Water polluted by pharmaceuticals, metals, and phosphates can be hazardous to both the environment and human health. The main aim of this study is to develop low cost, green adsorbents for removal of these pollutants from aqueous solution as a low cost alternative to activated carbon. Biochar was produced from the fast pyrolysis of Douglas fir. Magnetic biochar was prepared by magnetite (Fe3O4) precipitation onto the biochar’s surface from an aqueous Fe3+/Fe2+ solution upon NaOH treatment. Both Douglas fir and magnetic Douglas fir biochars have high uptake and adsorption capacity. Chapter I provides an overview of different biochar production techniques and modification methods. Chapter II is a study of the aqueous adsorption of pharmaceutical products, 4-nitroaniline (4NA), salicylic acid (SA), benzoic acid (BA) and phthalic acid (PA) using Douglas fir and magnetic Douglas fir biochar. The surface chemistry and composition of the magnetic biochar were examined by SEM, SEM-EDX, TEM, PZC, XPS, XRD, elemental analysis, and surface area measurements. Chapter III describes the removal of lead and cadmium using both magnetic and nonmagnetic Douglas fir biochar and Chapter IV describes the removal of phosphate from waste water. In Chapter V, this low cost adsorbent (magnetic Douglas fir biochar) was introduced into an undergraduate laboratory to expose students to water quality issues and methods of contaminant removal enhancing their understanding of these important environmental issues. This experiment introduces new and interesting approaches to water purification as well as deepens the student’s understanding of present environmental concerns regarding pharmaceutical contaminants in wastewater.

Molybdenum (Mo) is a naturally occurring trace element that is present in drinking water mostly in the molybdate (MoO42-) form in well water. Recently, the EPA deemed Mo as a potential contaminant because exposure can lead to health effects such as gout, hyperuricemia, and lung cancer. In this work, we have assessed the sorptive removal of Mo using Douglas fir biochar (DFBC) and its chemically-coprecipitated iron oxide analogue (DFMBC). Adsorption was studied varying the batch sorption conditions; pH, equilibrium time (5 min-24 h), initial Mo concentrations (2.5-1000 mg/L), temperatures (5, 25, and 40 °C) and equilibrium method. Langmuir capacities for DFBC and DFMBC (at pH 3, 2 h equilibrium) were in 359.3-487.9 mg/g and 288.3-571.9 mg/g range, respectively. Adsorbents and Mo-laden adsorbents were characterized by elemental analysis, BET, PZC, SEM, TEM, EDS, XRD, and XPS. These data suggest that DFBC and DFMBC can be potential candidates for Mo sorption.

The main aim of this research is to provide a low cost and sustainable biochar for the removal of organic pollutants from aqueous solution. Wastewater pollution by organic contaminants of emerging concern has become a subject of intense discussion. Removing these contaminants from aqueous solution is paramount to improve water quality for both humans and animal consumption. Traditional adsorption techniques using activated carbon are universal and fast, however, they are very costly. This dissertation therefore seeks to find an alternative low cost adsorbent which can be used to adsorb contaminants from aqueous solution. In chapter one, an overview of some of the selected organic contaminants of emerging concern is given. Pharmaceutical and pesticide entry into the environment, their fate and ecotoxicity are highlighted. Available techniques for the removal of contaminants from aqueous solution are also given. Chapter two is a study on the adsorption of some selected pharmaceuticals using a fast pyrolysis low cost biochar produced from pinewood feedstocks. The pinewood biochar used as the adsorbent in this study was made by fast pyrolysis in an augered reactor at a temperature of 425 oC and a residence time of 20-30 s during bio-oil production. In chapter three, switchgrass biochar has been tested for its potential for remediating water that is contaminated with two phenoxy herbicides, 2,4-dichlorophenoxyacetic (2,4-D) acid and 2-methyl-4-chloro-phenoxyacetic acid (MCPA). The adsorption capacity was remarkable when compared to commercial activated carbon per unit of measured surface area. Furthermore, in chapter four, magnetic and non-magnetic low cost biochars have been tested for the removal of the herbicide metribuzin from aqueous solution under different experimental conditions. The magnetic biochar synthesized from raw switchgrass biochar does not show a detrimental effect on the adsorption capacity. Additional value of this magnetic biochar is the ease of separation from contaminated solution following adsorption.

