Dissertations / Theses on the topic 'Zinc cadmium sulfide'

Thesis (M.S.)--California Polytechnic State University, 2008.<br>"June 2nd, 2008." "In partial fulfillment of the requirements for the degree [of] Master of Science in Engineering with Specialization in Materials Engineering." "Presented to the faculty of California Polytechnic State University, San Luis Obispo." Major professor: Richard Savage, Ph.D. Includes bibliographical references (leaves 98-100). Also available online and on microfiche (2 sheets).

A preocupação com a contaminação por metais reflete na busca de metodologias de recuperação de solos. O objetivo deste trabalho foi compreender os mecanismos de formação e oxidação dos sulfetos em solos e propor uma metodologia de imobilização de metais pela formação de sulfeto insolúvel e posterior fitoextração. Três experimentos foram conduzidos em solos contaminados com Cd e Zn. O primeiro teve como objetivo definir a concentração de (NH4)2S necessária para a formação dos sulfetos metálicos. Os resultados confirmam que a adição de sulfeto reduz a disponibilidade de Cd e Zn em Argissolos Vermelho-Amarelos distróficos e que concentrações de sulfetos superiores a 30 e 60 mmol kg-1, respectivamente para Cd e Zn, não melhora a capacidade de imobilização dos metais. O segundo experimento objetivou avaliar a influência da matéria orgânica, pH, tempo e ambiente na imobilização de Cd e Zn associado ao sulfeto. Foi demonstrado que a adição de matéria orgânica reduz a concentração de Cd solúvel e mantém o pH em faixa adequada às plantas. Para o Zn, a matéria orgânica não apresentou efeito significativo, prevalecendo o efeito do sulfeto. O aumento do pH, através da adição de carbonatos aumenta a imobilização do Cd e Zn em presença de sulfeto, influenciado pela formação dos respectivos hidróxidos. A exposição dos sulfetos metálicos a um ambiente oxidante reduz a imobilização de Cd e Zn devido à sua oxidação e consequente dissociação molecular. O terceiro experimento, desenvolvido em casa de vegetação, avaliou a disponibilidade de Cd e Zn e sua toxidez em Phaseolus vulgaris L. (feijão), utilizando a melhor dose de sulfeto com adição de matéria orgânica para obter maior eficiência na imobilização. A produção de massa seca da planta foi superior em solos que não continham sulfeto, o que indica fitotoxicidade. Concluímos que soluções de sulfeto podem ser utilizadas para imobilização temporária de Cd e Zn em solos contaminados, entretanto sua aplicação combinada à fitorremediação necessita de maiores estudos<br>The development of remediation of soil degraded areas methodologies reflects the concern with the metal contamination. The aim of this work was to understand the formation mechanisms and oxidation of sulfides in soils and propose a metal immobilization procedure by precipitation an insoluble sulfide and subsequent phytoextraction. Three experiments were conducted in contaminated soils with Cd and Zn. The first aimed to determine the (NH4)2S concentration necessary for the metallic sulfide formation. The results confirm that the sulfide addition reduces the Cd and Zn available in red-yellow dystrophic Argisoil and sulfide concentration above 30 and 60 mmol kg-1, respectively for Cd and Zn, not improve the metals immobilizations. The second experiment evaluated the organic matter, pH, time and atmosphere influence in the Cd- and Zn-sulfide immobilization. The addition of organic matter reduces the concentration of soluble Cd and maintaining the pH in adequate range for plants. For Zn, organic matter didn\'t show significant effect, prevailing the sulfide effect. The increase in pH by carbonates addition increases the Cd and Zn immobilizations in the sulfide presence. The exposure of metallic sulfide to an oxidizing atmosphere reduces Cd and Zn immobilization. The third experiment, developed in greenhouse, evaluated the Cd e Zn toxicity in Phaseolus vulgaris L. (bean) by using the best sulfide dose and addition of organic matter. The dry matter production was higher in soils without sulfide, indication phytotoxicity. We conclude that sulfide solutions can be used for Cd and Zn temporary immobilization in contaminated soils, however the application combined with phytoremediation needs further studies

