M.Ing. / Fouling of suspended solids on piping and equipment causes severe operating and maintenance problems in process, water treatment and miningrelated plants. In the SASOL environment fouling related problems are mainly experienced on equipment operating in process cooling water services. Suspended solids appear in the form of activated sludge in the cooling water system and the solid particle sizes are usually submicron in size. Conventional solid liquid separation techniques like centrifuging, sedimentation, filtration, etc. could up to this stage not be applied successfully to remove the finest solids from the process cooling water system. The possibility to separate solid liquid suspensions by means of acoustic energy was investigated. The theoretical principles of acoustic waves, especially standing waves, were studied and explained. A theoretical model indicates that separation of solid/liquid suspensions can be obtained virtually immediately after acoustic energy is applied. Theoretically the size and frequency of a tipical acoustic transducer can be calculated for a specific application. Based on theoretical calculations and findings, an experimental setup was prepared to carryout experiments on different suspensions. A control suspension made-up of water and powder, of Yttlich the particle sizes were approximately 10 pm, was prepared and exposed to a standing acoustic wave. Separation was achieved successfully. Follow-up experiments were carried out to establish the optimum conditions to which separation could be achieved. Different flow velocities were tested as well as different power inputs. The best separation was achieved with the lowest flow rate of 2.5 mils and the highest available voltage of 12 Volt. These conditions were not only used to separate a control suspension but also in a real situation where it was attempted to separate suspended solids from the cooling water system. The attempts were unsuccessful. Additional experiments were also done on ash water and cooling water blowdown which also failed. The failure of effective separation of the process cooling water suspensions is due to the extremely small sizes of the solid partides in suspension. Greater energy input than was available for this project, is required as the particle sizes decreases. Provision needs to be made for all particle sizes to achieve effective results. The separation of solid liquid suspensions is achievable with the aid of acoustic energy. The physical properties of the suspension however determines the size and magnitude of the separating equipment. A proposal for the implementation of a full scale acoustic separation system is given. The proposal comprises of a parallel system to ensure continuity of the cooling process.

An investigation of precipitation was carried out on the system Cu-Ni-Co at temperatures varying from 600°C to 800°C over a wide range of composition . The precipitation process was studied primarily by use of X-ray diffraction techniques. The precipitation was observed to procede by a spinodal decomposition process. The initial wavelength of the modulated structure was in the range 40 to 55Å, in good agreement with the theory for spinodal decomposition. On ageing, a coarsening was observed for all alloys aged inside the spinodal. This coarsening appeared to follow a law of the form Q[superscript: m] – Qo[superscript: m] = k (t-to) where Q = wavelength at time t Qo = wavelength before the coarsening begins at time to k and m = constants The activation energy of the coarsening process was found to be 65 kcal/mole + 10 kcal suggesting that volume diffusion was the controlling factor. RESUME Le présent travail étudie la formation de précipités dans divers alliages du systéme Cu-Ni-Co au cours de vieillissements à des temperatures de 600°C a 800°C. L’évolution de la précipitation a été suivie principalement par diffraction des rayons X. On a observé que la précipitation procède par décomposition spinodale. La longeur d'onde initiale de la structure modulée est comprise entre 40 et 55Å; en bon accord avec la théorie de la décomposition spinodale de Cahn. Au cours du vieillissement on a mesuré un accroissement de la longeur d'onde pourtous les alliages traités à l'intérieur du spinodal. Cet accroissement de longeur d'onde obéit à une loi de la forme Q[superscript: m] – Qo[superscript: m] = k (t-to) ou Q = longeur d'onde au temps t Qo = longeur d’onde avant que le grossisement commence, à to k et m = constantes if energie d'activation du mécanisme de croissance des précipités a été déterminée; sa valeur, 65 kcal/mole suggére que la diffusion en volume est le facteur préponderant. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Among various sources for biofuels, microalgae provide at least three-orders-of-magnitude higher production rate of biodiesel at a given land area than conventional crop-based methods. However, microalgal biodiesel still suffers from significantly lower harvesting efficiency, making such a fuel less competitive. To increase the separation efficiency of microalgae from cultivation solution, an orbital microchannel was utilized that enabled the isolation of biofuel-algae particles from the effluent. The results obtained showed that the separation efficiency in the microfluidic centrifugal separator can be as high as 76% within a quick separation time of 30 seconds. Multiple parameters of algae behaviors and separation techniques such as initial concentration, pH and temperature were studied and manipulated to achieve better efficiencies. It was found that changing these factors altered the separation efficiency by increasing or decreasing flocculation, or “clumping” of the microalgae within the microchannels. The results suggested that an acidic condition would enhance the separation efficiency since in a basic environment, large flocs of microalgae would block and hinder the separation process. Furthermore, a hot temperature solution (around 33 °C) yielded to a higher separation efficiency. The important characteristics of the separator geometry and the infusion rate on algae separation were also very effective in the separation process. This study revealed that there is an opportunity to improve the currently low efficiency of algae separation in centrifugal systems using much smaller designs in size, ensuring a much more efficient algae harvesting. / Includes bibliography. / Thesis (MS)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

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No description available.

