Seasonally snow covered alpine areas play a larger role in the hydrologic cycle than their area would indicate. Their ecosystems may be sensitive indicators of climatic and atmospheric change. Assessing the hydrologic and bio-geochemical responses of these areas to changes in inputs of water, chemicals and energy should be based on a detailed understanding of watershed processes. This dissertation discusses the development and testing of a model capable of predicting watershed hydrologic and hydrochemical responses to these changes. The model computes integrated water and chemical balances for watersheds with unlimited numbers of terrestrial, stream, and lake subunits, each of which may have a unique, variable snow-covered area. Model capabilities include (1) tracking of chemical inputs from precipitation, dry deposition, snowmelt, mineral weathering, baseflow or flows from areas external to the modeled watershed, and user-defined sources and sinks, (2) tracking water and chemical movements in the canopy, snowpack, soil litter, multiple soil layers, streamflow, between terrestrial subunits (surface and subsurface movement), and within lakes (2 layers), (3) chemical speciation, including free and total soluble species, precipitates, exchange complexes, and acid-neutralizing capacity, (4) nitrogen reactions, (5) a snowmelt optimization procedure capable of exactly matching observed watershed outflows, and (6) modeling riparian areas. Two years of data were available for fitting and comparing observed and modeled output. To the extent possible, model parameters are set based on physical or chemical measurements, leaving only a few fitted parameters. Thc effects of snowmelt rate, rate of chemical elution from the snowpack, nitrogen reactions, mineral weathering, and flow routing on modeled outputs are examined.

Molecular simulations have become an important tool within the last few decades to understand physical processes in the microscale and customize processes in the macroscale according to the understanding developed at the molecular level. We present results from molecular simulations we performed to study the adsorption of hazardous organics in nanoporous materials. Adsorption of water in silicalite, a hydrophobic material, and the effect of defects were investigated by Monte Carlo simulations. Silanol nests were found to have a big impact on the hydrophobicity of silicalite. Even the presence of one silanol nest per unit cell caused a significant amount of water adsorption. We also investigated the effect of four different cations, H+, Li+, Na+, and Cs+. Their presence in silicalite increased the amount of water adsorbed. Monte Carlo and molecular dynamics simulations of MTBE adsorption in silicalite, mordenite, and zeolite beta with different Na+ cation loadings were carried out. The results revealed the importance of the pore structure on the adsorption of MTBE. Although these three zeolites have similar pore volumes, zeolite beta, with its pore structure which is mostly accessible to MTBE molecules, is predicted to adsorb significantly more MTBE than silicalite and mordenite. The Na+ cation loading, up to four cations does not have a significant effect on the adsorption capacity of the zeolites studied here, however, for silicalite and zeolite beta increasing the Na+ content increases the amount adsorbed at very low pressures. A new force field was developed by Monte Carlo simulations for 1,4-Dioxane, an important industrial solvent which has emerged as a potentially significant threat to human health. The objective was to develop reliable atom-atom interaction parameters to use in the simulations of the adsorption of 1,4-Dioxane in different adsorbent materials. Predictions of critical point data, liquid and vapour densities, heats of vaporization with our new force field were in good agreement with experimental data and outperformed predictions from simulations with other force field parameters available in literature. To obtain the isotherms of MTBE and 1,4-Dioxane adsorption from water in silicalite Monte Carlo simulations were performed. First we optimized the interaction parameters between the atoms of silicalite and the atoms of MTBE and 1,4-Dioxane. Using these optimized parameters we simulated the adsorption of MTBE and 1,4-Dioxane from water in silicalite. Despite the agreement of simulated and experimental isotherms of pure components, simulated isotherms of MTBE and 1,4-Dioxane adsorption from water in silicalite did not yield satisfactory results. Monte Carlo simulations were performed to investigate the affinity between two hazardous materials, PFOA and 1,1-DCE; and four different zeolites. Binding energies and Henry's constants were computed. For both PFOA and 1,1-DCE zeolite-beta had the highest affinity. The affinity between activated carbon with polar surface groups and water, and 1,4-Dioxane were investigated to shed light on why activated carbon is ineffective to remove 1,4-Dioxane from water. Results showed that presence of polar surface groups increased the affinity between water and activated carbon, while the affinity between 1,4-Dioxane and activated carbon was not effected by the presence of polar surface groups.