Les Quantum Dots (QDs) sont des particules cristallines de semi-conducteur ou du métal de forme sphérique et de dimension nanométrique. L'intérêt majeur des QDs réside dans leur grande adaptabilité à de nombreuses applications biologiques.Le but de mon travail était de développer une nouvelle classe de QDs de faible toxicité afin de les utiliser pour la bio-imagerie des cellules cancéreuses. Pour cela, il est nécessaire de préparer des sondes hydrosolubles, photostables, biocompatibles, de luminescence élevée et possédant une faible toxicité. La synthèse des cœurs de type ZnS and ZnSe dopés au manganèse ou au cuivre et stabilisés par l’acide 3-mercapropropionique ou par le 1-thioglycérol a été réalisée par la voie hydrothermale. Les techniques analytiques de caractérisation utilisées sont la spectroscopie UV-visible, la spectroscopie de fluorescence, la diffraction des rayons X (XRD), la spectroscopie photoélectronique de rayon X (XPS), la microscopie électronique à transmission (TEM), la diffusion dynamique de la lumière DLS, la spectroscopie infra-rouge (IR), et la résonance paraélectronique (RPE). La toxicité des QDs a été déterminée sur des cellules cancéreuses. Les différents test de cytotoxicité (MTT, XTT et ferrous oxidation-xylenol orange) ont été réalisés. Finalement, les QDs de type ZnS:Mn conjugués à l’acide folique ont été utilisés pour la bio-imagerie des cellules cancéreuses par le biais d’une excitation biphotonique<br>Semiconductor QDs are tiny light-emitting crystals, and are emerging as a new class of fluorescent labels for medicine and biology. The aim of this work was to develop a new class of non-toxic QDs probes with essential attributes such as water dispersibility, photostability, biocompatibility, high luminescence and possible excitation with low-energy visible light, using simple processing method. Such nanoprobes could be used for bio-imaging of cancer cells. In the performed studies, I focused on ZnS and ZnSe QDs as they are cadmium-free and might be excited biphotonically.The synthesis protocols of ZnS and ZnSe QDs doped with two ions such as Mn or Cu and stabilized by 3-mercaptopropionic acid or 1-thioglycerol were established, followed by NCs characterization (diameter, surface charge, photophysical properties, …) using analytical techniques such as spectrophotometry UV-vis, fluorimetry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), dynamic light scattering (DLS), infra-red analysis (FT-IR), thin layer chromatography (TLC) and electron paramagnetic resonance (EPR). The cytotoxicity of synthesized bare and conjugated NPs was evaluated on cancer cell lines using MTT, XTT and ferrous oxidation-xylenol orange assay.Finally, chosen well fluorescent and weakly toxic types of as-prepared and characterized QDs were used for bio-imaging of cancer cells. In these experiments, FA-functionalized NCs were excited biphotonically. The performed experiments showed the potential of QDs as cancer cells fluorescent markers and that they accumulate around the cell nuclei

