<p>Dioxins and poly-chlorinated biphenyl (PCB) compounds are high priority organic pollutants which are similar in structure and well known for their toxicity, bioaccumulation and persistence in the environment. Dioxins and PCBs have a high affinity for certain types of clay minerals. However, the molecular mechanism for the observed high affinity of these compounds to clay minerals is not well understood and has been the main focus of this research work. The mechanisms that govern dioxin-clay and PCB-clay interactions were investigated from two perspectives. First, the influence of selected properties clay minerals on dioxin sorption was investigated via in-situ spectroscopic techniques (ATR-FTIRand Raman) structural (XRD) and macroscopic batch sorption methods using dibenzo-p-dioxin (DD) as a model solute. Second, the influence of solute properties, especially position and degree of chlorination and molecular planarity, on sorption was investigated.</p> <p> Smectites, especially, Cs-saponite effectively adsorbs dibenzo-p-dioxin (DD) from water with values reaching 10,000 mg kg^-1, or one weight percent which greatly exceeds that by other naturally occurring sorbents such as soil organic matter. Adsorption was promoted by clay interlayer exchangeable cations with low hydration energies, and by smectites in which negative charge in the smectite originate from the tetrahedral siloxane sheets. IR-active bands of DD sorbed to saponite in the 1280 to 1500 cm^-1region were perturbed compared to the ‘reference’ IR spectra. Combined batch sorption, XRD and spectroscopic data confirm that the intercalation of DD occurred in the clay interlayer and site specific interactions occur between DD molecule and Cs⁺ cation. </p> <p> Sorption of 1-chloro-dibenzo-p-dioxin (1-ClDD) and 2-chloro-dibenzo-p-dioxin (2-ClDD) on homoionic (Na⁺, K⁺, Rb⁺, and Cs⁺) smectites was evaluated to explore the effect of chlorine substitution position (and steric hindrance) of dioxin on sorption mechanisms. Similar to DD, adsorption was influenced by the hydration energy of exchangeable cations and the origin of negative charge in the smectite. XRD measurements revealed that 1-ClDD molecules were oriented nearly parallel to the siloxane surface of the clay while 2-ClDD adopted a tilted orientation, similar to DD. The location of the chlorine constituent in 1-ClDD prevents the molecule from its apparent energetically more favorable orientation. In-situ ATR-FTIR spectra revealed that sorption of 1-ClDD to Cs-saponite resulted in the loss of interfacial H₂O and suggested that the sorption 1-ClDD displaces interlayer H₂O and 2-ClDD is less sterically restricted in the clay interlayer. </p> <p> Sorption of three dioxins (DD, 1-ClDD and 2-ClDD) was compared to three PCBs (PCB-1, PCB-4, and PCB47) with similar octanol-partition coefficients (log K_ow) but varying molecular planarity and degree of chlorination onto Cs-saponite, which was shown to be representative of other smectites, revealed that despite having similar structure and hydrophobicity, dioxins have higher affinity for smectites than PCBs. Sorption studies also showed that sorption of PCBs is influenced by molecular planarity and hydrophobicity. Polarizability and dipole-moment were identified as important solute properties that affect the sorption behavior of dioxins and PCBSs. Linear relationships between these properties and log K_f’(subcooled liquid solubility normalized Freundlich sorption coefficient) values suggest that high sorption affinity of planar dioxins could be due to a combination of <i>Van der Waals</i> interactions with the siloxane surface, steric effects, and site-specific interactions between dioxin and exchangeable cations. In contrast, the sorption of PCBs was highly influenced by their molecular orientation.</p>

Este trabalho apresenta o desenvolvimento da tese intitulada: Estudo, em escala de laboratório, do uso de argilas do tipo Bofe na obtenção de argilas organofílicas e ativadas. Argilas do tipo esmectítico são as de maior utilização industrial, sendo considerada a mais interessante das argilas industriais. Todavia em diversos casos faz-se necessário submetê-las a tratamentos químicos para desenvolver suas potencialidades. Para o desenvolvimento da tese foram utilizadas quatro amostras de argilas do tipo Bofe, provenientes de jazidas localizadas no município de Boa Vista, PB. Esse tipo de argila, apesar de ser bastante abundante, possui baixo valor econômico dada a dificuldade de obter produtos com propriedades adequadas a partir delas. Neste estudo utilizamos dois tipos de tratamentos, para verificar a potencialidade destas argilas, que foram: ativação ácida e organofilização. Para ativação ácida, foi utilizado o ácido clorídrico com diferentes tempos de reação, variando de uma hora até sete dias e com estas amostras avaliou-se o poder descorante em óleo de soja. Para a organofilização foram utilizados três sais quaternários de amônio e com as argilas organofílicas obtidas realizou-se teste de sorção em solventes orgânicos. Os resultados obtidos indicam que o tratamento ácido