Dielectric constant is a physical property of soil that is often measured using non-invasive geophysical techniques in subsurface characterization studies. A proper understanding of dielectric responses allows investigators to make measurements that might otherwise require more invasive and/or destructive methods. Previous studies have suggested that dielectric models could be refined by accounting for the contributions of different types of mineral constituents that affect the ratio and properties of bound and bulk water. This study tested the hypothesis that the dielectric responses of porous materials are mineral-specific through differences in surface area and chemistry. An experimental design was developed to test the dielectric behavior of pure quartz sand (Control), quartz sand/kaolin clay mixtures and ferric oxyhydroxide coated quartz sand. Results from the experiments show that the dielectric responses of quartz-clay and iron oxyhydroxide modified samples are not significantly different from the pure quartz Control. Increasing clay content in quartz sands leads to a vertical displacement between fitted polynomials. The results suggest that the classic interpretation for the curvature of dielectric responses appears to be incorrect. The curvature of dielectric responses at low water contents appears to be controlled by unknown parameters other than bound water. A re-examination of the experimental procedure proposed in this study and past studies shows that a properly designed study of bound water effects on dielectric responses has not yet been conduct / Master of Science

<p>Development of products which can be produced from a country’s natural resources is very important as far as the industrialization of a nation and saving foreign exchange is concerned. Presently, industries in Uganda and the other states in the Lake Victoria region import all refractory-related-consumables, as the demand cannot be met locally. Based on the abundance of ceramic raw materials for high temperature applications in the region and the demand for refractories by industries it is pertinent to develop and manufacture firebricks by exploiting the locally available raw materials.</p><p>This thesis thus, concerns the characterisation of ceramic raw mineral powders from the Lake Victoria region, more particularly, Uganda, with the aim of developing firebrick refractories from the minerals. Two main deposits of kaolin and a ball clay deposit were investigated to assess their potential in the manufacture of refractory bricks. Raw- and processed sample powders were investigated by means of X-ray diffraction (XRD), thermal analysis (DTA-TG) and Scanning Electron Microscopy (SEM). In addition, the chemical composition, particle size distribution, density, and surface area of the powders were determined.</p><p>A comprehensive study on beneficiation of Mutaka kaolin was carried out using mechanical segregation of particles. The aim of the study was to explore other potential applications like in paper filling and coating. The beneficiation process improves the chemical composition of kaolin to almost pure, the major impurity being iron oxide.</p><p>A general production process scheme for manufacturing fireclay bricks starting with raw powder minerals (Mutaka kaolin and Mukono ball clay) was used to make six groups of sample fireclay brick. Experimental results from the characterization of formulated sample bricks indeed revealed the viability of manufacturing fireclay bricks from the raw minerals. Based on these results, industrial samples were formulated and manufactured at Höganäs Bjuf AB, Sweden. Kaolin from the Mutaka deposit was used as the main source of alumina while ball clay from Mukono was the main plasticizer and binder material. The formulated green body was consolidated by wet pressing and fired at 1350°C in a tunnel kiln. Characterization of the sintered articles was done by X-ray diffraction, scanning electron microscopy, and chemical composition (ICP-AES). In addition, technological properties related to thermal conductivity, thermal shock, alkali resistance, water absorption, porosity, shrinkage, permanent linear change (PLC), linear thermal expansion, refractoriness under load (RUL), and cold crushing strength were determined. The properties of the articles manufactured from the selected naturally occurring raw minerals reveal that the produced articles compare favourably with those of parallel types. Thus, the raw materials can be exploited for industrial production.</p>