Dissertation submitted in fulfilment of the requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology, 2009. / The activity coefficients at infinite dilution ( γ13 ) were calculated for alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols and aromatic compounds from gas liquid chromatography (glc) measurements at three temperatures (303.15 and 313.15 and 323.15) K. The γ13 values were calculated from the retention data for two ionic liquids (ILs) with the same cation but different anions. The ionic liquids: [methyltrioctylammonium bis(trifluoromethylsulfonyl)imide and methyltrioctylammonium thiosalicylate] were used as the stationary phase. The γ13 data for methyltrioctylammonium thiosalicylate were higher than for methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. For each temperature and each ionic liquid, γ13 values were determined for two columns and the average γ13 values were used for the calculation of the partial molar excess enthalpies at infinite dilution, H E 1 Δ , using the Gibbs-Helmholtz equation. Graphs of In γ13 vs 1/T were plotted to determine H E 1 Δ at T = 303.15 K. The selectivity, S12 , value for the hexane/benzene separation was calculated from the ratio of the avarage γ13 values to determine the suitability of the ILs as an entrainer for extractive distillation in the separation of aromatic and aliphatic compounds.The S12 values were also compared to the literature values for other ionic liquids. It was found that the longer chain alkyl group attached to the cation or anion gave lower S12 values. Both ILs have S12 values greater than one and in theory can be used as an entrainer for the hexane/ benzene separation. The capacities at infinite dilutions, k1 , were also calculated from the inverse of the avarage γ13 values for each IL at each temperature. / National Research Fund; Postgraduate Development and Support Directorate.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Ferrohydrostatic separation (FHS) of materials is a float and sink technique which utilizes ferrofluid exposed to a non-homogeneous magnetic field. The efficiency of material separation depends on numerous variables. The most important variables, which were investigated individually, are the effects of moisture content, ferrofluid level, feedrate, particle size and material density distribution on separation efficiency. It is important to recover and recycle the ferrofluid attached to the products of separation so as to reduce the cost of the FHS technology and the amount of kerosene disposed of to the environment. This prompted research into some of the factors affecting ferrofluid recovery. The factors that were investigated are the effects ofFHS operation, material moisture content, particle size and porosity. The separation efficiency was found to be dependent on all the variables investigated. The effect of material moisture content is less pronounced for particles larger than 2.8 mm. This implies that wet feed material should be screened before ferrohydrostatic separation and material which particle size is less than 2.8 mm should preferably be treated dry. Wet material (less than 2.8 mm) floats, even though its density is greater than the cut-point density. This is owing to the immiscibility of the water coating the particles and the kerosene-based ferrofluid used for separation. It was found that the effect of ferrofluid level on separation efficiency is a function of both the density difference of the particles to be separated and the particle size. Separation efficiency as a function of ferrofluid level is poor for particles larger than 2 mm and is good when the density difference of the material to be separated is high, for instance between 2700 kg/nr' and 3530 kg/nr'. This shows that for efficient separation of coarse particles and near density material (material with density close to the cut-point density), the ferrofluid level should be controlled, preferably close to the maximum possible level. The effect of feedrate on separation efficiency is also a function of the densities of the particles to be separated. An increase in feedrate leads to poor separation for particles with densities close t~ each other. This implies that separation of near density material requires accurate feedrate control. It has been shown from simulation and modelling that the effective cutpoint density changes as the particle moves through the chamber until it eventually reaches its terminal velocity, given that the chamber is of sufficient size for this to occur. The effective cut-point density increases to the maximum as the particle enters the