Fully-dynamic, continuous fugacity-based fate and transport models have been developed to examine all natural processes and interactions in the aquatic water systems. Within a body of surface water such as a lake or a river, a dynamic interaction among different media takes place. Chemical compounds are continuously dissolving, adsorbing into solid particles, attaching to suspended particles, resuspending, reacting, diffusing, and advecting. As the inclusion of all these interactions into a model is complex, the use of fugacity concept instead of concentration, renders the modeling task relatively easy. Fugacity, which is described as the escaping tendency of a chemical from a medium, is continuous among different phases, thus easier to follow the movement of the chemical. The first model has been developed to be used as an emergency response model by decision makers, which models the fate and transport of any contaminant in a lake. Due to uncertainties involved in the analysis, Monte Carlo simulations are performed. The fate of three representative contaminants; polychlorinated biphenyls (PCBs), atrazine, and benzene in air, water, and sediment compartments are examined. The second model developed is a continuous, dynamic river fugacity-based water quality model. In order to develop a continuous model, the hydrodynamics of the river system is solved first. Water depth and velocity at each point along the river are used in the advection-dispersion equation to determine the fate and transport of a contaminant. Interactions between different phases are also incorporated into the advection-dispersion equation which is solved numerically and coupled with a mass balance equation derived for the same contaminant in the sediments. The third model is a multispecies contaminant fate and transport model which can be used for the fate of a single contaminant and its daughter products. Trichloroethylene (TCE) and its daughter products, dichloroethylene (DCE) and vinyl chloride (VC), are used as representative of multispecies contaminants. The fate and transport of TCE and its daughter products has been analyzed first in a lake environment, and then in a river environment with the addition of a biofilm compartment where all biotransformations take place.

Failure of carbon steel boiler tubes from waterside has been reported in the utility boilers and industrial boilers for a long time. In industrial boilers, most waterside tube cracks are found near heavy attachment welds on the outer surface and are typically blunt, with multiple bulbous features indicating a discontinuous growth. These types of tube failures are typically referred to as stress assisted corrosion (SAC). For recovery boilers in the pulp and paper industry, these failures are particularly important as any water leak inside the furnace can potentially lead to smelt-water explosion. Previous research shows that metal properties, environmental variables, and stress conditions are the major factors influencing SAC crack initiation and propagation in carbon steel boiler tubes. A significant volume of work has also been published to show that the use of carbon steel in high temperature water applications strongly depends upon the formation and stability of a protective magnetite oxide film on the waterside of boiler tubes. This present study is aimed at evaluating above stated variables individually and interactively to identify SAC crack initiation and crack propagation behavior in carbon steel boiler tubes. Other goal of this research is to understand the mechanism of bulbous SAC crack formation under industrial boiler operating conditions, thus to figure out a practical way to predict and prevent SAC type failures in the industrial boilers.

Anthropogenic emissions of acidifying substances, mainly sulfur dioxide, during the second half of the 20th century caused a widespread acidification of many European freshwater environments. Even relatively remote areas, such as inland northern Sweden, experienced reduced pH-values, much due to low buffering capacity in the environment. Extensive liming has taken place in Sweden over the past fifty years to counteract negative effects on limnic ecosystems. Despite a general increase in pH over the last decades, problems with acidification still occur. However, this can be hard to separate from natural acidity due to a large landscape variability. This study aims at describing the temporal and spatial variation of pH and pH-related parameters in Bastuån, a 46 km2 watershed in Jämtland, Sweden, which is being investigated for future liming measures. Existing water chemistry data sets were analyzed and extended with an additional field study, sampling the twelve largest tributaries to Bastuån. Results show that pronounced high and low pH values has become increasingly rare while the average is basically unchanged between 1999 and 2017. Low pH is mainly associated with high discharge during snowmelt or rain events. Anthropogenic SO42- concentrations seems to contribute relatively little to pH-depressions while organic acids plays a more important role. Large water chemical variations in the tributaries indicate that several different biological and physical properties within the watershed regulates pH. However, any credible function that can predict pH using such properties remains to be found.

