Expansion or swelling behavior of expansive soil has always created problems in the field of geotechnical engineering. When any construction has been carried out on expansive soil without pre-knowledge of their properties under various environmental conditions, the damage is severe. One of the methods to find out swelling potential of expansive soil is the expansive index (EI). The present study investigates the reduction of EI for the two commercially available expansive soils i.e., kaolinite and bentonite when mixed with Ottawa sand and Class C fly ash. The percentages of Ottawa sand and Class C fly ash mixed with kaolinite and bentonite were 0 to 50% by weight. The results show that there is a significant reduction in the swelling properties of expansive soil with the addition of Ottawa sand and Class C fly ash. The reduction in expansive index ranged approximately from 10 to 50% and 4 to 49% for kaolinite and bentonite, respectively. Also the maximum swelling pressure of kaolinite and bentonite soil decreased approximately 93% and 64%, respectively with the addition of various percentages of Ottawa sand and Class C fly ash. These results help to identify the swelling potential and swelling pressure of expansive soil with different percentages of sand and fly ash which will be beneficial to the geotechnical engineer. Standard index properties test such as liquid limit, plastic limit and shrinkage limit test was conducted to see the characteristic of expansive soil when mixed with less expansive sand and Class C fly ash. Also, for these expansive soils one dimensional (1-D) consolidation characteristics was studied with sand and Class C fly ash mixtures and the results were compared with pure kaolinite and bentonite soil. Pre-consolidation (Pc) behavior, compression index (Cc) and recompression or swelling index (Cs) properties were also studied for the different percentages of sand and Class C fly ash with expansive soil.

A bibliometria é um instrumento quantitativo que através de medidas matemáticas e estatísticas permite mapear e gerar informações que auxiliam na tomada de decisões de uma determinada área científica. Verificou-se o evidente crescimento da produção científica na área de flotação de caulinita e da significativa importância desse assunto em meios acadêmicos, realizou-se a necessidade de um estudo de natureza bibliométrica. Este estudo é uma maneira de observar a quantidade do que está sendo produzido, quais são os principais trabalhos desenvolvidos e quais foram os resultados atingidos. O presente trabalho apresenta uma discussão de natureza bibliométrica sobre artigos publicados no mundo, relacionados sobre o assunto flotação de caulinita, em periódicos internacionais no período de 1992 e 2015. Através deste trabalho foi possível reconhecer e identificar quais são as tendências temáticas e metodológicas que estão sendo usadas, além dos principais coletores utilizados na flotação de caulinita. Os resultados mostram que é significativa a quantidade de artigos produzidos por autores chineses, especialmente a partir do ano de 2013, visto ser a China a maior produtora de alumínio no mundo, e a caulinita, é o rejeito no processo de flotação reversa do diásporo. Foram encontrados muitos estudos com propostas e estruturas semelhantes, utilizando métodos que são importantes para compreender os fenômenos físico-químicos na flotação, como: métodos de caracterização mineralógica, potencial zeta, métodos de adsorção e outros. Os artigos analisados tinham uma média de 7 páginas por artigo e todos foram pesquisados no SciVerse ScienceDirect, pertencente à editora Elsevier. Dos 39 artigos analisados, 31 possuem avaliação interdisciplinar da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) e são classificados no estrato A1, que são artigos de mais alta qualidade. Os resultados mostraram a dificuldade de trabalhar com o tema de flotação de caulinita individualmente e confirmou que existe uma colaboração científica entre autores. No estudo por palavras-chave, (ao todo 180) verificou-se a presença de termos como \"aluminossilicatos\", \"minérios oxidados\" e \"diásporo\" junto com o termo \"caulinita\", além de outras palavras-chave como \"flotação\" e \"adsorção\". Os minerais envolvidos na flotação junto com caulinita também foram avaliados, mineral diásporo aparece frequentemente relacionando com o mineral de interesse dessa dissertação. Na avaliação por citações pelo Scopus, os artigos foram classificados conforme sua importância no meio acadêmico. Além disso, através da análise bibliométrica verificouse que os reagentes utilizados nos testes de flotação de caulinita são de grande maioria derivados de nitrogenados catiônicos. Os valores de pH mais utilizado de flotação ocorreram em meio ácido, embora, muitos coletores apresentem também bons resultados em meio neutro e/ou alcalino. Observou-se também que ainda há muito para ser pesquisado, visto que a maior parte dos artigos amostrados realizam pesquisa em escala laboratorial e não descrevem a realidade das usinas de beneficiamento de caulinita no mundo. / Bibliometrics is a quantitative instrument that, through mathematical and statistical measures, allows to map and generate information that assists in the decision-making of a certain scientific area. In the area of kaolinite flotation, a clear growth of scientific production and a significant importance of this subject in academic areas were noted, thus warranting the need for a bibliometric study. This study is a way to observe the amount being produced, which are the main projects under development and which results have been obtained. The current work presents a bibliometric discussion on articles published worldwide concerning kaolinite flotation in international journals from 1992 to 2015. This work allowed to recognize and identify which are the thematic and methodological trends that are being used, in addition to the main collectors used in kaolinite flotation. The results show that a significant amount of articles is produced by Chinese authors, especially from 2013, as China is the largest aluminum producer in the world, and kaolinite is the reject in the reverse flotation process of diaspore. Many studies using methods that are important to understand physicochemical phenomena in flotation, with similar proposals and structures, were found, such as: mineralogical characterization methods, zeta potential, adsorption methods and others. Assessed articles had, on average, 7 pages each and all were searched in Elsevier\'s SciVerse ScienceDirect. Thirty-one out of the 39 analyzed articles have interdisciplinary evaluation of the Coordination for the Improvement of Higher Education Personnel (CAPES) and are rated at stratum A1, which corresponds to higher quality articles. The results showed the difficulty of working with kaolinite flotation individually and confirmed that there is scientific collaboration among authors. The study by keyword (180 in total) found terms as \"aluminosilicate\", \"oxidized ores\" and \"diaspore\" together with \"kaolinite\", in addition to other keywords, such as \"flotation\" and \"adsorption\". Minerals involved in flotation together with kaolinite were also evaluated, and diaspore mineral frequently appears related to the mineral of interest of this dissertation. Articles were rated according to their importance in the academic world using the assessment of citations by Scopus. In addition, bibliometric analysis showed that reagents used in kaolinite flotation tests are mostly derived from cationic nitrogenated compounds. Most used pH values in flotation are acidic, although many collectors also have good results in neutral and/or alkaline media. It was also noted that there is still much to be researched, since most articles sampled researched in laboratory scale and do not describe the reality of processing plants of kaolinite in the world.

