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Separation of solid-liquid suspensions with acoustic energyBekker, M. C. 05 February 2014 (has links)
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.
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Periodic precipitation in Cu-Ni-CoVandermousen, Roland F. January 1967 (has links)
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
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MICROALGAE HARVESTING IN A MICROFLUIDIC CENTRIFUGAL SEPARATOR FOR ENHANCED BIOFUEL PRODUCTIONUnknown Date (has links)
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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The effect of air flow rate and froth thickness on batch and continuous flotation kinetics /Kaya, Muammer January 1985 (has links)
No description available.
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A fundamental flotation model and flotation column scale-up /Dobby, G. S. (Glenn Stephen), 1952- January 1984 (has links)
No description available.
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Activity coefficients at infinite dilution for ILs : methyltrioctylammonium cation and bis(trifluoromethylsulfonyl)imide or thiosalicylate anions using glcGwala, Nobuhle V. January 2009 (has links)
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.
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Some aspects of ferrohydrostatic separation of minerals and the recycling of ferrofluidDumbu, Stanford 04 1900 (has links)
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.
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A mass transfer model for structured packingKawesha, David Mukuma 12 1900 (has links)
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.
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Separation of readily biodegradable aminocarboxylate complexes by electrodriven methodsKatata, Lebogang Maureen 03 1900 (has links)
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.
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Separation of 103Pd from Ag and Rh targets for production of '103 Pd seeds' for prostate cancer brachytherapyAardaneh, Khosro 12 1900 (has links)
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.
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