Biochar, the solid product of thermal conversion of biomass with little or no available air, is acknowledged as a carbon dioxide removal technique and soil enhancer among other applications. Its potential soil enhancing properties consists of increased water and nutrient holding capacities, liming effects and sorption of pollutants. However, not all soils benefit equally from biochar amendments. The thesis aims to investigate the suitability of biochar applications to agricultural soils in Sweden and communicate the results visually with a biochar indication map, illustrating where biochar could serve the highest benefits as a soil improver. A literature review was carried out to analyse the soil enhancing opportunities of biochar applications, which determined that the criteria soil texture, nitrogen leaching, ground moisture, soil pH and soil organic matter (SOM) were suitable for the analysis in a Swedish context. Then, a multi-criteria analysis was conducted in ArcGIS, based on spatial data of these criteria. Each arable land block was assigned a biochar class, varying from high indication to no indication. Arable land was considered highly recommended for biochar applications if the soil texture was sandy and at least one of the soil criteria was beyond a limiting agronomic threshold. At the national level, high indication for biochar application occupied 24.2% (528 thousand ha) of the arable land in Sweden, while the remaining land had either medium indication (13%), low indication (3.5%) or no indication (59.3%). Despite spatial variations, all Swedish counties (with data coverage above 84%) had at least 2% of high indication arable land. In particular, 66.1% of Halland’s arable land showed high indication. In turn, Skåne had the largest area (148 thousand ha, 35.7%) with high indication for biochar applications. The corresponding biochar volume potential, at the national level, suggested that between 0.5 and 26.4 million tonnes biochar can be applied to arable land with high indication for biochar applications, given application rates between 1 and 50 tonnes/ha over a 20 year timeframe. This means that arable land in Sweden can accommodate for a future production of 500 000 tonnes per year, which was suggested as an upper limit in an inquiry from the Swedish government, if application rates remain below 20 tonnes/ha. The multi-criteria analysis performed includes several subjective choices and uncertain parameters (criteria combination, data accuracy, agronomic thresholds, and classification scheme). Therefore, the biochar indication maps cannot yet be used for farm- or field-level recommendations for biochar applications. Nonetheless, despite uncertainties, the national- and county- level indication maps may still provide interesting order of magnitude. More field experiments are needed in Sweden as well as a more detailed analysis. To be able to make more precise recommendations, the present analysis can be refined by connecting all criteria to physical agricultural mechanisms and to the properties of biochar, and by using spatial data with higher resolution or even field-level data. This said, models need to be validated with experimental data, which is to date, non- existent: controlled biochar field experiments are therefore needed in Sweden. / Biokol, en solid produkt från termisk omvandling av biomassa med begränsat syre tillgängligt, är identifierad som en möjlig teknik för att minska halten av koldioxid i atmosfären och som jordförbättrare bland andra applikationer. Dess potentiella jordförbättrande egenskaper består av vattenhållning, näringsbindning, balansering av pH-värdet och minskad biotillgänglighet av föroreningar. Däremot så drar inte alla jordar samma nytta av biokolapplikationer. Arbetet syftar till att undersöka lämpligheten av biokolapplikationer på jordbruksmark i Sverige och kommunicera resultaten visuellt med en indikationskarta. En litteraturstudie genomfördes för att analysera jordförbättringsmöjligheterna till följd av biokolsapplikationer. Det fastställdes att kriterierna jordtyp, kväveläckage, markfuktighet, pH och organiskt material var lämpliga för analys i svensk kontext. En multikriterieanalys utfördes i ArcGIS, baserat på rumsliga data för dessa kriterier. Vardera jordbruksblock tilldelades en biokolklass, som varierade mellan hög indikation och ingen indikation. Jordbruksmark ansågs högt rekommenderad för biokolapplikationer om jordtypen var av sandig karaktär och minst ett av kriterierna översteg ett begränsande tröskelvärde. På nationell nivå ockuperade hög indikation för biokolapplikationer 24.2% (528 tusen hektar) av Sveriges jordbruksmark, medan den återstående marken hade antingen måttlig indikation (13%), låg