) au-dessus de 1 ont montré des réactivités de gazéification supérieures à celles des échantillons dont le ratio était inférieur à 1, et donc, une production de gaz et un rendement énergétique plus élevés. De plus, la composition inorganique a non seulement impacté le taux de gazéification des échantillons, mais également les propriétés du sous-produit solide. En particulier, une réactivité de gazéification plus élevée est liée à des chars avec une surface spécifique et un nombre de groupes fonctionnels plus importants. Une température de 850°C et une fraction de vapeur de 30% dans l’agent de réaction ont été identifiées comme les conditions les plus adaptées à la production simultanée de gaz combustible et de char pouvant être valorisé dans des applications agricoles. Le modèle de gazéification sous vapeur d'eau et les résultats expérimentaux présentés dans ce travail peuvent être une référence pour des applications réelles de gazéification travaillant avec différents types de résidus. Par ailleurs, dans le contexte présenté, la gazéification sous vapeur d’eau de déchets lignocellulosiques peut améliorer l’accès à l’énergie des zones rurales isolées, en promouvant simultanément le développement de projets productifs susceptibles de générer de nouveaux revenus pour les communautés locales. / In the context of most developing countries, steam gasification could be a very interesting process for both energy generation in isolated areas and the production of value-added products from lignocellulosic agrowaste. Considering that the availability of agricultural residues is often seasonal, gasification facilities should operate with different feedstocks. In consequence, this work is focused on the understanding of the impact of biomass characteristics on the gasification process and the properties of the gaseous and solid by-products. Three lignocellulosic agrowastes with different macromolecular structure and inorganic composition were selected for this study: Coconut shells (CS), bamboo guadua (BG) and oil palm shells (OPS). The thermal decomposition kinetics of the selected feedstocks was analyzed in a thermogravimetric scale under inert and steam atmosphere. Despite the differences in their macromolecular composition, inorganics showed to be the most important parameter influencing the steam gasification reactivity and kinetics of the samples. The beneficial impact of AAEM was confirmed, as well as the inhibitory effect of Si and P. More specifically, the ratio K/(Si+P) proved to be suitable to describe and compare the steam gasification behavior of lignocellulosic agrowastes. In accordance, a new kinetic modeling approach was proposed to predict the gasification behavior of samples, from the knowledge of their inorganic composition. The validity of the ratio K/(Si+P) to classify and predict the biomass steam gasification behavior was also confirmed from experiments in a lab-scale fluidized bed gasifier. Samples with K/(Si+P) above 1 exhibited higher gasification reactivities compared to samples with ratios below 1, resulting in greater gas yields and higher gas efficiencies. Moreover, inorganics impacted not only the gasification rate of the samples, but also the properties of the gasification solid by-products. In particular, higher gasification reactivities were related to greater char surface areas and contents of oxygenated surface functional groups. A temperature of 850°C and a steam fraction of 30% in the reacting atmosphere proved to be the most suitable gasification conditions for the simultaneous production of fuel gases for energy applications, and a valuable char that could be valorized in soil amendment applications. The gasification model and experimental results presented in this work might be an important reference for real gasification applications working with different kind of residues, when both the gaseous and solid by-products valorization is intended. Moreover, in the presented context, steam gasification of lignocellulosic agrowaste may improve the energy access in rural isolated areas, and simultaneously promote the development of productive projects that could generate new incomes for local communities.