em argilas, com tempos de reação muito longos, promove destruição significativa da estrutura do argilomineral esmectítico. As argilas na sua forma natural apresentaram, no descoramento de óleo de soja, comportamento superior ao de argilas industriais ativadas de alto desempenho o que potencializa o uso das argilas tipo Bofe como materiais descorantes naturais (terras fuller). Em relação à organofilização, observou-se a eficiência no tratamento aplicado, visto o aumento do espaçamento interplanar, medido por difração de raios-X e da alta capacidade de sorção de óleo Diesel e Tolueno dos materiais organofílicos obtidos. / This work present the development of the entitled thesis: Study, at laboratory scale, of the use of the Bofe type clay to obtain organophillic and activated clays. Clays of the smectite type are of the bigger industrial use, being considered most interesting of the clay minerals. However, becomes necessary to submit it to chemical treatments for develop its potentialities. For the development of the research four samples of clay from the Bofe type had been used, proceeding from deposits located in areas near to the city of Boa Vista, PB. This type of clays, in spite of they be quite abundant, possess low economic value because the difficulty to obtain products with adequate properties starting from them. In this study to verify the potentiality of these clays we used two types of treatments. Those treatments were: acid activation and organophillic modification. For the acid activation treatment, hydrochloric acid was used with different times of reaction, varying from one hour up to seven days and with the obtained samples the fade power was evaluated in soy oil. To the organophillic modification treatment three quaternary ammonium salts were used. With the samples of the treated clays were made sorption in organic solvents tests. The obtained results indicate that the acid treatment in clays, with very long times of reaction, promotes significant destruction of the structure of the smectite clay mineral. Clays in its natural form presented, in the soy oil fade, superior behavior to the one of industrial activated clays of high performance, that indicates the potential of use of the type Bofe clays as natural bleacher material (fuller\'s earth). In relation to the organophillic modification, it was observed efficiency in the applied treatment, seen the increase of the interplane spacing, measured by X ray diffraction and the high capacity of sorption of Diesel oil and Toluene of the gotten organophillic materials indicating its potential of use in the sorption of hydrocarbons.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-25T14:32:33Z No. of bitstreams: 1 ADRIANA ALMEIDA SILVA - TESE (PPGEP) 2008.pdf: 8434650 bytes, checksum: 7ca7e24f622bbd49778d99a13f342587 (MD5) / Made available in DSpace on 2018-09-25T14:32:33Z (GMT). No. of bitstreams: 1 ADRIANA ALMEIDA SILVA - TESE (PPGEP) 2008.pdf: 8434650 bytes, checksum: 7ca7e24f622bbd49778d99a13f342587 (MD5) Previous issue date: 2008-12-19 / Nas últimas décadas uma quantidade substancial de pesquisas foi realizada a fim de encontrar novas fontes de energia renovável e sustentável para substituir o diesel de petróleo. Uma fonte alternativa promissora de energia é o biodiesel, que é um combustível renovável que pode ser produzido a partir dos óleos e gorduras animais/vegetais ou mesmo ácidos graxos reciclados da indústria de alimentos. Os catalisadores heterogêneos podem melhorar os métodos de síntese eliminando os custos adicionais associados aos catalisadores homogêneos e minimizando a produção de poluentes. As argilas ativadas têm atraído atenção como catalisadores para uma variedade de reações ácidas. O comportamento físico-químico dos minerais argilosos tem sido estudado devido a sua relação como adsorvente e/ou propriedades catalíticas. Diante do exposto verifica-se a necessidade de desenvolver estudos sobre a utilização de argilas como catalisador na produção do biodiesel, tornando-se, portanto, fundamental conhecer a estabilidade e propriedades do biodiesel produzido a partir desses catalisadores. Visando avaliar a eficiência das argilas como catalisadores no processo de transesterificação deste combustível, foram estudados nesse trabalho 27 tipos de argilas, fornecidas pela empresa BENTONISA- Bentonita do Nordeste S.A, para produção do biodiesel na rota etílica e metílica, utilizando óleo de soja. Inicialmente foi realizada uma pré-seleção das argilas, utilizando as análises de umidade e pH, onde foram escolhidos 15 tipos de amostras, as mesmas foram submetidas a ensaios nos sistemas reacionais S1 e S2 e utilizando as técnicas de cor do óleo (aspecto visual) e viscosidade, optou-se pelos dois melhores catalisadores argilosos (A23 e A24) a serem testados no sistema padrão para produção do biodiesel, denominado S3. Os catalisadores A23 e A24 foram caracterizados por : fluorescência de raios-X (FRX); difração de raios-X (DRX); espectroscopia de absorção no infravermelho (IV); microscopia eletrônica de varredura (MEV); energia dispersiva de raios-X (EDS) e