The current study investigated application of natural adsorbents in brine treatment. Brines are hypersaline waters generated in power stations and mining industries rich in Mg2+, K+, Ca2+, Na+, SO4 2- , Cl- and traces of heavy metals, thus there is a need for these brines to be treated to recover potable water and remove problematic elements. Natural adsorbents have been successfully used in waste water treatment because of their high surface area and high adsorptive properties when they are conditioned with acid or base. The investigation of pH showed that natural adsorbents did not perform well at low pH of 4 and 6. The adsorbents were able to work efficiently at the natural pH of 8.52 of the brine solution. These results show that natural adsorbents hold great potential to remove cationic major components and selected heavy metal species from industrial brine wastewater. Heterogeneity of natural adsorbents samples, even when they have the same origin, could be a problem when wastewater treatment systems utilizing natural clinoptilolite and bentonite are planned to be developed. Therefore, it is very important to characterize the reserves fully in order to make them attractive in developing treatment technologies.

Water supply services in urban and rural areas of Tanzania were reviewed and specific studies were carried out on water supply and on purification of turbid water sources using locally available plant materials in rural villages of Singida Rural District. The review showed that large proportions of urban and rural populations in Tanzania face acute water supply problems mainly due to poor planning, implementation and management of water supply projects, including an inability to address social, technical, operation and maintenance and financial issues. Laboratory-scale experiments studied the effectiveness of crude seed extracts (CSEs) and purified proteins of Vigna unguiculata (VUP), Parkinsonia aculeata (PAP) and Voandzeia subterranea (VS) seeds, which are used traditionally for clarification of turbid water. The VUP and PAP were purified from CSEs using simple and straightforward two-step ion exchange chromatography. The coagulant proteins are thermoresistant and have a wide pH range for coagulation activity. Coagulation of turbid waters with CSEs, VUP and PAP produced low sludge volumes and removed turbidity along with other inorganic contaminants in line with Tanzania drinking water quality standards. The PAP also showed antimicrobial effect against river water bacteria. Citrus fruit juice (CF) enhanced the coagulation of turbid water by CSEs and inhibited bacterial growth, rendering it useful for disinfection of water prior to drinking in rural areas. It was concluded that natural coagulants should not be regarded as a panacea for rural water supply problems, but rather a tool in the development of sustainable water supply services in Tanzania. / QC 20100825

Previous studies in Dr. Yang’s laboratory have established a grafting, design, and subdomain approach in order to investigate the properties behind Ca2+-binding sites located in Ca2+-binding proteins by employing engineered proteins. These approaches have not only enabled us to isolate Ca2+-binding sites and obtain their Ca2+-binding affinities, but also to investigate conformational changes and cooperativity effects upon Ca2+ binding. The focus of my thesis pertains to optimizing the expression and purification of engineered proteins with tailored functions. Proteins were expressed in E. coli using different cell strains, vectors, temperatures, and inducer concentrations. After rigorous expression optimization procedures, proteins were further purified using chromatographic and/or refolding techniques. Expression and purification optimization of proteins is essential for further analyses, since the techniques used for these studies require high protein concentrations and purity. Evaluated proteins had yields between 5-70 mg/L and purities of 80-90% as confirmed by SDS-PAGE electrophoresis.

This dissertation focuses on key intergroup and intragroup separations found in the back end of the nuclear fuel cycle, specifically americium from lanthanides and americium from other actinides, most importantly americium from curium. Our goal is to implement a liquid-solid separation process to reduce waste and risk of contamination by the development of metal(IV) phosphate phosphonate inorganic organic hybrid ion exchange materials with the ideal formula of M(O6P2C6H4)0.5(O3POA) * nH2O, where M = Zr or Sn, A = H or Na. These materials have previously shown to have high affinity for Ln, this work will expand on the previous studies and provide methods for the above target separation, exploiting oxidation state and ion charge to drive the separation process. The optimum hydrothermal reaction conditions were determined by adjusting parameters such as reaction temperature and time, as well as the phosphonate to phosphate (pillarto-spacer) ligands ratio. Following these results four bulk syntheses were performed and their ion exchange properties were thoroughly examined. Techniques such as inductively coupled mass spectrometry and liquid scintillation counting were used to determine the affinity of the materials towards Na+, Cs+, Ca2+, Sr2+, Ni2+, Nd3+, Sm3+, Ho3+, Yb3+, NpO2+, Pu4+, PuO22+, Am3+, AmO2+, and Cm3+. Separation factors in the thousands have been observed for intergroup separations of the Ln from the alkali, alkaline earth, and low valent transition metals. A new method for Am oxidation was developed, which employed Na2S2O8 as the oxidizing agent and Ca(OCl)2 as the stabilizing agent for AmO2+ synthesis. Separation factors of 30-60 for Nd3+ and Eu3+ from AmO2+, as well as 20 for Cm3+ from AmO2+ were observed at pH 2. The work herein shows that a liquid-solid separation can be carried out for these difficult separations by means of oxidation and ion exchange.