ferrofluid pool but settles down to a relative constant once the particle has reached its terminal velocity. The effective cut-point density was shown to decrease with an increase in particle magnetisation. It was found that this decrease in the cut-point density determines the density difference (difference between two particles) achievable when non-magnetic material is treated together with magnetic material. It is therefore important to magnetically scalp the feed material for efficient separation. When the material is not scalped, magnetic and nonmagnetic material with the same density might report to different density fractions, which leads to poor separation. This magnetic contribution to the effective density can be utilised in the separation of material with same density but different magnetisation. The efficiency offerrofluid recovery was found to be dependent on all the variables investigated. The amount of ferrofluid drawn from the FHS separator was found to decrease with an increase in the magnetic field. Furthermore, the amount of ferrofluid that remains attached to the particles after allowing ferrofluid to drain from the material is the same as that attached to the FHS products of separation at high magnetic fields. This shows that it is important to operate the ferrohydrostatic separator at high magnetic fields in order to attract most of the ferrofluid back to the separator. T-heamount of ferrofluid adsorbed onto and absorbed by the particles was found to decrease with an increase in the material moisture content. This is due to two factors. The first is that water occupies the vacant pores in the material. The second is that water forms a layer on the particle surface which is immiscible with kerosene-based ferrofluid. This phenomenon leads to a reduction in cost of the ferrohydrostatic separation technology when wet material as opposed to dry material is treated. As already described coarse material larger than 2.8 mm can be treated wet without detrimental effects on separation. For -8+4 mm particles, the ferrofluid loss ranges from 0.6 down to 0.14 kg/tonne of feed for 0 to 10 % material moisture content respectively. The amount of ferrofluid lost per tonne of feed was found to range from 0.73 to 0.56 kg for-O.85+O.5 mm to -12+8 mm particle sizes respectively. The increase in ferrofluid loss in small particles is due to the increase in surface area in small particles for ferrofluid adsorption. The increase in porosity increases the amount of ferrofluid lost due to the difficulties in recovering ferrofluid embedded in the pores of the particles. Adding water to coarse material lowers the amount of ferrofluid lost by reducing porosity. Modelling the amount of ferrofluid lost, as a function of particle size and porosity, would assist in determining the amount of ferrofluid required to treat a known amount of material. The quality of ferrofluid recovered was found to be the same as that initially used for material separation. This implies that the separation efficiency would not be affected by the use of recycled ferrofluid. / AFRIKAANSE OPSOMMING: Ferro-hidrostatiese skeiding van materiale is 'n flotasie (dryf) en besinkingstegniek wat gebruik maak van ferro-vloeistof wat blootgestel is aan 'n magnetiese veld. Die effektiwiteit van die materiaal skeiding is afhanklik van verskeie veranderlikes. Die belangrikste veranderlikes wat die skeidingseffektiwiteit beïnvloed is individueel bestudeer, naamlik voginhoud, ferro-vloeistof vlak, voertempo, partikelgrootte en materiaal digtheid verspreiding. Dit is belangrik om die ferro-vloeistof te herwin en te hergebruik om die koste van die proses en tegnologie te verminder en dus ook die hoeveelheid keroseen wat aan die omgewing blootgestel is. Dit het navorsing tot gevolg gehad oor die faktore wat ferro-vloeistofherwinning beïnvloed. Hierdie.faktore wat ondersoek is in hierdie studie is materiaal voginhoud, partikelgrootte en porositeit. Die skeidingseffektiwiteit was afhanklik van al die faktore wat ondersoek is. Die effek van materiaal voginhoud was minder beduidend vir partikels groter as 2.8 mm. Dit wys dat nat voermateriaal moet gesif word voor ferro-hidrostatiese skeiding, en materiaal met 'n partikelgrootte kleiner as 2.8 mm moet verkieslik gedroog word. Nat materiaal (minder as 2.8 mm) floteer selfs as die digtheid groter is as die snypunt digtheid. Dit is as gevolg van ondeurlaatbaarheid van die water wat die partikels bedek en die keroseen basis ferro-vloeistofwat gebruik word vir die skeiding. Dit is gevind dat die invloed op die skeidingseffektiwiteit van die ferrovloeistof vlak is 'n