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The aim of this study was to develop an electrochemical procedure for the advanced detection of tetracycline (TC) in water using CoAl2O4 dispersed onto carbon nanofiber-epoxy composite electrode substrate, which was selected from a series of tested carbonbased electrode substrates, i.e., commercial glassy-carbon and boron-doped diamond electrodes and home-made carbon nanotubeepoxy and carbon nanofiber-epoxy composites. Carbon nanofiber-epoxy composite electrode was found the best host for CoAl2O4 modifier based on the electrocatalytic effect towards TC oxidation and detection using cyclic voltammetry (CV) technique. The electrochemical techniques applied for electrochemical detection applications were CV, differential-pulse voltammetry (DPV), square-wave voltammetry (SWV) and chronoamperometry (CA). All the tested electrochemical techniques allowed TC determination and the electroanalytical parameters varied related to the technique type. DPV operated at the step potential of 50 mV and the modulation amplitude of 200 mV allowed the lowest limit of detection of 9 nM for TC determination. The recovery test applied for real surface water spiked with known TC concentrations among the reproducibility and the repeatability showed the great potential for the advanced quantitative determination of TC in real water or in pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

This paper reports the possibility of using zinc ash as a secondary source for zinc oxide, which can be further used as white pigment. For the extraction of zinc from zinc ash, sulphuric acid was used. The impact of different parameters (ash fraction, contact time, sulphuric acid concentration and liquid:solid (L:S) ratio) upon the extraction degree of metallic ions from zinc ash was studied. The optimum conditions for the metallic ions extraction are: 20% H2SO4, 30 minutes contact time, 1:1 L:S ratio and the fraction of the ash <0.315 mm. The obtained solid zinc products were submitted to a complex study: chemical analysis, thermal analysis and X-ray diffractometry. It was established that from the resulting zinc ash from the hot-dip galvanizing process the zinc ions can be recovered and reused as useful products avoiding the negative impact of these wastes on the environment and at the same time it was shown that these wastes represent valuable zinc sources. Based on the experimental data, the non-polluting technological process scheme of reuse of zinc ashes in useful products was proposed. [ABSTRACT FROM AUTHOR]

In order to remove various radionuclides (Tl+, Sr2+and La3+) from wastewaters we used three solid supports of (styrenedivinylbenzene) grafted with different pendant groups (1-triphenylphosphonium; 2-izo-propylphosphonate; 3-aminoethylaminomethyl). The solid supports with different pendant groups were impregnated with ionic liquid (Cyphos IL-101-trihexyltetradecylphosphonium chloride). IR-spectra, EDX-ray and SEM image were used to characterize the adsorbent obtained after the impregnation of the studied solid support with Cyphos IL-101. The analysis used for the characterization of the samples proved the fact that the studied solid supports were impregnated with the ionic liquid, underling the increasing of the phosphorous and chlorine ions content. The styrene-divinylbenzene grafted with 3-aminoethylaminomethyl groups and impregnated with Cyphos IL-101 developed the highest adsorption capacity in the removal process of the studied radionuclides from aqueous solutions, due to the synergic effect obtained from the two ions of the adsorbent (amino groups from the solid support and phosphorous ions from the impregnated ionic liquid). [ABSTRACT FROM AUTHOR]

A series of experiments were performed to quantify the adsorption of Cesium on Silica impregnated with trihexyl(tetradecyl)phosphonium chloride (Cyphos IL-101). Non-radioactive cesium solution was used as a surrogate of the radioactive 137Cs. The obtained impregnated Silica with the studied ionic liquid was characterized through scanning electron microscopy, energy dispersive X-ray analysis and Fourier transform infrared spectroscopy in order to put in evidence that the impregnation with the ionic liquid occurred. The adsorption process has been investigated as a function of pH, solid:liquid ratio, adsorbate concentration, contact time and temperature. Three kinetic and two equilibrium models were employed to interpret the test results. The results indicate that the adsorption fitted well with the pseudo-second order kinetic model. Simple thermodynamic model has been applied to the isotherm sorption data and the relevant thermodynamic parameters were determined from the graphical representation of this model. The isotherm data was well described by Langmuir isotherm model. The reported results showed that the impregnated silica with Cyphos - IL 101 studied in this paper is an efficient adsorbent material for the removal of cesium ions from aqueous and wastewater solutions. [ABSTRACT FROM AUTHOR]