The aim of this diploma thesis was a statistical evaluation of the impact of farming methods and the land cover on hydrochemical parameters of surface waters drainage patterns in Novohradské mountains and identify the possible impact of agriculture on the valuesof these parameters. The area for the evaluation is consist of lower and upper parts of the basin of Pasecký, Bedřichovský and Váčkový stream. Sampling sites include agriculturally cultivated land, but also forest ecosystems. The work is mainly focused on the following parameters: conductivity, nitrate nitrogen (N-NO3-), suspended solids (NL105) and phosphate phosphorus (P-PO43-), which are parameters causing eutrophication of water. The parameters changes were analysed for the years 2014 - 2017. Significant differences were observed in the all three streams in the water chemisms between upper and lower parts of the watersheds of conductivity and nitrate nitrogen (N-NO3-). The results confirmed that the farming has a significant influence on the water quality in the Pasecký, Bedřichovský and Váčkový stream although it is an extensive farming.

Department of Ecology and Resource Management / PhDENV / Groundwater has traditionally been perceived to be low in chemical species toxicity and microbiologically 'pure'. However, depending on the geological chemistry, formations and anthropogenic activities creating the frequent occurrence of microbiological contamination and excess toxic chemical constituents, the high quality of groundwater as a drinking water source can easily be compromised rendering it unsafe, thus, leading to severe waterborne epidemics. The rapid increase in fluoride and microbial contamination of groundwater have become a global problem to human health. Fluoride in its acceptable concentration in drinking water (< 1.5 mg/L); is known to be beneficial for human growth and development but becomes detrimental at higher concentrations (> 1.5 mg/L) leading to the prevalence of dental and crippling skeletal fluorosis. On the other hand, consumption of microbiologically contaminated water has led to many types of diseases including diarrhea, cholera, typhoid, dysentery and other serious illnesses often leading to millions of deaths annually worldwide. South Africa had experienced water-borne diseases epidemic in the recent past due to failing water treatment facilities in many parts of the country including rural areas. Fluorosis, diarrhea, and cholera are among the chronic health hazards affecting a large population in South Africa. Continuous outbreaks of water-related diseases have been at an unimaginable high level with a reported increase in death rate. The inefficiency of conventional water treatment plants to remove fluoride and disinfect these pathogens from the contaminated domestic and rural community has led to the development of many techniques. These include membrane filtration, ion-exchange, coagulation-precipitation, adsorption among others of which adsorption process proves to be a more significant technology for fluoride removal. Equally, the emergence of nanomaterials has also proved to be the natural answer to solve problems associated with microbes in water since these are absolute barriers to pathogens whose size exceeds most sorbent pore sizes. Also, materials from natural biopolymers or biomass can be utilized at an affordable cost as effective sorbent material for toxic chemical ions and pathogens removal from contaminated water. Consequently, extensive research works have been channeled into the development of more advanced low cost sustainable functionalized sorbent materials and technologies with multifunctional properties for effective water purification. The present study focused on the development of a functionalized chitosan-cellulose hybrid nanocomposite decorated with metal-metal oxides nanoparticles for simultaneous fluoride and microbial removal from groundwater. This was to increase the selectivity and disruption of such pollutants for effective groundwater purification technology. The thesis is presented in nine chapters: (1) General introduction, problem statement, and motivation, research objectives, hypothesis and delimitations of the research are briefly discussed, (2) This chapter gives the literature review of occurrence and sources of fluoride, various fluoride removal techniques; sources, control measures and prevention of microbial pollution in groundwater; the importance of biosynthesis of nanomaterials as emerging novel water treatment adsorbents, the strength of Point-Of-Use as a means of water treatment, water treatment adsorbents synthesis and types of adsorbents with emphasis on hydroxyapatites and biopolymeric based sorbent materials, (3) Optimization of microwave-assisted synthesis of silver nanoparticle by Citrus paradisi peel extracts and its application against pathogenic water