In this study, the adsorption of Fe(III) from aqueous solution on zeolite and bentonite was investigated by combining batch adsorption technique, Atomic adsorption spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses. Although iron is commonly found in water and is an essential bioelement, many industrial processes require efficient removal of iron from water. Two types of zeolite and two types of bentonite were used. The results showed that the maximum adsorption capacities for removal of Fe (III) by Zeolite Micro 20, Zeolite Micro 50, blue bentonite, and brown bentonite were 10.19, 9.73, 11.64, and 16.65 mg.g⁻¹, respectively. Based on the X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF) analyses of the raw samples and the solid residues after sorption at low and high initial Fe concentrations, the Fe content is different in the surface layer and in the bulk of the material. In the case of lower initial Fe concentration (200 mg.dm⁻³), more than 95% of Fe is adsorbed in the surface layer. In the case of higher initial Fe concentration (4000 mg.dm⁻³), only about 45% and 61% of Fe is adsorbent in the surface layer of zeolite and bentonite, respectively; the rest is adsorbed in deeper layers.

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.

The implementation of industrial park investment projects in relation to the use of brownfields and greenfields is a constantly debated issue. Brownfields are unused areas, often with devastated building objects and environmental burden that pose potential risks to the investor but also contain the possibility of using the available infrastructure and facilities for the use of the proposed investment project. The objective of the study was to assess the positive and negative investment of these types of sites based on the available information on the possibilities of investing in the implementation of the brownfield industrial park compared to the greenfield in the western part of East Slovak region and to identify a more appropriate alternative of investing. Based on the assessment of investment in the industrial parks, the appropriateness of the allocation of investment capital was assessed through the simple additive weighting (SAW) method. The SAW approach allows us to objectivize the weighting value of selected factors and thus assess the appropriateness of the allocation of investment capital. Based on the results, it is more advantageous to allocate the investment capital to the greenfield as the return on investment of the project expressed as a percentage of the average annual profit was 9.5%, compared to brownfield with only 2.9%.

In the current post-COVID-19 era, online marketing is a supporting tool in marketing. The potential visitors to tourism destinations, such as geoparks, are increasingly guided and oriented by the rules of online marketing as the online space represents the main source of information. Geoparks should take this as a key fact. The research concentrates on the issue of geopark marketing from the view of the available information that geoparks present in the online space. The fundamental is to point out the information that is available on geopark websites. The method used in the research is based on an evaluation matrix that served as a basis for searching for information on websites. Based on the results of the analysis, geoparks in the EGN network present information of a general nature to a sufficient extent on their websites; they lack a better offer of product packages, online sales and orientation to new social networks that are used by the young generation. The clear answer is the professionalization of marketing, which would undoubtedly represent an effective step in the management of geoparks as well as the promotion of the country that the geopark represents.