Zeolites are among the least-known products for environmental pollution control, separation science and technology. Due to their unique porous properties, they are used in various applications in petrochemical cracking, ion-exchange and separation and removal of gases and solvents. The preparation of synthetic zeolites from chemical reagents is expensive. Therefore, in order to reduce costs, zeolite researchers are seeking cheaper aluminosilicate bearing raw materials, such as clay minerals, to produce synthetic zeolites. This research concerns the synthesis of zeolites and zeotypes derived from low-cost materials like kaolinite (KAO), natural clinker (NC) and fly ash (FA). The motivation for using these sources as the starting materials in zeolite synthesis is driven by factors, such as they are cheap and available in bulk quantities, are currently under-utilized, have high workability, and require less water (or solution) for activation. The raw materials were activated by two different routes: (1) classic alkaline hydrothermal synthesis and (2) alkaline fusion prior to hydrothermal synthesis. In the first method, the synthesis of zeolitic materials was carried out generally in alkaline media, although KAO or its calcination product, metakaolinite (MTK), was also activated in the presence or absence of structure directing agents (SDAs) and additional silica (precipitated SiO2), with the last one determining the SiO2/Al2O3 ratio of the reaction mixture and the time given for zeolitization. Synthesis in fluoride- and calcium-bearing media was also used to activate kaolinite. The process of synthesis was optimized by applying a wide range of experimental conditions with a wide range of reaction temperature, time, mineralizer concentration and solid/solution ratio. In the second approach, an alkaline fusion step was conducted prior to hydrothermal treatment, because it plays an important role in enhancing the hydrothermal conditions for zeolite synthesis. On the other hand, this approach was adopted because it can dissolve more aluminosilicates. The main synthesis products obtained after activation of KAO in NaOH solutions included zeolite LTA (LTA), sodalite (SOD), cancrinite (CAN), faujasite (FAU), zeolite Na-P1 (GIS), JBW-type zeolite (JBW), analcime (ANA), whereas the activation of KAO in KOH solutions produced chabazite (CHA), zeolite Barrer-KF, phillipsite (PHI) and K-feldspar. The hydrothermal conversion of kaolinite in fluoride media did not produce successful results, although traces of FAU, GIS, CHA, SOD and CAN crystallized. The activation of KAO in the system CaO-SiO2-Al2O3-H2O promoted the formation of different calcium silicate hydrate (C-S-H) phases, including hydrogarnet (HYD) and tobermorite (TOB). Following the fusion approach, the main zeolitic phases obtained using NaOH as mineralizer were LTA and CAN. The main as-synthesized zeolites obtained from NC by the conventional hydrothermal treatment method include PHI, SOD and CAN. Using the fusion approach, FAU and LTA were obtained with NaOH as an activator, whereas non-zeolitic material crystallized when KOH was used. The main as-synthesized zeolitic materials obtained by hydrothermal reaction of FA include PHI, zeolite Barrer-KF, CHA and SOD with traces of TOB, ANA, zeolite LTF (LTF) and herschelite (HER), appearing occasionally. By the fusion approach, FAU was obtained with NaOH as activator, whereas no zeolitic material crystallized using KOH. Experimental results indicate that the method, mineralizer, concentration and time have strong effects on the type and degree of crystallinity of the synthesis products. On the other hand, the type and chemical composition of the as-synthesized products are strongly dependent on the chemical composition of the starting material. The chemistry of zeolite synthesis was subject to perturbations caused by the presence of impurities in the raw materials, which may remain insoluble during crystallization and cause undesired species to nucleate, developing mixtures of different types of zeolites. However, other physicochemical factors may play a very important role in the thermodynamics and kinetics of zeolite formation. The raw materials have very high contents of SiO2 and Al2O3, with SiO2/Al2O3 ratios appropriate for the synthesis of low-Si zeolitic materials with high crystallinity and cation exchange capacity (CEC). However, although zeolites’ CEC represents a very important characteristic quality in the removal of undesired species from polluted effluents, it is not the deciding factor in determining zeolite performance during ion exchange processes, since numerous other factors also need to be considered. Finally, the potential application of the raw materials and their as-synthesized products as low-cost sorbents in the remediation of metal ions and ammonium from wastewater effluents was investigated. PHI showed a lower efficiency than FAU. Selectivity of FAU for metal removal was, in decreasing order, Fe>As>Pb>Zn>Cu>Ni>Cr. Based on these results, the use of these materials has the potential to provide improved methods for the treatment of contaminated effluents.