funksie van beide die digtheid van die partikels wat geskei word. Die partikelgrootte skeidingseffektiwiteit as 'n funksie van die ferro-vloeistof vlak, is swak vir partikels groter as 2 mm en is goed wanneer die digtheid verskil van die materiaal wat geskei moet word, hoog is, byvoorbeeld 2 700 kg/nr' en 3 530 kg/nr'. Dit wys dat vir die effektiewe skeidings vir groter partikels en naby digtheid materiaal (materiaal net 'n digtheid nabyaan die snypunt digtheid), moet die ferro- . vloeistofvlak baie goed beheer word, gewoonlik naby die maksimum vlak moontlik. Die effek van voertempo op die effektitiwiteit van skeiding is ook 'n funksie van die digtheid van die partikels wat geskei moet word. 'n Toename in die vloeitempo lei tot 'n swak skeiding van partikels met digthede wat naby mekaar lê. Dit wys weer daarop dat die skeiding van naby digtheid materiaal het die akkurate beheer van voertempo tot gevolg. Dit is gevind deur simulasie en modulering dat die effektiewe snypuntdigtheid verander soos die partikel deur die kamer beweeg totdat dit uiteindelik sy finale snelheid bereik (gegee dat die kamer groot genoeg is). Dit effektiewe snypunt digtheid verhoog tot 'n maksimum wanneer die partikel die ferro-vloeistof binne gaan, maar bereik na 'n kort tydperk 'n kostante waarde sodra die partikel sy finale snelheid bereik het. Die effektiewe snypunt digtheid verlaag met 'n toename in partikel magnetisme. Dit is gevind dat die afname in die snypunt digtheid bepaal die digtheidsverskil (verskil tussen twee partikels) wat bereikbaar is wanneer nie-magnetiese materiaal saam met magnetiese materiaal behandel word. Dit is dus belangrik om die voer materiaal magneties te skalpeer vir effektiewe skeiding. Wanneer die materiaal so behandel word, sal magnetiese en nie-magnetiese materiaal, met die dieselfde digthede, rapporteer in verskillende digtheidsfraksies wat sal lei tot swak skeiding. Die magnetiese bydrae tot die effektiewe digtheid kan gebruik word in die skeiding van materiaal met dieselfde digtheid, maar met verskillende magnetismes. Die effektiwiteit van ferro-vloeistof herwinning is afhanklik van al die veranderlikes wat ondersoek is. Die hoeveelheid ferro-vloeistof wat omtrek is van die ferro-hidrostatiese skeier verminder met 'n toename in die magnetiese veld. Verder is die ferro-vloeistof wat agterbly as gevolg van die feit dat hulle vas is aan die partikels na dreinering, dieselfde as die hoeveelheid wat vasgeheg is aan die die ferro-hidrostatisiese produkte van skeiding by hoë magnetiese velde. Dus is dit belangrik om die ferrohidrostatiese skeier te bedryf by hoë magnetiese velde om sodoende die meerderheid van die ferro-vloeistof in die skeier agter te laat bly. Die hoeveelheid ferro-vloeistof geadsorbeer aan en geabsorbeer deur die partikels verlaag met 'n toename in die materiaal voginhoud. Dit is gevolg van twee redes, nl. eerstens water wat die plek inneem van die oop porieë in die materiaal, en tweede is die feit dat water 'n lagie op die partikeloppervlakte vorm wat ondeurlaatbaar is vir keroseen-basis ferrovloeistof Dit lei tot die vermindering in koste van die ferro-hidrostatiese skeidingstegnologie wanneer nat materiaal in plaas van droë materiaal gebruik word. Soos alreeds genoem, partikels groter as 2.8 mm kan nat behandel word sonder enige negatiewe effekte op die skeiding. Vir -8+4 mm partikels is daar 'n ferro-vloeistofverlies van 0.6 tot 0.14 kg/ton voer vir' n 0-10% voginhoud. Die hoeveelheid ferro-vloeistof per ton voer materiaal wat verlore gaan wissel tussen 0.73 tot 0.56 kg vir -0.85+0.5 mm tot -12+8 mm partikelgroottes, respektiewelik. Die toename in ferro-vloeistofverlies by kleiner partikels is as gevolg van die toename in die oppervlakarea van kleinpartikels vir ferro-vloeistof adsorpsie. Daar is 'n toename in porositeit wat gepaard gaan met 'n toename in hoeveelheid in ferro-vloeistof wat verlore gaan as gevolg van probleme met die herwinning van ferro-vloeistof wat binne-in partikelporieë vasgevang IS. Die byvoeging van water by groter materiaal verlaag die hoeveelheid . ferro-vloeistofwat verlore gaan as gevolg van verminderde porositeit. Die modellering van die hoeveelheid ferro-vloeistof wat verlore gaan, as 'n funksie van die partikelgrootte en porositeit, sal help met die skatting van die hoeveelheid ferro-vloeistof benodig om 'n sekere hoeveelheid materiaal te behandel. Dit is gevind dat die kwaliteit van die ferro-vloeistof wat herwin word dieselfde is as die wat aanvanklik gebruik is vir die materiaal skeiding. Dit wys dat die skeidingseffektiwiteit beïnvloed nie die gebruik van gehersirkuleerde ferro-vloeistof nie.