Orientador: Maria Cristina Cintra Gomes Marcondes<br>Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia<br>Made available in DSpace on 2018-08-10T10:44:51Z (GMT). No. of bitstreams: 1 Yano_ClaudiaLumy_D.pdf: 4912629 bytes, checksum: 823824d694d0140eada41a1aa8e689a5 (MD5) Previous issue date: 2006<br>Resumo: Metais pesados como o cádmio são considerados agentes tóxicos devido sua extensiva utilização nas indústrias e agropecuária e, como conseqüência, são amplamente dispersados no meio ambiente. No entanto, o cádmio tem sido foco, também, de inúmeras pesquisas relacionadas a exposição humana e suas conseqüências patológicas como o câncer. Estudos, claramente, caracterizam as relações de tumor de pulmão com a inalação do cádmio e mostram a possível participação deste metal tanto na iniciação quanto na progressão tumoral. Por outro lado, são raros os relatos da literatura envolvendo o mecanismo de ação do cádmio em tecido muscular, uma vez que já foi observado acúmulo desse metal em musculatura esquelética de animais. A administração do cloreto de cádmio, metal pesado designado como carcinogênico, em linhagem de células musculares esqueléticas C2C12 promoveu lesões consistentes com estresse oxidativo, observado pela diminuição da viabilidade celular, aumento da peroxidação de lipídios (conteúdo de malondialdeído) e conseqüente diminuição da enzima antioxidante glutationa transferase (GST). O estresse oxidativo, possivelmente, alterou a adesão celular e, conseqüentemente, houve retração dos miotúbulos, observada através de microscopia de luz e microscopia eletrônica de varredura (Capítulo I- Trabalho publicado no periódico Free Radical Biology & Medicine, 2005). A atenuação das lesões promovidas pelo cloreto de cádmio em linhagem de células C2C12 foi verificada com o pré-tratamento com o sulfato de zinco antecedendo o tratamento com cloreto de cádmio. Os efeitos protetores foram observados através da preservação da viabilidade celular, da GST, e diminuição do conteúdo de malondialdeído. A ação protetora foi verificada, também, na maior preservação da adesão celular, principalmente, contra as maiores concentrações de cádmio (Capítulo II- Trabalho a ser submetido ao periódico Free Radical Biology & Medicine). Por outro lado, a exposição crônica de células tumorais, linhagem de adenocarcinoma de cólon MAC13, ao cloreto de cádmio promoveu alterações morfológicas associadas ao aumento da atividade mitocondrial, interferência quanto à atividade lisossomal e diminuição da viabilidade celular, principalmente, na maior concentração de cádmio, após 24hs de exposição (Capítulo III- Trabalho a ser submetido ao periódico International Journal of Cancer)<br>Abstract: The heavy metals as cadmium are a toxic agent since it is extensively utilized in industry and can be amply distributed in environment. The cadmium is research focused as its pathological consequences in human exposure as it has been classified as carcinogenic agent. This fact is evident since the cadmium inhalation can be related to lung tumour and many studies show the possible participation of the cadmium on tumoral cells initiation and progression. However, few studies observed that cadmium can be accumulated in animal skeletal muscle cells and its action mechanisms are not completed known. The cadmium chloride exposure promoted oxidative stress and morphologic changes in C2C12 myotubes cell, in vitro, associated to decrease on cellular viability, high lipid peroxidation (increase on malondialdehyde content, MDA) and decrease on glutathione-S-transferase (GST) activity. The cadmium chloride produced chances on the cellular adhesion, integrity and retraction in C2C12 myotubes cells. These effects could be attenuated by zinc sulphate pre-treatment, which maintained the cellular viability, GST activity, reducing the MDA content. The zinc sulphate pre-treatment preserved the cellular adhesion, especially in high cadmium chloride concentration. Additionally, the tumoral cells (colon adenocarcinoma MAC 13) chronically exposed to cadmium chloride showed increase on the mitochondrial activity, and reduction on lysosomal and cellular viability, especially at high cadmium chloride concentration after 24h of treatment, probably indicating the tumoral cell changes<br>Doutorado<br>Biologia Celular<br>Doutor em Biologia Celular e Estrutural

Etude de la faisabilite de cet imageur utilisant, comme principe d'acquisition de l'image x, l'effet gudden-pohl, phenomene de luminescence retarde stimulee electriquement (lse). Seuls zns et cds dopes par cu, au ou ag donne l'effet lse adequat apres une phase de sensibilisation. Variation de la luminescence en fonction de la dose de rayons x, du champ electrique, de la temperature, du dopage, etc. Modelisation de l'effet lse: l'enregistrement de l'image se fait par piegeage de trous sur des accepteurs dans la couche d'appauvrissement superficielle, la recombinaison radiative se produisant avec ces trous lorsque le champ electrique applique abaisse la barriere de potentiel superficielle. Elaboration d'une maquette en vue du developpement d'un imageur mammographique numerique

Un appareillage de déposition de composés semi-conducteurs dans des conditions proches des équilibres thermodynamiques a été réalisé. Il est constitué par deux cellules quasi-étanches à quatre zones de température ce qui permet le contrôle simultané des différentes pressions de vapeur ainsi que celui de la température du substrat. Il offre en outre la possibilité de réaliser in-situ un empilement de couches de composition chimique et de dopage différents. Le travail comporte deux parties : 1) La réalisation et l'étude des propriétés de couches de CdS, CdTe, CdZnTe et CdMnTe sur différents substrats : silice, ITO/verre, molybdène et saphir. Un module théorique simple est proposé pour décrire la réalisation entre la vitesse de déposition et la température des sources et du substrat. Nous avons pu noter, dans le cas du CdS une chute brutale de la résistivité lorsque le rapport des pressions partielles indium et cadmium passe par une valeur critique. Des traitements de recuits thermiques ultérieurs améliorent la cristallinité et modifient la morphologie de surface des couches. Sur substrat saphir (0001) nous avons pu réaliser l'hétéroépitaxie de différents composés, la croissance s'effectuant toujours suivant la direction (111). 2) La réalisation et l'étude des propriétés des photopiles solaires font l'objet de la deuxième partie. D'après l'analyse des aractéristiques I-V nous avons montré que le mécanisme de conduction est l'effet tunnel. La jonction est de type abrupt et la hauteur de barrière est élevée. Les réponses spectrales et leur modélisation ont permis de déterminer les longueurs de diffusion des porteurs dans les zones (n) et (p), ainsi que la contribution de la zone de charge d'espace au photocourant.