Nine beryllium deposits were studied in order to determine the geological environment of beryllium mineralization in southern Arizona. Beryllium occurs in two pegmatite areas, two contact metamorphic deposits, two quartz-tungsten veins, two quartz-feldspar veins, and in one quartz monzonite stock. It is associated in almost all of these deposits with purple fluorite and tungsten. Beryllium mineralization is associated with granitic and quartz monzonite intrusions of Laramide age, and generally occurs at the intersection of northwest-trending lineaments and the Texas lineament.

No description available.

The assemblage of ca. 6–4 Ma volcanic rocks exposed at the Sagehen Research station in the Truckee-Tahoe region of the northern Sierra Nevada, United States, is interpreted to be, within the Ancestral Cascades volcanic arc, a Lassen-type stratovolcano complex. Sagehen is of particular importance because it is one of the few Tertiary arc volcanic centres in California which has not been heavily glaciated during the Pleistocene. The volcanic rocks are variably porphyritic or aphanitic, including abundant plagioclase with clinopyroxene and amphibole. The rocks range from basalt to basaltic-andesite to andesite in composition. Basalts are olivineand clinopyroxene-bearing with minor phenocrysts of plagioclase. The basaltic-andesites are primarily pyroxene bearing while the andesites contain pyroxene-, plagioclase- and hornblende porphyritic phases. Sagehen arc lavas are calc-alkaline and enriched in the large ion lithophile elements and depleted in High Field Strength Elements. The basalts are depleted in Zr and Hf while the andesites are enriched with Zr and Hf relative to the middle rare earth elements. Compared to previously studied Ancestral Cascade arc samples, Sagehen region basalts have lower 143Nd/144Nd isotopic values that do not correspond to proposed mantle-lithosphere mixing lines, while the andesite samples appear to represent the interplay of these two components on a 87Sr/86Sr vs. 143Nd/144Nd. The trace element data and isotopic plots suggest that the melts that produced the basalts are from subduction modified mantle wedge peridotites that ponded near the base of the lithosphere similar to the generation of other subduction related calc-alkaline lavas along convergent continental margins. The andesitic samples appear to be the result of further modification through crustal assimilation as seen in the higher isotopic Sr contents in the andesites and Ce/Smpmn vs. Tb/Ybpmn plots. Finally, the proposed map units from Sylvester & Raines (2007) were found to contain various geochemical facies based on the samples collected indicating that some map units may have to be redefined or sub-divided.

A large amount of information concerning interatomic distances in the solid state is available, but little has been done in recent times to comprehensively filter, summarize and analyze this information. Here, I examine the distribution of bond lengths for 135 ions bonded to oxygen, using 180,331 bond lengths extracted from 9367 refined crystal structures collected from the Inorganic Crystal Structure Database (ICSD). The data are used to evaluate the parameterization of the bond-length—bond-valence relation of the bond-valence model. Published bond-valence parameters for 135 cations bonded to oxygen, and the various methods used in their derivation, are evaluated. New equations to model the relation are tested and the common form of the equation is found to be satisfactory. A new method (the Generalized Reduced Gradient Method, GRG method) is used to derive new bond-valence parameters for 135 cations bonded to oxygen, leading to significant improvements in fit for many of the ions. The improved parameterization is used to gain crystal-chemical insight into the milarite structure. A literature review of 350+ published compositions is done to review the end-members of the milarite group and to identify compositions that should have been described as distinct minerals species. The a priori bond-valences are calculated for minerals of this structure, and are used to examine the controls of bond topology on site occupancy, notably by localizing the major source of strain of the structure (the B site). Examination of the compositions of all known milarite-group minerals shows that compositions with a fully occupied B site are less common than those with a vacant B site, in accord with the idea that the B site is a local region of high strain in the structure. The bond-length distributions for the ions of the alkali and alkaline-earth metal families are examined. Variations in mean bond-lengths are only partly explained by the distortion theorem of the bond-valence model. I have found that bond length also correlates with the amount of vibrational displacement of the constituent ions. The validity of some uncommon coordination numbers, e.g., [3]-coordinated Li+, [3]-coordinated Be2+, is confirmed. / October 2016