Development of products which can be produced from a country’s natural resources is very important as far as the industrialization of a nation and saving foreign exchange is concerned. Presently, industries in Uganda and the other states in the Lake Victoria region import all refractory-related-consumables, as the demand cannot be met locally. Based on the abundance of ceramic raw materials for high temperature applications in the region and the demand for refractories by industries it is pertinent to develop and manufacture firebricks by exploiting the locally available raw materials. This thesis thus, concerns the characterisation of ceramic raw mineral powders from the Lake Victoria region, more particularly, Uganda, with the aim of developing firebrick refractories from the minerals. Two main deposits of kaolin and a ball clay deposit were investigated to assess their potential in the manufacture of refractory bricks. Raw- and processed sample powders were investigated by means of X-ray diffraction (XRD), thermal analysis (DTA-TG) and Scanning Electron Microscopy (SEM). In addition, the chemical composition, particle size distribution, density, and surface area of the powders were determined. A comprehensive study on beneficiation of Mutaka kaolin was carried out using mechanical segregation of particles. The aim of the study was to explore other potential applications like in paper filling and coating. The beneficiation process improves the chemical composition of kaolin to almost pure, the major impurity being iron oxide. A general production process scheme for manufacturing fireclay bricks starting with raw powder minerals (Mutaka kaolin and Mukono ball clay) was used to make six groups of sample fireclay brick. Experimental results from the characterization of formulated sample bricks indeed revealed the viability of manufacturing fireclay bricks from the raw minerals. Based on these results, industrial samples were formulated and manufactured at Höganäs Bjuf AB, Sweden. Kaolin from the Mutaka deposit was used as the main source of alumina while ball clay from Mukono was the main plasticizer and binder material. The formulated green body was consolidated by wet pressing and fired at 1350°C in a tunnel kiln. Characterization of the sintered articles was done by X-ray diffraction, scanning electron microscopy, and chemical composition (ICP-AES). In addition, technological properties related to thermal conductivity, thermal shock, alkali resistance, water absorption, porosity, shrinkage, permanent linear change (PLC), linear thermal expansion, refractoriness under load (RUL), and cold crushing strength were determined. The properties of the articles manufactured from the selected naturally occurring raw minerals reveal that the produced articles compare favourably with those of parallel types. Thus, the raw materials can be exploited for industrial production. / QC 20101029

Vertical and inclined soil nails under footings as settlement &ndash / reducing elements is investigated using a physical 1g model in the laboratory. Nails are not connected to footing, they are not so long and vertical settlement of nails is very large compared to usual limits encountered for piles or micropiles. Following the settlement of footing, they share the load together with the footing. The skin friction is mostly mobilized and end-bearing failure occurs continuously during the settlement. The system of footing- soil nail is studied by model square footings of 30 mm x 30 mm and 50 mm x 50 mm breadth dimensions and remoulded kaolin clay consolidated under constant controlled stress of 50 kPa in 200 mm cube boxes. In the first section of the testing series 4, 5, 9 and 12 nails were inserted into soil in 3B, 2.4B, 1.33B and B lengths, respectively. In the second section, 4 and 6 nails in 1.5B and 2B lengths were tested for vertical and 15 degrees and 30 degrees inclined cases. Settlements of footings were measured under constant footing pressure for all groups. Several tests were repeated in each group of testing series. It is concluded that keeping the total nail length constant, decreasing the nail number thus using longer individual nails is more effective in decreasing the footing settlements. 15 degrees inclined nails decrease total settlements more.

Heavy-metal contamination in soils has become a serious environmental problem. Among all metals, excessive amount of zinc was released to soils over the years. Zinc is not only toxic to human being, but also to plants. High concentration of zinc is extremely phytotoxic. Currently, the most popular method to remediate heavy-metal contaminated soils is stabilization/solidification (S/S) technique as it is cheaper, faster and more effective to remediate heavy metals than other remediation methods. Portland cement is the most-used binder in S/S technique. However, the production of Portland cement has released a significant amount of carbon dioxide, which strongly contributes to global warming. In addition, zinc retards the setting and hydration of Portland cement, which would require more Portland