área específica pelo método BET. O óleo de soja e o biodiesel formado foram caracterizados através das seguintes técnicas: composição química, umidade, acidez, densidade 20ºC, glicerol total e viscosidade 40ºC, teor de éster, teor de álcool e cromatografia gasosa. Os resultados mostraram que é possível obter o biodiesel a partir de catalisadores argilosos. / In the last decades a substantial amount of research has been undertaken to find new sources of renewable and sustainable energy to replace Diesel. A promising alternative energy source is biodiesel, which is a renewable fuel produced from vegetable oils and animal fats or even from recycled fat from the food industry. Heterogeneous catalysts can improve the synthesis methods eliminating additional costs associated with the homogeneous catalysts and minimizing the production of pollutants. Activated clays have attracted attention as catalysts for a variety of acid reactions. The physical and chemical behavior of clay minerals has been studied because of their property as adsorbent and / or catalysts. Therefore the need to develop studies on the use of clays as a catalyst in the production of biodiesel, making it, therefore, necessary to know the stability and properties of biodiesel produced by these catalysts. To evaluate the efficiency of clays as catalysts in the transesterification process of this fuel, 27 types of clay supplied by the company BENTONISA- Bentonite Nordeste SA, were studied in this work. The biodiesel was produced on the ethyl and methyl route, using soybean oil as raw material. The initial preselection for the clays was carried out on moisture and pH analysis, whereby 15 samples were selected. These were submitted to the testing systems in the S1 and S2, using the techniques of oil color (visual aspect) and viscosity. The two best clay catalysts (A23 and A24) were chosen to be tested in the standard system for production of biodiesel called S3. The catalysts A23 and A24 were characterized by: FRX; XRD; IR, SEM, EDS and BET. The soybean oil and biodiesel were characterized by the following techniques: chemical composition, moisture, acidity, density 20ºC, viscosity 40ºC, total glycerol, ester content, alcohol content and gas chromatography. The results showed that it is possible to get biodiesel from clay catalysts.

Este trabalho apresenta o desenvolvimento da tese intitulada: Estudo, em escala de laboratório, do uso de argilas do tipo Bofe na obtenção de argilas organofílicas e ativadas. Argilas do tipo esmectítico são as de maior utilização industrial, sendo considerada a mais interessante das argilas industriais. Todavia em diversos casos faz-se necessário submetê-las a tratamentos químicos para desenvolver suas potencialidades. Para o desenvolvimento da tese foram utilizadas quatro amostras de argilas do tipo Bofe, provenientes de jazidas localizadas no município de Boa Vista, PB. Esse tipo de argila, apesar de ser bastante abundante, possui baixo valor econômico dada a dificuldade de obter produtos com propriedades adequadas a partir delas. Neste estudo utilizamos dois tipos de tratamentos, para verificar a potencialidade destas argilas, que foram: ativação ácida e organofilização. Para ativação ácida, foi utilizado o ácido clorídrico com diferentes tempos de reação, variando de uma hora até sete dias e com estas amostras avaliou-se o poder descorante em óleo de soja. Para a organofilização foram utilizados três sais quaternários de amônio e com as argilas organofílicas obtidas realizou-se teste de sorção em solventes orgânicos. Os resultados obtidos indicam que o tratamento ácido em argilas, com tempos de reação muito longos, promove destruição significativa da estrutura do argilomineral esmectítico. As argilas na sua forma natural apresentaram, no descoramento de óleo de soja, comportamento superior ao de argilas industriais ativadas de alto desempenho o que potencializa o uso das argilas tipo Bofe como materiais descorantes naturais (terras fuller). Em relação à organofilização, observou-se a eficiência no tratamento aplicado, visto o aumento do espaçamento interplanar, medido por difração de raios-X e da alta capacidade de sorção de óleo Diesel e Tolueno dos materiais organofílicos obtidos. / This work present the development of the entitled thesis: Study, at laboratory scale, of the use of the Bofe type clay to obtain organophillic and activated clays. Clays of the smectite type are of the bigger industrial use, being considered most interesting of the clay minerals. However, becomes necessary to submit it to chemical treatments for develop its potentialities. For the development of the research four samples of clay from the Bofe type had been used, proceeding from deposits located in areas near to the city of Boa Vista, PB. This type of clays, in spite of they be quite abundant, possess low economic value because the difficulty to obtain products with adequate properties starting from them. In this study to verify the potentiality of these clays we used two types of treatments. Those treatments were: acid activation and organophillic