Ces systèmes présentent la percolation et la frustration. Le premier composé est ferromagnétique, tandis que le second présente des interactions antiferromagnétiques. On étudie en fonction de x les transitions de ces composés. Les transitions de phase du gallate ont été étudiées par effet Mössbauer. On a mis en évidence que pour x0,75 l'ordre magnétique tend vers un ordre caractéristique de la "vraie" phase verre de spin.

This thesis investigates the biodistribution and toxicological effects of amphiphilic polymer coated CdSe/ZnS quantum dots (QDs) in two aquatic species, Daphnia magna (daphnia) and Danio rerio (zebrafish). The use of QDs in the life sciences has become common practice over the past decade. In addition QDs are being incorporated in commercially available light emitting diodes and photovoltaic solar cells. As the widespread commercial use of QDs increases, environmental release is inevitable, and water will contain the highest environmental concentrations based on life cycle assessments. Despite increased attention to the aquatic toxicology of nanomaterials in recent years, little information exists on the biological fate of QDs in aquatic organisms. Quantitative data on the uptake and excretion of QDs from daphnia and zebrafish were collected using fluorescence imaging paired with metal analysis. First, daphnia were examined after aqueous and dietary exposure to amphiphilic polymer coated CdSe/ZnS QDs. Surface coating influenced QD acute toxicity and high particle aggregation correlated with daphnia mortality. QDs were readily ingested by daphnia and accumulated in the intestines. High body burdens of 150-200 μg/g were found in the daphnia, with intestinal QD concentrations significantly elevated above the exposure media concentration. The slow elimination observed in daphnia suggested that trophic transfer of QDs to higher organisms may occur. Using daphnia and zebrafish as a model food chain revealed that QDs can transfer to zebrafish through dietary exposure with body burdens of 8-9.5 μg/g found. However, no biomagnification between daphnia and zebrafish was observed and the biomagnification factor (BMF = 0.04) was significantly less than one. This work demonstrates that aqueous and dietary exposures to QDs can result in high total body concentrations in aquatic organisms with little to no gross toxicity. The low acute toxicity observed for some surface coated QDs encourages further design optimization to improve the biocompatibility and reduce the environmental impact of QDs.

碩士<br>大同大學<br>化學工程研究所<br>80<br>With soluble sulfide precipitation, removal of cadmium and zinc from wastewater has been investigated in this study. The precipitator used in this study is Na2S 9H2), solubility of which was obtained to be 95% in water at room temperature. The studies were carried out by performing the precipitation of cadmium and zinc with soluble sulfide in Batch Reactor and Continuous Flow stirred Tank Reactor at room temperature, respectively. The concentrations of cadmium and zinc of the original wastewater and the effluent stream were analyzed by using atomic absorption spectrometry (AA), and that of free sulfide by using methylene blue method. The characterizations of the original wastewater: pH value=6.5-7.0, [Cd(II)]=20-25ppm, [Zn(II)]=90-120ppm. 　　The experimental results showed that the optimum initial pH value is 6.0 at room temperature and atmospheric pressure for the treatment of wastewater contaminated with cadmium and zinc. The residual concentrations of cadmium and zinc of the effluent stream were obtained to be lower than the requirement of EPA Regulations after the treatment of soluble sulfide precipitation (Proposed EPA Regulation, Cd(II) : 0.1 ppm, Zn(II) : 5.0ppm). Compared with traditional treatment method of hydroxide precipitation, soluble sulfide precipitation improved well. The relationship between the percetage removal of cadmium and zinc and residence time of wastewater was obtained and discussed on the design of the reactor in scale up.

碩士<br>國立臺北科技大學<br>材料及資源工程系所<br>94<br>ZnS-coated CdS:Mn and ZnS-coated CdS:Zn core/shells structured nanocrystals are synthesized via a reversed micelle process. The optimum luminance intensity can be obtained in 2 mol% Mn-doped CdS/ZnS and the emission wavelength exhibits blue-shifted. The emission wavelength decreases with the increase with the concentration of Zn in CdS:Zn/ZnS. The crystal structures are identified by using XRD. The distribution of the size is from 10 nm to 100 nm. From TEM, the nanoparticle size is about 20 nm.

