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This document discusses the importance of removing heavy metals from water sources due to their increased concentrations from industrial activities. The focus is on adsorption as an effective method for removing pollutants from contaminated streams using various adsorbents. The document highlights several research papers that explore different materials and technologies for heavy metal removal, including the use of yeast cells, magnetic biocomposites, cherry pit biochar, alkali-modified sawdust, nano-biocomposites, calcined mussel shells, mineral-organic hybrid adsorbents, and natural bentonites. These studies demonstrate the potential of these materials for efficient and cost-effective heavy metal removal from water sources. [Extracted from the article]

The heavy metal removal from wastewater is very important due to their persistent character in aquatic environment. The use of wooden sawdust is emerging as a potential alternative to the existing conventional technologies for the removal of metal ions from aqueous solutions. The aim of this work is to study the Cu(II) removal of from water by unconventional waste products including the wooden sawdust of poplar, cherry, spruce and hornbeam. The FT-IR spectra of the studied wooden sawdust confirmed the presence of functional groups that have potential for heavy metal binding. The highest efficiency of Cu(II) removal was observed for poplar wooden sawdust at static (86 %) and dynamic (88 %) adsorption experiments. Data obtained by neutron activation analysis revealed that ion exchange is also a mechanism of metal removal by the selected wooden sawdust.

Large-scale disasters at nuclear power plants (NPPs) and their consequences are still the subject of discussion by the world scientific community, which makes mankind recognize the unsolved problem of radiation pollution. Accordingly, the search for new effective biocomposite materials with high sorption capacity to eliminate harmful effects associated with radiation contamination of large territories is an urgent task on a global scale. This paper is devoted to the study of the decontamination processes of the areas contaminated with radionuclides, the search for new mechanisms of fixation of radionuclides and heavy metals in the soil using the matrix material of different origin. In order to intensify the process of radionuclide fixation in the soil-plant system the method consisting of introducing into the soil the organic-mineral biocomposite based on sewage sludge and phosphogypsum after anaerobic fermentation was proposed. It is necessary to further study the processes of sorption and radionuclides solubilization due to complexation with organic agents present in matrix materials of different nature. The mechanisms of radionuclide and heavy metal fixation using matrix material of different origin were analyzed and a general model was formed. The direction of integration of radionuclide-contaminated soil decontamination technologies into the process of ecological, social, and economic development of the territories under rehabilitation after the accidents at the Chernobyl NPP and Fukushima-1 NPP is proposed. [ABSTRACT FROM AUTHOR]

Quality is one of the most important risk indicators in river basins. Therefore, monitoring and evaluating water and sediment quality has a very important role in process of risk management. The aim of the monitoring is provide for the sustainability of water bodies and these results are the basis for the risk management in the river catchment area. Hornad, Laborec and Poprad are the rivers in Eastern Slovakia. Hornad and Laborec belongs to basin of Danube and Poprad belongs to basin of Vistula. Sediment sampling was carried out according to ISO 5667-6. Monitoring was carried out in the spring on 2017-2018. The chemical composition of sediments was determined by means of X-ray fluorescence (XRF) using SPECTRO iQ II (Ametek, Germany, 2000). The results of sediment quality evaluated by method PERI revealed that the quality of sediment in 2018 was better than 2017. Results of XRF analysis of sediments were compared with the limited values according to the Slovak Act 188/2003 Coll. of Laws on the application of treated sludge and bottom sediments to fields. It can be state that limit values comparing with Slovak legislation were not exceeding in all sediment samples in rivers in Eastern Slovakia. Based on the monitoring data of sediment quality in the study area, a quantitative analysis of heavy-metal pollution in sediment was conducted using the method of potential ecological risk index (PERI) which is method for evaluate the potential ecological risk of heavy metals. It is based exclusively on chemical parameters of sediments because sediment data show mean integrated values in time, with higher stability than water column parameters; sediments are easily sampled at field work; sediment samples are more representative for time and space scales and analytical data are easily obtained, especially because sediments present high concentrations of contaminants, decreasing the possible errors due to detection limits of the applied analytical method. This method comprehensively considers the synergy, toxic level, concentration of the heavy metals and ecological sensitivity of heavy metals. Potential ecological risk index can be obtained using three basic modules: degree of contamination (CD), toxic-response factor (TR) and potential ecological risk factor (ER). The results show on the basis on potential ecological risk index that the quality of sediment in 2018 is better than 2017. The worst result shows Hornad in 2017. Significant improvement occurred at the sampling point S2 in Hornad in 2018. The best results show Laborec in 2018. The results show on the basis on potential ecological risk index that quality of sediment in 2018 is better than 2017. [ABSTRACT FROM AUTHOR]