The performance of two cation exchanger resins, Amberjet UP1400 and Amberlite IR120 in the process of Cs(I) ions removal from aqueous solutions was examined. Batch experiments were carried out to determine the influence of several parameters (resin dosage, contact time, temperature and initial concentration of Cs(I) ions) on the removal process. The equilibrium was reached after 60 min for Amberlite IR120 and after 120 min for Amberjet UP1400, with an overall adsorption performance of ~97% for both materials. The kinetics of the adsorption process was well approximated by the pseudo-second-order kinetic model. The equilibrium adsorption data were well described by the Langmuir model for Amberjet UP1400 and by the Sips model for Amberlite IR120. The calculated maximum adsorption capacities towards Cs(I) were of 6.36 mg/g for Amberjet UP1400 and of 8.67 mg/g for Amberlite IR120. The values of thermodynamic parameters ΔH° and ΔG° obtained demonstrated that the adsorption process was endothermic and spontaneous. The values calculated for the activation energy were of 3.48 kJ/mol for Amberjet UP1400 and 4.85?kJ/mol for Amberlite IR120. [ABSTRACT FROM AUTHOR]

Statistical thinking and statistical methods play an important role in planning, conducting, analyzing and interpreting data from experiments. When several variables influence a certain characteristic of a product, the best strategy is then to design an experiment so that valid, reliable and sound conclusions can be drawn effectively, efficiently and economically. The present paper investigates the efficiency of chromium ions removal onto Amberlite XAD7 using the solvent impregnated resin (SIRs) method. The Amberlite XAD7 resin was impregnated with di-(2-ethylhexyl)-phosphoric acid (DEHPA) and ethylic alcohol as solvent by dynamic column impregnation method. The results showed that the maximum efficiency of chromium ions removal was reached after 60 min. At this moment, the efficiency of chromium ions removal was of ~90%. In this paper the design of experiments was used to study the performance of a chemical process. The process transforms the inputs into an output that has two observable responses (absorbability and efficiency). By analyzing the results of the second-order model, the process has been optimized. [ABSTRACT FROM AUTHOR]

The adsorption performance of a novel support for metal ions sorption and their removal from aqueous solutions was examined. The support is a new solvent-impregnated resin (SIR) which can be considered as an alternative adsorbent material capable of selective sorption. The adsorbent was prepared by impregnating di-(2-ethylhexyl)-phosphoric acid (D2EHPA) onto Amberlite XAD7 resin beads, by dry impregnation method. The interaction between XAD7 resin and D2EHPA was evaluated by FTIR spectroscopy. Batch sorption experiments were carried out for the removal of Zn(II) and Cd(II) from synthetic aqueous solutions using the impregnated resin. The influences of various experimental parameters like pH, initial concentration, contact time and the effect of temperature were evaluated. The optimum pH range was 4-8 for Cd(II) ions and 4-7 for Zn(II) ions. The equilibrium was reached after 30 min with an overall adsorption performance of ~85% for Cd2+ and ~96% for Zn2+. The equilibrium adsorption data were well described by the Langmuir model. The values of the dimensional separation factor, RL, indicated favorable adsorption. The maximum adsorption capacities of the XAD7-D2EHPA were ~5.0 mg Zn(II)/g and ~4.5 mg Cd(II)/g, respectively. The kinetics of the adsorption process was well explained and approximated by the pseudo-second-order kinetic model, and intra-particle diffusion was the rate-controlling step after rapid saturation of surface and big pores of XAD7-D2EHPA beads. The variation in the extent of adsorption with temperature was used to evaluate the thermodynamic parameters for the adsorption process. The values of ΔH° and ΔG° obtained demonstrated that the adsorption process was exothermic and spontaneous. [ABSTRACT FROM AUTHOR]