Acid mine drainage (AMD) typically involves waters with low pH (pH 2-4) and high concentrations of Fe, SO4 and potentially toxic trace metals. Adsorption onto iron oxyhydroxides is the dominant mechanism controlling the transport and toxicity of trace metals in water bodies impacted by AMD. The purpose of this study was to apply the Diffuse Layer Model (DLM) to describe the adsorption of trace metals by iron oxyhydroxides from these systems, using synthetic iron oxyhydroxide minerals, ferrihydrite, pure acicular goethite, SO4-rich goethite prepared from FeSO4 oxidation and a synthetic schwertmannite. The ferrihydrite adsorption of the trace metals Cu, Zn, Cd and Co from single sorbate systems was accurately described using the DLM with two surface site types (type-1 and type-2) having site densities of 0.005 and 0.2 mol (mol Fe)-1 respectively. The ferrihydrite adsorption of SO4 from single sorbate systems was accurately described using the DLM with adsorption on the type-2 sites. However, the enhanced adsorption of Cu, Zn, Cd and Co in the presence of SO4 was not predicted using adsorption constants derived from single sorbate systems. By including a neutral ternary complex with stoichiometry Fe(2)OHMeSO4 (where Fe(2)OH is a type-2 surface site and Me is the trace metal) the effect of SO4 on metal adsorption was accurately described for the range of Me, Fe and SO4 concentrations studied. The adsorption of Cu and Zn onto schwertmannite at total metal to iron ratios (MeT:Fe) up to 8 x 10-3 was almost identical to that predicted for ferrihydrite in the presence of 0.01 mol kg-1 SO4. To model the ferrihydrite adsorption of Pb from single sorbate systems a third higher affinity site (type-0) with a site density of 0.00035 mol (mol Fe)-1 was required. The effect of SO4 on Pb adsorption could only be modelled by including a neutral ternary complex on both the type 1 and type 2 sites in the case of Pb. Metal adsorption onto a pure acicular goethite could be accurately described by the DLM with two surface site types. The type 2 site density that provided the best fit to the goethite adsorption data was 0.027 mol (mol Fe)-1 corresponding to 2.3 nm-2. The type-1 site density that provided the best fit to goethite adsorption of Cu, Pb and Cd was 0.00028 mol (mol Fe)-1 corresponding to 0.024 nm-2. For Zn adsorption on goethite the type-1 site density was significantly larger at 0.0015 mol (mol Fe)-1 corresponding to 0.13 nm-2. In all cases studied the presence of SO4 caused an increase in the extent of metal adsorption by goethite. This increased adsorption of metals in the presence of SO4 was accurately predicted by including ternary complex formation at both the high and low affinity adsorption sites. For both ferrihydrite and goethite the values of adsorption constants for ternary complex formation (logKxMeTC) were related to the adsorption constant for metal adsorption in the absence of SO4 (logKxMeINT). This was evident from a plot of logKxMeTC as a function of logKxMeINT for all metals, which showed a linear relationship with slope of 0.69 and intercept of 8.03. This relationship suggests that the enhancement of metal adsorption on both oxyhydroxides due to SO4 occurs by the same process. When comparing Cu, Zn and Cd adsorption onto ferrihydrite and acicular goethite the effect of the larger goethite adsorption constants are approximately compensated for by the lower goethite site densities. Therefore the Cu, Cd and Zn adsorption isotherms on ferrihydrite and acicular goethite are fairly similar at low adsorption densities. In the case of Pb, the site densities and adsorption constants are both larger on ferrihydrite and there is a large difference between the ferrihydrite and acicular goethite adsorption isotherms. Sulfate-rich goethite had considerably higher site densities, per mol of oxide, than the pure acicular goethite. Adsorption onto the sulfate-rich goethite could be modelled reasonably accurately using the parameters developed to model adsorption onto the pure acicular goethite but with a higher surface area and a higher ratio of type-1 to type 2 sites. In general, therefore, the parameters developed for pure goethite are apparently similar to those for the sulfate-rich goethite, but are not directly transferable. The difficulty in measuring the surface area of the highly aggregated sulfate-rich goethite makes comparisons between the two goethites more difficult. The adsorption of Cu, Zn and Cd onto the SO4-rich goethite exceeds that of ferrihydrite because the higher adsorption constants of goethite are combined with the considerably higher site densities of the SO4-rich goethite compared to the acicular goethite. In contrast the higher site densities of the SO4-rich goethite does not completely compensate for the low logKINT values of Pb adsorption on goethite. Therefore SO4-rich goethite adsorption of Pb is lower than that of ferrihydrite. When applied to literature data from AMD oxides the parameters derived in this thesis have significantly improved the ability of the DLM to predict trace metal adsorption in AMD systems, compared to using ferrihydrite as a proxy for all iron oxyhydroxides and adsorption data derived only from single sorbate systems.

