Sorpce vybraných těžkých kovů z odpadních vod pomocí netradičních sorpentů

The environment incl. water is exposed to heavy metals in the long term. Typically, industrial activities are the source of heavy metals penetrating the environment. The heavy metals are contained in many products and are a part of many waste substances. This paper deals with removal of copper, zinc and lead from waste waters by means of adsorption. Adsorbents are typically cheap substances, such as synthetic zeolite, bentonite or slovakite. Attention is paid to the adsorption rate and efficiency of removal of the heavy metals mentioned from the water.Ţivotní prostředí včetně vod je dlouhodobě zatěţováno těţkými kovy. Tyto se do prostředí dostávají hlavně činností průmyslu, jsou obsaţeny v celé řadě výrobků a tvoří součást mnoha odpadních látek. Tento článek se zabývá odstraňováním mědi, zinku a olova z odpadních vod pomocí adsorbce. Jako adsorbenty jsou vybrány látky, které jsou cenově dostupné, Jedná se o syntetický zeolit, bentonit a slovakit. Je sledována rychlost adsorpce a účinnost odstraňování uvedených těţkých kovů z vody

The Model of Supplier Quality Management in a Transport Company

The submitted article deals with the supplier quality management in a selected transport company in the Slovak Republic (SR). It describes evaluation of suppliers based on explicitly defined indicators in relation to the overall economic management in the given company. The evaluation model described in the final part of the article, based on the weighed amount method, is open, i.e. it can be supplemented with additional specifics characteristics depending on the needs of a specific company, and applied at the same time to other production as well as non-production companies

Removal of heavy metals from waste water using a hybrid membrane process

Soil and water pollution by heavy metals is currently a very important problem in environmental and other sectors. The origin of metals in water may be of either natural character (erosion of rocks and sediments, leaching of mineral resources) or anthropogenic character (mining and extraction of metals, industry, agriculture, etc.) (Martins et al. 2010). Many heavy metals, such as Pb, Cd, Cu, Zn, etc., are the most polluting factors in industrial wastewater and may get into the ground water. Subsequently they are bio-accumulated in living organisms and cause various diseases and disorders (Jamil et al. 2010). These problems need to be responded by developing new and more efficient methods for wastewater treatment (Martins et al. 2010). In practice several methods are used for removal of heavy metals from water. One of the promising methods for the removal of metal ions from water is a hybrid membrane processes. This method includes two processes – adsorption of metal ions on the natural zeolite and microfiltration of zeolite suspension through ceramic membrane. Experiments were carried out using model solutions containing Cu2+ ions (from CuSO4.5H2O and Cu(NO3)2.3H2O) and Zn2+ ions (from ZnSO4.7H2O and Zn(NO3)2.6H2O).In the experiments zeolite from Nižný Hrabovec localization (Zeocem JSC Bystré), Slovakia was used. Zeolite is mainly composed of mineral clinoptilolite (84%), other mineral are cristobalite (8%), clay (4%) and plagioclase (3-4%). Its structure is formed by three-dimensional network. Clinoptilolite is composed from silicate tetrahedron (SiO4)4- bound together by oxygen atoms, where part of the Si atoms is replaced with aluminum (AlO4)5-. This creates space structures with a number of cavities and channels, in which are accommodate metal cations and water molecules. The total volume of cavities is 24 to 32%. Zeolite has a bulk density of 1600 to 1800 kg.m-3, a specific gravity of 2200 to 2440 kg.m-3 and the specific surface of 30 to 60 m2.g-1 (www.zeocem.com).Adsorption experiments on model solutions were performed with the zeolite with particle size 20 microns. Before and after the experiments the concentrations of Cu and Zn were determined by atomic absorption spectrophotometry (AAS) using iCE 3300 AA Spectrometer Thermo Scientific. Solutions with concentrations of 10 to 5000 mg.l-1 were prepared from each of the chemicals. The solutions were shaken with 1 g of zeolite in 100 ml PET flasks on a shaker for 2.5 hours at 25°C and 220 rpm. The amounts of metals (Cu or Zn) in solutions were measured after stabilization, filtration and required dilution by AAS. The equilibrium between the concentration in solution and the adsorbed substance was evaluated using Langmuir, Freundlich and Redlich-Peterson models. According to the results of the adsorption experiments zeolite adsorbed of both the nitrates ions (Cu2+ and Zn2+) (equilibrium concentrations 1.48 mg.g-1 and 1.49 mg.g-1, respectively) best and the sulfate ions (0.34 mg.g-1 and 0.85 mg.g-1, respectively) less. Due to better adsorption capacities of zeolite for  ions derived from nitrates, further experiments were made from chemicals Cu(NO3)2.3H2O and Zn(NO3)2.6H2O.The next step was microfiltration of suspension of zeolite since a hybrid process for removal of Cu and Zn ions was used. Microfiltration was carried out at a constant pressure of 50 kPa, the flow rate of suspension 2.2 m.s-1 and various concentrations of zeolite (1 g.l-1 to 6 g.l-1). Tubular Membralox ceramic membrane was used, with length of 25 cm, internal diameter of 0.5 cm, external diameter of 0.7 cm and porosity of 50 nm. Active surface of the membrane was 49.48 cm2. Zeolite was added to the solution of ions circulating in the cross-flow microfiltration system. Metal ions were adsorbed by zeolite and the suspension was filtered by the membrane. The adsorbed metal remained circulating in the system and the permeat was purified water. Using this method, at suitable selection of the experimental conditions, up to 90 to 100% of metal ions can be removed from the solution