cement to remediate zinc-contaminated sites. Therefore, researchers are looking for new materials to improve the performance of Portland cement in zinc-contaminated soils. In recent years, the application of graphene-based materials in concrete had proved to be effective. Due to relative cost-effectiveness and comparable properties, multi-layer graphene, known as graphene nanoplatelets, may show a promising potential in construction. Moreover, research has reported that graphene nanoplatelets can be exfoliated from graphite and potentially scaled up for full-scale applications. At present, there is no application of graphene nanoplatelets in the S/S of contaminated soils and the roles of graphene nanoplatelets in cement-stabilized zinc-contaminated clay remained unknown. In this research, graphene nanoplatelets were dispersed in solution with a high-shear mixing apparatus. Dispersed graphene nanoplatelets solution was then applied to zinc-contaminated soil along with cement. To evaluate the efficacy of this S/S method, various influencing factors such as mixing sequence, graphene nanoplatelets content, zinc content, cement content, and curing time were studied. An optimum graphene nanoplatelets content was determined through the unconfined compressive strength (UCS) of the stabilized/solidified samples. It was found that at the optimum content, the unconfined compressive strength of cement-stabilized zinc-contaminated clay was improved by 22.3% with the addition of graphene nanoplatelets. Also, graphene nanoplatelets were effective at moderate zinc content and low cement content. Graphene nanoplatelets accelerated cement hydration effectively at early ages. Microstructural analyses indicated that more hydration products were developed in samples with graphene nanoplatelets. At current stage, it is still expensive to apply graphene nanoplatelets in S/S technique; however, it is possible to exfoliate graphite into graphene nanoplatelets in future research. / Graduate / 2022-05-12

<p>Predmet ovog istraživanja je razvoj nove generacije<br />mineralnih dodataka, dobijenih termičkom i<br />mehanohemijskom aktivacijom kaolinske gline i ispitivanje<br />svojstava kompozita, u kojima je deo portland cementa<br />zamenjen dobijenim pucolanskim materijalima,<br />metakaolinom i amorfnim kaolinom, za različite režime<br />nege. Rezultati su pokazali da su termička i mehanohemijska<br />aktivacija kaolinske gline jednako pogodne metode za<br />dobijanje pucolanskih materijala. Pozitivni efekti na<br />čvrstoće pri pritisku postižu se primenom do 30 %<br />metakaolina u kompozitima pri normalnom režimu nege, a uz<br />dodatno mlevenje, sadržaj metakaolina se može povećati do<br />40 %, uz dodatak CH. Amorfni kaolin se može primeniti u<br />kompozitima, sa stepenom zamene portland cementa do 10 %,<br />pri normalnom i autoklaviranom režimu nege.</p> / <p>The subject of this research is development of a new generation<br />of mineral admixtures, obtained by thermal and<br />mechanochemical activation of kaolin clay, and testing of the<br />properties of the cement based composites, where a part of the<br />portland cement is replaced by pozzolanic materials, metakaolin<br />and amorphous kaolin, for different curing conditions. The<br />results showed that thermal and mechanochemical activation of<br />kaolin clay were equally suitable for obtaining pozzolanic<br />materials. Positive effects on the compressive strength could be<br />achieved by using up to 30 % of MK, and with additional grinding<br />after thermal activation, content of MK could be increased up to<br />40 %, with the addition of CH, under the normal curing<br />conditions. Amorphous kaolin could be used in composites with<br />a cement replacement level of 10 %, under the normal and<br />autoclave curing conditions.</p>

The present dissertation investigates the flow behavior of concentrated Kaolin slurries and furthermore novel rheological measurement-, analysis-, and assessment procedures for characterizing static and dynamic flow behavior in industrial and research applica- tions. Ten different Kaolins with divergent property profiles were investigated in detail. At first, novel measurement and analysis procedures are presented and the raw material inherent properties are correlated with the resulting flow characteristics. The results describe the structural building and breakdown (in both static and dynamic states) of concentrated Kaolin slurry suspensions with and without deflocculant and also the determination of the point of optimal deflocculant concentration through the develop- ment of a novel analysis method and linking of the parameters to a condition matrix. The results lead to a better understanding of the flow behavior of concentrated Kaolin slurries. Due to the use of a strict