Determination of the physico-chemical parameters and aggregation number of surfactant in micelles in binary alcohol–water mixtures

2008 ◽  
Vol 137 (1-3) ◽  
pp. 74-79 ◽  
Author(s):  
S. Javadian ◽  
H. Gharibi ◽  
B. Sohrabi ◽  
H. Bijanzadeh ◽  
M.A. Safarpour ◽  
...  
2011 ◽  
Vol 17 (1) ◽  
pp. 107-115 ◽  
Author(s):  
Nada Babovic ◽  
Dejan Markovic ◽  
Vojkan Dimitrijevic ◽  
Dragan Markovic

This paper shows the results obtained in field analysis performed at the Tamis River, starting from the settlement Jasa Tomic - border between Serbia and Romania to Pancevo - confluence of Tamis into the Danube. The Tamis is a 359 km long river rising in the southern Carpathian Mountains. It flows through the Banat region and flows into the Danube near Pancevo. During the years the water quality of the river has severely deteriorated and badly affected the environment and the river ecosystem. In situ measurements enabled determination of physico-chemical parameters of water quality of the Tamis River on every 400 m of the watercourse, such as: water temperature, pH value, electrical conductivity, contents of dissolved oxygen and oxygen saturation. The main reason of higher pollution of Tamis is seen in connection to DTD hydro system. Sampling was performed at 7 points with regard to color, turbidity, total hardness, alkalinity, concentration of ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, iron, chlorides and sulphates in samples. The aim of the present work was to evaluate water quality in the Tamis River taking into account significant pollution, which originates from settlements, industry and agriculture, and to suggest appropriate preventive measures to further pollution decreasing of the river's water.


2020 ◽  
Author(s):  
Boussaid Khadidja ◽  
Chebouti–Meziou Nadjiba

The article deals with the determination of the factors responsible for the degradation of the Reghaia nature reserve. The objective of this research was to evaluate the spatial variation of chemical pollutants including the accumulation of some heavy metals (Iron, Zinc, Copper, Cobalt, Cadmium, Silver, Nickel and Lead) in the water of Lake Reghaia, Algiers. The study was carried out on 64 water samples taken from Reghaia Lake. For physico-chemical parameters and for MTEs that have been assayed by atomic absorption spectrophotometry. On the chemical level, high levels of nitrates have been recorded in water between 4mg / l, 30mg / l and concerning the phosphate, it has a high content (5.7 mg / l). Surface waters have high levels of suspended solids. BOD5 and COD are high, with COD / DBO5 ratios well above 3, dissolved oxygen values do not comply with WHO standards with P = 0.000001. Water degradation is caused by the presence of latrines, piles of garbage, farms, draining of sanitation facilities in nature and especially in watercourses. Heavy metal pollution is significant and has been reported for Plomp (Pb), copper (Cu), iron (Fe) and cobalt (Co), which reached the high risk level (p <0.01) especially upstream of the Reghaia Lake. And that the MTE contents vary irregularly from one station to another and from one depth to another. The results reveal that the waters of the Réghaia Lake are of very poor quality and the degradation of the ecosystem is more and more increased, to this effect a treatment is recommended.


2013 ◽  
Vol 39 (2) ◽  
pp. 3-16 ◽  
Author(s):  
Aleksandra Ibragimow ◽  
Barbara Walna ◽  
Marcin Siepak

Abstract The occurrence of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) has been determined in the fluvial sediment samples collected along three transects in the Middle Odra River (western Poland) with a width of 360 m. The total concentrations of the metals were obtained after HNO3 microwave digestion and the available fractions of heavy metals were determined by single extraction procedures using two extractants: 0.01M CaCl2 and 0.05M EDTA. The measurement of physico-chemical parameters was also performed. The determination of total and available fractions of heavy metals, except potential available fractions of Cr, revealed high concentrations of studied elements detected in the sediment samples characterized by high content of coarse and very coarse-grained sand fraction and high content of organic matter. It was found that the concentrations of total and available fractions of metals could increase along with the content of organic matter, Eh values and concentrations of H+. Apart from the above, those concentrations become the lowest, the higher the content of medium grain size fractions is. Furthermore, the amounts of CaCl2 and EDTA extractable metals increase in the sediments samples characterized by the lowest total and available concentrations of heavy metals.


2015 ◽  
Vol 59 (2) ◽  
pp. 37-49 ◽  
Author(s):  
Lidija Svečnjak ◽  
Goran Baranović ◽  
Marko Vinceković ◽  
Saša Prđun ◽  
Dragan Bubalo ◽  
...  

Abstract Although beeswax adulteration represents one of the main beeswax quality issues, there are still no internationally standardised analytical methods for routine quality control. The objective of this study was to establish an analytical procedure suitable for routine detection of beeswax adulteration using FTIR-ATR spectroscopy. For the purpose of this study, reference IR spectra of virgin beeswax, paraffin, and their mixtures containing different proportions of paraffin (5 - 95%), were obtained. Mixtures were used for the establishment of calibration curves. To determine the prediction strength of IR spectral data for the share of paraffin in mixtures, the Partial Least Squares Regression method was used. The same procedure was conducted on beeswax-beef tallow mixtures. The model was validated using comb foundation samples of an unknown chemical background which had been collected from the international market (n = 56). Selected physico-chemical parameters were determined for comparison purposes. Results revealed a strong predictive power (R2 = 0.999) of IR spectra for the paraffin and beef tallow share in beeswax. The results also revealed that the majority of the analysed samples (89%) were adulterated with paraffin; only 6 out of 56 (11%) samples were identified as virgin beeswax, 28% of the samples exhibited a higher level of paraffin adulteration (>46% of paraffin), while the majority of the analysed samples (50%) were found to be adulterated with 5 - 20% of paraffin. These results indicate an urgent need for routine beeswax authenticity control. In this study, we demonstrated that the analytical approach defining the standard curves for particular adulteration levels in beeswax, based on chemometric modelling of specific IR spectral region indicative for adulteration, enables reliable determination of the adulterant proportions in beeswax.


2013 ◽  
Vol 11 (11) ◽  
pp. 1757-1767 ◽  
Author(s):  
Jan Tengler ◽  
Iva Kapustíková ◽  
Ondřej Stropnický ◽  
Petr Mokrý ◽  
Michal Oravec ◽  
...  

AbstractEight hydrochlorides of 3-{2-[(2/4-fluorophenoxy)-ethylamino]}-2-hydroxypropyl-4-alkoxybenzoates and four hydrochlorides of 3-tert-butylamino-2-hydroxypropyl-4-butoxybenzoates were prepared as potential antagonists of the β1-adrenergic receptor (beta-blockers). A multistep synthesis of these compounds is described as well as their detailed analytical characterization. The pharmacokinetic properties of these weak base compounds are significantly influenced by their acid-base dissociation constant, pK a. The knowledge of this value is crucial for new drug development. This paper is aimed at developing a methodology that utilizes pH-dependent 1H NMR spectroscopy for its routine analysis. The selected predicted physico-chemical parameters of the new (arylcarbonyloxy)aminopropanols (i.e., aryloxyaminopropanol derivatives) were compared with the model drugs esmolol and flestolol.


2001 ◽  
Vol 434 (1) ◽  
pp. 133-141 ◽  
Author(s):  
M Blanco ◽  
S Maspoch ◽  
I Villarroya ◽  
X Peralta ◽  
J.M González ◽  
...  

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