modification. For the acid activation treatment, hydrochloric acid was used with different times of reaction, varying from one hour up to seven days and with the obtained samples the fade power was evaluated in soy oil. To the organophillic modification treatment three quaternary ammonium salts were used. With the samples of the treated clays were made sorption in organic solvents tests. The obtained results indicate that the acid treatment in clays, with very long times of reaction, promotes significant destruction of the structure of the smectite clay mineral. Clays in its natural form presented, in the soy oil fade, superior behavior to the one of industrial activated clays of high performance, that indicates the potential of use of the type Bofe clays as natural bleacher material (fuller\'s earth). In relation to the organophillic modification, it was observed efficiency in the applied treatment, seen the increase of the interplane spacing, measured by X ray diffraction and the high capacity of sorption of Diesel oil and Toluene of the gotten organophillic materials indicating its potential of use in the sorption of hydrocarbons.

The aim of the thesis has been to evaluate and understand the effect of caustic alkali solution of varying composition on the behaviour of expansive soil containing mixed layered minerals. Mixed layered minerals are formed of two or more kinds of inter grown layers, not physical mixtures. Illite - smectite is the most abundant and wide spread of the mixed layered clay minerals in sedimentary rocks and soils and also more common than either discrete illite or smectite. In geotechnical engineering much attention has not been paid to the behaviour of soils containing mixed layered minerals. Much less is known about the behaviour of these soils in polluted environment. Mixed layered minerals are more susceptible to environmental changes as the structural linkages between the layer minerals are weak compared to normal layered phyllosilicates. One important pollutant that can have considerable effect on the behaviour of soils is the caustic alkali contamination released from various industries. Recent studies have shown that the behaviour of even stable minerals is affected by alkali contamination. However, the effect of caustic alkali contamination on the behaviour of soils containing mixed layered minerals is not known and has been chosen for detailed study. Also to understand the mechanism of their interaction with alkali, it is necessary to study the effect of alkali solutions on the constituent clay minerals viz., montmorillonite and illite under similar conditions. To elucidate the mechanism of soil alkali interaction limited tests were conducted with simple electrolyte solution, as the alkali solution also acts as electrolyte apart from being alkaline. To confirm the mechanism of interaction, tests are also conducted on these soils with industrial spent liquor containing high caustic alkali and suspended alumina obtained from an alumina extraction plant treating bauxite with high alkali solutions at high temperatures. The results obtained in the laboratory are compared with the soil samples contaminated with leaking industrial Bayer's liquid in the field. Studies are also conducted to suggest remedial measures to control the adverse effects of alkali solutions on soil containing mixed layer minerals. The content of the thesis is broadly divide into 8 Chapters - viz., Introduction, Background and overview, Experimental program and procedures, Behaviour of soils containing mixed layer mineral illite - smectite (BCSI), Behaviour of montmorillonite and illite, Influence of Bayer's liquor and study on the field contaminated soils, Measures to control the influence of alkali contamination on BCSI and Summary and conclusions. The broad outline of these chapters is given in Chapter 1. A review of literature on the behaviour of soils containing different types of clay minerals with emphasis on mixed layer minerals has been presented in Chapter 2. The influence of different inorganic contaminants on the properties of soils in terms of their physical and chemical characteristics as well as their concentration has been summarized. The importance of changes in surface characteristics of soil particles and the changes in the thickness of diffuse double layer in altering the property of soils at low concentration of contaminants and changes in the mineralogy with high concentrated contaminants such as acids and alkalis has been highlighted. This forms the background information necessary to bring out the scope of the study. Four soils having different mineralogy have been used in this study. These soils are, black cotton soil containing predominantly mixed layer mineral illite - smectite mineral called rectorite, illite, montmorillonite (common smectite) and black cotton soil containing predominantly montmorillonite. The properties of the soils used are described in Chapter 3. Caustic alkali solutions of 1N, 4N concentration prepared in the laboratory and industrial alkali-spent liquor are used as contaminants. The