strain, (4) Biosynthesis of ultrasonically modified Ag-MgO nanocomposite and Its potential for antimicrobial activity, (5) Green synthesis of Ag/MgO nanoparticle modified nanohydroxyapatite and its potential for defluoridation and pathogen removal in groundwater (6) Green Synthesis of AgMgOnHaP nanoparticles supported on Chitosan matrix: defluoridation and antibacterial effects in groundwater, (7) Biosynthesis of nanofibrous cellulose decorated Ag-MgO-nanohydoxyapatite composite for fluoride and bacterial removal in groundwater, (8) Defluoridation and removal of pathogens from groundwater by hybrid vi cross-linked biopolymeric matrix impregnated Ag-MgOnHaP nanocomposite (9) Conclusions and Recommendations. It is important to point out that Chapters 3 to 8 contains a collection of the research deliverables produced in forms of paper publications and manuscripts and are summarized in a systemic order of experimental protocol. This first output (Chapter 3) of this study evaluated the optimization of a time-dependent microwave-assisted biosynthesis of silver nanoparticles using aqueous peel extracts of Citrus paradisi (Grapefruit red) as a reducing, stabilizing and capping agent with emphasis on its antibacterial property. Optical, structural and morphological properties of the synthesized Citrus paradisi peel extract silver nanoparticle (CPAgNp) were characterized using UV-visible spectrophotometer, transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Brunauer–Emmett–Teller (BET) and X-ray diffractometer (XRD). The antimicrobial activity was evaluated using the well- and disc-diffusion as well as microdilution methods. Characteristic surface plasmon resonance (SPR) wavelength in the range of 420-440 nm at an optimized intensity growth rate typical of silver nanoparticles was obtained. Microwave irradiation accelerates the reaction medium within seconds of nucleation compared to conventional heating methods of synthesis. The influence of the reaction mixtures affected the SPR patterns on the different nucleation, stability and nanoparticle growth. The mixing ratio of 2:3 (C. paradisi peel extracts: 1 mM AgNO3) was chosen as the optimum reaction mixing ratio relative to the bio-reduction intensity of SPR process contributing to the particle size growth of CPAgNps. The presence, interaction and shifting of the functional groups in the FT-IR spectra of biosynthesized CPAgNps indicated that bioactive compounds present in C. paradisi peel extract were responsible for the bio-reduction of the silver ion to silver nanoparticles. The electron micrographs of the synthesized CPAgNps showed a face-centered cubic (FCC) unit phase structure, spherically-shaped nanoparticles size of 14.84 ± 5 nm with a BET pore diameter of 14.31 nm. The use of biological material allowed the control of the size and stability of the nanoparticle but was obtained in low quantity. The Citrus paradisi peel extract mediated AgNp were found to possess a broad-spectrum antimicrobial activity against water-borne pathogenic microbes in the order: Escherichia coli > Staphylococcus aureus > Klebsiella pneumonia. In Chapter 4, a synergistic bi-layered Ag-MgO nanocomposite from Ag and MgO precursor salts using a natural source from the waste product (citrus fruits outer cover) as a reducing and capping agent was successfully synthesized by a simple rapid, integrated bio-mediated microwave and ultrasonic methods. This was carried out to investigate the interfacial interaction and the encapsulated growth rate behind their combination in obtaining an enhanced antibacterial activity against common water fecal pathogen (Escherichia coli). The growth sequence, structural and morphology interface as well as the composition of the nanocomposite were examined and evaluated by the different characterization techniques. The respective potential application as an antimicrobial agent was evaluated and compared against Escherichia coli. The bio-mediated core-shell Ag-MgO nanocomposite showed characteristic synergetic UV-visible absorption bands at 290 nm for MgO nanoparticle and at around 440 nm for Ag nanoparticle, which moved to a lower wavelength of 380 nm in the composite. The shifting to a lower wavelength confirmed the reduction in the particle size as influenced by the growth rate optical property of biomolecular capped Ag-MgO nanocomposite from the phytochemical constituents in the peel extract of the Citrus paradisi. FTIR analysis further elaborated the role of the organic moieties in the Citrus paradisi extracts acting as the capping and stabilizing agent in the formation of the core-shell Ag-MgO nanocomposite. SEM analysis revealed an agglomeration of layered clustered particles, which was poly-dispersed while XRD showed the cubical crystal lattice network phase structure of the Ag-MgO nanocomposite. The TEM micrograph vii showed a structurally