The overall goal of this research is concerned with understanding the effects of bentonite on the external corrosion of bare mild steel well casing. Na-bentonite is mainly used in enormous amounts in drilling processes, so it used as the main electrochemical environment surrounding the casing at different condition. The major part of the current study was divided into 3 stages; the first stage is constant current cathodic protection (CP) with a range of 0.0 (Open Circuit Potential) to 200mA.m-2 was applied respectively to protect bare mild steel buried vertically inside the bentonite layer contains 45% (w/w) 0.5 M NaCl Solution. This study was attempted to investigate the polarisation potential distribution over depth. The second stage is polarisation potential with a range of OCP to -1.15V/SCE was applied to protect mild steel exposed to 0.5M sodium chloride solution containing different concentration of bentonite, namely 0.0%, 1.0 and 10.0% (w/w). The third stage was concerning with the ZnCl2 added at 500ppm and 1000ppm to the bentonite as cathodic inhibitor to investigate its effects on the corrosion process of mild steel. CP at 0.0mV (OCP) and -1.15 V against saturated calomel electrode (SCE) were applied for this experiment. Weight loss, visual observation, Open Circuit Potential (OCP), cathodic protection and linear polarisation resistance (LPR) techniques were employed for this study. Optical microscope, Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDX), and X-Ray diffraction (XRD) analysis are illustrated to study, examine and analyse the films that formed on the metal surface. It is demonstrated that the corrosion rate produced from LPR measurement data was fairly lower than that obtained by experimental weight loss data. Low corrosion rate was recorded for the specimens immersed in 0.5NaCl solution, containing bentonite compared to that were obtained for solution free of bentonite. Magnesium hydroxide and calcium carbonate were the main chemical compounds that detected on the metal surfaces when cathodic protection (CP) was applied at -1.15V vs. SCE. It was confirmed that, the addition of ZnCl2 at two different concentration, 500ppm and 1000ppm has reduced the current density applied to a considerable value. This was ascribed to the formation of compacted and uniform film on the protected surface. The examination of the specimens using EDX and XRD has shown the formation of zinc containing compounds. Small amount of NaCl in the form of halite for both concentrations was also detected.

Until recently, concrete flow in tremie-placed drilled shafts has been mischaracterized as rising uniformly with laitance formation occurring only at the top of the rising concrete in the shaft. In actuality, concrete first fills a portion of the reinforcement cage to a sufficient height to promote radial flow into the cover region. Depending on support fluid type, the radial flow can produce laitance-filled creases/channels projecting the reinforcing cage configuration to the side of shaft surface. The flow pattern (and creases) can affect filter cake thickness, cover quality and propensity for corrosion. This research examines 52 tremie-placed laboratory drilled shaft specimens constructed using bentonite, polymer or natural support fluid to identify correlations between support fluid type and laitance channel formation. The extent of the laitance channel effect was quantified with surface texture, corrosion potential, and strength distribution methods. A direct correlation between the use of bentonite support fluid and laitance channel formation was identified which showed a high propensity for corrosion and lower concrete strengths.

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The objective of this experiment was to evaluate the effects of free-choice intake of sodium bentonite and sodium bicarbonate on physiological and production parameters. Eight Jerseys and seventeen Holsteins (four fistulated) were randomly assigned to two groups to equalize stage of lactation, age and production history. Two diets were fed: diet 1 without added sodium bicarbonate and diet 2 with sodium bicarbonate added at 1.2% of dry matter. Each group followed a different diet regime: 1) diet 1 with no free-choice (D1-NFC), 2) diet 2 with no free-choice (D2-NFC), 3) diet 1 with free-choice (D1-WFC), and 4) diet 2 with free-choice (D2-WFC). Free-choice options of sodium bentonite and sodium bicarbonate were offered side by side in a covered feeder to breed groups. Diets were changed every 10 d to provide 8 periods with a repetition of each diet regime. All diets were adjusted to 17% ADF and 17% CP. There were no differences with either breed among diets for blood and fecal observations or milk protein. Urine specific gravity was lower in both breeds when sodium bicarbonate was force-fed. Holsteins force-fed sodium bicarbonate had greater intake and milk production than Holsteins not force-fed. In Jerseys, milk urea nitrogen (MUN) decreased when sodium bicarbonate was added to the TMR. During periods in which cows were allowed free-choice access to sodium bentonite and sodium bicarbonate, Jerseys had higher urine pH, fat-corrected milk, MUN, and dry matter intake (DMI), and Holsteins had higher milk fat percentages and fecal pH. / Master of Science