indikation (3.5%) eller ingen indikation (59.3%). Trots rumsliga variationer, hade samtliga svenska län (med datatillgänglighet över 84%) minst 2% åkermark med hög indikation. I synnerhet, 66.1% av Hallands åkermark visade hög indikation. Vidare, Skåne hade den största arealen (148 tusen hektar, 35.7%) med hög indikation för biokolapplikationer. Den motsvarande potentialen för biokol, på nationell nivå, antyder att mellan 0.5 och 26.4 miljoner ton biokol kan appliceras på jordbruksmark med hög indikation för biokolapplikationer, givet appliceringsgrader mellan 1 och 50 ton/hektar över en 20-årsperiod. Detta innebär att svensk jordbruksmark kan rymma en framtida produktion på 500 000 ton per år, förslaget av en statlig utredning, ifall appliceringsgraden förblir under 20 ton/ha. Den utförda multikriterieanalysen inkluderar flertalet subjektiva val och osäkerheter (kriteriakombination, datans noggranhet, tröskelvärden, och klassificeringsmetod). Därmed kan indikationskartorna för biokol ännu inte användas för rekommendationer på jordbruksblocknivå. Resultaten kan emellertid, trots osäkerheter, antyda intressanta storleksordningar på nationell- och länsnivå. Fler svenska fältexperiment samt en mer detaljerad analys behövs. För att kunna ge mer exakta rekommendationer, kan den nuvarande analysen utvecklas genom att koppla samtliga kriterier till fysiska jordbruksmekanismer och biokolsegenskaper och genom att tillämpa rumsliga data av högre upplösning eller till och med fältnivådata. Modeller måste valideras med experimentella data, som hittills är obefintlig: kontrollerade fältförsök med biokol behövs därmed i Sverige.

Electrosorption-based capacitive deionization (CDI) has become a viable process for brackish water desalination and defluoridation. In this study, activated Douglas fir biochar is used as a low-cost electrode material with adsorption capacity comparable to activated carbon obtained from biomass precursors. Adding functional groups to the activated biochar enhanced salt removal capacity, providing cation and anion selectivity. The functionalized electrodes were prepared by Nafion, titanium isopropoxide, and p-phenylenediamine treatment, respectively, which introduced sulfonate, titanium dioxide and amine functional groups to the electrode surface. These modification methods are versatile and can be easily performed without sophisticated laboratory environment. Modified biochar electrodes were characterized by TEM, SEM-EDX, XRD, and XPS. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were performed to analyze the electrochemical properties of the electrodes. The salt adsorption capacity (SAC) was evaluated in a 3D-printed capacitive deionization flow cell using a chloride and fluoride ion sensor. It was found that functionalized biochar electrodes had increased SAC and charge efficiency in asymmetrical setup due to reduced co-ion effect. For example, the asymmetrical CDI cell with Nafion cathode and amine biochar anode improved NaCl removal capacity by 54% over the activated biochar symmetrical cell (identical anode and cathode), with SAC 6.01 mg NaCl/g biochar at the symmetrical cell and 9.25 mg/g for the asymmetrical cell. The charge efficiency also increased by ≈ 67% from symmetric AcB cell to asymmetric TB-05 cathode and AmB anode. This work shows that biochar can be engineered and explored broadly as an inexpensive sustainable electrode material for asymmetrical capacitive deionization.

Land application and storage of horse manure and municipal sludge can increase nutrient and bacteria concentrations in runoff. Biochar increases soil nutrient retention when used as a soil amendment. The objectives of this study were to determine if biochar, when mixed with horse manure or sludge, affects runoff concentrations of total Kjehldahl nitrogen (TKN), ammonia-nitrogen (NH3-N), nitrate (NO3-N), total phosphorus (TP), dissolved phosphorus (DP), total suspended solids (TSS), chemical oxygen demand (COD), and fecal coliforms (FC). Horse manure and sludge were applied to 2.4 x 6.1 m fescue plots (six each), with three plots of each material amended with 5-8% biochar w/w. Simulated rainfall (101.6 mm/h) was applied to the 12 treatment plots and three control plots. The first 0.5 h of runoff was collected and analyzed for the above-listed parameters. The data were analyzed using an ANCOVA, with SCS runoff curve number (CN) used as the covariate. In general, CN was directly correlated to runoff concentrations of parameters. Plots with low CN values displayed no treatment differences for any measured parameter. Biochar reduced runoff concentrations of TKN and NH3-N for municipal sludge treatments, and TKN, NH3-N, TP, TSS, and FC for horse manure treatments.