Thesis (MScEng) -- Stellenbosch University , 2002. / ENGLISH ABSTRACT: The distillation process is the most widely used separating process in the chemical process industry. The optimal design of the distillation units can lead to reduced capital costs and improved energy utilisation. This is particularly the case for structured packed distillation column where design methods tend to over-predict the column efficiency. This work seeks to contribute to the development of a reliable mass transfer model for structured packing. A gas phase mass transfer correlation was developed based on the evaporation of pure components into an air stream. The mass transfer rates were measured in a short triangular wetted wall channel with a corrugated surface wall. The influence that the geometric configuration as well as surface structure has on the mass transfer rates was investigated. The channel geometry and surface wall structure resembled that of the structured packing (Flexipac 350Y). The influence of the channel geometry on the gas mass transfer rates was not significant except at low flow conditions. The liquid phase resistance was investigated for binary mixtures in the triangular wetted wall channel. It was found that the overall mass transfer rate decreased with increasing composition of the volatile component. The enhancement of the gas phase mass transfer rate masked the presence of the liquid resistance. ii The gas phase mass transfer correlations were used in the mass transfer model to predict the separation efficiency of a structured packed distillation column. The structured packing used to validate the mass transfer model was high-capacity Flexipac 350Y and normal Flexipac 350Y. The binary distillation experiments were done at total reflux conditions for the pressure range O.33-1atm. The accuracy of the separation efficiencies of the mass transfer model improved with increasing pressure for both materials. The mass transfer model was able to predict the variation of separation efficiencies with column loadings. / AFRIKAANSE OPSOMMING: Distillasie is die skeidingsmetode wat die meeste in die chemiese industrie gebruik word. Die optimale ontwerp van distillasie eenhede kan lei tot verlagings in kapitaalkostes en 'n verbeterde gebruik van energie. Dit is veral waar in die geval van kolomme met gestruktureerde pakking waar huidige ontwerpsmetodes, die kolomeffektiwiteit nie akkuraat beskryf nie. Hierdie studie het ten doelom 'n bydrae te lewer tot die ontwikkeling van 'n betroubare massa-oordragsmodel vir gestruktureerde pakking. 'n Gasfase massa-oordragskorrelasie is ontwikkel gebaseer op metings van die verdampingstempo van suiwer komponente in 'n lugstroom. Die massaoordragstempos is gemeet in 'n kort driehoekige benatle wand kanaal waarin die wand 'n bepaalde oppervlakprofiel het. Die invloed van beide die kanaalgeometrie en die oppervlakprofiel is ondersoek. Die geometrie en oppervlakprofiel is soorgelyk aan die van Flexipac 350Y gestruktureerde pakking. Die invloed van die kanaalgeometrie op die gasfase massaoordragstempos is slegs beduidend by lae vloeitempos. Die vloeistoffase weerstand vir binêre mengsels is ondersoek in die driehoekige kanaal. Dit is gevind dat die algehele massa-oordragstempo verlaag met 'n verhoging in die konsentrasie van die vlugtige komponent. Die verhoging in die gasfase massa-oordragstempo verberg die invloed van die vloeistoffase weerstand. Die gasfase massa-oordragskorrelasies is in 'n massa-oordragsmodel gebruik om die skeidingseffektiwiteit van gestruktureerde pakking in "n kolom te voorspel. Metings op hoë-kapasiteit Flexipac 350Y en normale Flexipac 350Y is gebruik om die modelvoorspellings te evalueer. Die binêre distillasies is by totale terugvloei gedoen in die drukbereik 0.33 - 1.0 atm. Daar is gevind dat die model meer akkuraat is by hoër drukke. Die massa-oordragsmodel is in staat om die variasie in skeidingseffektiwiteit met veranderende kolomlading te voorspel.