uniform and spherical biosynthesized Ag-MgO nanocomposite with a diameter of about 20–100 nm with an average particle size of 11.92 nm. The bi-layered Ag-MgO nanocomposite exhibited a higher level broad-spectrum of antibacterial potential on E. coli with 22 mm zone of inhibition and MIC of 20 (μg/mL) in comparison with the Ag (9 mm; 40 μg/mL) and MgO (9 mm; 80 μg/mL) nanoparticles. The leaching and toxicity level of the time-dependent releases of metal ions indicates that the effluents contain a lower concentration of Ag and Mg ions as compared to World Health Organization permissible limit of < 100 ppb (Ag). The biosynthesized Ag-MgO nanocomposite exhibited an enhanced antibacterial activity synergistic effect against E. coli than Ag and MgO nanoparticles, thus, proving to be a potential disinfect material against common pathogens in water treatment. Chapter 5 presented the biosynthesis, characterization, and assessment of simultaneous fluoride and pathogen removal potential in aqueous solutions of a multi-layered Ag-MgO/nanohydroxyapatite (Ag-MgOnHaP) composite. The successful incorporation of Ag-MgO into nanohydroxyapatite (Ag-MgOnHaP) sorbent via an in-situ solution-gelation (sol-gel) method was ascertained from UV-visible absorption spectrum bands at 290 and 440-378 nm typical of MgO and Ag nanoparticles combination in Ag-MgOnHaP composite. FTIR analysis showed the main surface functional groups involved to be –OH, C=N, carbonate and phosphate species on the backbone of Mg-O-Mg vibrational mode. The hydroxyl and amine groups indicated the interaction of a variety of metabolites components present in citrus peel extract as bio-reductive compounds associated with the Ag-MgO and also in fluoride ion exchange. SEM, TEM images and XRD analysis showed a well-dispersed discretely embedded layered-spherical Ag-MgOnHaP nanocomposite without any form of agglomeration after ultrasound exposure ranging in size from 20 to 100 nm with an average mean particle size diameter of 16.44 nm. The high purity of the synthesized Ag-MgOnHaP nanocomposite was confirmed by the presence Ag, Mg and O impregnated on the nanohydroxyapatite template from EDS spectrum analysis. Batch sorption studies using the nanocomposite under different experimental parameters were conducted and optimized. Equilibrium fluoride adsorption capacity of 2.146 mg/g at 298 K was recorded with more than 90% fluoride removal at optimized conditions of 60 min, 10 mg/L initial F- concentration, 0.3 g/L dosage, and pH 6 at 250 rpm. pHpzc of Ag-MgOnHaP nanocomposite was established to be 8. The equilibrium data were best fitted to the Freundlich isotherm model and followed the pseudo-second-order kinetics model at room temperature. The presence of competing anions such as Cl−, NO3−, does not have an impact on percentage fluoride uptake efficiency, but SO42− and CO32− reduce the F- removal efficiency. Moreover, as the concentration of the co-anions increased, fluoride adsorption uptake decreases. The biosynthesized nanohydroxyapatite incorporated Ag/MgO nanoparticle adsorbent (Ag-MgOnHaP) showed strong antibacterial activity against Escherichia coli and Klebsiella pneumonia when compared to hydroxyapatite alone. The presence and interaction between the Ag, MgO nanoparticles with the respective bacterial genomes was suggested to have accounted for this bioactivity. The synthesized Ag-MgOnHaP sorbent was found to portray a better sorption capacity compared to other adsorbents of similar composition in the literature and could be successfully regenerated with 0.01 M NaOH with fluoride removal of 74.24% at the 4th cycle of re-use. The impregnation of metal-metal oxide nanoparticles on sustainable natural biopolymers from waste products was presented in Chapters 6, 7 and 8. The use of these sustainable natural biopolymers (chitosan and cellulose) was targeted with more emphasis on surface functionalization, improved structural diversity and improved specific surface area with the sole aim of increasing the adsorptive capacity of fluoride ions as well as antimicrobial properties. The selected polymers were chosen because of their biodegradability, viii non-toxicity, renewability, selectivity and abundance in nature, which makes them promising starting materials for the purpose of sustainable water treatment. Chapter 6 presents the successful sol-gel biosynthesis, characterization, potential application for fluoride and pathogens removal from aqueous solution using Ag-MgOnHaP embedded on a chitosan polymer backbone (AgMgOnHaP@CSn) sorbent material. The overall formation of the AgMgOnHaP@CSn nanocomposite from different surface functionalization precursors and phases were supported by the various characterization methods such as UV–vis spectroscopy, SEM-EDS, FTIR, TEM, and Brunauer–Emmett–Teller (BET) techniques. Batch fluoride sorption experiments were conducted