Logo
User Name

Indira Šestan

Društvene mreže:

Physical chemical milk is an emulsion of milk fat in an aqueous solution of proteins, milk sugar and mineral salts. The high molar conductivity of goat milk samples compared to cow's milk indicates a high content of mineral substances. That goat milk is rich in total proteins is also indicated by the protein content in the samples, which are higher than the cow's milk samples. However, higher fat content was recorded in cow's milk samples, which also results in higher surface tension of cow's milk. The freezing point and refractive index of goat milk are higher compared to literature data and cow milk samples. The acidity of goat's milk comes from the acidic properties of casein, citrate, phosphate, etc. it is lower than cow's milk and is in accordance with literature data. The viscosity of pasteurized goat's milk at all temperatures is also higher than that of cow's milk.

I. Šestan, Sabina Begić, Melisa Ahmetović, H. Keran, Erna Begić, Dženana Mehmedović, Vanja Srebro

In accordance with consumer requirements, the water must be adequately purified, and the corresponding parameters within the defined values. Various methods are used for this purpose, of which the ion exchange method can be highlighted as the simplest, most efficient and economically profitable. Ion exchange is a reversible process of ion exchange between a solid phase and an electrolyte solution. The ion exchanger is a macromolecular insoluble material that has chemically bound electrified groups and mobile, oppositely charged ions that compensate for this electrification. Ion exchangers are usually used in the form of compact or granular beds that fill the column through which the solution with the ions to be exchanged flows.They usually contain phenolic, carboxylic, sulfonic amino and other groups, which is why the treatment also results in decarbonization, softening, demineralization and denitrification of water. As the assessment of water quality is based on the most significant physico-chemical parameters, the aim of the work is the analysis of drinking water before and after treatment with an ion exchanger.For this purpose, organoleptic parameters such as smell, taste and color were first analyzed. After that, physico-chemical parameters were analyzed: pH values, electrical conductivity, m-alkalinity, p-alkalinity, water hardness, organic matter content, chloride content, iron and manganese content. An ion exchanger based on resin was used, which after use was regenerated by washing with NaClsolution.The analysis of the water sample, before and after the ion exchange treatment, showed that the treatment process was effective and that the decarbonization and softening of the water was carried out, whereby the water was categorized as soft water (water <9⁰dH).The analyzed water is tasteless, odorless and colorless before and after treatment. The results of the analysis showed that all the values of the analyzedphysico-chemical parametersare in accordance with the Rulebook on the Healthiness of Drinking Water(Official Gazetteof Federation of Bosnia and Herzegovina No.40/10) arebelow the maximum allowed values. KEYWORDS:water, ion exchange, physical-chemical parameters; water treatment

Waste water in the galvanic process contains high concentrations of heavy metals that pose a direct danger to humans and the environment. Conventional methods for their removal are quite expensive and generate a large amount of waste. The development of new and improvement of existing methods for the removal of heavy metals from galvanic wastewater are the subject of many studies. Compared to other purification methods, the adsorption is becoming an increasingly popular method of wastewater purification, especially if the adsorbent is cheap, easily available and does not require any other treatment before use. Therefore, the aim of the work was to investigate the possibility of using natural bentonite for the removal of heavy metal ions from multi-component water systems of the galvanic industry. For this purpose, the physico-chemical characterization of natural bentonite was performed, and then the influence of pH value, time and temperature on the adsorption efficiency was examined. The results of adsorption showed that natural bentonite can be used as an adsorbent for the removal of heavy metal ions from waste galvanic waters, and that at pH 5 it achieves the maximum removal efficiency for Cu(II):Cr(III):Ni(II) ions in the percentage ratio 100 : 99.990 : 99.998. The results showed that the highest removal efficiency for Cu (II) ions was achieved in the first 10 minutes, and 20 minutes for Cr (III) and Ni (II) ions. The maximum efficiency of Cu (II) removal was achieved at all temperatures, while for Cr (III) 99.99% and Ni (II) 100% maximum efficiency was achieved at 35°C, which indicates that the adsorption process is endothermic. The experimental results of the adsorption of Cu (II) metal ions are in good agreement with the Langmuir and Freundlich theoretical models, while for Cr (III) and Ni (II) ions they are in better agreement with the Langmuir adsorption model.

