Polarographic behaviour of petroleum components in aqueous solutions: A study using DPP and convective adsorption accumulation

1986 ◽  
Vol 51 (8) ◽  
pp. 1587-1594 ◽  
Author(s):  
Robert Kalvoda ◽  
Ladislav Novotný

Tensametric behaviour of solutions of petroleum and its fractions in aqueous base electrolytes was studied by differential pulse polarographic method (DPP) using a stationary mercury drop electrode with adsorptive accumulation. The results indicate that water pollution with petroleum can be determined by DPP, the sensitivity of the determination depending on the quality of the pollutant and on the composition of the base electrolyte. Well utilizable calibration curves were obtained with Diesel oil at concentrations from 30-50 μl/l to 0.5 mg/l and with Saratov petroleum from 0.1-0.2 mg/l to 3.3 mg/l. Use of adsorptive accumulation led to a marked increase of the sensitivity of the analysis.

1992 ◽  
Vol 57 (6) ◽  
pp. 1230-1236
Author(s):  
Jiří Barek ◽  
Viktor Mejstřík ◽  
Saafa Toubar ◽  
Jiří Zima

A study was made of the polarographic behaviour of 1-(4'-carbamoylphenyl)-3,3-dimethyltriazene and optimum conditions were found for its determination by tast polarography and differential pulse polarography at a static mercury drop electrode and by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-4 to 2 . 10-7 mol l-1. A further increase in the sensitivity can be achieved through adsorptive accumulation of the test substance on the surface of a hanging mercury drop, permitting the determination to be extended to the concentration range 1 . 10-7 - 2 . 10-9 mol l-1.


1986 ◽  
Vol 51 (8) ◽  
pp. 1595-1603 ◽  
Author(s):  
Ladislav Novotný ◽  
Robert Kalvoda

Electrocapillary investigations by the drop time method revealed a rather strong surface activity of aqueous petroleum solutions and some petroleum fractions in solutions of base electrolytes at the dropping mercury electrode, depending on the quality of the surfactant. The highest surface activity and sensitivity of analytical determination was found between -0.4 and -0.6 V (S.C.E.). The detection limit of the electrocapillary method was 10-20 μg/l for Diesel oil and up to 5 times higher for petroleum samples. The sensitivity of the measurements at lowest concentrations was increased by convective adsorption accumulation at the surface of the growing drop.


1991 ◽  
Vol 56 (10) ◽  
pp. 2073-2081 ◽  
Author(s):  
Jiří Barek ◽  
Safa Toubar ◽  
Jiří Zima

A study was carried out of the polarographic behaviour of the genotoxic substance 1-(2’-carbamoylphenyl)-3,3-dimethyltriazene and optimum conditions were found for its determination by tast polarography or differential pulse polarography at a static mercury drop electrode and by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-4 -2 . 10-7 mol 1-1. The sensivity of the determination can be further improved through adsorptive accumulation of the test substance on the surface of the hanging mercury drop electrode; five-minute accumulation in unstirred solution permits determination in the concentration range (2-10 . 10-8 mol 1-1 and two-minute accumulation in stirred solution allows determination in the range (2-10) . 10-9 mol 1-1.


1996 ◽  
Vol 61 (3) ◽  
pp. 333-341
Author(s):  
Jiří Barek ◽  
Roman Hrnčíř ◽  
Josino C. Moreira ◽  
Jiří Zima

The polarographic behaviour was studied for 6-β-D-glucopyranosyloxy-7-hydroxycoumarin, a natural compound serving as an optical whitening agent. The substance can be quantitated by tast polarography, differential pulse polarography using a conventional dropping mercury electrode, and differential pulse polarography using a static mercury drop electrode over the regions of 20-1 000, 2-1 000, and 0.2-1 000 μmol l-1, respectively. The methods developed for the quantitation of the compound were applied to its direct determination in a raw product.