ABSTRACT EXCHANGES OF STRONTIUM ON CLINOPTILOLITE ZEOLITE G&Uuml / L, &Ouml / zkan MS, Department of Chemical Engineering Supervisor: Prof. Dr. Hayrettin Y&uuml / cel November 2003, 110 Pages Sr-90 and Cs-137, nuclear fission products, are the major sources of medium-level radioactive waste which must be decontaminated. Inorganic ion exchangers are the preferred materials to eliminate radioisotopes from aqueous nuclear waste because of their high selectivity, radiation and thermal stability, low cost and likely compatibility with cement containment. Clinoptilolite and other zeolites are widely used in nuclear industry for the removal of radioisotopes from aqueous nuclear waste. In this study, the performance of local clinoptilolite zeolite from G&ouml / rdes region has been investigated so as to determine the conditions under which it can be used effectively in the column for strontium and cesium removal. It was found that under different loading conditions, breakthrough capacity varied from 0 to 0.4078 meq/g for strontium removal, breakthrough capacity varied from 0.1178 to 0.7800 meq/g for cesium removal. It was also determined that the increase of the flow rate reduced the exchange capacity of the bed. Effect of cationic form of the zeolite (Na-CLI: Sodium form of clinoptilolite and Original-CLI: Original form of clinoptilolite) on the breakthrough capacity was also searched. It was observed that Na-CLI performed much better for the removal of strontium and cesium with respect to its original form. In addition, effect of presence of calcium in the feed solution on the breakthrough capacity was investigated and it was found that presence of calcium in the feed solution makes strontium removal essentially impossible, in the case of cesium, presence of calcium in the feed solution decreases breakthrough capacity significantly.

Results have shown that flow batteries may be a solution in the future as an effective and environmental friendly method to an energy storage system (ESS). The technology is reliable and has a high efficiency that comes with low energy losses and a long lifetime. The range of possible fields is suitable for cutting energy peaks in the power grid, by always have a ready and available energy storage that balances the production. By comparing the advantages of flow batteries with conventional batteries it is mainly the fact that they can conserve energy for a long time without being self-discharged thanks to that the storage capacity is in principle endless and limited by the size of the electrolytes tanks that makes them a great energy storage system. The batteries won’t take any damage or decrease in performance when charging or discharging it or if you exhausts it to 100 % and leave it discharged for a long time. The only disadvantages with flow batteries are that they are built upon an advanced design and are built of components made of expensive materials. The main objective of this thesis is to develop an experimental basis for assessing a small pilot module of a flow battery with respect to how different concentrations of salts, flow rates and different currents/voltages affect the performance of the battery. We start by performing the experiment with a polymeric ion exchange membrane and see what values and the advantages and disadvantages it entails.