Thesis(PhD)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Aminopolycarboxylic acids (APCAs) are chelating agents widely used to inactivate various metal ions by complex formation in industrial and household applications. Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are the widely used agents. Their use is under scrutiny due to their persistence in the environment because they cannot readily biodegrade. This led to the introduction of readily biodegradable agents namely ethylenediaminedisuccinic acid (EDDS) and iminodisuccinic acid (IDS) as alternatives especially to EDTA. Therefore, there was an interest to study the separation of EDDS, IDS and other APCAs using a simple, quick and accurate method. Capillary electrophoresis was used to determine the separation and speciation of iminodisuccinic acid with various metal ions at various pH levels. Speciation modelling was also utilized to compare and validate the presence and distribution of metal-ligand species. The obtained CE results were compared with speciation profiles and a reasonable agreement was obtained. The degradation studies at various time intervals for the metal-ligand (ML) complexes of DTPA, S,S-EDDS, IDS and R,S-IDS with various metal ions (Cd2+, Cr3+, Cu2+, Fe3+, Mn2+, Pb2+ and Zn2+) at pH 7 and 9 was evaluated using CE. New peaks were observed in some ML complexes when the pH was changed from pH 9 to 7. Sharp peaks were seen for CuL (L = DTPA, S,S-EDDS, IDS and R,S-IDS), FeDTPA and FeEDDS at both pH s. While small broad peaks were observed for FeIDS, CrL and MnL complexes. CuDTPA and CuEDDS complexes showed a greater stability over some considerable time as compared to CuIDS, CuR,S-IDS and other metal complexes at pH 9. This work also investigated the effect of various cationic electroosmotic flow (EOF) modifiers and counter anions on the CE separation of EDTA, EDDS and IDS as Cu(II) complexes. The performance of the modifiers was evaluated in terms of migration times, resolution and plate numbers. The best results were observed when Tetradecyltrimethylammonium bromide (TTAB) and Cetyltrimethylammonium bromide (CTAB) was used as modifiers in order to reverse the EOF in the fused silica capillary. This resulted in short analysis time and better peak shapes. The effect of different counteranions attached to EOF modifiers on the separation was also shown. It was also found that the counter anions of EOF modifiers used influences the separation of the complexes. The EOF modifiers namely Cetyltrimethylammonium chloride (CTAC) and Tetradecyltrimethylammonium chloride (TTAC) were further utilized for the determination of EDTA in South African river waters and industrial effluents. A method for the simultaneous separation of Fe (III) complexed with EDTA, S,S -EDDS and IDS was developed by CE and high-performance liquid chromatography (HPLC). The recalcitrant EDTA is used in combination with readily biodegradable analogues like EDDS and IDS in many commercial products. The methodology performance was evaluated in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ) and reproducibility for both CE and HPLC methods. The LOD values obtained from HPLC were low when compared with CE. The applicability of both methods was demonstrated for the analysis of cosmetic products such as foam bath and shower cream. The results obtained by both CE and HPLC were found to be comparable and are in good agreement. / AFRIKAANSE OPSOMMING: Aminopolikarboksiel sure (APCAs) is komplekseer middels wat algemeen gebruik word om verskillende metaal ione te deaktifeer deur kompleks vorming in industriële en huishoudige toepassings. Etileendiamientetraasynsuur (EDTA) en dietileentriamienpentaasyn suur (DTPA) is die mees algemene APCA s. Hul gebruik word deesdae noukerig ondersoek as gevolg van hul volharding in die omgewing. Daar is n intense soektog na bio-afbreekbare agente soos etieleendiamiendisuksien suur (EDDS) and iminodisuksien suur (IDS) wat