Influence of Crisis to Activity Indexes in Chosen Industrial Companies of the Country

Presently, the economic effectiveness of the company is becoming decisive alternative how to obtain competitiveness at the market. Reliable statement about financial situation can be obtained by analysis of the ability to pay the debts. Development in the industrial companies had been searched by indexes of activity, which express and quantify if the economy of the company is effective by the way of its assets. Results of the analysis show the most effective and less effective areas from the view of payment terms and assets turnover. Strengthening of the less effective areas can contribute to the whole economy of the regions and countries

Adsorption efficiency of selected natural and synthetic sorbents

Sorbents are substances binding other substances on their surface. Effective sorbents have a porous surface. The adsorption activity of the surface is closely related to the local radius of curvature of surface irregularities. Suitable sorbents are natural and synthetic solids of amorphous or microcrystalline structure (Kyncl, Pavolová, Kyseľová, 2008). Globally, the following adsorbents are the most used: activated carbon, zeolites, silica gel, activated alumina (Bakalár et al., 2005). A characteristic of effective adsorbents is large surface area of hundreds of m2.g -1. Other important features of adsorbents include specific volume, porosity, average pore diameter, pore distribution, etc.For sorption of heavy metal cations some natural materials or industrial waste with high sorption capacity, which naturally reduces the overall cost of their disposal, can be used. Some of low-cost sorbents are: lignin, chitin, seaweed / algae, zeolites, clays, fly-ash, peat, sand grains coated with iron oxide, modified cotton and wool (Pavolová, Bakalár, Kyseľová, 2006).In experiments of Cu and Zn removal from wastewater the following adsorbents were used (Bakalár et al., 2005):Lewatit S100 is strongly acidic, gel-like cationic ion exchange resin with particles of equal size based on styrene-divinylbenzene copolymers. Monodisperse beads are chemically and osmotically highly stable.Chitosan is prepared from chitin, naturally occurring in the shells of crustaceans, by deacetylation using strongly alkaline solution. Chitin is a homopolymer composed of β-(1-4)-N-acetyl-D-glucosamine. The ability of crustaceans shells to bind metal ions is assigned to the presence of oxoskeleton in the molecule of chitin and chitosan.Synthetic zeolite, which is the included in the group of aluminosilicates, was prepared by zeolitization of fly-ash from energy industry.Bentonite is included in the group of hydrated aluminosilicates, the main ingredient is mineral montmorillonite.Slovakia is an inorganic composite sorbent made from pure natural ingredients.In removal of Cu2+, Zn2+ and Pb2+ cations the aspect of time, i.e. the time the specific sorbent reaches the maximum sorption capacity for the heavy metal removed, is also important. The experimental measurements of cations sorption using the above mentioned sorbents are made at the initial concentration of 10 mg.l-1 of heavy metal.The time aspect of separation of Cu2+ cations from model solutions of wastewater reached relatively very good results because the time to reach the equilibrium for all sorbent was about 60 seconds except for chitosan for which it was almost 2 minutes.The equilibrium of Zn2+ cations sorption was reached by about 80 seconds at the experimental measurements for all the selected sorbents except for chitosan for which this time was 2 minutes 5 seconds. This time was on average around 20 minutes longer compared to the sorption of Cu2+ ions.The sorption of Pb2+ cations was carried out at the experimental measurements in about 83 seconds for all the selected sorbents, except for synthetic zeolite for which the time was 1 min 15 s. The sorption of Pb2+ cations compared to the cations of Cu2+ was 23 s faster and compared to the cations of Zn2+ was 3 s longer.From the used sorbents the most appropriate for the removal of Cu2+, Zn2+, and Pb2+ is Lewatit S100, the equilibrium was reached in approximately 35 s, 45s, and 83 s for Zn2+, Cu2+, and Pb2+, respectively. According to the experimental measurements the longest adsorption time was for chitosan – about 2 minutes for Cu2+ and Zn2+, and about 1.5 minutes for Pb2+