This paper reports a study of the removal of heavy metals from water by unconventional waste products including the wooden sawdust of poplar, cherry, spruce and hornbeam. The efficiency of Cu(II), Zn(II), and Fe(II) ion sorption under various initial concentrations from model solutions by raw and alkaline-modified sawdust was investigated. Data obtained by neutron activation analysis revealed that ion exchange is one of the mechanisms underlying metal removal by the selected sawdust from the model solutions. Analysis of the structure and morphology of natural and alkali-modified wooden sawdust by SEM/EDX did not reveal significant changes. The FT-IR spectra showed changes in functional groups due to the alkaline modification of sawdust where the intensity of hydroxyl peaks was considerably increased. It was found that the sorption capacity of the modified sawdust for the model solutions of 50 mg.L-1 of Cu(II) and Zn(II) was approximately 4.5 times higher in comparison to the untreated sawdust; however, the alkaline-modified sawdust had a negative influence on Fe(II) ion removal because of organic-metallic dye formations. The adsorption capacity of the alkaline modified wooden sawdust for the removal of heavy metals from wastewater was improved. [ABSTRACT FROM AUTHOR]

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Sediments are normally the final pathway of both natural and anthropogenic components produced or derived from the environment. Sediment quality is a good indicator of pollution in the water column, where heavy metals and other organic pollutants tend to concentrate. Metals are introduced in aquatic systems as a result of the weathering of soils and rocks, from volcanic eruptions, and from a variety of human activities involving the mining, processing, or use of metals and/or substances that contain metal pollutants. Heavy metal concentration in the water column can be relatively low in some cases, but the concentrations in the sediment may be elevated. The presented work aimed to investigate the pollutant levels of some heavy metals (Fe, Mn, Al, Cu, Zn, As, Cd, Pb) in the water and sediments related to acid mine drainage (AMD) produced from an abandoned sulphide mine in Smolnik in Eastern Slovakia. A metal pollution index was used to compare the total content of metals at five sampling stations. The level of partitioning of the metals between the surface water and sediments in the area was calculated using Partition coefficients and the correlation coefficients between the metal pairs in both media were calculated by a Pearson coefficient. [ABSTRACT FROM AUTHOR]

This research was realized in order to determine and analyze selected heavy metals present in sediment samples from Smolnik creek (Slovakia). The creek is permanently contaminated by acid mine drainage (AMD) from the Pech shaft with average annual flow rates of 6.5 L/s and pH ≈ 4, which acidifies and contaminates surface water and sediment with heavy metals. The pH decreases due to the mixture of AMD with surface water and is followed by metal precipitation and sedimentation in the (aquatic) environment. Potential ecological risk indexes were used to study the pollution status of heavy metals, Cu, Zn, As, and Pb, in sediment and assess their potential ecological risk to the environment. The heavy metals under investigation in the sediment reflected a low ecological risk for both sediment samples (S1 = 68.43; S2 = 53.47). The degree of sediment contamination in the Smolnik creek (Slovakia), for Fe, Mn, Al, Cu, Zn, As, and Pb, has been evaluated using an Enrichment factor, Pollution load index, Geo-accumulation index, single-factor index analysis, Neremo index comprehensive evaluation method, and metal pollution index to compare the total content of metals at the different sampling stations. The high PLI values 1.61 (S1) and 1.54 (S2) indicate strong signs of pollution deterioration. The results from Neremo index comprehensive evaluation method indicate that the S1 location is heavily polluted (3.12) and S2 is moderately polluted (2.95). These results confirmed the fact that the quality of sediment improves with the distance from source of contamination. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Organic waste materials and semi-products containing cellulose are used as low-cost adsorbents that are able to compete with conventional sorbents. In addition, their capacity to bind heavy metal ions can be intensified by chemical treatments using mineral and organic acids, bases, oxidizing agents, and organic compounds. In this paper, we studied the biosorption capacity of natural and modified wooden sawdust of poplar, cherry, spruce, and hornbeam in order to remove heavy metals from acidic model solutions. The Fourier transform infrared spectroscopy (FTIR) spectra showed changes of the functional groups due to the alkaline modification of sawdust, which manifested in the considerably increased intensity of the hydroxyl peaks. The adsorption isotherm models clearly indicated that the adsorptive behavior of metal ions in treated sawdust satisfied not only the Langmuir model, but also the Freundlich model. The adsorption data obtained for studied sorbents were better fitted by the Langmuir isotherm model for both metals, except for spruce sawdust. Surface complexation and ion exchange are the major mechanisms involved in metal ion removal. We investigated the efficiency of the alkaline modified sawdust for metal removal under various initial concentrations of Cu(II) and Zn(II) from model solutions. The highest adsorption efficiency values (copper 94.3% at pH 6.8 and zinc 98.2% at pH 7.3) were obtained for poplar modified by KOH. For all types of sawdust, we found that the sorption efficiency of modified sorbents was higher in comparison to untreated sawdust. The value of the pH initially increased more in the case of modified sawdust (8.2 for zinc removal with spruce NaOH) and then slowly decreased (7.0 for Zn(II) with spruce NaOH). [ABSTRACT FROM AUTHOR]