spent Bayer's liquor had about 4N alkali concentration and 10% alumina in suspension. To simulate the effect of suspended alumina, two more caustic alkali solutions of 1N and 4N solutions containing 10% alumina by weight of solutions are also prepared. To isolate the effect of electrolyte solutions from that of alkali solution, two electrolyte solutions of 1N and 4N sodium chloride solutions are also used. Test procedures for conducting various tests such as pH, water adsorption characteristics, X-ray diffraction studies, SEM studies, thermal characteristics and geotechnical properties such as Atterberg limits, Oedometer tests and Shear Strength are given in this chapter. The test procedures are modified, wherever necessary, to bring out the effect of contaminants, particularly the effect of duration of interaction on the properties of soils. The source and properties of black cotton soil are presented in Chapter 4. Detailed x-diffraction studies have confirmed the presence of inter layered illite-smectite mineral viz., rectorite, which is uncommon in Indian expansive soils, and is classified as CH (Clay of high compressibility) as per ASTM soil classification. Effect of alkali and salt solutions of 1N and 4N concentration on all physico chemical and geotechnical properties are studied in this chapter. As it is known that presence of certain elements such as aluminium influence the soil alkali interaction, the effect of suspended alumina along with alkali solution has also been investigated. The effect of contaminating fluids such as 1N NaOH, 4N NaOH with and without alumina, 1N NaCl and 4N NaCl on the geotechnical properties of the soil has been studied. Mineralogical changes were observed by XRD and thermal studies in the soil treated with 4N NaOH solution and 4N NaOH + 10% alumina. The interlayer potassium of illite is released and potassium hydroxide is formed in soil treated with 4N NaOH. Swelling compounds such as sodium aluminium silicate hydroxide hydrate (SASH) has formed due to attack of 4N NaOH + 10% alumina on silica rather than on rectorite. Thus the studies clearly bring out that the rectorite present in the soil is dissociated only in the presence of strong alkali solutions of concentration of about 4N. The liquid limit of soil decreased with increase in the electrolyte concentration in the case of NaCl solutions. With 1N NaOH, the liquid limit of soil increased due to increase in the thickness of diffuse double layer due to increased pH. However, Proctor's maximum dry density increased and optimum moisture content decreased with 1N NaOH. With increase in the concentration of alkali solution to 4N, the rectorite dissociates into constituent minerals with the formation potassium hydroxide. The liquid limit of soil decreased probably due to the dominating influence of electrolyte nature of hydroxide solution over the effect of increased negative charge on clay particles due increase in the pH on the constituent minerals. Proctor's maximum dry density decreased and optimum moisture content increased with 4N NaOH. Sediment volume and oedometer free swell at seating/nominal surcharge load of 6.25 kPa of soil increased in 1N and 4N caustic alkali solutions, though by different mechanisms. The increase with 1N solution is essentially due to increased negative charges on clay mineral surface. However, the increase in swelling with 4N solution is associated with the dissociation of rectorite mineral and occurs in two distinct phases unlike in the case of 1N solution. While the first phase can be attributed to the effect of alkaline nature of the solution after reduction in its concentration due to reaction with rectorite and the consequent reduction in its electrolyte nature. The second phase is due to the swelling of the separated constituent minerals in the presence of excess of alkali and occurs after much delay. Consolidation behaviour of rectorite in 1N and 4N alkali solutions has been studied in two ways: 1). Loading without waiting for the second stage of swelling to occur, as in standard consolidation procedure and 2). Loading after completion of second stage of swelling which is occurring after considerable delay as explained earlier. Normally one would initiate loading after equilibrium is reached at the end of first stage of swelling and second stage of swelling is not suspected. As there is no second stage of swelling with 1N solutions, these two types of consolidation tests produced the same results. Abnormal rebound is observed during unloading with 4N solution in which loading cycle is initiated without waiting for second stage of swelling to complete. It is interesting to note that while the liquid limit of soil decreased with increase in the concentration of alkali solution, the swelling increased. The testing procedure and period of interaction as well as the concentration of alkali solution during the test in these two tests are different. The effects of alkali solution are more severe in case of liquid limit because of thorough mixing and consequent effective reaction during testing. Similarly, the