Cytomegalovirus (CMV) is a significant cause of mortality and morbidity in immunocompromised patients and an important cause of birth defects if acquired in utero. The licensed CMV antivirals, ganciclovir, cidofovir and foscarnet, all target the viral DNA polymerase. For each drug prolonged use is associated with significant toxicities and development of drug resistance. None are approved for use during pregnancy. Therefore, development of new anti-CMV drugs that target different pathways would be beneficial. All herpesviruses encode an alkaline nuclease. That genetic disruption of the CMV alkaline nuclease, UL98, reduces CMV replication by 1,000-fold suggests that UL98 may be a useful target for development of novel anti-CMV drugs. Moreover, using herpes simplex virus type 1 Hsiang and Ho found that the anthraquinone emodin inhibits activity of the viral alkaline nuclease, blocks viral replication in cell culture, and reduces viral pathogeneses in a mouse model (Brit. J. of Pharm., 2008). Earlier studies also showed that anthraquinone derivatives including emodin have anti-CMV activity (Barnard et al., Antiviral Research 1992 & 1995), although the mechanism of CMV inhibition has not been further studied. We therefore sought to confirm the anti-CMV activities of emodin and related anthraquinone derivatives, to characterize their mechanisms of action, and to determine specifically if they act through inhibition of UL98. Using a luciferase-based CMV yield reduction assay emodin inhibited CMV replication (IC50 = 4.9 μM); however, that the TD50 for cytotoxicity (determined using an luciferase-based cell viability assay) was only 2-fold higher suggested that emodin may act non-specifically. Two additional anthraquinone derivatives (acid blue 40 and alizarin violet R) inhibited CMV only at high concentrations (IC50 = 238; 265 μM) that were also cytotoxic. Atanyl blue PRL, however, exhibited anti-CMV activity (IC50 = 6.3 μM) with low cytotoxicity (TD50 = 216 μM). Thus, characterization of atanyl blue PRL (impact on gene expression, GFP expression, viral spread, infectivity, time of addition studies, and inhibition of UL98 nuclease activity) should be informative. Atanyl blue PRL appears to block immediate-early gene expression and reduce early and late gene expression. Atanyl blue PRL also blocked GFP expression, reduced viral spread, and also lowered the infectivity of CMV. Finally, atanyl blue PRL inhibits UL98 alkaline nuclease activity at an IC50 of 5.7 μM. This suggests that atanyl blue PRL may inhibit CMV through inhibition of UL98. Thus, atanyl blue PRL represents a novel class of anti-herpesvirals and provides a lead structure for structure based drug discovery.

Hyaluronic acid is commonly used in dermatological fillers in the form of gels. It is established how these gels' firmness is affected by the amount of cross linker and hyaluronic acid respectively. However, the effect of hydroxide ions in solution is rather unknown. This thesis examines how the alkalinity of the solvent affects the intrinsic viscosity of 3 MDa hyaluronic acid by using the method of Ubbelohde capillary viscometry. Sodium hydroxide solutions between 2 and 10 wt% were prepared to study the variation in intrinsic viscosity at concentrations relevant for cross linking (1<wt%). From these respective solutions, four solutions of different mass concentrations of hyaluronic acid were made. The flow time of respective samples were measured between two points in the capillary viscometer in a controlled temperature of 25 °C with an SI Viscoclock to ensure a high accuracy.From the resulting flow times, the intrinsic viscosity was calculated. The intrinsic viscosity varied between 0,55 and 0,70. The relation between intrinsic viscosity and hydroxide ion concentration had a correlation coefficient r < 0,001. No trend could be ensured as the confidence interval for the intrinsic viscosity at the different concentrations was too large.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology / Several technologies are currently being developed to mitigate the greenhouse gas CO2. One of these promising processes is industrial mineral carbonation whereby alkaline industrial wastes are taken as raw material. The process is a multi-step process which involves the extraction of calcium from industrial alkaline wastes and the subsequent reaction of extracted calcium rich supernatant with CO2 at elevated pH to form stable carbonates. Steelmaking slags were selected from four different plants in SA and used for this investigation owing this to their high calcium content. The potentially-suitable four slags were selected on the basis of their Ca content and high chemical reactivity. The objective of this investigation was to develop a common leach process for all four steel slags to achieve a complete Ca extraction from slags. A Ca rich solution was carbonated to achieve a stable carbonate that can be used. Experiments were carried out using ammonium reagents and a hydroxide reagent to investigate their suitability for the rapid, selective extraction of calcium. Calcium was leached under different experimental conditions including varying leachant concentrations, temperatures and solid to liquid ratios. The slags exhibited contrasting reactive properties to different leachants, which can essentially be explained in terms of differences in mineralogical composition, hence mineral solubility characteristics. Leaching with 2M NH4NO3 aqueous solution at room temperature extraction efficiency increased with increasing concentration. The extent of extraction was different for the four slags. WMO5 showed a complete dissolution of Ca within 20 min of experiment. This difference is due to their different Ca-containing minerals. Same is observed with aqueous NH4CL but WMO5 did not reach a complete dissolution as with NH4NO3. Aqueous NaOH made it impossible for Ca extraction due to its high pH and upon slag addition it was more elevated. Increasing solid to liquid ratio had an influence in percentage slag loss. The pH of leach solution was elevated to 9 making it difficult to extract Ca. Under controlled conditions (pH kept under 1) optimal slag dissolution was achieved with traces of larnite and large amount of brownmillerite. The generated Ca-rich leachate was carbonated in a 600 ml reactor vessel with liquid CO2. A stable carbonate aggregate was produced. / Council for Geoscience Vaal University of Technology