as plaasvervangers kan dien vir nieafbreekbare EDTA. Daar is dus n behoefte om te kyk na eenvoudige, vinnige en noukeurige metodes vir die bepaling van EDTA, EDTA , IDS en ander APCA s. Kapillere elektroforese (CE) was gebruik vir die skeiding en spesiering van iminodisuksien suur met verskillende metale by verskillende pH s. Spesiasie modellering was ook gebruik om die teenwoordigheid en verspreiding van metaal- spesies te vergelyk. Die CE uitslae was met die spesiasie profiele vergelyk en n redelike ooreenkoms was gevind. Die degraderings studies as n funksie van tyd was met CE bestudeer vir verskillende metal-ligand (ML) samestellings van DTPA, S,S-EDDS, IDS en R,S-IDS met verskillende metal ione (Cd2+, Cr3+, Cu2+, Fe3+, Mn2+, Pb2+ en Zn2+) by pH 7 en 9. Nuwe pieke was opgemerk in sommige ML samestellings wanneer die pH van pH 9 na 7 verander. Hoë pieke was vir CuL (L = DTPA, S,S-EDDS, IDS and R,S-IDS), FeEDTA en FeEDDS by alle pH s gevind. Lae, breë pieke was vir FeIDS, CrL en MnL komplekse gevind. CuDTPA en CuEDDS komplekse het n goeie stabiliteit gewys oor ʼn redelike tyd as dit met CuIDS, CuR,S-IDS en ander metal komplekses by pH 9 vergelyk word. In hierdie werk was die effek van verskillende kationiese elektro-osmotiese stroom (EOF) modifiseerders ook ondersoek. Veral die effek wat teen ioone op die CE skeidings het van EDTA, EDDS en IDS asook Cu(II) komplekse was ondersoek. Die effek van die modifiseerders was ondersoek en ge-evalueer in terme van migrasie tye, resolusie en plaat getalle. Die beste skeidingskondisies was bereik wanneer tetradesieltrimetielammonium bromied (TTAB) and setieltrimetielammonium bromied (CTAB) as modifiseerders gebruik word. Hierdie kondisies het ook aanleiding gegee tot korter ondersoek tye en beter piekvorme. Die effek van verskillende teen ioone wat aan die EOF modifiseerders gekoppel was het ook interresante resultate opgelewer. Die EOF modifiseerders setieltrimetielammonium chloried (CTAC) en tetradesieltrimetielammonium chloried (TTAC) was ook gebruik vir die bepaling van EDTA in Suid Afrikaanse rivier waters en industrieel afloop. ʼn Metode vir die gelyktydige skeiding van Fe(III) met EDTA, S,S’-EDDS en IDS was met behulp van CE en hoedruk vloeistof chromatography (HPLC) ontwikkel. Die metodologie was ondersoek ingevolge lineariteit, limiet van deteksie (LOD), limiet van kwantifisering (LOQ) en die herhaalbaarheid van CE en die HPLC metodes. Die LOD waardes verkry vanaf HPLC was swakker vergeleke met die verkry deur CE. Die toepaslikheid van al die metodes was vir die ontleding van kosmetiese produkte soos bad skuim en stortbad room getoets. Die uitslae deur CE en HPLC was vergelykbaar en ʼn goeie ooreenkoms was gevind.

Thesis (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Radiochemical separation of 103Pd from natAg, usmg a 66 MeV proton-induced reaction at iThemba LABS, was studied and a radiochemical method was developed for the separation. For the separation, which comprises the separation of Pd from a large amount of target material (16 g Ag), as well as Rh radioisotopes produced from decay of their Pd parents (mainly 101Rhand IOORh),three ion exchange resins were tested: a Chelex 100 chelating resin, the AG 1-X8 anion exchange resin and a AG MP-I anion exchange resin. For the optimum elution ofPd from the latter two resins, two elution curves using water and 5% ammonia solution, were obtained. With an average recovery of 97.4% and sharper elution curve from the macroporous AG MP-I, this resin was finally chosen for routine production. To achieve the separation, a simple, easily operated radiochemical processing system was designed and installed in a hot cell. Radiochemical separation of 103Pd from a Rh target was also studied and several cation and anion exchange resins were tested. A carrier-free separation of 103Pd was developed, using an AG 1-X8 anion exchange resin. Bombarded tablets of RhCh.3H20, as the targets, were used for