1991 ◽  
Vol 56 (3) ◽  
pp. 595-601 ◽  
Author(s):  
Jiří Barek ◽  
Gulamustafa Malik ◽  
Jiří Zima

Optimum conditions were found for the determination of 4-nitrobiphenyl by fast scan differential pulse voltammetry at a hanging mercury drop electrode in the concentration range 1 . 10-5 to 2 . 10-7 mol l-1. A further increase in sensitivity was attained by adsorptive accumulation of this substance on the surface of the working electrode, permitting determination in the concentration range (2 – 10) . 10-8 mol l-1 with one minute accumulation of the substance in unstirred solution or (2 – 10) . 10-9 mol l-1 with three-minute accumulation in stirred solution. Linear scan voltammetry can be used to determine 4-nitrobiphenyl in the concentration range (2 – 10) . 10-9 mol l-1 with five-minute accumulation in stirred solution, with the advantage of a smoother baseline and smaller interference from substances that yield only tensametric peaks.


Author(s):  
E. Yu. Kulikova ◽  
Ju. A. Sergeeva

One of the problems of functioning of coal industry enterprises is the formation of mine waters, which are discharged into water bodies and cause their dangerous pollution. The total volume of water pumped by the enterprise includes up to 15 % for the recycling cycle, the remaining 85% is discharged to surface water bodies. As a result, the ecological balance of coal regions is disturbed, their sanitary and hygienic state on the environment worsens, and the quality of coal is reduced due to the intake of polluted water for technological operations. The volume of mine water contamination increases during mining operations at deeper horizons and in difficult mining and hydrogeological conditions. In turn, this leads to pollution and depletion of underground aquifers and the formation of environmental risk factors. In Kuzbass, all these factors contribute to the development of water crisis, since the state of surface reservoirs has already reached a critical limit. Especially dangerous is the process of liquidation of mines. Closing mines and sections disrupt natural water flows, resulting in all water from the aquifers going to deeper horizons. More pollutants enter the water, which poison the underground hydrosphere of the regions. The paper analyzes the pollutants entering the underground and surface hydro grid at coal-fired plants and offers a Conceptual model for minimizing the risk of water pollution.


1970 ◽  
Vol 33 (1) ◽  
pp. 47-54 ◽  
Author(s):  
S Ferdous ◽  
J Podder

Highly transparent and well faceted large size epsomite single crystals have been grown in pure form and doped with KCl from aqueous solutions by slow cooling and isothermal evaporation method. The optical quality of the epsomite improves on doping by KCl. Mass growth rates were found to increase with doping of lower concentrations of KCl and then decreases with the higher concentration of KCl. KCl doped epsomite crystal reveals that structures are slightly distorted due to adsorption of Cl- ion into the crystal lattice. DC conductivity along the growth axis for all of the grown crystals increases with temperature in the range of 25 to 70ºC and also increases with the KCl concentration. Dielectric constant is found to be almost independent of frequency up to range of 106Hz. The dielectric studies show the suitability of these grown crystals for optoelectronic applications. DOI: 10.3329/jbas.v33i1.2949 Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 47-54, 2009


2019 ◽  
Vol 178 (3) ◽  
pp. 240-246
Author(s):  
Mirosław KARCZEWSKI

The problem of the military vehicles engines fuelling increases with the growth of the amount of vehicles in the armies. At the same time, another problem with fuel supply in modern engines is the use of bio component additives, which changes characteristics (quality) of the used fuels. Therefore, it is important to take actions to adapt engines to powering with fuels coming from renewable sources.The aim of the research was to evaluate the possibility of feeding the diesel engine (influence on the useful parameters and composi-tion) with mixtures of the unified battlefield fuel F-34/F-35 with biocomponents in the form of anhydrous ethyl alcohol and RME. The tests were conducted during fuelling of the engine with six kinds of fuels: basic fuel (diesel oil), NATO code F-34/F-35 fuel, as well as fuel mixtures: F-34 and RME with different ratio and F-34/F-35 with bioethanol. In the result of the research it was concluded that the parameters of the G9T Renault engine with the common rail fuel system in terms of F-34 and RME consumption (using) decreased in comparison to diesel oil basic fuel. It is not possible to supply the engine with the mixture of ethyl alcohol and F-34 fuel – alcohol pre-cipitation and obliteration of fuel system components


Sign in / Sign up

Export Citation Format

Share Document