This thesis forms part of a project with the objective of developing and implementing a novel, wood-based, process for the industrial production of cellulose textile fibres. This new process should not only be cost effective but also have far less environmental impact then current processes. Natural and man-made fibres are usually plagued with problems (e.g. economic and environmental) and are unsuitable in meeting growing demands. The focus of this thesis was therefore to investigate the dissolution of cellulose derived from various pulps in novel aqueous solvent systems.             It was shown that cellulose could be dissolved in a NaOH/H2O solvent at low temperatures (<0°C) and that such an alkaline solvent can be improved regarding the solubility, stability and rheological properties of the cellulose dopes formed if different additives (salts or amphiphilic molecules) are used. The effect of different kinds of pretreatment (individually and combined) and the influence of pulp properties on cellulose accessibility and dissolution were also evaluated. These pretreatments affected, as expected, some characteristic properties of the pulps mainly by reducing the DP but also, for example, changing the composition of the carbohydrates. Not only did the pretreatment affect the solubility it also increased the stability of the cellulose dopes, resembling the effect of chemical additives to the NaOH system. According to multivariate data analysis it was established that, of the pulp properties analyzed, only the composition of carbohydrates and the DP had a significant influence on the solubility of the pulps used in this study. Finally, it was emphasized that the dissolution of cellulose pulps seemed to be controlled by a very complex interaction between both kinetic and thermodynamic parameters. / CelluNova

Depuis le début de l'industrialisation, de nombreux déchets contaminés en éléments métalliques et métalloïdes sont rejetés dans l'environnement sans aucune gestion. L’activité minière a généré des quantités colossales de déchets, fins et non consolidés, riches en EMM stockés sous forme de terrils ou entreposés dans des bassins de décantation puis laissés à l’abandon à l’air libre sans aucun aménagement ni protection. Ces déchets restent sur place exposés à une forte érosion éolienne et hydriques induisant une dissémination des particules contaminées dans les différents compartiments de l’environnement (sols/sédiments/eau/atmosphère). Dans un premier temps, l’étude du devenir des éléments métalliques et métalloïdes dans les sols contaminés relatif à l’activité minière ont mis en évidence la présence de risques environnementaux et sanitaires associés. Les résultats soulignent que (i) le comportement géochimique des trois éléments (cadmium, zinc et plomb) est différent, (ii) la spéciation de ces éléments change clairement entre les déchets miniers et les sols, (iii) le Pb plomb peut causer des effets néfastes sur la santé pour les enfants. Dans un second temps, deux techniques de réhabilitation des sites contaminés ont été appréhendées: i) dans le cadre de la refonctionnalisation des sols, la potentialité d’une phytostabilisation assistée par des amendements organique et inorganique de parcelles contaminées avec le sapin de Douglas, ainsi que ii) la valorisation ex-situ par attaque des déchets miniers par voie alcaline qui mets en jeu la réduction de la source de pollution. / Since the beginning of industrialization, many wastes contaminated with metal(loid)shave been released into the environment without any management. Mining has generated huge quantities of fine, unconsolidated waste, rich in metal(loid)s, stored in tailing or in settling ponds and then left to be abandoned in the open air without any development or protection. This waste remains on site exposed to strong wind and water erosion leading to the spread of contaminated particles in the various environmental compartments (soil/sediment/water/atmosphere). First, the study of the fate of metal(loid)s in contaminated soils related to mining activity revealed the presence of associated environmental and health risks. The results highlight that (i) the geochemical behaviour of the three elements (cadmium, zinc and lead) is different, (ii) the speciation of these elements clearly changes between tailings and soils, (iii) Pb lead can cause adverse health effects for children. In a second step, two techniques for the rehabilitation of contaminated sites were apprehended: (i) in the context of soil refunctionalization, the potential for phytostabilization assisted by organic and inorganic amendments of plots contaminated with Douglas fir, as well as (ii) ex-situ recovery by attacking mining waste by alkaline way, which involves reducing the pollution source.