Nitrous oxide (N2O) is a powerful greenhouse gas (GHG) which has a global warming potential 296 times greater than that of carbon dioxide (CO2). Agriculture is a major source of N2O and in the UK approximately 71 % of N2O emissions are produced by agricultural soils, mainly as a result of the application of nitrogenous fertilisers. Despite previous research into agricultural N2O emissions which has demonstrated that N2O emissions have high spatial and temporal variability, there is still a lack of knowledge surrounding the factors that influence the magnitude of emissions from agricultural soils. Agricultural N2O emissions for the UK’s annual GHG inventory are currently estimated using a 1.25 % emission factor (EF) (to be decreased to 1 % in 2015) which assumes that 1.25 % of applied nitrogen (N) fertiliser is emitted as N2O. The EF does not take into account influencing factors such as location or fertiliser type. Mitigation of N2O emissions is vital if future climate change is to be prevented, yet this must also be combined with the need to intensify agricultural production to feed the increasing global population. Biochar which is a carbon rich material produced during the pyrolysis of biomass has been identified as a potentially useful soil amendment with the ability to mitigate N2O emissions. However, most previous research has focused on laboratory scale experiments and there is a need to investigate the use of biochar in a field environment. Other N2O mitigation options such as nitrification inhibitors, or altering fertiliser management practices, require testing under different conditions to assess their suitability for use. This thesis aims to investigate a). The factors affecting N2O emissions from synthetically and organically fertilised arable soils, and b). To explore the potential of various N2O mitigation options for arable systems, including biochar. This thesis firstly investigates N2O emissions from synthetically fertilised arable soil. Varying application rates of ammonium nitrate fertiliser were applied to a Scottish arable soil during a year long field experiment and the effects of mitigation options such as a nitrification inhibitor (DCD) were assessed. N2O emissions were shown to be significantly affected by soil water filled pore space and the 1.25 % EF was demonstrated to be generally greater than those calculated in this experiment. The use of DCD significantly decreased N2O emissions and crop yields. A second year long field experiment was carried out to investigate N2O and NH3 emissions from an organically fertilised arable soil and to explore the effect of the timing, form and method of organic fertiliser application on emissions and EFs. Slurry, poultry litter, layer manure and farmyard manure were applied in the autumn and the spring. Cumulative N2O emissions were generally greater from the autumn applications and NH3 emissions were greater from the spring applications, due to wetter soil conditions and incorporation of fertiliser during the autumn. The type of fertiliser applied affected the magnitude of emissions with the greatest cumulative N2O and NH3 emissions from the layer manure. The method of fertiliser application had no effect on emissions. The following experiment investigated the ability of different biochars to retain N from a solution and the effect of biochar particle size on retention. A batch sorption experiment was used to test the affinity and capacity of six biochars for ammonium (NH4+) and nitrate (NO3-) from different concentrations of NH4NO3 solution. All of the biochars studied demonstrated the ability to retain NH4+ and NO3- from solution although greater NH4+ retention was observed. Differences in biochar affinity for N could be explained by pyrolysis temperature, but there was no effect of particle size or pH. Oil seed rape straw biochar was demonstrated to have the greatest NH4+ and NO3- retention capacity and as such was chosen for use in the next experiment. This work investigated the potential for oil seed rape straw biochar to decrease emissions of N2O, CH4 and CO2 from stored slurry and whether any GHG mitigation effects would continue following application of the slurry to arable soil. The effect on emissions of amending the biochar and slurry mixture with DCD after application to the soil was also explored. There was no significant effect of the biochar on GHG emissions from the stored slurry although the slurry initially acted as a sink for N2O and CO2. There were no significant differences between emissions from any treatments following application to the soil. The overall results of these studies indicate that N2O emissions are highly dependent on weather conditions, and hence location, in addition to fertiliser type and application timing. It was concluded that the use of a standard 1.25 % EF for synthetic and organic N fertiliser applications for the whole of the UK is inappropriate. Mitigation options such as the use of DCD, altering fertiliser application season or fertiliser type have been shown to possess the potential to mitigate N2O emissions but tradeoffs between N2O and NH3 emissions, and impacts on crop yields must be considered. Biochar was demonstrated to retain NH4+ and NO3- ions and this property may account for biochar’s N2O mitigation capabilities as observed by previous researchers. However, if N retention is taking place, the N appears to still be available for production of N2O and crop uptake.