to assess fluoride uptake efficiency through optimization of several operational parameters such as contact time, adsorbent dosage, initial pH and co-competing anions. The antimicrobial activity of the synthesized AgMgOnHaP@CSn nanocomposites was also determined. The presence and bio-reduction processes of both Ag and MgO chemical species due to the interaction and coordination of bonds within the bioactive functional species of the polymer matrix was confirmed by the emergence of a sharp peak appearing at around 290 nm to a broad plateau plasmon absorbance above 440 nm on the AgMgOnHaP@CSn nanocomposite. FTIR analysis further supported the presence of the main bioactive functional species to be –OH, –NH2 CO32−, PO43-, Mg–O-Mg amongst other groups on the material surface. SEM and TEM displayed homogeneously dispersed particles within the aggregated biopolymeric composite with a diameter ranging between 5-30 μm. Pore sizes were observed to be in the micro-mesoporous range with an average size of about 35.36 nm and a pore diameter of 33.67 nm. The optimized conditions were as follows: 30 mins contact time, a dose of 0.25 g/50 mL, adsorbate concentration of 10 mg/L F-, initial pH 7 while adsorption capacity decreases with increase in temperature. AgMgOnHaP@CSn composite has a pHpzc value of ≈ 10.6 and the maximum sorption capacity was established to be 6.86 mg/g for 100 mg/L F- concentration at 303 K. The effect of co-existing anions was observed to be of the following order: Cl- < NO3- < SO42- << CO32-. The fluoride sorption experimental data was well described by Langmuir adsorption isotherm while the sorption reaction mechanisms were diffusion-controlled and followed the pseudo-second-order sorption model. F- sorption process could best be described as a combination of ligand exchange, electrostatic attraction, and improved structural surface modification. The antimicrobial susceptibility analysis through the zone of inhibition (mean and standard deviation) showed the potency to pathogens of the following order: Staphylococcus aureus > Escherichia coli. Chapter 7 gives an insight into the development of cellulose nanofibrous matrix (isolated from saw-dust) decorated with Ag-MgO-nanohydroxyapatite (CNF-AgMgOnHaP) and its application in fluoride and pathogen removal from contaminated water. The synthesized CNF-AgMgOnHaP, unlike the cellulose nanofiber, showed characteristic absorption bands in UV–vis spectroscopy between 270-290 nm typical of MgO together with a broad band around 420 nm associated with the characteristic of silver nanoparticles. FTIR spectrometry suggested the presence of nanohydroxyapatite (nHaP) and MgO species impregnation within the CNF matrix. SEM, TEM, XRD, and EDS analysis showed a well-established structural and morphological modifications between cellulose nanofiber alone, biosynthesized CNF-AgMgOnHaP and fluoride sorbed CNF-AgMgOnHaP nanocomposite. A granulated aggregation of micro-mesoporous particles with an improved BET surface area of 160.17 m²/g was developed. Optimum fluoride sorption capacity was 8.71 mg/g for 100 mg/L F- solution at 303 K. F- sorption capacities decreased as the operating temperatures increases. Optimum F- removal of 93 % was achieved at optimum conditions established: pH 5, solid/liquid ratio of 0.25 g/ 50 mL, 10 mg/L F-, contact time 10 min, temperature 25 ± 3 °C and shaking speed of 250 rpm. Percent F- removal decreased with increasing initial adsorbate concentration. The pHpzc value of the CNF-AgMgOnHaP occurred at ≈ 4.7. Co-existing ions were observed to have an effect on the adsorption of F- in the following order: NO3- < Cl- < SO42- <<CO32-. Equilibrium fluoride sorption onto the CNF-AgMgOnHaP was best described by non-linear Freundlich isotherm model across all the operating temperatures. The linear Dubinin-Radushkevvich (D-R) model for F- sorption energies were in the 3.54 – 4.08 kJ/mol across all operating temperature. This suggested the physical adsorption mechanism processes were involved in the F- uptake by the CNF-AgMgOnHaP sorbent. The overall kinetic results indicated that the mechanisms not only depend on the pseudo-second-order process but were also governed by mass transfer of the adsorbate molecules across the CNF-AgMgOnHaP surface. The thermodynamic parameters revealed that the sorption process of F- onto CNF-AgMgOnHaP was endothermic and spontaneous at the sorbent/solution interface. The regeneration-reuse study showed that the synthesized adsorbent can be reused for a maximum of 5 adsorption-desorption cycles using Na2CO3 and NaOH as regenerants. Overall surface chemistry by XPS, FTIR, EDS as well as sorption isotherm and kinetic models analysis suggested that both physical and chemical adsorption processes were involved in the fluoride uptake by CNF-AgMgOnHaP nanocomposite. The observed zone of inhibition demonstrated that