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Bucharest, Romania

Al-Sabha T.N.,University of Mosul | Bunaciu A.A.,Science HOFIGAL SA | Aboul-Enein H.Y.,National Research Center of Egypt
Applied Spectroscopy Reviews

The H-point standard addition method (HPSAM) is a modification of the standard addition method that transforms the incorrigible error resulting from the presence of a direct interferent in the determination of an analyte into a constant systematic error. This error can then be evaluated and eliminated. The method was established for resolving strongly overlapping spectra of two analytes and permits both proportional and constant errors produced by the matrix of the sample to be corrected directly. The technique is based on the principle of dual-wavelength spectrophotometry and the standard addition method. The application of the method requires only two wavelengths, and the analytical signal caused by one of the species should be constant and that of the other should differ as much as possible. This overview discusses both the theoretical and practical aspects of HPSAM applications. © 2011 Copyright Taylor and Francis Group, LLC. Source

Pascu D.-E.,Polytechnic University of Bucharest | Modrogan C.,Polytechnic University of Bucharest | Miron A.R.,Polytechnic University of Bucharest | Albu P.C.,Polytechnic University of Bucharest | And 4 more authors.
Revista de Chimie

Nowadays, there are many problems related to water pollution, which is a result of intermittent or continuous release of pollutants in the environment. Novelty of this paper is to identify an alternative able to overcome the limitations and drawbacks of the traditional methods in the wastewater field. In this line, a commercial bioactivator, namely, Micropan complex was used for wastewater treatment. The inffluence of contact time, initial pH and bioactivator amount was studied. The optimal parameters determination was achieved through an experimental model created using MATHCAD 14 programme. The correlation coefficient value indicates the precision with which the set of experimental values was characterized by the determined function. The value obtained was 0.889. When coefficient is the closer to 1 the better description is achived. Source

Pascu D.-E.,University of Bucharest | Pascu M.,University of Bucharest | Pascu M.,Science HOFIGAL SA | Traistaru G.A.,Science ENECO Consulting S.R.L | And 3 more authors.
Revista de Chimie

In this paper we intended to study the ability of iron adsorption from drinking water by two types of membranes: cellulose and composite. Adsorption studies were highlighted by means of adsorption isotherms: Langmuir, Freundlich, Flory-Huggins and Frumkin. The results revealed that iron adsorption was influenced by pH increase. The identification of iron in drinking water was done using two methods: spectrophotometry method and potentiometric redox titration with cerium sulphate method. The adsorption capacity of composite membrane increased when temperature was increased. Spectrophotometry method has proved to be better than potentiometric redox titration with cerium sulphate method. After 150 min was recorded the total iron removal from aqueous solution using the composite membrane. The pH value influenced significantly the adsorption capacity. As the pH increased, the adsorption capacity for both membranes decreased. Source

Segarceanu M.,Polytechnic University of Bucharest | Pascu D.E.,Polytechnic University of Bucharest | Traistarif G.A.,Science ENECO Consulting S.R.L | Pascu M.,Polytechnic University of Bucharest | And 3 more authors.
Revista de Chimie

In this paper we studied the optimization of the process parameters of membranes. We studied four ions: nitrate, sulfate, chloride and phosphate. The results of the experimental study were processed using the following mathematical models: Langmuir, Freundlich and Temkin - Pyzhev. The four ions were microfiltered through a composite membrane with pores of different sizes (0.1 μm and 0.5 μm). The four ions analyzed were: nitrates, sulfates, phosphates and chlorides. To determine these, ions were used together with spectrophotometric and titrimetric methods. Experiments were conducted at three different temperatures: 288K, 308K, 328k. The sorption parameters and the fitting of the models were determined by nonlinear regression and then discussed. Wastewaters containing these ions were filtered through polysuifone! polyaniiine (PSf/PANI) membrane composites. The morphological characterization of the membrane was performed using scanning electron microscopy SEM and the stmctural characterization was performed using infrared spectroscopy (FT-IR). The best results were obtained using the Langmuir model for nitrate ions and Temkin- Pyzheu for chloride ions. The following parameters for each ion in part were: initial ion concentration, solution pH, working adsorption capacity, size and thickness of the composite membrane and temperature. The best results for the adsorption capacity were obtained with 0.1pm composite membranes for nitrate and sulfate ions. Source

Pascu D.-E.,Polytechnic University of Bucharest | Nechifor A.C.,Polytechnic University of Bucharest | Pascu M.,Science HOFIGAL SA | Traistaru G.A.,Science ENECO Consulting S.R.L | And 3 more authors.
Revista de Chimie

In the literature, the kinetics of the adsorption process is described by the help of mathematical models, which attempt to approximate as closely as possible the process' mechanism. In this study, for modelling were chosen two dynamic models namely: Thomas model and Yoon-Nelson model. It was pursued the investigation of nitrate, sulphate, chloride and phosphate ions in aqueous solutions in a dynamic flow(flowthrough) adsorption process, an adsorbent material made of a composite membrane. It was aimed to establish an optimum ratio between the adsorbent material and solution volume for each pollutant separatelly. Source

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