measurement protocol with a focus on the elimination of external disturbances on the determination of flow behavior, the phases of dynamic structure construction and destruction (with exclusion of temporal structure effects and vice versa) can be analyzed. It was identified that the construction of particle networks requires less energy than their destruction. Furthermore it could be demonstrated that the occurrence of a transient shear stress peak in kaolin slurries is the cause for the breakdown of an existing particle network and not, as conventionally reported, due to an insufficient measurement time. Moreover, through the combination and modification of two measurement protocols described here, manufacturing companies have a potentially useful tool for composition development and quality control without the necessity of purchasing a highly precise research rheometer.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang / In der vorliegenden Arbeit wird das Fließverhalten von konzentrierten Kaolinsuspensio- nen untersucht und neuartige rheologische Mess-, Analyse- und Bewertungsverfahren zur Charakterisierung der Belastungs- und Zeitabhängigkeit für Industrie- und Forschungsanwendungen vorgestellt. Hierzu wurden zehn Kaoline mit divergierenden Eigenschaftsprofilen untersucht. Zunächst werden neuartige Mess- und Analyseverfahren vorgestellt und die Eigenschaften der Rohstoffe mit den ermittelten Fließcharakteristika korreliert. Die Ergebnisse beschreiben den strukturellen Auf- und Abbau (zeit- und belastungsabhängig) von konzentrierten Kaolinsuspensionen mit und ohne Dispergierhilfsmitteleinsatz und darüber hinaus die Ermittlung der optimalen Dispergierhilfsmittelkonzentration durch Entwicklung einer neuartigen Analyse und Verknüpfung von Parametern an eine Bedingungsmatrix. Die Erkenntnisse tragen zum besseren Verständnis des Fließverhaltens konzentrierter Kaolinsuspensionen bei. Aufgrund der entwickelten Messvorschriften und der darin elementar verankerten Elimination von Störgrößen auf die Ermittlung des Fließverhaltens konnten die Phasen des strukturellen Auf- und Abbaus unter Belastung (unter Ausschluss von temporalen Struktureffekten und umgekehrt) analysiert werden. Es wurde festgestellt, dass die Konstruktion von Partikelnetzwerken weniger Energie benötigt, als deren Destruktion und das Auftreten des Schubspannungshügels auf den Zusammenbruch des Partikelnetzwerkes und nicht, wie allgemein beschrieben auf zu geringe Messzeiten zurück zu führen ist. Darüber hinaus wird der produzierenden Industrie, durch Abwandlung und Kombination zweier Messvorschriften ein Werkzeug zur Versatzentwicklung und Qualitätskontrolle, auch ohne die Notwendigkeit des Erwerbs von hochpräzisen Forschungsrheometern bereitgestellt.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang

PhD (Environmental Sciences) / Department of Ecology and Resource Management / The presence of arsenic in groundwater has drawn worldwide attention from researchers and public health officials due to its effects on human health such as, cancer, skin thickening, neurological disorders, muscular weakness, loss of appetite and nausea. World Health Organisation (WHO) has set the limit of 10 μg/L for arsenic in drinking water in trying to reduce the effects of arsenic. This was further adopted by South African National Standard (SANS). The present study aims at evaluating arsenic concentration in selected groundwater sources around Greater Giyani Municipality in Limpopo Province and further synthesize clay based adsorbents for arsenic removal using Fe3+ and Mn2+ oxides and hexadecylammonium bromide (HDTMA-Br) cationic surfactant as modifying agents. The first section of the work presented the hydrogeochemical characteristics of groundwater in the Greater Giyani Municipality. The results showed that the pH of the samples ranges from neutral to weakly alkaline. The dominance of major anionic and cationic species was found to be in the order: HCO3 ->Cl->SO4 2->NO3 - and Na+>Mg2+>Ca2+>K+>Si4+, respectively. Hydrogeochemical facies identified in the study area include CaHCO3 (90%) and mixed CaNaHCO3 (10%) which shows the dominance of water-rock interaction. About 60% of the tested samples contains arsenic concentration above 10 μg/L as recommended by SANS and WHO. Concentration of arsenic was found to be ranging between 0.1 to 172.53 μg/L with the average of 32.21 μg/L. In the second part of this work, arsenic removal efficiency of locally available smectite rich and kaolin clay was evaluated. Results showed that the percentage As(V) removal by kaolin clay was optimum at pH 2 while the percentage As(III) removal was greater than 60% at pH 2 to 12. For smectite rich clay soils, the percentage of As(III) and As(V) removal was found to be optimum at pH between 6 and 8. The adsorption isotherm