CNF-AgMgOnHaP adsorbent possesses antibacterial activity against all the bacterial strains in the following order: E. Coli > S. aureus > K. pneumonia. The antibacterial potency increased with increasing sorbent concentration. In chapter 8, Defluoridation and antimicrobial activity of synthesized cross-linked cellulose-chitosan impregnated with the developed nanomaterial (AgMgOnHap) are presented. The before and after fluoride sorption by the synthesized CECS@nHapAgMgO nanocomposites were characterized using several physical and chemical techniques which include, BET, SEM-EDS, TEM, XPS, XRD, and FTIR. The overall batch fluoride sorption processes and adsorption capacity through optimization of different experimental sorption parameters, sorption isotherms, and kinetic mechanisms as well as antibacterial potency were studied and reported. SEM and TEM analysis showed densely irregular multiple-layered structures, homogeneous deposition of the AgMgOnHaP on the polymeric matrices. Equilibrium fluoride sorption capacity on CECS@nHapAgMgO sorbents showed an increased affinity of 26.11 mg/g for 150 mg/L F- solution at 313 K.at optimized conditions of 40 min contact time, dosage of 0.3 g and pH of 5. The pH point of zero charge was found to be 7.27. The reaction pathway model sequence of fitness follows the order Pseudo first order < Elovich < Pseudo-second order kinetic model while intra-particle diffusion model and mass transfer of fluoride molecules from the external surface onto the improved pores of the adsorbent were found to be involved in the rate-controlling step. Although both non-linear Langmuir and Freundlich isotherms showed appropriate trends in the F- sorption process, the adsorption isotherm data were better fitted to the non-linear Freundlich isotherms models, suggesting stronger heterogeneous adsorption onto the active binding sites of the CECS@nHapAgMgO surface. The fluoride sorption was observed to be a favorable process across the operating temperatures. Temkin heat of sorption (BT) and the mean free adsorption energy (E) of the D-R isotherm model was within the range of 0.68-3.39 J/mol and 1.58 -7.45 kJ/mol respectively. The fluoride sorption process was observed to be temperature-dependent; while adsorption capacities (Qm) and Temkin heat of sorption (BT) increased with increasing temperature, D-R Mean free sorption energy (E) decreased at higher temperatures. The thermodynamic analysis demonstrated that fluoride sorption on the CECS@nHapAgMgO surface was exothermic, feasible and spontaneously inclined with a decrease in the degree of randomness at the sorbate-sorbent interface. The influence of co-existing anions on fluoride removal exhibited the following trend Cl−< NO3− <SO42- << CO32- <<HCO3−. The practical and economic viability, potential for regeneration showed its reusability up to 3 cycles with water and Na2CO3 as regenerants. The potential ability of CECS@nHapAgMgO to disinfect both gram- positive and gram-negative water bacterial was confirmed by the zone of inhibition and Minimum Inhibitory Concentration (MIC) measurements. The observed values showed the inhibitory efficiency in the following order: S. aureus > E. Coli > K. pneumonia where the MIC values of 20 μg/mL were recorded for S. aureus and E. Coli respectively and 10 μg/mL for K. pneumonia. Lastly, the applicability of the sorbents was tested with a field water sample collected from a high fluoride borehole water from a local village (Lephalale Municipality of Limpopo province, South Africa). The before and after analysis showed the excellent potential of CECS@nHapAgMgO sorbent in removing fluoride. In conclusion, the successful surface functionalization synthesis of these improved surface area hybrid nano-sorbents supported by the different morphological techniques was found to be effective in creating more surface-active binding sites for fluoride adsorption and disinfection of waterborne pathogens from aqueous solution. The originality of this developed sorbent lies firstly, in the ability to simultaneously remove both chemical and biological water pollutants; secondly, the use of biodegradable, eco-friendly and non-toxic abundance wastes raw materials to develop a water purification material and in solving waste management issues was a key factor towards environmental sustainability. Above all the developed materials were established to possess superior fluoride adsorption capacity when compared to other reported sorbent materials. Lastly, the project findings /innovation will contribute to Sustainable Development Goals (SDG) 3 and 6, aimed at improving clean water supply and health of the communities and the world at large. However, the following recommendations were made following the findings from this study: 1) In order to increase the surface area to volume ratio, greater selectivity, porosity, and mechanical