Several health problems may be caused by excess nitrate in drinking water, the most important of which being methemoglobinemia, a potentially fatal disorder, in infants under six months of age. Many different parts of the world have been facing the problem of nitrate contaminated surface and groundwaters due in large part to excessive use of nitrate-based chemical fertilizers. In the Region of Waterloo, Ontario, Canada some groundwater sources have nitrate concentrations approaching the Health Canada and Ontario Ministry of the Environment maximum acceptable concentration (MAC) of 10 mg NO3--N/L. Finding a practical and economical way to reduce nitrate concentrations in representative groundwater in the Region of Waterloo was the overall objective of this research. To achieve this goal, nitrate removal technologies including biological denitrification, ion exchange (IX), reverse osmosis (RO), electrodialysis (ED), and chemical denitrification were reviewed and compared. IX and RO were found to be the most promising technologies for nitrate removal. They have also been approved by the United States Environmental Protection Agency (USEPA) as Best Available Technologies (BAT). To investigate the feasibility of IX and RO for nitrate removal from representative groundwater in the Region of Waterloo, bench-scale experiments were conducted and compared. These technologies could be considered for application at full- or point-of-use (POU)-scale. Decision support assistance for the selection of the appropriate technology for different technical and economical conditions is provided as an outcome of this work. Two nitrate-selective ion exchange resins (Dowex™ NSR-1 and Purolite® A-520E), two non-selective resins (Purolite® A-300E and Amberlite® IRA400 Cl), and a commercially-available RO POU device (Culligan® Aqua-Cleer® model RO30), which included a particle filter and a carbon block, were tested with deionized water and real groundwater.* IX results confirmed that production time before resin exhaustion was influenced by operating conditions, specifically bed depth as would be expected. It was also confirmed that the presence of competing anions (sulfate, chloride) and alkalinity adversely affected performance, with sulfate being the main competitor for nitrate removal. The extent of these effects was quantified for the conditions tested. At the end of the runs, the non-selective resins were prone to potential nitrate displacement and release into product water and are therefore not recommended. The nitrate-selective resins did not release previously adsorbed nitrate as their capacity became exhausted. Purolite® A-520E was identified as the best alternative amongst the four resins for removing nitrate from the representative groundwater source. The RO unit removed roughly 80% of the nitrate from groundwater. Background ions didn’t appear to compete with each other for removal by RO units, so RO might be a more appropriate technology than IX for nitrate removal from waters with high concentrations of sulfate or TDS. Since RO removes other background ions as well as nitrate, the product water of RO is low in alkalinity and can potentially be corrosive, if water from a small full-scale system is pumped through a communal distribution system. Post-treatment including pH adjustment, addition of caustic soda, and/or corrosion inhibitors may be required. While the carbon block did not play a substantial role with respect to removal of nitrate in the groundwater tested, a potential issue was identified when running RO systems without the carbon block. In deionized water (and presumably in very low alkalinity real waters) it was noted that RO nitrate removal efficiency dropped substantially as the alkalinity of the influent water approached zero. With respect to the scale of application of IX and RO devices, IX can be applied at full-scale without requiring large amounts of space. However, if feed water contains high concentrations of sulfate or TDS, nitrate leakage happens sooner and regeneration would be needed at more frequent intervals. Also, chloride concentrations in IX product water might exceed aesthetic objectives (AO) and should be monitored in cases of high feed water TDS. POU IX devices are not recommended when feed water nitrate concentration is high due to potential nitrate leakage into the product water when the resin is nearing exhaustion which increases public health risk. Issues associated with RO application at full-scale are high energy demand, low recovery, high costs, need of pre-treatment (fouling control), and post-treatment (corrosion control). On the other hand, POU RO devices may be acceptable since low recovery is of less importance in a household system, and product water corrosivity is less relevant. POU RO devices are preferable to POU IX units due to their lower risk of nitrate leakage into treated water. * Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Several health problems may be caused by excess nitrate in drinking water, the most important of which being methemoglobinemia, a potentially fatal disorder, in infants under six months of age. Many different parts of the world have been facing the problem of nitrate contaminated surface and groundwaters due in large part to excessive use of nitrate-based chemical fertilizers. In the Region of Waterloo, Ontario, Canada some groundwater sources have nitrate concentrations approaching the Health Canada and Ontario Ministry of the Environment maximum acceptable concentration (MAC) of 10 mg NO3--N/L. Finding a practical and economical way to reduce nitrate concentrations in representative groundwater in the Region of Waterloo was the overall objective of this research. To achieve this goal, nitrate removal technologies including biological denitrification, ion exchange (IX), reverse osmosis (RO), electrodialysis (ED), and chemical denitrification were reviewed and compared. IX and RO were found to be the most promising technologies for nitrate removal. They have also been approved by the United States Environmental Protection Agency (USEPA) as Best Available Technologies (BAT). To investigate the feasibility of IX and RO for nitrate removal from representative groundwater in the Region of Waterloo, bench-scale experiments were conducted and compared. These technologies could be considered for application at full- or point-of-use (POU)-scale. Decision support assistance for the selection of the appropriate technology for different technical and economical conditions is provided as an outcome of this work. Two nitrate-selective ion exchange resins (Dowex™ NSR-1 and Purolite® A-520E), two non-selective resins (Purolite® A-300E and Amberlite® IRA400 Cl), and a commercially-available RO POU device (Culligan® Aqua-Cleer® model RO30), which included a particle filter and a carbon block, were tested with deionized water and real groundwater.* IX results confirmed that production time before resin exhaustion was influenced by operating conditions, specifically bed depth as would be expected. It was also confirmed that the presence of competing anions (sulfate, chloride) and alkalinity adversely affected performance, with sulfate being the main competitor for nitrate removal. The extent of these effects was quantified for the conditions tested. At the end of the runs, the non-selective resins were prone to potential nitrate displacement and release into product water and are therefore not recommended. The nitrate-selective resins did not release previously adsorbed nitrate as their capacity became exhausted. Purolite® A-520E was identified as the best alternative amongst the four resins for removing nitrate from the representative groundwater source. The RO unit removed roughly 80% of the nitrate from groundwater. Background ions didn’t appear to compete with each other for removal by RO units, so RO might be a more appropriate technology than IX for nitrate removal from waters with high concentrations of sulfate or TDS. Since RO removes other background ions as well as nitrate, the product water of RO is low in alkalinity and can potentially be corrosive, if water from a small full-scale system is pumped through a communal distribution system. Post-treatment including pH adjustment, addition of caustic soda, and/or corrosion inhibitors may be required. While the carbon block did not play a substantial role with respect to removal of nitrate in the groundwater tested, a potential issue was identified when running RO systems without the carbon block. In deionized water (and presumably in very low alkalinity real waters) it was noted that RO nitrate removal efficiency dropped substantially as the alkalinity of the influent water approached zero. With respect to the scale of application of IX and RO devices, IX can be applied at full-scale without requiring large amounts of space. However, if feed water contains high concentrations of sulfate or TDS, nitrate leakage happens sooner and regeneration would be needed at more frequent intervals. Also, chloride concentrations in IX product water might exceed aesthetic objectives (AO) and should be monitored in cases of high feed water TDS. POU IX devices are not recommended when feed water nitrate concentration is high due to potential nitrate leakage into the product water when the resin is nearing exhaustion which increases public health risk. Issues associated with RO application at full-scale are high energy demand, low recovery, high costs, need of pre-treatment (fouling control), and post-treatment (corrosion control). On the other hand, POU RO devices may be acceptable since low recovery is of less importance in a household system, and product water corrosivity is less relevant. POU RO devices are preferable to POU IX units due to their lower risk of nitrate leakage into treated water. * Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