This study investigates the impacts of selected Leguminous Tree Species (LTS) and kaolinite pre-amendment on oil-contaminated soil. It covered assessment of different levels of contamination (0, 25, 50, 75 and 100 ml in 4000 g soil; which represents the degree of light crude oil spillage concentration as 0.0, 0.63, 1.25, 1.88 and 2.5 %v/w) on the growth performance of Albizia adianthifolia, Albizia odoratissima, Bauhinia monandra, Delonix regia, Peltophorum pterocarpum and Tetrapleura tetraptera LTS investigated. Percentage germination, seedling height, seedling girth, number of leaves and number of nodules decreased as the concentrations of crude oil in soil samples increased. LTS affected soil physicochemical properties. Soil acidity decreased; soil organic matter, carbon content and exchangeable ions increased. N, P and K were altered in the LTS planted soil as compared to controls, but there were no significant (P > 0.05) differences. There were increased microbial counts in the crude oil-contaminated soil planted with LTS as compared with non-LTS planted soils. Hydrocarbon removal was significantly higher (P < 0.05, n = 3) in LTS planted soil than in non-planted soil. D. regia planted soils had most hydrocarbon removal and had significantly more growth in terms of plant height, girth and leaf production in the field. Kaolinite (10 and 20 g samples) applications were suitable and effective sorbent agents for oil-contamination at the different oil concentrations. The sorption potential of kaolinite increased with the increase in kaolinite to 20 g. The potential re-usability of kaolinite after the initial use for oil sorption was analysed and 10 g of burnt kaolinite sorbed 43.62%, while 20 g sorbed 58.90%. The rate of oil sorption by fresh kaolinite was significantly higher than burnt kaolinite. Results show the considerable potential of phytoremediation protocols with LTS and kaolinite as combined remediating agents for oil spill remediation in the humid tropics.

A kaolinite-nylon 6 composite was prepared by a polycondensation reaction from 6-aminohexanoic acid (AHA) intercalated in the kaolinite interlayer space. The basal spacing of kaolinite-AHA was 1.47 nm and the basal spacing of the heated products decreased to 1.16 nm. The signals attributed to nylon 6 were detected in the 13C CP/MAS NMR spectra of the heated products. Formation of nylon 6 in kaolinite was confirmed by appearance of IR band due to amide I and amide II. Sarcosine was intercalated in kaolinite for the first time by guest displacement with methanol from the kaolinite-methanol precursor. The basal spacing of kaolinite-sarcosine was 1.27 nm. This intercalation compound was characterized by NMR, TGA, XRD, and IR. The physical and chemical properties of natural clay sample from Mirandela formation (Portugal) were determined in terms of external skin treatment. The low CEC 4,45meq/100g is consistent with high content of kaolinite in the sample

The thesis deals with the issue of increasing the whiteness index of kaolin raw material. The research was focused on floating the kaolin suspension and the subsequent processes related to increasing the whiteness index. Increasing the whiteness of the kaolin raw material took place on the basis of acid leaching. The eluents were based on sulfuric acid, phosphoric acid, oxalic acid and sodium bisulfite. The leaching process was influenced by the temperature and concentration of the leaching agent. Floated and leached kaolin samples were characterized by several methods. The XRD method investigated the mineralogical composition and the kaolinite structure order. The distribution of chromogenic components was monitored by SEM-EDS. Residues of organic matter was determined by COD test and the concentration of chromogenic components in the extract was monitored by the ICP-OES method. Last but not least, the index of whiteness was measured, the increase of which is the aim of the diploma thesis, using a UV-VIS spectrometer with reflective extension.

