scholarly journals ENTHALPY OF INTERACTION OF ION-EXCHANGE HETEROGENEOUS MEMBRANES AND THEIR GRANULAR ANALOGUES WITH AMMONIUM NITRATE SOLUTION

Author(s):  
Sabukhi I. Niftaliev ◽  
Yuriy S Peregudov ◽  
Olga A. Kozaderova ◽  
Kseniya B. Kim

Ion-exchange membranes are widely used for extraction, separation and concentration of aqueous nitrogen-containing solutions. In the study the heterogeneous ion-exchange membranes of cationic type- MK-40, Ralex CM (H) -PP, MK-41 – and anionic type - MA-41, Ralex AM (H) -PP and also their granular analogues – cation exchanger  KУ-2·8 and anion exchanger AB-17·8 were used. Sorption of nitrate ions and ammonium ions was conducted from the ammonium nitrate solution with concentration of 0.012 mole / dm³. To determine sorption thermochemical characteristics of the studied ions the calorimetric method was used. It was found that for all the studied types of membranes and ion exchangers the processes were accompanied by heat evolution. From the calorimetric measurements the thermokinetic interaction curves of cation-exchange membranes and KУ-2×8 with the ammonium nitrate solution and anion-exchange membranes and AB-17×8 with the solution of the same salt were obtained. According to the curves the power of heat evolution and time of the process were determined. It was shown that the ion exchangers KУ-2·8 and AB-17·8 are characterized by a longer time to achieve the maximum of heat evolution and process time than for the similar membranes. This fact is explained by the different number and accessibility of the functional groups in the membranes and ion exchangers. From the thermo-kinetic curves the enthalpies of interaction were calculated. The process of the interaction between the granular ion exchangers and ions is characterized by higher values of the enthalpy than for the membranes which large steric effects are common for. Saline concentration, nature of exchangeable ions and type of functional groups of the ion exchanger and also its moisture content influence the enthalpy value. Experimental calorimetric data indicated that the energy costs connected with the effects of dehydration and conformational changes in the sorbent polymer chains do not overlap the exothermic sorption effect. The calorimetric method is informative to determine the nature and mechanism of sorption.

2021 ◽  
Vol 325 ◽  
pp. 131-136
Author(s):  
Iveta Plšková ◽  
Petr Hrubý ◽  
Libor Topolář ◽  
Michal Matysík

The paper summarizes partial results of a study of degradation of materials based on alkali-activated blast-furnace slag (AAS) and comparative on cement CEM III/A 32.5 R after exposure to aggressive environments. It further specifies the possibilities for utilising destructive and non-destructive techniques to determine the progress of degradation and characterizes the degree of their correlation. After 28 days of ageing in a water environment, the produced test specimens (40×40×160 mm beams) were placed in aggressive media (ammonium nitrate solutions; sodium sulfate, rotating water) and after subsequent 28, 56 and 84 days of degradation were subjected to testing. Testing comprised both a destructive form (determination of compressive strength and flexural strength) and a selected non-destructive technique (Impact-echo method). The partial outputs were supplemented by the results acquired from monitoring weight changes. In addition, the development of Ultrasonic Pulse Velocity in relation to the progress of the degradation processes was also monitored. While the exposure of both test specimens to water and sodium sulfate did not result in any significant changes, the exposure to the ammonium nitrate solution exhibited rapid signs of degradation associated with a significant reduction in functional characteristics.


2014 ◽  
pp. 431-438 ◽  
Author(s):  
Quoc Phung ◽  
Norbert Maes ◽  
Diederik Jacques ◽  
Geert De Schutter ◽  
Guang Ye

2001 ◽  
Vol 79 (8) ◽  
pp. 1207-1212 ◽  
Author(s):  
Abdul Wahab ◽  
Sekh Mahiuddin

Density, electrical conductivity, speeds of sound, and viscosity of aqueous ammonium nitrate solutions were measured as functions of concentration (m, mol kg–1) (0.1599 [Formula: see text] m [Formula: see text] 20.42) and temperature (T, K) (273.15 [Formula: see text] T [Formula: see text] 323.15). Experimental values are consistent with the reported data. Variation of isotherms of electrical conductivity, isentropic compressibility, and structural relaxation time with concentration evoke structural information on the ion solvation in aqueous ammonium nitrate solution at different concentration regions. The primary hydration numbers of ammonium nitrate were estimated at a particular concentration at which the isentropic compressibility isotherms converge. The existence of free hydrated ions, resulting from strong ion solvent interactions in dilute to 9.1 mol kg–1, the solvent-separated ion-pairs resulting from the relative competition between the ion–solvent and the ion–ion interactions in 9.1 to 12.0 mol kg–1, and the solvent-shared ion-pairs beyond 12.0 mol kg–1 resulting from a decrease in the number of solvent molecules, govern the transport process.Key words: electrical conductivity, speeds of sound, viscosity, ammonium nitrate, hydration number.


1983 ◽  
Vol 23 (7) ◽  
pp. 733-752 ◽  
Author(s):  
Pushpalatha C. Bhat ◽  
M.P. Sathyavathiamma ◽  
N.G. Puttaswamy ◽  
R.M. Mallya

Author(s):  
O. Kruchynenko ◽  
A. Antipov

The coproovoscopic methods involving count chambers are widely used in the veterinary practice for diagnostics. These methods are important in assessments of the prevalence rates of nematode infections in pigs and for FECR tests. However, more basic data is needed on the efficiency of the commercial methods of diagnostics, tested at the different specific gravity of the flotation solutions. In a thorough analysis of publications of Ukrainian scientists, we have found that the data is sparse on the efficiency comparison of the modified McMaster’s and MiniFLOTAC methods. The aim of our study was to compare the efficiency of the commercial coproovoscopic techniques: the modified McMaster’s method (with sensitivity of 25 EPG), and MiniFLOTAC combined with Fill-FLOTAC (with sensitivity of 5 EPG) in testing for A. suum infection in piglets. Results of approbation of the mentioned methods are presented for the following saturated solutions: NaCl (SG=1.2), MgCl2 •6H2 O (SG =1.27) and NH4 NO3 (SG=1.28). Fecal samples were taken at own private farm, in Mlynok village of Onufriivka district, Kirovohrad region from 20 4 month old pigs with spontaneous A. suum infection. The laboratory assessments were performed in the Scientific Laboratory of Parasitology and Veterinary and Sanitary Expertise of the Poltava State Agrarian Academy. It is established that at high rates of A. suum infection in young pigs, McMaster’s method with the ammonium nitrate solution is more efficient compared to the Mini-FLOTAC method. In average, 5331.2 eggs of A. suum were determined per 1 g of feces using the former method, compared to 4567.5 EGP according to the Mini-FLOTAC technique (P < 0.001). The highest diagnostic efficiency of the modified McMasters method and the combination of Mini-FLOTAC and Fill-FLOTAC is seen when ammonium nitrate (NH4 NO3 ) solution of 1.28 SG is used (P < 0.001). Our results add new data on the efficiency of the commercial methods of diagnostics with varying specific gravity of the flotation solutions, for pigs infected with nematodes. Key words: EPG, pigs, nematode, ascariasis, diagnostics, efficiency.


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