data for As(III) and As(V) removal by both clays fitted better to Freundlich isotherm. Adsorption of both species of arsenic onto the clay mineral occurred via electrostatic attraction and ion exchange mechanisms. Both clay soils could be regenerated twice using Na2CO3 as a regenerant. Kaolin clay showed a better performance and was selected for further modification. In the third section of this work, Fe-Mn bimetal oxide modified kaolin clay was successfully synthesized by precipitating Fe3+ and Mn2+ metal oxides to the interlayer surface of kaolin clay. Modification of kaolin clay increased the surface area from 19.2 m2/g to 29.8 m2/g and further v decreased the pore diameter from 9.54 to 8.5 nm. The adsorption data fitted to the pseudo second order of reaction kinetics indicating that adsorption of As(III) and As(V) occurred via chemisorption. The adsorption isotherm data was described by Langmuir isotherm models showing a maximum As(III) and As(V) adsorption capacities of 2.16 and 1.56 mg/g, respectively at a temperature of 289 K. Synthesized adsorbent was successfully reused for 6 adsorptiondesorption cycles using K2SO4 as a regenerant. Column experiments showed that maximum breakthrough volume of ≈2 L could be treated after 6 hours using 5 g adsorbent dosage. Furthermore, the concentration of Fe and Mn were within the WHO permissible limit. In the fourth part of the work kaolin clay was functionalized with hexadecyltrimethylamonium bromide (HDTMA-Br) cationic surfactant and its application in arsenic removal from groundwater was investigated. The results revealed that adsorption of As(III) and As(V) is optimum at pH range 4-8. The maximum As(III) and As(V) adsorption capacities were found 2.33 and 2.88 mg/g, respectively after 60 min contact time. Pseudo first order model of reaction kinetics described the adsorption data for As(V) better while pseudo second order model described As(III) adsorption data. The adsorption isotherm data for As(III) and As(V) fitted well to Langmuir model indicating that adsorption of both species occurred on a mono-layered surface. Adsorption thermodynamics model revealed that adsorption of As(III) and As(V) was spontaneous and exothermic. The As(III)/As(V) adsorption mechanism was ascribed to electrostatic attraction and ion exchange. The regeneration study showed that synthesized adsorbent can be used for up to 5 times. In the firth part of the work inorgano-organo modified kaolin clay was successfully synthesized through intercalation of Fe3+ and Mn2+ metal oxides and HDTMA-Br surfactant onto the interlayers of the clay mineral. The batch experiments showed that As(III) removal was optimum at pH range of 4-6, while the As(V) removal was optimum at pH range 4-8. The adsorption data for both species of arsenic showed a better fit to pseudo second order of reaction kinetics which suggest that the dominant mechanism of adsorption was chemisorption. The isotherm studies showed better fit to Langmuir isotherm model as compared to Freundlich model. The maximum adsorption capacity As(III) and As(V) at room temperature as determined by Langmuir model were found to be 7.99 mg/g and 7.32 mg/g, respectively. The thermodynamic studies for sorption of As(III) and As(V) showed negative value of ΔGᴼ and ΔHᴼ indicating that adsorption process occurred spontaneously and is exothermic in nature. The regeneration study showed that the vi inorgano-organo modified kaolin clay can be reused for up 7 adsorption-regeneration cycles using 0.01 M HCl as a regenerant. Thomas kinetic model and Yoon-Nelson model showed that the rate of adsorption increases with increasing flow rate and initial concentration and decreases with increasing of the bed mass. In conclusions, adsorbents synthesized from this work showed a better performance as compared to other adsorbents available in the literature. Among the synthesized adsorbents, inorgano-organo modified clay showed highest adsorption capacity as compared to surfactant functionalized and Fe-Mn bimetal oxides modified kaolin clay. However, all adsorbents were recommended for use in arsenic remediation from groundwater. The following recommendations were made following the findings from this study: 1) routine monitoring of arsenic in groundwater of Greater Giyani Municipality, 2) evaluating the possible link between arsenic exposure and arsenic related diseases within Giyani in order to find the extent of the problem in order to establish the population at risk, 3) The toxicity assessment for HDTMA-Br modified kaolin clay should be carried out, 4) Materials developed in the present study should be modeled and tested at the point of use for arsenic removal, and lastly, 5) this study further encourage the development of other arsenic removal materials that can be used at household level. / NRF