Medicinal plants have become an increasing subject of interest worldwide due to the large amount of biologically active substances that have potential beneficial health properties. One of the more interesting popular medicinal plants is hawthorn (Crataegusspp.), a deciduous branched shrub that is increasingly used for health purposes. Various parts of this plant, including berries, flowers and leaves, are rich in nutrients and beneficial bioactive compounds that are effective in the treatment of numerous diseases. Honey is a natural sweetener produced by bees from plant secretions. Known for its nutritional and medicinal values, it gives strength to the body, which is why it is indispensable in the human diet. The combination of these two ingredients represents a significant source of vitamins and minerals in daily use, but also for use in various pharmaceutical and medical purpose. Taking into account all of the above, the aim of the work is to test samples of the mixture of honey and hawthorn in different proportions and determine the physical and chemical characteristics: pH value, electrical conductivity, refractive index, viscosity, water activity, HMF, DPPH. Based on the analysis, appropriate conclusions will be drawn and more information will be obtained about their quality and possible use as a food supplement. On the basis of the conducted analyses, it can be concluded that the parameter values are within the permitted limits defined by the Rulebook (Official Gazette Bosnia and Herzegovina No. 37/09). The analysis of the mentioned parameters showed that the chemical composition of the sample plays a major role in the value of the measurement results, and that Sample III has the best antioxidant properties. KEYWORDS:physicochemical characteristics; honey; hawthorn (Crataegus spp.);mixture; food suplement

Using natural and modified Ca-bentonite as an adsorbent to observe a satisfactory trend in the removal of heavy metal ions As(V) and Hg(II) from simulated wastewaters. In this original scientific paper, Ca-bentonite was modified in two ways, thermally activated at a temperature of 300 °C for 3 hours and acid activated with HCl and H2SO4, molar concentrations 0,4 mol/L. Ca-bentonite used in this original scientific work was used from the Shipovo mine (Šipovo mine), Bosnia and Herzegovina and proved to be an excellent bioadsorbent for the removal of present ions from simulated wastewaters. Also this is eco-friendly adsorbent and low costed compared to other expensive adsorbents. Due to its chemical composition in which two oxides predominate, namely SiO2 (48.28 mass %) and Al2O3 (23.04 mass%), it can be concluded that Ca-bentonite from the Shipovo mine (Šipovo mine), Bosnia and Herzegovina belongs to the group of refractory materials. The highest removal efficiency of As(V) ions expressed in % was 75.11 at the initial concentration of 1.5 mg/L and was recorded using HCl acid-activated Ca-bentonite. The efficiency of Hg(II) ion removal was the highest using thermally activated Ca-bentonite and this value was 99.66% at an initial concentration of 1 mg/L.

I. Šestan, Melisa Ahmetović, B. Salkić, E. Imširović, Nedžad Šeper

Cement dust is created as a by-product during the production of cement, and in its composition it contains high concentrations of calcium oxide (CaO), potassium oxide (K2O) and other important micro and macro elements. Due to its composition, it is suitable for correcting the pH of the soil, as well as for the uptake of essential elements by plants. The ability to accumulate essential and non-essential heavy metals also depends on the cultivated plant species, and vegetables show the greatest affinity for these elements. The application of cement dust as a soil additive used to improve the physico-chemical soil properties is examined in the paper. After the addition, the soil was mechanically cultivated and planting of the vegetable crop tomato was carried out. The content of essential elements and heavy metals was determined in the soil, cement dust, and tomato fruits grown on soil with and without the addition of cement dust. Due to the high pH value, high conductivity as well as the high content of CaO, it is very important to examine in real conditions how the addition of cement dust to the soil affects the formation of micro and macro elements as well as the content of heavy metals when growing tomatoes. The results showed that the cement kiln dust is an effective addition to the soil because it is a source of calcium, potassium and other essential elements without affecting the loss of quality or contamination with heavy metals during production.

pH represents the concentration of free H+ in pine needles extracts (PNE) and is therefore an important initial parameter in quality control. Electrical conductivity and pH of samples of fresh and stored for 20 days of PNE with black cumin oil and olive oil had values of 0.00 due to the encapsulation of water molecules, pH and electrical conduction was not possible. The pH of the other samples was in a weakly acidic environment because the pH of natural pine needles is 3.8. Electrical conductivity values in all samples except pine needle extract and honey increased during storage. By monitoring the parameters of pH and electrical conductivity in the quality control of PNE, it gives us a significant insight into the physical state of the phases and the way of storage.

I. Šestan, Demira Bedak Ogri, A. Odobaši, Amra Bratov i, Ema Obrali

The influence of wetting additive based on C12 - C14 alkyl ester sulfate with essential oils on the quality of nickel coatings is examined in the paper. The additive was tested at different concentrations added to the base electrolyte, taking the following concentrations: the concentration recommended twice lower (C1); lower recommended concentration (C2); upper recommended concentration (C3); the concentration twice higher compared to the lower recommended (C4) and the concentration twice higher compared to the upper recommended (C5). The value of the surface tension of the solution was determined, and the corrosion resistance in the salt chamber was examined. In addition, what is important in the production itself is the visual appearance of the coating, which was determined using the Hull cell test. The additive has been proven to be effective in reducing the surface solutions, which directly affects the production of nickel coatings of better quality and aesthetic appearance.

...
...
...

Pretplatite se na novosti o BH Akademskom Imeniku

Ova stranica koristi kolačiće da bi vam pružila najbolje iskustvo

Saznaj više