stability of the polymers as well as size-exclusion mechanism without a large energy penalty of the microbes and fluoride ion for effective water treatment, a more effective and an enhanced multifunctional, multi-layer nanofibrous hybrid sorbent through electrospinning techniques should be considered for future work, 2) More studies on the mode of actions and morphological changes in the pathogens leading to the cell death through the influence of the nanocomposites should be further explored, 3) Application of this advanced technology vis-à-vis other biomaterials to generate filter membrane towards efficient microbial removal and deflouridation is a great challenge worth looking at, 4) Lastly, materials developed in the present study should be modeled, tested and fabricated at the point of use for fluoride and pathogen removal at household level. / NRF

Indiana University-Purdue University Indianapolis (IUPUI) / The shale and mudstone directly superjacent to Desmoinesian coal seams of southern Indiana (Springfield, Houchin Creek, Survant, and Seelyville coals) were initially deposited under marine waters and are shown to exhibit high concentrations of organic carbon, sulfur and redox-sensitive metals (Mo, V, Ni, Fe, and U) that were sequestered during times of benthic anoxia and intermittent to sustained euxinia (anoxic and sulfidic). Strata upsection display geochemical signatures that indicate increasingly oxic and nearshore sedimentation that mirrors cyclothemic sequence stratigraphic trends Carbon source, nearshore and offshore proximity, freshwater and marine influence, and redox conditions of the epeiric sea overlying southern Indiana during the Late Middle Pennsylvanian were identified and tracked throughout the deposition of four drill cores of the Petersburg, Linton and Staunton Formations. Carbon, nitrogen, and sulfur data (total organic carbon [TOC], total nitrogen [TN], and total sulfur [TS]); paleoredox proxies ([Mo/Al], [V/Al], [Th/U], [Fetot/Al]); organic carbon isotopes (δ13Corg); and detrital influx concentrations (Zr) were all used in conjunction with lithological and paleontological interpretations to better understand the mode of deposition in this unique midcontinent ancient epeiric sea. Geochemical results when combined with lithologic and paleontologic interpretations reveal a dynamic environmental system where water column geochemistry varies with the influence of variable magnitudes of epeiric seawater flooding on the extensive peatlands of equatorial Late Middle Pennsylvanian southern Indiana.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / This study investigates the hydrological functioning of a riparian zone in central Indiana in a glaciated valley with concave topography (16% slope gradient) and ground water seeps on the valley walls. Unlike sites found in most riparian zone studies with lateral ground water inputs (Clement et al., 2003; Jordan et al., 1993; Blicher-Mathiesen and Hoffman, 1999; Hoffman et al., 2000), the site in this study is connected to thin, permeable upland sediments (≈2 m). The objectives of this research include: 1) understanding the influence of the hydrogeomorphic (HGM) setting on riparian hydrology (including determining the sources of water to the site), 2) determining how the HGM setting influences riparian zone water quality functioning, and 3) comparing the results from this site with conceptual models of riparian zone hydrologic functioning. Water chemistry and hydrometric data were collected over a 16-month period. Three factors influence riparian zone hydrological functioning at the site: 1) the nature of water contributions from upland sources, 2) riparian zone soil texture, and 3) the location of a preWisconsinan till unit. When the uplands are contributing water to the riparian zone a shallow water table is found near the hillslope and ground water flows from the hillslope to the stream. Conversely, when upland contributions cease a large water table drop occurs and ground water flows in a downvalley direction. Fine textured soils near the hillslope result in shallow water tables and small ground water fluxes. Hydrometric data, water chemistry, and statistical analyses suggest water from an intertill layer adjacent to the site is the primary source of water to the site. NO3- concentrations decreased in ground water flow in the riparian zone suggesting the site is removing nutrients. A preWisconsinan glacial till deposit at shallow depths in the riparian zone limits ground water flow to horizontal flow paths. Overall, the hydrologic functioning of the site agrees well with riparian zone conceptual models (Vidon and Hill, 2004a; Vidon and Hill, 2004b; Devito et al., 1996; Hill, 2000; Baker et al., 2001; Burt et al., 2002). The results of this study are important additions towards conceptualizing riparian zone hydrologic functioning.