Hydroxyapatite/iron oxide nanocomposite prepared by high energy ball milling

Nanocomposites (HAp/iron oxide), made of hydroxyapatite (HAp) and ferrimagnetic iron oxide, were synthesized by high-energy ball milling a mixture consisting of iron oxide nanoparticles and the starting materials used for the HAp synthesis: calcium hydrogen phosphate anhydrous (CaHPO4), and calcium hydroxide (Ca(OH)2). Two HAp/iron oxide samples with the magnetic phase content of 12 and 30 wt.% were prepared and their microstructure, morphology and magnetic properties were analysed by X-ray diffraction and transmission electron microscopy. Furthermore, the measurement of particle size distribution was performed by laser scattering, and temperature/field dependence on magnetization was determined. X-ray diffraction data confirmed the formation of two-phased samples (HAp and spinel iron oxide) without the presence of any other parasite phase. The shape of particles was nearly spherical in both samples, ranging from only a few to several tens of nanometres in diameter. These particles formed agglomerates with the most common value of the number-based particle size distribution of 380 and 310 nm for the sample with 12 and 30 wt.% of iron oxide, respectively. Magnetization data showed that both HAp/iron oxide composites had superparamagnetic behaviour at room temperature. © 2019 University of Novi Sad, Faculty of Technology. All rights reserved

Multivariate analysis of the contents of metals in urban snow near traffic lanes in Novi Sad, Serbia

During December 2009, snow was collected at twenty two locations across the urban area of Novi Sad, directly from roads and from traffic islands near crossroads. The total metal concentration was determined for each of ten metals (Al, Ca, Cu, Fe, K, Mn, Na, Ni, Pb and Zn) using the ICP-OES analytical technique. Ni was found to have the lowest concentration (0.0265 mg dm(-3)). Na was the metal with the highest concentration (10786 mg dm(-3)), which was the consequence of sodium chloride being used as a de-icing salt on the roads. The metal with the second highest concentration at all locations was Ca; this was most likely the result of soil dust. The Spearman rank correlation coefficients between analyzed metals were calculated to determine how the concentrations of the metals were related. Cluster analysis was performed on the obtained data sets, using both the hierarchical and partitioning methods in order to identify associations among metals and/or locations. It was shown that traffic density was not the most important factor that caused the differences between the concentrations of the metals in the samples

Photocatalytic decolorisation of selected organic dyes by mesoporous tio2 thin films

The mesoporous TiO2 films were prepared by dip coating technique combined with the evaporation-induced self-assembly method using selected polymer templates. Influence of specific surface area, pore size, (nano)crystal structure and morphology of TiO2 films on the photocatalytic behaviour was investigated. In addition, particular process parameters were considered in decolorisation of organic dyes, such as: thickness of TiO2 films, initial concentration of selected pollutants and number of reaction cycles

In situ XRPD and DSC study of order-disorder phase transition in nanosize Li-ferrite

An order-disorder phase transition of nanosize Li-ferrite (Li0.50Fe2.50O4) was studied by DSC measurements and in situ XRPD technique. The phase transition temperature is found to be 762 °C (DSC) and (745±5) °C (XRPD).Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Distribution of mercury in soil according to the geomorphological units of Vojvodina province

Establishing Hg background levels in various soils is problematic. The main problem is distinguishing human input (pollution) from natural Hg input. Geostatistical methods and Geographic Information System (GIS) mapping have been used in numerous studies to determine spatial distribution and behavior of heavy metals in soils and to identify their sources. A grid superimposed on Vojvodina land by means of a GIS tool (GIS ArcView 10) has divided land into 4x4 km units, each representing an area of 16 km 2 . Total number of 1,370 bulked soil samples were taken (0-30 cm depth) from agricultural land and analysed for total mercury content THg. The samples were analysed using Direct Mercury Analyzer DMA 80 Milestone. Quality control was carried out with IRMM BCR reference materials 143R. The aim of this study was to determine the total con- tent of Hg in agricultural soils, its spatial distributions in different parts of Vojvodina Province. It was indicated that the content of Hg coincides with main geomorphological units of Vojvodina Province. Hg spatial distribution indicated that most of Vojvodina Province area has geochemical origin of Hg. Average values of Hg concentrations for soils format- ted on different geomorphological units were: 0.031 for sandy area with dune fields, 0.048 for alluvial terraces, 0.055 for upper Pleistocene terraces, 0.058 for loess plateaus, 0.083 for mountains, and 0.092 mg kg-1 for alluvial plains

Efficacy of diatomaceous earth in controlling major store product pests: Plodia interpunctella, Tribolium confusum and Acanthosclides obtectus