Open-framework inorganic materials constitute an important area of study in materials chemistry, because of their potential applications in areas such as sorption and catalysis. After the discovery of nanoporous aluminium phosphates (AlPOs) by Flanigen et al in 1982, there has been a tremendous growth in the area of porous solids that are based on phosphates. Apart from phosphates, phosphites, arsenates, sulfates, sulfites, selenates, selenites etc. have also been investigated. In addition to the different anions, the framework compounds now encompass almost all the elements of the periodic table. The compounds exhibit wide variety and structural diversity. New building units, such as thiosulfate and borate have also been explored as a network builder in the formation of framework structures. In this thesis, the results of the investigations on open-framework metal thiosulfates, metal borates and metal sulfates are presented. The studies are aimed not only at the synthesis of the new compounds based on the new anions, but also their possible applications. In Chapter 1 of the thesis an overview of inorganic open-framework materials with different anions is presented. In Chapter 2 (Part A), the synthesis, structure and transformation of inorganic-organic hybrid open-framework cadmium thiosulfate are presented. The lack of stability of the thiosulfate ion in solution prompted the exploration of new approaches such as low temperature solvothermal methods, use of rigid linkers etc. The transformations of lower to higher dimensional structures have been accomplished. The possible mechanisms for such transformations were investigated. In Part B, the physical and chemical properties of the hybrid cadmium thiosulfate frameworks are presented. The studies indicate that the anionic dyes selectively adsorb on the compounds in the water medium and also desorb reasonably in alcoholic medium. The cadmium thiosulfate compounds appear to be reasonable photocalysts for the photodecomposition of the cationic dyes under UV irradiation as well as under sunlight with good recyclability. The compounds also exhibit heterogeneous catalytic behavior (Lewis acidity) for the cyanosilylation of the imines. In Chapter 3, a new family of organically templated open-framework borate materials is presented. The zinc and aluminoborate structures, prepared in the present study, are rationalized using the HSAB theory. The [B4O9H2] units polymerize differently to form different zinc borate structures. The amine molecules act as a ligand by binding with the metal. The nature of the amine appears to control the dimensionality of the final zinc borate structures. The zinc borate compounds exhibit absorption of UV-light (λ = 365 nm) suggesting that the zinc borate compounds could be exploited for UV-blocking applications. Organically templated aluminoborates have connectivities between the Al3+ ions and the [B5O10] cyclic pentaborate units. The aluminoborate structures exhibit graphite layer and three-dimensional diamond structure. Detailed studies and comparison of the various amine templated open-framework aluminoborate structures reveals subtle relationships between the organic amines (shape and length of the amines) and the final framework structures. In Chapter 3, the synthesis, structure and catalytic studies of a variety of cadmium sulfate phases have been carried out. Polyazaheterocyclic ligands were employed to study their possible role in the formation of such structures. All the compounds have structures built up by the connectivity involving the cadmium octahedra and the sulfate tetrahedra in which the heterocyclic organic molecules act as the ligand. The connectivity between the Cd2+ and (SO4)2− ions form one-, two-and three-dimensionally extended cadmium sulfate phases, though the starting source is cadmium sulfate (CdSO4.8/3H2O) in all the cases. The connectivity between Cd2+ ion and the heterocyclic ligand also gives rise to one-and two-dimensional structures. The interconnectivity between the two units gives rise to the final observed structure. As part of the study, a variety of properties i.e. adsorption-desorption, photocatalytic degradation and cyanosilylation reaction, exhibited by the cadmium sulfate compounds have been investigated and the properties are comparable to the cadmium thiosulfate phases. AlPOs are well known for their many important properties. The wide varieties in their structures and heterogeneous catalytic properties have been extensively investigated. The photocatalytic behaviors, on the contrary, have not been investigated in detail. The photocatalytic properties of the metal-doped AlPOs, for the photodegrdation of organic dyes have been investigated in the Chapter 5. The metal ions (Mg2+, Zn2+ and Co2+) have been substituted in place of Al3+ and Ti4+ in place of both the Al3+ and P5+ in a variety in AlPO structures and the synthesized phases are characterized by a variety of techniques. Photodecomposition studies of organic dye molecules under UV-light were carried out in aqueous medium. The studies suggest that the photocatalytic activity is reasonable and appears to depend on the dopant concentration. Ti-substituted phase exhibits the maximum catalytic activity.