Eutrophication, caused by phosphate, can be detrimental both for the aquatic environment and human health. This research aims to provide deep knowledge about the adsorption properties of low-cost Fe/Mg layered double hydroxide modified biochar (LDHBC) for removal of phosphate from aqueous solution. Firstly, Fe/Mg layered double hydroxide (LDH) was synthesized by mixing FeCl3 and MgCl2. 6H2O salts in water, followed by NaOH treatment (coprecipitation method). For LDHBC, FeCl3, and MgCl2. 6H2O salts were dissolved in water, and Douglas fir biochar was added to the salts mixture to make a slurry, followed by NaOH treatment. The surface chemistry and elemental composition of both adsorbents and phosphate-laden adsorbents were characterized using Elemental analysis, BET, PZC, TGA, DSC, XRD, SEM, and TEM. Adsorption ability of LDH and LDHBC was studied by pH effects, kinetics, and the highest capacity for the analyte.

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.

Es esencial hoy en día y especialmente para un futuro próximo atender la demanda de energía y ofrecer una alternativa de fuentes renovables que no dañen el medio ambiente. Los residuos agroindustriales están ampliamente disponibles, por lo que su utilización en procesos de producción puede reducir significativamente los costes. El residuo de café y la semilla de algodón son residuos con alto contenido lignocelulósico, lo que los torna atractivos para aplicación en tecnologías de degradación termoquímicas como la pirólisis. La pirólisis consiste en la conversión de biomasa en energía y productos químicos de valor añadido. En esta tesis se realizó el estudio de la pirólisis del residuo de café y semilla de algodón. Estas biomasas fueron sometidas a la pirólisis en lecho fijo con flujo continuo de nitrógeno, generando bio-óleo, gases y biochar. Los principales productos (bio-óleo y biochar) también se han estudiado. En los bio-oleos, a través del análisis por cromatografía gaseosa bidimensional, se encontraron compuestos de gran importancia para la industria química, alimenticia, farmacéutica, para biocombustibles y alternativas de derivados del petróleo, por ejemplo, ácidos grasos e hidrocarburos identificados en el bio-oleo de la biomasa del residuo del café, y un gran contenido de compuestos fenólicos y nitrogenados, para el bio-oleo de la semilla de algodón. Las biomasas y los biochars se caracterizaron por diversas técnicas (análisis elemental, poder calorífico, contenido de cenizas, TGA SEM, FT-IR, etc.). Los biochars fueron modificados por dos distintos procesos de activación química y probados para su aplicación como adsorbente en la remoción del colorante catiónico azul de metileno en solución acuosa. La capacidad de retención del colorante para los biochars activados químicamente (de las dos biomasas), quedarán muy cerca de los resultados obtenidos para el carbón activado comercial. Los biochars también demostraron tener buenas características, como el alto poder calorífico, que sugieren su aplicación como sustituyentes de combustibles fósiles sólidos.Los productos de la pirólisis, bio-óleo y el biochar, de ambas biomasas, presentaron resultados que promueven la valorización de estos residuos tanto en aspectos energéticos, como también de innovación de materiales, contribuido a la reducción de residuos y aportando soluciones para el cuidado del medio ambiente. / It's essential nowadays and especially for the near future to meet the energy demand and offer an alternative of renewable sources that don't injury the environment. Agroindustrial waste is widely available and low cost, so its use in production processes can significantly reduce costs. The spent coffee grounds and cottonseed are residues with high lignocellulosic content, which makes them attractive for application in thermochemical technologies such as pyrolysis, which consists of the conversion of biomass into energy and value-added chemical products. In this work the pyrolysis of spent coffee grounds and cottonseed was carried out. These biomasses were submitted to pyrolysis in fixed bed with nitrogen flow, generating bio-oil, gases and biochar. The main products (bio-oil and biochar) were studied in detail. In both bio-oils, through the analysis by two-dimensional gas chromatography, compounds of great importance were found for the chemical, food, pharmaceutical, biofuels and petroleum products alternatives, for example, fatty acids and hydrocarbons identified in the bio-oil of spent coffee grounds, and a high content of phenolic and nitrogen compounds, for the cottonseed bio-oil. Biomasses and biochars were characterized by several techniques (elemental analysis, calorific value, ash content, MEV, FT-IR, etc.). The biochars were modified by two distinct chemical activation processes and tested for use as an adsorbent in the removal of the methylene blue cationic dye in aqueous solution. The results for the adsorption tests were very promising. The ability of the activated biochars in the adsorption of the dye was very close to the results obtained for commercial activated charcoal. Biochars have also demonstrated good characteristics, such as high calorific power, which suggest their application as substituents for solid fossil fuels. The products of the pyrolysis, bio-oil and biochar of both biomass presented results that promote the recovery of these residues both in energy aspects as well as in materials innovation, contributed to waste reduction and providing solutions for the care of the environment. / Avui dia en dia i, especialment de cara a un futur pròxim, és essencial atendre la demanda d'energia a través de noves alternatives basades en fonts renovables que no perjudiquen el medi ambient. En aquest sentit, els residus agroindustrials són materials àmpliament disponibles i la seua utilització en la producció d'energia podria reduir significativament els costos associats a aquest procés. El residu de cafè i la llavor de cotó són materials amb alt contingut lignocel·lulòsic, fet que els torna atractius per a la seua aplicació en tecnologies de degradació termoquímiques com la piròlisi. La piròlisi consisteix en la conversió de biomassa en energia i productes químics de valor afegit. En aquesta tesi es va realitzar l'estudi de la piròlisi del residu de cafè i de la llavor de cotó, els quals van ser sotmeses a la piròlisi en llit fix amb flux continu de nitrogen, generant bio-oli, gasos i biochar. Així mateix, s'han estudiat i caracteritzat els principals productes obtinguts (bio-oli i biochar). A través de l'anàlisi mitjançant cromatografia gasosa bidimensional dels bio-olis, es van trobar compostos de gran importància per a la indústria química, alimentària i farmacèutica, així com per a biocombustibles i alternatives de derivats del petroli. Concretament, es va identificar una gran quantitat d'àcids grassos i hidrocarburs en el bio-oli de la biomassa del residu del cafè, i un gran contingut de compostos fenòlics i nitrogenats al bio-oli de la llavor de cotó. Les biomasses i els biochars es van caracteritzar a través de diverses tècniques (anàlisi elemental, poder calorífic, contingut de cendres, TGA, SEM, FT-IR, etc.). Una vegada caracteritzats, els biochars van ser modificats a través de dos processos diferents d'activació química i provats per a la seua aplicació com adsorbents en l'eliminació del colorant catiònic blau de metilè en solució aquosa. La capacitat de retenció del colorant trobada per als biochars químicament activats (de les dues biomasses) foren comparables amb resultats obtinguts amb carbó activat comercial. Els biochars també mostraren altres característiques interessants, com un alt poder calorífic, fet que obri la possibilitat d'aplicació com a substituents de combustibles fòssils sòlids. En definitiva, els productes de la piròlisi d'ambdues biomasses, el bio-oli i el biochar, van presentar resultats prometedors pel que fa a la seua valorització energètica, com també d'innovació de materials, contribuint a la reducció de residus i aportant potencials solucions per a la reducció de la contaminació del medi ambient. / Primaz, CT. (2018). Valorização de resíduos agroindustriais de café e algodão para pordução de bio-óleo e biochar [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/110086