The aim of this study was to investigate the effects of biochar amendment on soil greenhouse gas (GHG) emissions and to elucidate the mechanisms behind these effects. I investigated the suppression of soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions in a bioenergy and arable crop soil, at a range of temperatures and with or without wetting/drying cycles. More detailed investigation on the underlying mechanisms focused on soil N2O emissions. I tested how biochar altered soil physico-chemical properties and the subsequent effects on soil N2O emissions. In addition, 15N pool dilution techniques were used to investigate the effect of biochar on soil N transformations. Biochar amendment significantly suppressed soil GHG emissions for two years within a bioenergy soil in the field and for several months in an arable soil. I hypothesised that soil CO2 emissions were suppressed under field conditions by a combination of mechanisms: biochar induced immobilisation of soil inorganic-N (BII), increased C-use efficiency, reduced C-mineralising enzyme activity and adsorption of CO2 to the biochar surface. Soil CO2 emissions were increased for two days following wetting soil due to the remobilisation of biochar-derived labile C within the soil. Soil N2O emissions were suppressed in laboratory incubations within several months of biochar addition due to increased soil aeration, BII or increased soil pH that reduced the soil N2O: N2 ratio; effects that varied depending on soil inorganic-N concentration and moisture content. These results are significant as they consistently demonstrate that fresh hardwood biochar has the potential to reduce soil GHG emissions over a period of up to two years in bioenergy crop soil, while simultaneously sequestering C within the soil. They also contribute greatly to understanding of the mechanisms underlying the effect of biochar addition on soil N transformations and N2O emissions within bioenergy and arable soils. This study supports the hypothesis that if scaled up, biochar amendment to soil may contribute to significant reductions in global GHG emissions, contributing to climate change mitigation. Further studies are needed to ensure that these conclusions can be extrapolated over the longer term to other field sites, using other types of biochar.

Biochar is a carbon sequestration technology that has shown potential to inhibit greenhouse gas (GHG) emission and nutrient leaching from soils, however the majority of biochar research thus far has focused on arable cropland rather than livestock systems or grasslands. Livestock production is an important agricultural system, and manure generated from livestock systems is a source of GHG emission as well as nutrient loading to surface- and groundwater. The high environmental impact of livestock production in the very areas that biochar has shown potential may suggest that this would be an ideal system for biochar incorporation. However, as grassland systems in the context of livestock production often receive high nutrient inputs in the form of manure which increases the potential for nutrient leaching or runoff, the high-nutrient ash content of biochar may potentially exacerbate this problem rather than suppress nutrient loss from soils. As private companies and government-funded programmes discuss the possibility of scaling the global manufacturing and soil-incorporation of biochar to a rate of gigatonnes per year, understanding the potential of biochar for use within a livestock system could be crucial in helping to develop an appropriate deployment plan for this material. This thesis is therefore focused on the use of biochar in grassland and livestock systems. It first examines the nutrient release from biochar in a sequential leaching experiment. Phosphorus (P) release indicated that provision of soil P (though quantitatively small) may be sustained over time whilst potassium (K+) release was quantitatively large but declined rapidly following the first extraction. An incubation study was then carried out using soil columns amended with farmyard manure, liquid manure (slurry) or fertiliser (plus an unamended control), each with and without biochar, which sought to determine the impact of biochar on N2O release and N and P leaching from soils with diverse nutrient sources. N2O emission from the columns was significantly suppressed by the presence of biochar, as was the leaching of mineral N. However, the amount of PO4 3--P in leachate was increased in biocharamended columns, relative to their unamended counter-parts. A slurry incubation study was then conducted, with a control slurry and four biochar-amended treatments, which explored whether biochar could suppress GHG and NH3 emission from manure prior to land application. The resulting data