The essay presents the Sixth Environment Action Programme of the European Community entitled "Environment 2010: Our future, our choice", which covers the period from 1 January 2001 to 31 December 2010. The programme has been guided by the Fifth Environment Action Programme (1992-2000). This paper describes the U.E priorities regarding four important areas: climate change, nature and biodiversity, environment and health, management of natural sources and waste. [ABSTRACT FROM AUTHOR]

In this paper studies regarding the recovery of zinc and iron from sludge resulted during thermal zinc coating were performed. The sludge results after the neutralisation of discharged wastewaters. It was tried to establish the optimum conditions of heavy metals removal from sludge by extraction with sulphuric acid. Through the optimum condition was followed to obtain a high separation degree of zinc and iron in the extraction solution and the smallest separation degree of calcium and lead, so that the valuable metals to can be reuse. [ABSTRACT FROM AUTHOR]

The paper presents studies on the extraction of copper and zinc from sterile resulted in mining activities in order to find the optimum conditions for their extraction, in view of put them in good use. We studied the influence of the stirring time and the nature and concentration of extraction agents on the extraction degree of copper and zinc from samples collected in a mining area of Apuseni Mountains. [ABSTRACT FROM AUTHOR]

The roots of this study are generated by the problems of plastic waste accumulations: insufficiency of storage spaces, storage costs and outgoings of plastic waste recycling, recovery, decomposition or reprocessing. The paper develops and details a modular prototype, for multifunctional territorial use, offering non-polluting and aesthetic possibility of plastic waste storage. The progress in the related fighting pollution areas have been approached, such as waste management through ecological design and the widespread use of green walls new techniques. The construction techniques are designed and calculated in order to be easy feasible from the technical and costs point of view. The proposed prototype has a metallic resistance structure in which compressed bales of unprofitable plastic waste (PET and plastic bags) are incorporated. The exterior surface of this structure is aesthetically designed, dressed with decorative-treated pieces of wood, also with vertical and horizontal boxes with selected plants, resistant to pollutants and climate, requiring a minimal maintenance. Regarding the multifunctional utility, the modular elements can be used as: anti noxious, noise, wind and snow barriers protecting various areas and traffic routes; enclosure or masking elements for various types of territorial sites; vertical support for territorial public advertising/information boards. For reasons of environmental sustainability, this proposal should be only an interim ecological solution, until efficient and low cost decomposition solutions for all kind of plastic waste will be found. [ABSTRACT FROM AUTHOR]

The main aim of this research work is to investigate by the means of X-ray analysis methods the spent catalysts and the recovered valuable metals in order to prove the efficiency of the recycling process as a main environmental issue. The materials used for analysis were spent catalyst samples based on Cu, Cr, Zn, Al, Ni, from Romanian petroleum refining industry. By hydrometallurgical route it has been recovered Ni, Al and Cu. The methods used for analysis were X-ray diffraction and X-ray fluorescence spectrometry. This research has practical implications for wastes recycling not only for recovery the valuable metals and lowering catalysts costs but also to prevent the environmental pollution. [ABSTRACT FROM AUTHOR]

In this work is presented a research on water treatment by using coagulation reagent such as Sachtoklar aluminium bases polychlorides and alkalinization reagent like sodium aluminate. The purpose of this research is to study the efficiency or inefficiency of these reagents to break up the colloidal systems and to reduce the turbidity of the treated water. To obtain the normal turbidity of water, it was established the relationship between the Sachtoklar aluminium bases polychlorides and the aluminate, as well as the best conditions of the coagulation process. Also it was studied the deposition time of formed floccules of the turbidities obtained at different doses of aluminum. [ABSTRACT FROM AUTHOR]

The paper defines the weight toxicity index (WTI) and gives some information about the technique of their computation. There are also presented numerical results for interest cases in environmental protection. [ABSTRACT FROM AUTHOR]