Selective Organic Reactive For Determination Of Several Heavy Metals From Different Materials

The research regarding the synthesis and characterization of tiobis-βnaphthol have established that it can be used as an efficient analytical reactive for separating through extraction the heavy metals in watery environments. These studies have been presented in the CALIST program

Mercury Determination from Incidentally Polluted Waters by Collecting Gravimetry in Organic Stage Method

Determination of mercury in incidentally polluted waters, presented in CALIST Program, was carried out using tiobis-β-naphthol as a reagent. The method proposed for mercury determination, named “collecting gravimetry in organic stage” is original, thus being superior to other simpler methods used in laboratory

Decorative Composite Layers

Part of the materials used in the chemical industry, metallurgical, machine construction, can be coated, as with time it occurs either a decrease of its properties, or even a process of advanced faulting, because of the stresses suffered. The paper presents the structure of some composite coatings with the nickel matrix also pointing out their decorative aspect. The layer is obtained through electrochemical methods, using as a complementary phase carbure and oxide particles (Al2O3, ZrO2, B4C, SiC) with contents of cca. 4-6%. The maintaining times in electrolyte ranged from 10 to 60 minutes. The macro and microstructural analysis had as objectives: the exterior aspect at composite depositions; the adherence of the film deposited at the support; the width of the deposition; the film compactity; the size, shape and orientation of the grains in the deposited layer; the distribution of the disperse phase in the metallic matrix. The microstructures of the composite films Ni + Al2O3 and Ni + SiC, performed in cross and longitudinal sections, reveal a dispersion relatively uniform of the aluminum oxide particles and respectively, silicon carbure in the Nickel matrix, a uniform deposition, lack of pores, a good compactity, a very good adherence at the metallic frame

Morphological Aspects of Thermosetting Polymers/Zn Composite Coatings

The present work has the purpose of studying the morphological aspects of composite coatings having zinc matrix and thermosetting polymers (PF resin type NOVOLAC - RESITAL 6358/1 and epoxy resin type DINOX 110L) as dispersed phase obtained during the electrodeposition process of zinc. The composite coatings layers were electrodeposited from a suspension of resin particles in aqueous zinc sulphate electrolyte by adding 10 g/L resin particles with size 0.1-5 μm into electrolyte solution. The structure of the coatings was investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods. The surface morphology of thermosetting polymers/Zn composite coatings layers is different compared with pure zinc coatings: the regular crystal structure characteristic of electroplated zinc coatings was disturbed. The decreases in the roughness of composite coatings layers compared to roughness of pure zinc layers can be determined by the fine structure of the composite coatings

Electrodeposition Obtaining and Corrosion Behaviour of Phenol Formaldehyde Resin/Zinc Composite Coatings

The present work has the purpose of obtaining composite coatings in zinc matrix by using phenol - formaldehyde resin type NOVOLAC (RESITAL 6358/1) in the electrodeposition process of zinc. The PF resin/Zn composite coatings were electrodeposited from a suspension of PF resin particles (diameter < 56 μm) in aqueous zinc sulphate electrolyte. Suspension was prepared by adding 10 g/L and 25 g/L PF resin particles into solution. The pure zinc coating has a rather regular surface, whereas the composite coatings surface has fine surface structure. For layers obtained at 3 A/dm2 the polarization resistance is higher for composite coatings with 10 g/L PF resin (Rp = 238.75 Ω cm2) than pure zinc (Rp = 34.54 Ω cm2). For layers obtained at 5 A/dm2 the polarization resistance is higher for composite coatings with 25 g/L PF resin (Rp = 430.19 Ω cm2) than pure zinc (Rp = 127.34Ω cm2). As test solution 0.5 M sodium chloride was used, it was observed that by adding PF resin particles in zinc electrolyte for electrodeposition it was obtained a very good distribution of resin particles on zinc surface and PF resin/Zn composite coatings obtained are most resistant at corrosive attack than pure zinc obtained from electrodeposition under the same conditions

Morphological Aspects and Corrosion Behaviour of Phenol Formaldehyde/Zn Composite Coatings

The present work has the purpose of studying morphological aspects and corrosion behaviour of pure zinc and composite coatings having zinc as metal matrix and phenol – formaldehyde resin type Novolac (RESITAL 6358/1) as dispersed phase obtained during the electrodeposition process of zinc. The phenol – formaldehyde resin/Zn composite coatings were electrodeposited from a suspension of phenol – formaldehyde resin particles in aqueous zinc sulphate electrolyte by adding 10g/L and 25g/L of phenol – formaldehyde resin particles in the electrolyte solution. The dimensions of resin particles were 0.1 - 5μm. The morphological aspects of the coatings were investigated by scanning electron microscopy method. While the pure zinc coatings have a rather regular surface, the composite coatings surfaces have finer grains and different morphologies. The electrochemical behaviour of the coatings in the corrosive solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy methods. As electrochemical test solution, 0.5M NaCl was used in a three electrode open cell. The polarization resistances of phenol – formaldehyde resin/Zn composite coatings are bigger than that of pure zinc coatings obtained under the same condition for electrodeposition