volume changes in soil that has already reacted with 4N alkali solution when exposed to further to alkali contamination are considerably less compared to uncontaminated soil exposed to fresh contamination. The shear strength of soil treated with 4N-alkali solution has increased particularly after long period of interaction. This indicates that the soil after mineralogical changes posses good strength. Chapter 5 presents the effect of alkali and salt solutions on the physico chemical and geotechnical properties of component minerals of mixed layered illite/smectite. For this study, commercially obtained montmorillonite (bentonite), naturally occurring black soil containing montmorillonite and commercially pure illite are used. It was observed that montmorillonite alkali reactions would not produce significant mineralogical changes where as illite is dissociated into smectite with the formation of potassium silicate by the interaction of released potassium with soluble silica. This confirms that the ultimate products of rectorite with alkali solutions would be smectite and compounds of potassium. In the absence of mineralogical alterations the liquid limit of montmorillonite decreases due to suppression of diffuse double layer thickness due to dominating influence of alkali solutions on this highly active clay. However a small increase in liquid limit is observed in illite with alkali solutions. Thus the net effect of alkali on rectorite is to decrease the liquid limit with increase in alkali concentration. While the free swell and oedometer swelling of montmorillonite generally decreases with increase in the alkali concentration, they increase in illite. However, in both the minerals the swelling occurs only in one phase. Thus the second phase of swelling that has been observed in rectorite can be attributed to delayed swelling of montmorillonite that has been released by the attack of alkali on rectorite. The behaviour of black soil containing mixed layer mineral contaminated in the field and laboratory by leaking Bayer's spent liquor in an alumina extraction plant has been studied in Chapter 6. The Atterberg limits of the samples treated with liquor are reduced and sediment volume increased. Similarly the swelling at seating load in consolidation test is higher in sample compacted with water and inundated with liquor. X-ray diffraction studies showed that the mineralogical changes are similar to those occurred with 4N caustic alkali solution. The mineralogical and micro structural changes in the soil samples that are contaminated by leaked spent liquor in the field are relatively more marked. Also the behavior of highly montmorillonite clay, bentonite, has been studied contaminated with liquor in the laboratory. The study on the effect of high concentrated alkali solutions on montmorillonite can be useful to study the effect of interaction on the dissociated montmorillonite. These studies are helpful to suggest some possible remedial measures to control the adverse effect of alkali on soils. Possible Remedial schemes that can be adopted before and after contamination of the soil to control the adverse effect of alkali solutions on the black cotton soil containing mixed layered mineral are listed and their effectiveness examined in Chapter 7. The suggested remedial measures include flushing with water to dilute the effect of alkali, neutralisation with dilute hydrochloric acid, stabilisation of soil with lime and calcium chloride and use of impervious membrane to separate the foundation soil from alkali solution. The effectiveness of different measures as well as the method of their application has been described. Efforts are made to understand the mechanism of remedial action. Consolidation tests conducted on soil contaminated with 4N alkali solution and inundated with water showed increased swelling due to dilution of the alkali concentration. Though the swelling of contaminated soil can be controlled by passing dilute hydrochloric acid (1N), the method is not advocated as it can lead to ground water contamination. Mixing the soil with solutions containing up to 5% by weight of calcium compound in water could not prevent the alkali induced heave in the long run when inundated with 4N alkali solution. This was due to dissolution of silica by the strong alkali solutions and formation of swelling compounds such as sodium aluminium silicate hydroxide hydrate (SASH). The formation of sodium aluminates occurred only when the alkali solution contained alumina or soil contained calcium compounds. There are no significant variations in the effects of calcium chloride or calcium hydroxide on contaminated soil. Replacing the foundation soil with soil thoroughly contaminated with 4N alkali solutions and controlling the migration of contaminants into the foundation soil using high-density polyethylene (HDPE) geosynthetic membranes can be an effective measure to control the heaving in alkali contaminated foundation soil containing interstratified illite – smectite. Summary and the major conclusions of the thesis are presented in Chapter 8.