The preparation and thermophysical properties of some In(I), Ga(I) and Ag(I) substituted NZP type materials were explored. Many compositions with the NZP framework show low and negative thermal expansion. Previously reported material, GaZr2(PO4(3, transforms from one NZP related phase into another NZP type phase due to oxidation under air above 300oC. In addition, it exhibits hysteresis under inert atmosphere; the cell parameters are different on heating and cooling cycles for a given temperature. The synthesis, and characterization of a new material, InZr2(PO4)3, is outlined. It crystallizes in space group R -3 c. In addition, as GaZr2(PO4)3, it oxidizes above 300oC under air and exhibits hysteresis under inert atmosphere. Furthermore, the synthesis of AgTixZr2-x(PO4)3 solid solution compositions, their ion exchange characteristics with Ga(I) and their thermophysical properties are described. Thermal expansion anisotropy (the difference between a and c ) of the solid solutions decreases as the bigger ion, Zr4+, is substituted by the smaller one, Ti4+. Thermal expansion characteristics of GaZr2(PO4)3, InZr2(PO4)3 and AgZr2(PO4)3 are compared with MZr2(PO4)3 ( M = Li, Na, K, Rb, Cs). Ionic radii for Ga(I) and In(I) in a six coordinate oxygen environment were proposed.

Organic matter is ubiquitous in the environment and exists in many different forms. Reactions involving organic matter are diverse and many have significant economic and environmental implications. In this research, calorimetric techniques were used to study organic- inorganic reactions in two different systems. The primary objectives were to elucidate potential mechanism(s) by which: (i) natural organic matter (NOM) influences strength development in lime-stabilized soils, and; (ii) plant-derived biochars reacts with cations in aqueous environments. Natural organic matter influenced strength development in lime-stabilized soils through the direct inhibition of the formation of pozzolanic reaction products. The degree of inhibition was dependent mainly on the type of pozzolanic reaction product, and the amount and source of organic matter. The formation of the pozzolanic reaction product, calcium silicate hydrate II (CSH2) was less affected by NOM, than was the formation of CSH1. For a given pozzolanic product, the inhibition increased with NOM content. The effect of organic matter source followed the order fulvic acid> humic acid&gt; lignite. Formation of CSH pozzolanic reaction products decreased by 50-100%, 20-80% and 20-40% in the presence of ?2% fulvic acid, humic acid and lignite, respectively. Cation interactions with plant-derived biochars were complex and depended both on the nature of the cation and biochar surface properties. Reactions involving the alkali cation, K+; occurred via electrostatic ion exchange, on deprotonated functional groups located on the biochar surface and; were exothermic with molar heats of reaction (?Hads) between -3 and -8 kJ mol-1. In contrast, reactions involving the transition metal cation, Cd2+ were endothermic with delta Hads between +10 and +30 kJ mol-1. Reaction mechanism(s) for Cd2+ varied from ion exchange/surface complexation in biochars formed at <350 oC, to an ion exchange/surface complexation/diffusion-controlled mechanism in biochars formed at >/=350 oC. For a given cation, differences in sorption characteristics were attributable to temperature-dependent or plant species dependent variations in the properties of the biochars.