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.

Coal strip mining leaves widespread degraded soil throughout the southeastern US. These soils tend to have low pH, high bulk density, impacted hydrologic processes, and an accumulation of heavy metals that limit revegetation and reforestation efforts. Shortleaf pine (Pinus echinata) can tolerate these poor conditions on post-mined sites and has the largest native pine range in the southeastern US, making it an ideal species for restoration efforts. Additionally, the use of soil amendments to improve soil physical and chemical parameters is expected to lead to improved plant establishment and growth. To address the challenges associated with degraded post-mined landscapes, two studies were conducted using a biochar (BC) and microbial amendment (MA). Few empirical studies have been conducted on the success of soil amendments for soil physical properties, chemical properties, and tree growth. To fill this knowledge gap, a three year field trial was established on a reclaimed mining site in Alabama. Shortleaf pine seedlings were planted in a complete randomized block design with two soil amendment treatments: BC and MA. The second study then evaluated how climate change impacts restoration efforts. Specifically, this study observed how precipitation uncertainty affects the effectiveness of existing restoration techniques. This comprehensive 6-month greenhouse experiment in Mississippi examined shortleaf pine restoration under dry and wet moisture regimes. Soil amendments were applied to one year old seedlings replicated across moisture treatments including the same mixtures of amendments as the field experiment in addition to a no tree treatment, a pot with only post-mined soil. Findings from both studies indicate that BC did not improve measured soil properties or tree growth as expected, while the MA induced short-term impacts on soil physical and chemical properties that impacted tree growth. The greenhouse results also indicated that changes in precipitation do not impact the effects of any soil amendment. Additionally, MA may have the potential to change the allocation of biomass for shortleaf pine, which has implications for survival and restoration. In the short-term, the application of commercially recommended levels of treatments were ineffective at supporting tree growth through improvements to measured soil characteristics.