Examination of the influence of phenyltrimethylammonium chloride (PTMA) concentration on acetochlor adsorption by modified montmorillonite.

The results presented in this paper show an impact of the concentration of the aromatic organic cation on the adsorption of acetochlor on the surface of the organic-modified montmorillonite. Natural montmorillonite from Bogovina (Boljevac municipality, Serbia) was used for organic modification in this experiment. Cation exchange capacity of this montmorillonite (86 mmol 100 g-1 of clay) was determined using the methylene blue method. In pretreatment, montmorillonite was modified with NaCl. For the purpose of organic modification, three different concentrations of phenyltrimethylammonium chloride (PTMA) have been selected, based on calculated CEC value: 43 mmol 100 g-1 of clay (0.5 CEC), 86 mmol 100 g-1 of clay (1 CEC) and 129 mmol 100 g-1 of clay (1.5 CEC). The changes in the properties of the inorganic and organic modified montmorillonite were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and batch equilibrium method. Freundlich coefficients show higher uptake of the herbicide by montmorillonite modified with PTMA, compared to inorganic-modified montmorillonite. The results also indicate the influence of the organic cation concentration on the adsorption of the selected herbicide.

Preliminary investigation of mineral content of pollen collected from different Serbian maize hybrids - is there any potential nutritional value?

BACKGROUND: Bee pollen has already proved to be a good supplement rich in iron and zinc. Studies on the application of flower pollen in the food industry and medicine have begun. Bearing in mind the prevalence of maize as a crop culture, its pollen will be easily available. The mineral composition of pollen of seven Serbian maize hybrids was analyzed in order to establish its nutritional value and the benefits of its implementation in the human diet using the inductively coupled plasma method. RESULTS: The presence of twenty four different macro- (nine) and micronutrients (fifteen) was detected. The most common minerals were phosphorus and potassium, while arsenic, cobalt, lead, nickel and molybdenum were found in some samples. CONCLUSION: Comparing the results obtained with recommended or tolerable dietary intake references for adults, it was found that maize pollen can be used as a very good source of zinc, iron, chromium and manganese for humans. With regard to selenium content, pollen samples proved to be moderately good source of this important micronutrient. Contents of some elements (Fe, Zn, Mn, Cr, Se, Al and V) showed significant differences depending on hybrid type. In some samples increased concentrations of aluminum and vanadium were recorded, which may pose a potential problem due to their toxicity. © 2016 Society of Chemical Industry.

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite.

This study was undertaken to determine the impact of the organic complex concentration on the adsorption of herbicide (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina (Boljevac municipality, Serbia) was used for organic modification. Cation-exchange capacity of this montmorillonite was determined using a methylene blue method (86 mmol/100 g of clay). Montmorillonite has been modified first with NaCl and then with hexadecyltrimethylammonium bromide (HDTMA-bromide) organic complex. Saturation of cation exchange capacity (CEC) was 50%, 100%, and 150%. Changes in the properties of the inorganic and organic montmorillonite have been examined using the X-ray diffraction, Fourier transform infrared spectroscopy, and batch equilibrium method. Montmorillonite modified with HDTMA-bromide demonstrated higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, it can be seen that the adsorption of acetochlor decreased in the series: 0.5 CEC HM > 1 CEC HM > 1.5 CEC HM > NaM.