In industry, copper sulfate is used as an activator in the froth flotation of sulfide ores, production of chromated copper arsenate wood preservatives, electroplating, azo-dye manufacture, as a mordant for textile dyes, in petroleum refining and in the manufacture of other inorganic and organometallic compounds (ATSDR, 1990).
Copper is used in industry as an activator in froth flotation of sulfide ores, production of wood preservatives, electroplating, azo-dye manufacture, as a mordant for textile dyes, in petroleum refining and the manufacture of copper compounds.
Widely spread of chemically industry producing many types of environmentally pollutants (e.g dyes, herbicides, pesticides, insecticides, drugs, bacteria and others), most of these pollutants reach our drinking water resources, different strategies have been followed to purify contaminated water, one of the low-cost technology is using semiconductors as catalyst for photodegradation of water-organic contaminants. TiO2 nano- and microparticles have been used for photo-degradation of widely spread water organic contaminants. Due to its wide band gap (~3.2 eV) TiO2 photo-catalytic activity is limited to shorter wavelengths only (UV region). As only ~4% of the solar spectrum falls in the UV region, smaller bandgap semiconductors (e.g. CdS, with 2.3 eV) are used to sensitize TiO2 particles. The TiO2/CdS system has been used as a catalyst in water purification by photo-degradation of organic contaminants such as methyl orange and Phenazopyridine (Medically active compound). However, the TiO2/CdS system is unstable under photodegradation conditions yielding hazardous Cd2+ ions. Alternative ZnO nanoparticles naked and substrate to different materials like (clay, sand, and activated carbon) were used in photodegradation process; also natural dyes (anthocyanin & Curcumin) were used as a sensitizer for the TiO2 nanoparticles. The different prepared nano-catalyst systems were used to photo-degrade various contaminants of water and soil, such as methyl orange, phenazopyridine, paracetamol, phenols, and halo-phenols, with solar radiation. Furthermore, the ZnO nanoparticles were used in water purification and disinfection (from bacteria that cause water contamination) by complete mineralization under solar light. Different reaction parameters (such as catalytic efficiency, effects of catalyst concentration, catalyst recovery, contaminant concentration, temperature, pH and complete mineralization) will be discussed together.
Zeolitic imidazolate frameworks (ZIFs), a subclass of metal-organic frameworks (MOFs), havebeen recently employed in various fields such as gas separation, catalysis, water purification anddrug delivery.1 Their high importance is due to their chemical and thermal stability in addition tothe flexibility of their design. ZIFs have been synthesized solvothermally or at room temperatureusing organic solvents (e.g. methanol, DMF) or pure water.2 The control of size and morphologyof crystals has been achieved using reverse microemulsion methods, microwave, ultrasoundassistedsyntheses and coordination modulation methods.1-3 Herein, we investigate a newsynthesis method where ZIF crystals are produced using the reaction-diffusion framework (RDF)in a gel medium at room temperature. The method is based on the diffusion of an outer solutionof the organic linker or mixed linkers into an agar gel containing the inner metal ions Zn(II)and/or Co(II) where a precipitation reaction takes place leading to the formation of the ZIFcrystals. A propagating supersaturation wave, initiated at the interface between the outer solutionand the gel matrix leads to a precipitation front endowed with a gradient of crystal sizes rangingbetween 100 nm and 55 μm along the same reaction tube. While the precipitation fronts of ZIF-8 and ZIF-67 travel the same distance for the same initial conditions, ZIF-8 crystals therein areconsistently smaller than the ZIF-67 crystals due to the disparity of their rate of nucleation andgrowth. The effects of temperature, the concentration of the reagents, and the thickness of thegel matrix on the growth of the ZIF crystals are investigated. We also show that by using RDF,we can envisage the formation mechanism of the ZIF crystals, which consists of the aggregationof ZIF nanospheres to form the ZIF-8 dodecahedrons. Moreover, using RDF the formation of asolid-solution ZIF via the incorporation of Co(II) and Zn(II) cations within the same frameworkis achieved in a controlled manner. Finally, we demonstrate that doping ZIF-8 by Co(II)enhances the photodegradation of methylene blue dye under visible light irradiation in theabsence of hydrogen peroxide.
The partial introduction of electron rich elements (especially rhenium) in place of molybdenum in Chevrel phases allowed to control the electronic density in these compounds and to reach the magic number of 24 electrons per cluster, with three consequences: the stabilization of the metastable Mo6S8, the experimental confirmation of the energy diagramme of these materials (illustrated by the changes in transport properties), and the possible existence of rhenium octahedral clusters, provided the ligands were well selected. Indeed, a number of new compounds were synthesized by high temperature solid state reaction and structurally characterized. They belong to the ternary Re-Y-X (Y = chalcogen, X = halogen) and the quaternary diagrammes M-Re-Y-X (M = countercation, in most cases alkaline). Selecting both the total number of ligands and the halogen/chalcogen ratio, a wide variety of stackings were controlled, including molecular or ionic 0-D, 1-D, 2-D and 3-D structures that involve different types of bridges. Some of these compounds are soluble in polar organic solvents, and even in water for restricted examples, giving access to new organic/inorganic hybrids and a nonmaterial approach. Examples are the substitution of counter cations by organic (alkylammonium or TTF derivatives), organometallic, complex, solvated or kryptate ones, the substitution of halogen apical ligands by cyano, azo or pyrazine ligands.
All the others, including polycyclic hydrocarbons (smoke), aromatic amines, amides, and azo dyes, natural plant products, and nitrosamines all require activation toultimate carcinogens.
Nine variously substituted azo dyes derivatives 2-10 of antipyrine were prepared. The effects of the nature and orientation of the substituents on the color and dyeing properties of these dyes on polyester fibres were evaluated. The newly synthesized compounds were characterized by elemental analyses and spectral data (IR, 1H NMR, 13C-NMR and MS). The investigated dyes were applied to polyester fabrics and showed good light, washing, heat and acid perspiration fastness. The remarkable degree of brightness after washings is indicative of good penetration and the excellent affinity of these dyes for the fabric. The results in general revealed the efficiency of the prepared compounds as new azo dyes.
An FDA review committee acknowledged problems, but said evidence of harm was not "consistent" or "substantial." Like other dyes, Red 40 is used mainly in junk foods.