Contribution of Mining Industry in Chosen EU Countries to the Sustainability Issues

In recent years, the mining industry has achieved an important position in the national economy due to its increasing productivity. However, since 2000, there have been signs of a slowdown, resulting from the national and local conditions of the mining industry. It is for these reasons that we have concluded that this type of industry must be assessed not only from the economic but also from the national and regional sectors, because the performance of the mining industry is directly affected by the value of mineral deposits and the structure of other industries. The present paper aims to analyze the development of the mining industry in Slovakia, in comparison with similar development in chosen European Union countries. Slovakia has been considered as a country with mineral resources and mineral-based products representing an important part of Slovakia’s foreign trade, with the significant imported mineral resources including mainly mineral fuels and ore raw materials. The development of the mining industry is assessed from the economics through the growth rate of gross domestic product (GDP) and through the national aspect through the rate of growth of the national economy. The aspects are evaluated by the multi-criteria method Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), with which we evaluated the country with the best mining industry development. The results of detailed quantitative analyses of the selected indicators for mining industry development for individual European Union countries show a fluctuating trend during the observed period, which is characterized by development disparities. Such results can be used to determine raw material policies in the relevant countries

Application of organic waste for adsorption of Zn(II) and Cd(II) ions

Biosorption of Zn(II) and Cd(II) ions from aqueous solutions onto organic waste – orange peel, hazelnut shell, and walnut shell was studied using batch adsorption experiments. In the biosorption studies, equilibrium metal ion concentration was determined. Experimental data obtained were analysed in terms of Freundlich, Langmuir, Temkin, Dubinin–Radushkevich, Redlich–Peterson, Sips, Toth, and Khan isotherms. The results of the study showed that orange peel, hazelnut shell, and walnut shell can be adequately used as low-cost alternatives for the removal of Zn(II) and Cd(II) ions from aqueous solutions with maximum sorption capacities of 15.51 and 19.8 mg/g, 11.55 and 16.65 mg/g, and 26.60 and 21.10 mg/g, respectively. The highest removal efficiency of Zn(II) and Cd(II) ions was obtained for hazelnut shells. The process was fast and about 90% of metal ions were removed by all the studied biosorbents. The sorption process was possibly chemisorption occurring on a heterogeneous surface

Analysis and Model of River Basin Sustainable Management by SWOT and AHP Methods

The sustainable management of river basins is a comprehensive problem involving not only environmental quality but also socio-economic aspects. The primary objective of the study is to propose a sustainable management model of a river basin based on a clear identification of the good water quality in the river basin applicable for any river basin. The proposal is based on a monitoring of the quality of surface water in the basin, a quantitative and qualitative analysis of pollution, a questionnaire survey on the sewer systems and wastewater treatment in the basin and the diffuse sources of water pollution. For a better outline, a case study of Hornád river basin, Slovakia, was carried out. Two methodologies were applied: SWOT analysis for identification of indicators and the priorities and AHP analysis for a prioritization of the decisions. These analyses can be carried out for any activity based on identification of indicators and the priorities of the defined indicators to promote sustainable development. Based on the findings and the results of the analyses the model for managing the development of surface water quality in the basin was proposed. Generally applicable principles of sustainable development, accepting legislation in the field of water management, considering the quality of surface water in the basin, the impacts of wastewater discharges into the recipient, the identification and evaluation of positive and negative aspects of surface water quality, and the implementation of the proposed measures and post-implementation monitoring of qualitative development were covered in and by the proposed model

Development of Košice Region by Implementation of Environmental Projects in the Field of Water Management - Case Study

The development of the regions in Slovakia in recent years has significant disparities in both so-cio-economic as well as environmental issues, as evidenced by the eight environmentally polluted areas (these areas are highly urbanised with industrial agglomerations or intensive agricultural production)