Solid State Phenomena Vol. 244

Abstract: Nowadays, the material recycling is growing trend in development of building materials and therefore using of secondary raw materials for production of new building materials. Transition from application non-renewable sources of raw materials to renewable raw materials in terms of sustainable composite is required. Renewable raw materials include organic sources of raw materials coming from natural plant fibres. This material is used to contribute environmental protection and to save non-renewable resources of raw materials. Wood fibres and cellulose fibres made from waste paper were selected for reinforcing cement-based materials. Application of cellulosic fibres into composites depends on their properties. Therefore, this paper is aimed to study of morphology and properties of cellulosic fibres. The comparison of strength parameters of 28 days hardened composites with 5% adding bleached wood and unbleached recycled fibres with those of reference composite without fibres showed that the values of compressive strength of fibrous cement based specimens were lower by 17 to 29 %.

Abstract: The development of biocomposites based on natural fibres coming from plants and inorganic binder materials is in the foreground of research in the field of sustainable building materials. Biocomposites ́ properties are influenced by both particulate constituent characteristics. In last decades, the growing trend in using of plant fibres as filler and / or reinforcing material into biocomposites for building application is due to their renewability and environmentally friendly properties. Inorganic powdered binder substances, mainly Portland cement and/or hydraulic lime are used as matrix material in bio fibres reinforced composites. In this paper, the important characteristics of fibrous and isometric particles affecting the final properties of hardened composites will be discussed.

Abstract: During the process of monitoring of pulp fibres swelling, which is directly related to absorptivity, it was found that with the growing number of recycling cycles this characteristics significantly decreases. This phenomenon, which is considered as negative from the point of view of pulp fibres utilizing for paper manufacturing, could potentially find its positive application in other areas, eg. in the civil engineering for production of lightweight composites, where the reduction of water absorption of natural fibre materials is desirable.

Abstract: Particulate matter (PM) is one of the striking pollutants and causes appreciable degradation of the environment and therefore the quality of life of the population. PM may originate in various natural resources or anthropogenic sources. Among the natural sources sea salt is to be counted on, dust of the earth crust, pollen and volcanic ashes. Anthropogenic sources do include, predominantly, burning fossil fuels in the fossil-fuel power plants, local heating of households, burning liquefied fossil fuels in the combustion engines of vehicles, non-combustion related emissions as a result of vehicular traffic, resuspension of the road-traffic-related dust. Their harmful effect and impact on the ambient environment is determined predominantly by the aerodynamic diameter of PM and by the presence of various chemical substances and elements. The subject of this presentation is monitoring particulate matter along the cycle of its creation in the vicinity of highway in rural area and an evaluation of fraction ratios PM₁₀, PM_2.5 and PM₁ with regard to meteorological conditions and traffic volume. Wind speed and temperature appear to be the most significant meteorological factors with proven impact on particulate matter in ambient air. The fine fraction PM_2.5 is determining for the total measured fraction PM₁₀. It has also been monitored the chemical composition of PM, in particular the presence of metals in fractions of PM. Some chemical elements (metals) are characteristic for fine fraction PM_2.5 and some for coarse fraction PM_2.5-10. It depends primarily on measuring seasons, the distribution of potential sources of particulate matter and metals in the time and space.

Abstract: Increase in particulate matter air contamination and its negative impact on human health have resulted in efforts to monitor and identify the sources. Particles are produced by photochemical atmospheric reactions and the coagulation of combustion products from automobiles and stationary sources, with lifetimes of several days or more. The occurrence of particulate matters indoors depends on outdoor pollution and its transport indoors as well as on the presence of indoor sources. This paper aims to carry out a measuring of particular matters concentrations in indoor air of selected buildings and in outdoor air in village of Jasov. The mass concentrations of particulate matters for fractions of 0.5, 1.0, 2.5, 5.0, and 10.0 micrometers were measured and evaluated in order to determine the extent of exposure of people.

Abstract: The total atmospheric deposition (AD) was sampled in the urban and industrial area with iron and steel works and other urban sources of pollution. The eleven sampling sites have been placed on the roof above the height of the surrounding buildings at a distance of between 1 and 15 kilometers from the largest industrial source of air pollution in Slovakia. Qualitative and quantitative characteristics of the AD of solid particles (PM) and the fluxes AD of elements (Fe, Al, Mn, Zn, Pb, Cu, Cr, Cd, As) were studied. Particle size distribution, SEM and EDX analysis were applied for PM characterization. Relatively high occurrence of fine particles under 10 µm (12.1 - 47.7%) were found in the samples. SEM and EDX analysis showed the presence of particles whose origin is mainly from emission sources of ironworks (Fe oxides, Fe-rich particles, Ca-rich particles, Mn-Fe oxides). The extremely high values of AD of Fe (18,551 and 27,232 µg.m^-2.day^-1) and Mn (695 and 1295 µg.m^-2.day^-1) were measured at two sites near (1.3 and 4.5 km) the iron and steel works compared to the AD of the other areas. The portion of emission sources iron and steel works on the AD of Fe and PM fluxes at the individual sites in the city was calculated in the range of 21.8 to 51.4%. The results from 2009–2014 are introduced.