Diatomaceous earth (DE) is a dust formed from fossilized skeletal remains of single-celled algae – diatoms. Diatoms have a fine skeleton made of amorphous silicon dioxide (SiO2), as a major constituent of DE, which additionally contains minor amounts of minerals (aluminium, iron oxide, calcium hydroxide, magnesium and sodium). Insecticidal activity of DE is a result of desiccation that occurs after the particles of DE absorb the waterproof lipids from the arthropod cuticle (destroy epicuticular lipid layers) leading to high rate of water loss. Efficacy of DE depends on chemical composition, particle size and geographic origin. This work aimed to assess the efficacy of DE originating from Kolubara open-pit mine, Serbia, in comparison to commercially available preparation SilicoSec®. Efficacy was assessed in contact toxicity test, against indian meal moth (Plodia interpunctella) larvae and confused beetle (Tribolium confusum) and bean weevil (Acanthoscelides obtectus) adults. DEs were applied at rates: 5, 10, 15 and 20 mg-2 and mortality was recorded after 24, 48, 72 h and seven days

Health risk assessment of toxic elements in sedimentable dust from landfills

Four monitoring campaigns of sedimentable dust were provided from two large non-sanitary landfills (Zrenjanin and Novi Sad) in Serbia during 2021. Particle size analysis by laser diffraction and inductively coupled plasma-optical emission spectrometry were carried out in order to obtain the particle size distribution (PSD) and the toxic elements (TEs) concentrations. The health risk assessment of the landfill employees was performed according to the United States Environmental Protection Agency methods based on TEs concentrations. The PSD results demonstrated that the majority of sedimentable dust samples mass were not concentrated neither within PM2.5 neither within PM10 fraction. Analysis revealed high concentration of TEs at both landfills: an extremely high concentrations of Cr and Zn in samples from Zrenjanin landfill was detected. Health risk potential of elements was as follows for both landfills: Cr > Co > Pb > Ni > Zn > Cu. According to the results, maximal hazard index for landfill employees in Zrenjanin (0.197) and Novi Sad (0.113) showed that non-cancer risk was very low. For both landfill sites, cancer risk was highest for Cr (2.75×10-5 for Zrenjanin and 2.02×10-7 for Novi Sad), though still within the defined threshold for tolerable cancer risk

Textile-based heating system for safe localized warts treatment

We present an integrated system for the home treatment of cutaneous warts. Our work includes the development of a textile-based heater and electronic module regulating the temperature within the range of 43–46 °C. Commercially available silver-coated polyamide conductive threads were used for embroidering three space filling curves: a standard serpentine, a Peano curve with rounded angles, and a Gosper curve. Embroidered heaters were characterized using Electrical Impedance Spectroscopy, thermal imaging, and Scanning Electron Microscopy. All three designs showed similar thermal performance. However, owing to the lower consumption of materials and easier attachment of the feedback temperature sensor, the serpentine structure was selected for the integrated system development. Response and recovery times were determined to be less than 1 minute. The developed system was validated by means of monitoring the temperature regulation over a prolonged period, as well as in contact with human skin. The presented heat patches, along with an efficient electronics system, have the potential to enhance the personalized treatment of warts using local hyperthermia

METALS DISTRIBUTION AND PARTICLE SIZE ANALYSIS IN WATER AND SEDIMENT OF THE DJETINJA RIVER AND DRAGIĆA SPRING (SERBIA)

This paper reports the results on total metal concentration (Al, Fe, Cr, Cu, Ni and Zn) in water and sediment of the Djetinja river basin in the area of western Serbia. Samples were collected in spring season. Based on the comparison of the concentrations of all analyzed metals it is possible to differentiate two zo¬nes: zone I (sampling sites 1-4), affected by the discharge of the Dragića spring, and zone II (sites 5-8), affected by the confluence of the Dragića spring with the Djetinja river. The analysis of suspended solid particle size in water as well as in sediment samples was performed in size range 0.02-2000 m and a posi¬tive corelation was found with the concentration of aluminium, zinc, iron and nickel in water samples. The study of particle size and metals distribution through the river basin of the Djetinja was a useful tool for getting information about the distribution degree of the polluting agents, and their possible evolution growth and pollution sources. The research of metals distribution and particle size analysis in water and sediment of the Djetinja river and Dragića spring (Serbia) was conducted for the first time

Potential factors affecting accumulation of unsupported Pb-210 in soil

Airborne Pb-210, daughter of Rn-222, is frequently used as a tracer in different studies concerning atmospheric transport, sedimentation, soil erosion, dating, etc. Concentration of Pb-210 was measured in 40 soil samples collected in urban and industrial areas in order to get evidence of possible influence of some factors on accumulation of airborne Pb-210 in soil. Different soil properties such as the content of organic matter, free CaCO3, and available phosphorus (P2O5) were measured to explore their possible correlation with the amount of Pb-210 Special attention was given to the correlation between 210Pb and stable lead accumulated in the soil. Several samples were taken near a battery manufacturer to check if extremely high concentrations of lead can affect the uptake of the airborne Pb-210 in soil. Soil samples were also taken at different depths to investigate the penetration of lead through the soil