Organoclays modelling the Athabasca oil sands were prepared in heptane and toluene showing indole loading occurring exclusively on the external surface of the clay, via a multilayer adsorption mechanism. Solvent adsorption was minimal. Vermicular microstructures, similar to natural kaolinite were formed. Isotherms were constructed and fitted to the BET equation, giving monolayer quantities (9.28mg) that matched well to the theoretical amount calculated from surface area measurements (8.87mg). Dispersing the organoclays in isopropanol and in toluene left a monolayer equivalent. Using cellulose as a competitive desorption agent in asphaltene based organoclay dispersions achieved complete disaggregation of the dispersed organoclay stacks.13 C CP - MAS NMR, showed up to a 25% increase in desorption for aliphatic and up to 40% increase in desorption for aromatic functionalities of the loaded organic matter. Investigation of other saccharides and modified celluloses as competitive agents is recommended for future work.

The objective of this work is development of a new adsorbent on the base of an organoclay with a chelating ligand covalently attached to the clay mineral surface. The presence of a chelating ligand in the clay structure significantly improves its ability to immobilize heavy metal ions from contaminated sludge of wastewater. Montmorillonite and kaolinite were chosen as typical examples of expandable and non-expandable clay minerals. A two-step modification procedure comprised of sequential modification with oxides and grafting of a chelating agent to the modified clay minerals was used. Modifications with silica and ferric oxide were conducted by reacting the dispersed raw clay minerals with tetraethoxysilane and ferric nitrate solution. A chelating ligand, N-[3-(trimethoxysilyl)propyl]ethylenediamine triacetic acid trisodium salt, was introduced into interlayer space of raw and modified clay minerals in aqueous solutions. Laboratory tests of the organoclay efficiency for purification of wastewater were conducted with the most promising sample, i.e., organoclay with the highest specific loading of chelating agent. Experiments were conducted with model wastewater containing either individual or mixed heavy metal ions. The modified organoclay displayed high adsorption capacity for heavy metal cations even in acidic media. The method of modification presented in this work can be used for synthesis of efficient adsorbents for applications in contaminated areas.

No description available.

This study presents the results from laboratory investigations of the capacity of kaolinite to adsorb heavy metals including copper, nickel, cadmium, and lead. Kaolinite is a clay commonly found in suspended solids and sediments in natural water systems. The purpose of the study was to evaluate the validity of the competitive adsorption equation presented by weber in describing metal adsorption on kaolinite. This equation describes adsorption competition among the components of a mixture of solutes. Adsorption studies were conducted for single and mixed metal systems. Controlling factors considered include solution pH, clay dosage, and cation competition. The investigation demonstrated that the competitive adsorption equation is a valid and useful equation for describing the adsorption of mixed metal systems on kaolinite. The equation may be used to predict equilibrium metal concentrations in mixed metal systems. The results of the study also indicated that the rate of adsorption of the metals on kaolinite was very rapid. Equilibrium was complete within thirty minutes of the addition of the metals to the clay. / Master of Science

This study focuses on the interaction of wash load particles with gravel bed rivers. The effects of excess fine sediment loading to streams on general water quality, contaminant transport, and benthic organism mortality has been well examined. A fundamental assumption in fluvial geomorphology and river engineering is that wash load particles ($d<63mu m$) do not deposit to stream beds, but are instead transported downstream until they deposit in reservoirs or estuaries. The goal of this study is to determine if wash load sized particles can deposit to gravel beds, where within the bed substrate deposition occurs, under what hydraulic conditions it occurs, and how the composition of the bed affects the spatial and temporal deposition pattern. Further, this study attempts to quantify the mass flux of wash load to the bed based on a simple mass conservation model using the aforementioned conditions as model parameters. This was accomplished through a series of experiments in which a mixture of pure kaolinite clay was allowed to deposit at constant shear over an acrylic, gravel, or sand-gravel mixture. Discharge was then increased to determine the effects of increased bed shear stress on deposited material and further wash load interaction with the bed. Results indicate that wash load will deposit to acrylic, gravel, and sand-gravel beds during conditions where no bedload movement is occurring. Bed composition is the primary factor controlling the mass flux of wash load from the water column to the bed. Deposition on acrylic beds forms clay ripples which translate downstream, while deposition in porous beds occurs primarily within the bed substrate. Shear stress also affects mass flux and the magnitude of its effects are related to the bed composition. Discharge increases below the threshold of bedload movement only cause large scale entrainment of deposited particles over non-porous beds. Periods of higher discharge over porous beds result in continued deposition within the bed substrates. This research enhances not only our knowledge of sediment processes within fluvial systems, but also allows for the quantification of the wash load portion of those processes given minimal initial condition information. The model developed here may be used within larger hydrologic models when examining contaminant spills or mass loading of stream networks with wash load to estimate the mass deposition to the bed. Instances where wash load is contaminated the mass of contaminated sediment retained by the bed is of great importance to local communities given a reliance of residents on that water source for water, livelihood, and recreation. / Master of Science