Abstract: In surface winning particulate matters are generated from a range of site preparation, stockpiling, loading, transportation and processing activities. This article aims to review issues relevant to particulate matters produced by the surface winning and impact on people living near by the quarry. Due to the areal extent of the site and limitations imposed by readily available data, the article has focused upon activities associated with quarry. On the base of obtained data was composed mathematical model of the distribution of particulate matter from the source to the surroundings to visual impact of the quarry and potential impact of the particulate matters. The visualization is shown direction of particulate matters propagation and allows decide on used measures to eliminate negative impact on people and environment.

Abstract: The removal of Cu (II) ions from aqueous solutions using the adsorption process onto natural Slovak bentonites from deposits Jelšový potok, Hliník nad Hronom and Lieskovec has been investigated in this study. The adsorption experiments were carried out under batch process with initial concentration Cu (II) ions, time and temperature as the variables. A flame atomic absorption spectrometer was used for measuring the copper concentration before and after adsorption. Adsorption was very fast at low coverage and equilibrium was approached within 30 min. The results best fitted the pseudo-second order kinetic model. Langmuir and Freundlich isotherms were applied and isotherm coefficients were computed. The Langmuir isotherm was found to fit better the experimental data measured for used bentonites. The Langmuir maximum adsorption capacity of the adsorbents was from 13.4 to 43.1 mg g⁻¹. The effect of temperature on the equilibrium adsorption of copper from aqueous solution using natural bentonites was investigated at three different temperatures (293, 303 and 313 K). Thermodynamic parameters, such as standard free energy changes (ΔGo), standard enthalpy change (ΔHo) and standard entropy change (ΔSo), were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. The copper adsorption on bentonite was a spontaneous and endothermic process. The results suggested that natural bentonites are suitable as a adsorbent material for recovery and adsorption of Cu (II) ions from aqueous solutions. Comparing the measured results for used bentonites is evident that for the removal of Cu (II) ions from aqueous solutions is more suitable the bentonite from Jelšový potok.

Abstract: The paper deals with the use of blast furnace slag in the production of plain concrete and with its impact on the elements of the environment. The finely ground granulated blast furnace slag with the weight of 10, 20, 30, 40, 50, 60, 80, 95 and 100 % was used as a substitute of Portland cement in ratio 1:1 of weight. The following properties were observed in all prepared experimental mixtures: consistency of concrete mixture, density of fresh concrete mixture, cube and prism strengths, water tightness, frost resistance and static modulus of elasticity. Subsequently, the life cycle assessment as well as the comparison of environmental impact of selected plain concretes by the LCA method was made. They were monitored total environmental impacts in terms of threats to soil, water, air and human health in order to select the most suitable alternative. The comparison of the reference mixture and mixture with 60% wt. of blast furnace slag showed that using secondary raw materials visibly decreased the impact in each category: Abiotic depletion of 56%; Acidification of 52%; Eutrophication of 56%; Global warming of 58%; Ozone layer depletion of 50%; Terrestrial ecotoxicity of 59%; Photochemical oxidation of 50%, Primary energy (non-renewable fossil) of 53% and of 58% for Human toxicity, Fresh water aquatic ecotoxicity and Marine aquatic ecotoxicity, respectively.

Abstract: Permeable reactive barriers (PRBs) are passive, in-situ remediation systems that comprise the filtration of a contaminated groundwater through a reactive media able to degrade, adsorb or precipitate the pollutants. Selection of the reactive media depends on the nature of the contamination. While the majority of PRBs are used to treat groundwater contaminated with chlorinated volatile organic compounds or acid mine drainage, the present study is focused on heavy metals, namely Fe, Al, Cu, Ni, Zn, Mn and As. To remove such inorganic pollutants, four methodologies are usually implemented: a) redox reaction, b) adsorption and ion exchange, c) biological treatment (e.g. metal sulphides precipitation) and d) pH control and precipitation. The present paper deals with the last methodology in which an adjustment of pH by alkalinity-generating materials leads to the precipitation of metal hydroxides and the decrease in the concentration of dissolved species. As the solubility of metals depends on their valence, redox-potential, concentrations and kinetics of reaction, the target pH varies with respect to the considered metal. A pH of about 10 allows the precipitation of hydroxides of divalent ions (zinc, manganese, copper, lead, nickel, cobalt and cadmium), while a pH of around 6-7 is adapted to trivalent ions (iron, aluminium and chromium). However, the accumulation of precipitates in the pore spaces can cause clogging of the pores, hence decrease the porosity and hydraulic conductivity of the reactive media and alter its efficiency. To validate this assumption, the neutralizing ability of alkaline materials such as activated zeolite and magnesite were examined in a test column by monitoring the resultant pH with attention to impact of precipitates on the hydraulic properties of reactive materials. Based on the test results, both materialls are considered suitable to remove the groundwater contaminants with high efficiency (up to 99%) and suitable grain size to encourage flow through the PRB.