Both crystalline and sedimentary rocks are being considered as potential host rocks for a deep geological repository in Canada. Deep-seated sedimentary rocks in the Michigan Basin, Ontario, Canada contain highly saline ground and pore waters. The relatively high I of these waters may influence speciation and rock matrix sorption properties. To this end, laboratory sorption experiments were conducted to examine sorption of Pd(II) on sodium bentonite, illite and Ordovician age shale as a function of pH and solution I and initial concentration of Pd. Solutions with pH values in the range of 5 to 9, I ranging from 0.1 to 4 M and initial concentration of Pd ranging from 5×10 −8 to 1×10 −6 M were considered. A sorption time of 14 days was used and the separation method was by centrifuge. Experiments were performed under aerobic conditions at 25 ◦ CC, and the Eh value of the solution ranged from 300 to 600 mV. The data from sorption experiments were used to validate surface complexation models developed in PHREEQC with the JAEA TDB. The sorption of Pd on bentonite, shale and illite all showed strong dependence on I and pH. The dependence on initial concentration of Pd was used to plot sorption isotherms. The slope of the isotherms showed that Pd was forming inner- and outer- sphere complexes inside the stern layer for sorption onto bentonite and illite. It also showed however that shale was most likely undergoing cooperative sorption. Strong fit was found between the single layer surface complexation model for montmorillonite (the major constituent clay mineral of sodium bentonite) and experimental data, but not for illite (the major constituent clay mineral of shale). / Thesis / Master of Applied Science (MASc)

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The increasing use of non-sustainable materials in technology has led to severe environmental consequences, prompting a global search for more sustainable and eco-friendly alternatives. Clay, with its low cost, non-toxicity, recyclability, natural abundance, and versatile properties, has emerged as a beacon of hope for a greener future. Since prehistoric times, clay has found extensive use in the pharmaceutical, petroleum, biomedical, and energy industries. Its high surface area, cation exchange capacity, intrinsic porosity, and ease of functionalization make it a versatile and sustainable choice for a variety of applications. The dissertation focuses on synthesizing hybrid clays functionalized with zwitterionic molecules for antimicrobial and ionic membrane applications. It also studies the rheological properties of bentonite clay modified with betaines of different carbon chain lengths. The research aims to investigate the flow and stability of these functionalized clays. In addition, it offers valuable insights into how carbon chain length and pH affect the rheological properties of clays. This is followed by engineering pathogen-resistant clay composites embedded with antimicrobial agents like silver ions and terbinafine hydrochloride against pathogens (viz. S. aureus, E. coli, and C. albicans). Another part of the dissertation focuses on developing and investigating flexible and durable betaine-functionalized clay membranes as ion-conducting separators for batteries and fuel cells. The low-cost membranes exhibit excellent ionic conductivity, chemical-thermal stability, recyclability, and ease of engineering making them an exceptional material for such applications. Overall, this dissertation presents a comprehensive study of the structure-property relationship of hybrid clays, bridging the fields of chemistry, materials engineering, electrochemistry, and biology. The research is poised to inspire the scientific and industrial communities with the potential of novel clay-based materials, encouraging them to embrace cleaner technologies and reduce their carbon footprints.

Ce travail de thèse porte sur l'étude des mécanismes de blocage d'un écoulement d'eau dans un milieu granulaire par injection d'un produit de colmatage, et s'inscrit plus généralement dans la problématique de l'érosion interne des sols (Projet National ERINOH). Cette recherche, à dominante expérimentale, s'appuie sur une modélisation physique unidimensionnelle. Pour cela, une conduite d'écoulement de 18 cm de diamètre intérieur et 300 cm de longueur maximale, constituée par plusieurs tronçons de 50 cm de longueur assemblés, a été développée. Celle-ci est tout d'abord remplie du matériau granulaire perméable à étudier ; on établit ensuite un écoulement d'eau permanent à pression imposée à l'amont ; finalement on vient injecter localement un produit de colmatage pour essayer de bloquer l'écoulement. Le dispositif est équipé de plusieurs capteurs de pression, de débitmètres, d'un turbidimètre afin de mettre en évidence les paramètres significatifs qui contrôlent le processus de blocage. Les paramètres expérimentaux sont les caractéristiques du milieu granulaire (type de sol, conductivité hydraulique, état de compacité…), les caractéristiques de l'écoulement (vitesses, gradients hydrauliques, régime de l'écoulement…), les propriétés rhéologiques du coulis d'injection (densité, viscosité, seuil de cisaillement…) et la technique d'injection associée. Sur la base des résultats obtenus, on propose des critères de blocage de l'écoulement combinant ces derniers paramètres sous une forme suffisamment simple, utilisable dans la pratique, pour répondre à la demande des industriels impliqués dans le projet de recherche ERINOH, qui sont confrontés à ces pathologies / The present PhD thesis focuses on the mechanisms of blocking permanent water flow through a granular soil by injection of a grout. This work is part of the more general problem of internal erosion of soils (French National Project ERINOH). This research, mainly experimental, is based on a one-dimensional physical modelling. For this, a new original prototype setup, allowing to generate permanent flow in a 18 cm inner diameter and 3 m long plexiglas pipe, has been developed. It is first filled with a highly permeable granular medium, then permanent flow of water is generated at controlled upstream pressure, and finally the grout is injected locally in order to try to block the water flow. The set-up is equipped with multiple pressure sensors, flowmeters, a turbidimeter to monitor the significant parameters that control the clogging process. The experimental parameters are the characteristics of the granular medium (soil type, hydraulic conductivity, density ...), the flow characteristics (flow rate, hydraulic gradient, flow regime ...), the rheological properties of the grout (density, viscosity, yield stress ...) and the associated injection technique. Based on the results obtained, clogging criteria are proposed, as a function of the parameters involved, in a simple form for use in practice.Key-words: internal erosion, clogging, injection, grout, bentonite, yield stress, viscosity.