these separations. The procedure, originally designed for the separation of Pd from Cu and Rh, was modified using H202 for the oxidation of Ru prior to the sorption on the resin and successfully used for the separation of isotopes of Rh from the isotopes of Pd, Ru, Tc, Nb, Mo, Zr and Y, which were produced by 400 MeV 160_ and 12C-induced RhCb.3H20 targets. To elute the Pd from the resin, 5% ammonia solution was used; the recovery was about 92%. To prepare the Rh target for routine production, an electroplating method of Rh on a Cu substrate was developed. Rh(CI04)3, in 0.5 M perchloric acid, was used as the electrolyte bath. The electroplated Rh was then dissolved by an alternating current technique, using 6 M HCI and a current density of 2 Alcm2. For production of the seeds, I03Pd was sorbed on the weakly basic anion exchange resin Amberlite IRA-93 (600-700 Il), by recycling a 0.5 M Hel solution of Pd through a 0.5 cm x 1 cm column for 2 hours. The distribution of I03Pd on the resin beads was measured and RSD of5.7% was obtained. A funnel was designed to transfer the I03Pd-loaded resin beads into the Ti tubes to prepare the seeds (0.7 mm LD., 0.8 mm D.D., and 4.5 mm length). To enclose the tubes as capsules, the end caps were made from 0.02 mm Ti sheet and several pieces were designed and machined for the welding of the caps to the tubes. A spotwelding machine was used for the welding, after small, but vital modifications. / AFRIKAANSE OPSOMMING: Palladium-l03 kan volgens twee produksieroetes by iThemba LABS vervaardig word, naamlik deur die volgende protongeïnduseerde reaksies: natAg(p,xn)lo3Cd (ty,=7.3 m) ~ 103Ag (ty,=1.1 h) ~ 103Pden I03Rh(p,n) ~ 103Pd. 'n Radiochemiese metode om 103Pd van die Ag-skyfmateriaal te skei, is ontwikkel. Hierdie metode, wat gebaseer is op anioonuitruilerchromatografie met die makroporeuse hars AG MP-I, behels die skeiding van I03Pd van 'n groot hoeveelheid skyfmateriaal (16g Ag), sowel as van Rh-radionukliede (hoofsaaklik looRh en IOlRh), wat geproduseer word deur die verval van hulle Pd-moederisotope. As die Pd met 5% ammonia oplossing geëlueer word, is 'n 97.4% herwinning moontlik. 'n Radiochemiese paneel is ontwerp, gebou en in 'n warmsel geïnstalleer vir roetine produksie. 'n Metode om Rh op 'n kopersubstraat te elektroplateer is ook ontwikkel om 'n Rh-skyf te verkry vir die protonbombardement. 'n Oplossing van 0.5 M HCI04 - Rh(HCI04)3 is as die elektrolietbad gebruik. Die geëlektroplateerde Rh is opgelos in 6 M HCI deur gebruik te maak van 'n wisselstroomtegniek, met 'n stroomdigtheid van 2A1cm2. 'n Metode om "draervrye" I03Pd vanaf die Rh-skyfmateriaal te skei, is ook ontwikkel. Gebombardeerde pille van RhCh.3H20 is as skywe gebruik in die onaktiewe studies. AGI-X8 anioonuitruilerhars is vir hierdie skeidings gebruik en daar is gebruik gemaak van 'n metode wat oorspronklik ontwerp is vir die skeiding van Pd van Cu en Rh. Hierdie prosedure is net effens aangepas deur H202 te gebruik vir die oksidasie van Ru, alvorens dit op die hars gesorbeer is. Hierdie metode is ook suksesvol gebruik vir die isolering van Rh van radionukliede van Pd, Ru, Tc, Nb, Mo, Zr, ens, wat geproduseer is deur 400 MeV 160_ en 12C-geïnduseerde reaksies met Rh in RhCi).3H20 skywe. 5% ammoniakoplossing is gebruik om die Pd uit die hars te elueer, met 'n herwinning van 92%. Om die saadjies vir implantering te maak, is 103Pd op 'n matige basiese anioonuitruilerhars Amberlite IRA-93 gesorbeer deur 'n 103pd-oplossing, in 0.5 M Hel, deur 'n 0.5 ' lcm kolom te hersirkuleer vir 2 uur. 'n Tregter is ontwerp om die I03Pd-gelaaide harskorrels oor te dra na die titaanbuisies (0.7 mm binnedeursnit, 0.8 mm buitedeursnit en 4.5 mm lank). Om die buisies te verseël, is dekseltjies uit 'n 0.02 mm titaanplaat gesny. Verskeie dekseltjies is gemasjieneer om op die buisies vas te sweis. 'n Punt-sweismasjien is gebruik vir die sweiswerk nadat geringe, maar belangrike, aanpassings aan die masjien gedoen is.