Marian Holub

Properties Characterization of Chemically Modified Hemp Hurds

The effect of chemical treatment of hemp hurds slices in three solutions (EDTA (Ethylenediaminetetraacetic acid), NaOH and Ca(OH)2) on the properties of natural material was discussed in this paper. Changes in the morphology, chemical composition and structure as well as thermal stability of hemp hurds before and after their modification were investigated by using FTIR (Fourier transform infrared spectroscopy), XRD (X-ray powder diffraction analysis) and TG (thermogravimetry)/DSC (differential scanning calorimetry). Size exclusion chromatography (SEC) measurements were used for determination of degree of cellulose polymerization of hemp hurd samples. Chemical modification is related to the partial removal of non-cellulosic components of lignin, hemicellulose and pectin as well as waxes from the surface of hemp hurd slices. Another effect of the chemical treatment applied is connected with increasing the crystallinity index of cellulose determined by FTIR and XRD methods. Decrease in degree of cellulose polymerization and polydispersity index in chemically modified hemp hurds compared to the original sample was observed. Increase in thermal stability of treated hemp hurd was found. The most significant changes were observed in alkaline treated hemp hurds by NaOH.

Precipitation of heavy metals from acid mine drainage and their geochemical modeling

Abstract Geochemical modeling plays an increasingly vital role in a number of areas of geoscience, ranging from groundwater and surface water hydrology to environmental preservation and remediation. Geochemical modeling is also used to model the interaction processes at the water - sediment interface in acid mine drainage (AMD). AMD contains high concentrations of sulfate and dissolved metals and it is a serious environmental problem in eastern Slovakia. The paper is focused on comparing the results of laboratory precipitation of metal ions from AMD (the Smolnik creek, Slovakia) with the results obtained by geochemical modeling software Visual Minteq 3.0.

Quality of the bottom sediments in the area affected by mining activities

The remains of human activities may be seen in several places of the landscape in positive or negative form. Probably the most common phenomenon that fundamentally impacts the country is mining activity. The environmental problems caused by mining have attracted a great deal of research attention and led to development of numerous sediment heavy metal contamination assessment methods, including the index method, the dynamic method, the synthesis methods in chemistry, ecology and toxicology, etc. This research was undertaken in order to determine and analyze selected heavy metals present in sediment samples collected from different sampling localities inside and around water reservoir Ruzin, Slovakia. Reservoir and its inflows are located in the vicinity of region with historical Cu, Fe, Ag, Au-deposit, which was exploited from the 14th century to 1990 and currently causing environmental burden. For the determination of sediments quality different methods (XRD and XRF analysis) have been used. Based on the...

Study of Precipitates from Mine Water after Defrosting and Oxidation

Acid mine drainage contains many toxic pollutants, mainly heavy metals and sulphates, which have negative impact on the environment. This paper deal with a study of two precipitates from acid mine drainage outflowing from the abandoned mine Smolnik (Slovakia). The precipitates were created after defrosting of mine water and after the process of oxidation. After drying the precipitates were analysed by infrared spectrometry and scanning electron microscopy (SEM) with EDX analysis. Using infrared spectrometry it was found that the precipitate contained OH-, SO42- functional groups. The inhomogeneous structure of the precipitate was observed by SEM with EDX analysis. The presence of CaSO4.2H2O (approx. 90 %) in precipitate after defrosting was confirmed by FTIR and SEM with EDX. Particulate substances after oxidation consisted mainly iron (30.5%), oxygen (44.4 %) and sulphur (7.9 %). Complex compounds with mainly contents of iron (III), hydroxides and sulphate with crystal bound water in structure were identified.

Influence of Acid Mine Drainage on Surface Water Quality

Acid mine drainage (AMD) has been a detrimental by-product of sulphidic ores mining for many years. In most cases, this acid comes primarily from oxidation of iron sulphide, which is often found in conjunction with valuable metals. AMD is a worldwide problem, leading to ecological destruction in watersheds and the contamination of human water sources by sulfuric acid and heavy metals, including arsenic, copper and lead.

The Influence of Phosphogypsum Addition on Phosphorus Release in Biochemical Treatment of Sewage Sludge

The paper is focused on the research of biochemical treatment of sewage sludge and phosphogypsum under sulphate-reducing conditions with a phosphorus release process. The theoretical foundations of the work were based on the biochemical formalization using the principles of autocatalysis of natural systems. During the experimental research for the control of physicochemical parameters of the process spectroquantic, X-ray fluorescence analysis and other techniques were used. A schematic model of the dephosphatation process under anaerobic stabilization of sewage sludge and phosphogypsum was developed. The increase of phosphogypsum dosage had a close correlation with the release of phosphate ions. At the stimulating action of the phosphogypsum additive, a 2.5–5.0-fold increase in soluble phosphate concentration was observed. The rational dose of phosphogypsum was determined. Along with an increase the ratio of COD (Chemical Oxygen Demand)/phosphogypsum to 0.1, an increase in the phosphate ions in solution was observed. A further increase in the ratio of COD/phosphogypsum did not affect the concentration of phosphate ions in solution.

Analysis of Building Stone of the Medieval Historical Building

The reconstruction of the historical buildings needs the replacement of the original and damaged materials using possible compatible materials that closely replicates the original ones in its appearance, chemical, physical and mineralogical properties, strength and durability. Thus, a complex approach based on advanced analytical methods is needed to identifying of the suitable materials. The paper is aimed at the study of the chemical and mineralogical properties of the historical stones of the medieval castle in the East Slovakia in order to replacement the original materials by the new ones with similar composition. The carbonates and silicates were confirmed as the main components of the stones by X ray fluorescence (XRF) and Fourier transformation infrared (FTIR) methods. The mineralogical analysis confirmed the presence of the calcite as the dominated carbonate minerals as well as the presence of the quartz and muscovite representing the silicate forms.