indicated that biochar demonstrates potential for GHG suppression but does not demonstrate potential for NH3 suppression from slurry in storage. Finally, a one-year field-based experiment was completed which analysed the impact of biochar on CH4, N2O, and NH3 emission as well as nutrient leaching from grassland soils that had been amended with a high rate of manure application (151.4 m3 ha-1 or 409 kg N ha-1). In this study, biochar demonstrated the potential to suppress each of the three types of gaseous emissions from manure-amended soil, though the differences between mean values were not statistically significant. Extracts from ion exchange resins indicated that annual cumulative K+ leached from biochar-amended plots was significantly higher than the control, and that P and NH4 + leached from biochar-amended plots was higher than the control at the time of the first rain event following biochar and manure application. Together, the results of these component studies indicate that biochar may indeed have potential to suppress GHG emissions from livestock systems, most likely through suppression of microbial activity by organic compounds that are sorbed to the char, though (as the mechanisms of GHG suppression by biochar are thus far not well understood) the capacity of biochar to do so may vary based on the type of biochar used, the soil characteristics, and other factors. Overall, the results of these studies suggest that some types of biochar should be used with caution in systems with high rates of nutrient application, unless the ash is removed prior to soil application.

La possibilité de produire un gaz combustible (syngaz) à partir des composés carbonés outre que le charbon et le pétrole permettrait aux pays pauvres en ressources énergétiques de se diriger vers une indépendance énergétique.La vapogazéification est un procédé qui permet de produire un gaz riche en hydrogène à partir des matériaux carbonés (par exemple le char de biomasse) et de la vapeur d’eau. Etant donné que la gazéification est un processus endothermique, la source d’énergie est le premier souci à résoudre. Si l’on ne veut pas contribuer au réchauffement de la planète, la source d’énergie et de carbone doivent rester renouvelables. Jusqu’à présent, les ingénieurs concevaient les gazéifieurs en pensant à une uniformité des propriétés à l’intérieur du réacteur, cela simplifie la modélisation et le contrôle des variables, cependant, avec les sources de chaleur innovantes et la possibilité de n’utiliser que de la vapeur d’eau pour la gazéification, on peut conclure qu’un gradient de températures améliore la production d’hydrogène. Les nouvelles technologies de gazéification nécessitent donc une compréhension des phénomènes de transfert afin d’être améliorées et optimisées. Trois types de réacteurs ont modélisés dans le cadre de cette thèse, il est mis en évidence qu’il existe un manque de critères solides à l’heure de choisir le dispositif réactionnel le plus adéquat selon les ressources disponibles. La théorie du gradient de température est conçue à partir des principaux résultats de cette thèse et s’intéresse à la création d’un outil simple à utiliser pour que l’ingénieur puisse prendre des décisions qui aident à améliorer la production de gaz combustible. / The possibility of producing syngas from carbon compounds other than coal or oil would allow countries lacking energy resources to move toward energy independence. The steam gasification is a process that could help to this predisposition, producing a hydrogen-rich gas from carbon-rich materials (e.g. biomass char) and steam. Since gasification is an endothermic process, the energy source is the first concern to be addressed in the gasifierdesign. If we want it to not contribute to global warming, the energy source and carbon must remain renewable.Until now, engineers designed gasifiers thinking about uniformity of properties within the reactor, it simplifies the variables modeling and control, however, with innovative heat sources and the possibility to use only steamfor gasification, it can be concluded that a temperature gradient enhances the hydrogen production, thus the syngas quality is improved. The new gasification technologies therefore require the understanding of transport phenomena to apply this advantage in order to improve the syngas production and quality. Three reactor typesare modeled as part of this work, it is shown that there is a lack of firm criteria to choose the reaction device according to the resources, consequently, the reactors performance could be diminished if the energy source is not properly used. The theory of the temperature gradient is built based on the main results and it is a simple toolto help the engineer to make decisions that will improve the fuel gas production.