The aim of the work described in this thesis was to study the removal of ammonium ions from water by ion exchange. The classical technique is to use biological nitrification and denitrification to convert ammonia into nitrogen gas. Removal by ion exchange offers a number of advantages, such as the ability to handle shock loadings and to polish water to a very high specification. The ion exchanger used in this project was clinoptilolite, a naturally occurring zeolite. Previous research has included characterisation of clinoptilolite, the effect of other common cations on uptake, biological regeneration, and a few other studies. A comparison with other exchangers was also conducted. Much of the available literature is concerned with clinoptilolite and occasionally with mordenite, however modern ion exchangers are polymer based. Two polymeric ion exchangers (Dowex 50w-x8, and Purolite MN500) were evaluated in this project. The main scope of this thesis was to look at the effect that organic pollutants has on ammonium ion removal during ion exchange. The results of batch equilibrations of NH4+ and the three exchanger resins can be seen in chapter 4.0. They show that the presence of an organic compound enhanced the uptake of NH4+ in most cases onto clinoptilolite and Purolite MN500. There was no apparent uptake onto Dowex 50w-x8. Further experiments with a sample of real industrial wastewater (woolscour wastewater) showed varied results, showing that each site should carry out its own pilot scale testing during plant design. Other experimental work showed that the exchanger resins adsorb little or none of the organic compounds in solution. These results can be seen in chapter 5.0. ii Removal of ammonia from wastewater by ion exchange in the presence of organics. Studies in a packed column showed that the presence of organic compounds had little or no effect on NH4+ removal. There was however an increase in capacity after each regeneration of the bed and continued removal after breakthrough. The same results were achieved in the control experiment with no organic compounds present, hence these results are not related to the presence of an organic compound. The presence of NH4+ and various compounds did however provide micro-organisms with substrates from which to grow causing hydraulic difficulties in the column. See chapter 6.0 for these results. The final section of experimental work studied whether the presence of organic compounds changed the rate of uptake of NH4+. The results in chapter 7.0 show that there was no effect on the rate of NH4+ uptake.

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NMR experiments performed under the effect of electric fields, either continuous or pulsed, can provide quantitative parameters related to ion association and ion transport in solution.  Electrophoretic NMR (eNMR) is based on a diffusion pulse-sequence with electric fields applied in the form of pulses. Magnetic field gradients enable the measurement of the electrophoretic mobility of charged species, a parameter that can be related to ionic association. The effective charge of the tetramethylammonium cation ion in water, dimethylsulphoxide (DMSO), acetonitrile, methanol and ethanol was estimated by eNMR and diffusion measurements and compared to the value predicted by the Debye-Hückel-Onsager limiting law. The difference between the predicted and measured effective charge was attributed to ion pairing which was found to be especially significant in ethanol. The association of a large set of cations to polyethylene oxide (PEO) in methanol, through the ion-dipole interaction, was quantified by eNMR. The trends found were in good agreement with the scarce data from other methods. Significant association was found for cations that have a surface charge density below a critical value. For short PEO chains, the charge per monomer was found to be significantly higher than for longer PEO chains when binding to the same cations. This was attributed to the high entropy cost required to rearrange a long chain in order to optimize the ion-dipole interactions with the cations. Moreover, it was suggested that short PEO chains may exhibit distinct binding modes in the presence of different cations, as supported by diffusion measurements, relaxation measurements and chemical shift data. The protonation state of a uranium (VI)-adenosine monophosphate (AMP) complex in aqueous solution was measured by eNMR in the alkaline pH range. The question whether or not specific oxygens in the ligand were protonated was resolved by considering the possible association of other species present in the solution to the complex. The methodology of eNMR was developed through the introduction of a new pulse-sequence which suppresses artifactual flow effects in highly conductive samples. In another experimental setup, using NMR imaging, a constant current was applied to a lithium ion (Li ion) battery model. Here, 7Li spin-echo imaging was used to probe the spin density in the electrolyte and thus visualize the development of Li+ concentration gradients. The Li+ transport number and salt diffusivity were obtained within an electrochemical transport model. The parameters obtained were in good agreement with data for similar electrolytes. The use of an alternative imaging method based on CTI (Constant Time Imaging) was explored and implemented. / <p>QC 20140825</p>

Based on preliminary reports, an extended series of bolamphiphilic oligoester compounds with structural symmetry were synthesized and then tested using a planar bilayer experiment with the voltage-clamp technique. The main structures of these compounds are identical, consisting of a mono or tri-aromatic core, two octamethylene chains and two benzoyl headgroups which are all connected through ester linkages. The structural variance was provided by the four differently functionalized benzoyl headgroups. The synthetic methods of three to five steps were mainly adapted from the previously reported method.1 The methods successfully produced eight compounds with overall yields of 20 to 30%. The voltage-clamp data suggested voltage-dependent behaviors occur at low concentrations while Ohmic behaviors require at high concentrations. The activity at low potentials showed relatively erratic behavior but the channels frequently switched between opening and closing states. The activity at high potential lasted longer as the channel maintained a longer state of opening. The exponential voltage-dependent behaviors were observed at higher potential while the voltage-independent Ohmic behaviors occur at low potential. These channel behaviors are highly time-dependent as there is no control over the stability and the aggregation level for the compounds forming active channels in the membrane. In some cases the current-voltage responses appear to be asymmetrical between the positive and the negative potentials. Mechanisms consistent with the observations are proposed. / Graduate / 0485 / 0490 / yzong@uvic.ca

Based on preliminary reports, an extended series of bolamphiphilic oligoester compounds with structural symmetry were synthesized and then tested using a planar bilayer experiment with the voltage-clamp technique. The main structures of these compounds are identical, consisting of a mono or tri-aromatic core, two octamethylene chains and two benzoyl headgroups which are all connected through ester linkages. The structural variance was provided by the four differently functionalized benzoyl headgroups. The synthetic methods of three to five steps were mainly adapted from the previously reported method.1 The methods successfully produced eight compounds with overall yields of 20 to 30%. The voltage-clamp data suggested voltage-dependent behaviors occur at low concentrations while Ohmic behaviors require at high concentrations. The activity at low potentials showed relatively erratic behavior but the channels frequently switched between opening and closing states. The activity at high potential lasted longer as the channel maintained a longer state of opening. The exponential voltage-dependent behaviors were observed at higher potential while the voltage-independent Ohmic behaviors occur at low potential. These channel behaviors are highly time-dependent as there is no control over the stability and the aggregation level for the compounds forming active channels in the membrane. In some cases the current-voltage responses appear to be asymmetrical between the positive and the negative potentials. Mechanisms consistent with the observations are proposed. / Graduate / 0485 / 0490 / yzong@uvic.ca