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Effect Of Environmental Load On The Toxicity Of Bottom Sediments

Abstract

This study is devoted to Ecotoxicity tests, Terrestrial Plant Test (modification of OECD 208), Phytotoxkit microbiotest on Sinapis alba and chronic tests of Earthworm (Eisenia veneta), modification of OECD Guidelines for the testing of chemicals 317, Bioaccumulation in Terrestrial Oligochaetes on polluted sediments. Earthworms can accelerate the removal of contaminants from soil. The study materials are river sediments, which were obtained from a monitoring station - the Water reservoir the Ružín No.1 particularly, the river Hornád, Hnilec and sample from sludge bed Rudňany. The samples of sediment were used to assess of the potential phytotoxic effect of heavy metals on higher plants. Total mortality was established in earthworms using chronic toxicity test after 7 and 28 exposure days. Based on the phytotoxicity testing, phytotoxic effects of the metals contaminated sediments from the sludge bed Rudňany on S. alba seeds was observed. The largest concentration differences were recorded in the sample R7 after 7 days earthworms exposure. The earthworms mortality was not influenced by sediment neither after 7 nor 28 exposure days The spectra of samples H, HO and R showed broad peak at 1 419 - 1 512 cm−1 characteristic for carbonate radical. In the spectra of the samples (R and R7) the vibration of C-H groups at 2 926 and 2 921 cm−1, respectively were also observed, demonstrating the presence of organic matter. Our research will continue with determination of metals concentration in earthworms.

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Effect Of Wood-Based Biochar And Sewage Sludge Amendments For Soil Phosphorus Availability

Abstract

This study investigated the effects of two biochars (pyrolysed wood chips and garden clippings) on phosphorus (P) availability in a heavy-metal contaminated soil poor in phosphorus. Short-term 14-days incubation experiments were conducted to study how applications of biochars at different rates (1 and 5 %) in combination with (1:1) and without dried sewage sludge from a municipal waste water treatment plant (WWTP) affected the content of soil extractable P. For P-availability analyses deionized water, calcium acetate lactate (CAL), Mehlich 3 and Olsen extraction protocols were applied. In addition, the content of total and mobile forms of potentially toxic heavy metals (PTHM) was studied. Application of both biochars caused a significant decrease of PTHM available forms in sewage sludge amended soil samples. The concentration of total and available P increased with higher biochar and sewage sludge application rates.

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Hydrodynamic Study Of Column Bioleaching Processes

Abstract

The modelling of flow leaching solution through the porous media has been considered. The heap bioleaching process can be tested using the column experimental equipment. This equipment was employed to the hydrodynamic studies of copper ore bioleaching. The copper ore (black shale ore) with the support, inertial materials (glass small balls and polyethylene beads) was used to the bioleaching tests. The packed beds were various composition, the ore/support ratio was changed. The correlation between the bed porosity and bioleaching kinetics, and copper recovery was investigated.

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Influence Of Fine-Grained Montmorillonite On Microfungal Pellets Growth In Aqueous Suspensions

Abstract

The paper presents an inhibition effect of clay mineral – montmorillonite – on the growth of microscopic filamentous fungus Aspergillus niger in the aqueous solution. The significant reduction in growth of the final size of spherical fungal pellets as well as total amount of produced microbial biomass was found out. Within the observed range of additions of clay mineral of 1, 5, 10, 15 and 20 g in the total volume of the 80 ml suspension, this size was in indirect relation to the weight of montmorillonite. However, the most significant inhibition effect was observed at the lowest concentration of the sorbent (1 g). Microscopic analysis of pellets referred to the presence of mineral particles in their pore structure and the distribution of particles in the spatial structure of fungal hyphae was variable. The experiment clearly demonstrated an inhibition effect of montmorillonite. This inhibition could be answered by the experiments focused on the detection of the influence of size and shape of inorganic sorption particles together with the influence of the physicochemical properties of its surface. It could be stated that the simultaneous application of the microscopic fungus Aspergillus niger and the clay mineral montmorillonite for decontamination of waste waters should be disadvantage due to their interaction if compared with the decontamination based on bioaccumulation and sorption separately.

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Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

Abstract

Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al) from printed circuit boards (PCBs). In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

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Magnetostructural Relationships For Fe(III) Spin Crossover Complexes

Abstract

Structural data for fifteen complexes of Fe(III) of a general formula [FeL5X], with pentadentate Schiff-base ligands L5 and unidentate coligands X, were subjected to a statistical analysis. The multivariate methods such as Pearson correlation, cluster analysis and principal component analysis split the data into two clusters depending upon the low-spin and/or high-spin state of the complex at the temperature of the X-ray experiment. Some of these complexes exhibit a thermally induced spin crossover. The numerical analysis of the magnetic susceptibility and magnetization data for an enlarged set of Fe(III) spin crossover systems yields the enthalpy ΔH and entropy ΔS of the transition along with the transition temperature T 1/2 and the solid state cooperativeness. The thermodynamic data show a mutual relationship manifesting itself by linear ΔS vs ΔH and T 1/2 vs ΔH correlations.

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The Metal And Sulphate Removal From Mine Drainage Waters By Biological-Chemical Ways

Abstract

Mine drainage waters are often characterized by high concentrations of sulphates and metals as a consequence of the mining industry of sulphide minerals. The aims of this work are to prove some biological-chemical processes utilization for the mine drainage water treatment. The studied principles of contamination elimination from these waters include sulphate reduction and metal bioprecipitation by the application of sulphate-reducing bacteria (SRB). Other studied process was metal sorption by prepared biogenic sorbent. Mine drainage waters from Slovak localities Banská Štiavnica and Smolník were used to the pollution removal examination. In Banská Štiavnica water, sulphates decreased below the legislative limit. The elimination of zinc by sorption experiments achieved 84 % and 65 %, respectively.

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Non-Ferrous Metal Industry Waste Disposal Sites As A Source Of Poly-Extremotolerant Bacteria

Abstract

Waste disposal sites from non-ferrous metal industry constitute environments very hostile for life due to the presence of very specialized abiotic factors (pH, salt concentration, heavy metals content). In our experiments microflora of two waste disposal sites in Slovakia – brown mud disposal site from aluminium production near Ziar nad Hronom and nickel sludge disposal site near Sered - was analyzed for cultivable bacteria. Isolated bacteria were characterized by a combination of classical microbiological approaches and molecular methods and the most of isolated bacteria shown a poly-extremotolerant phenotype. The most frequently halotolerant (resistant to the high level of salt concentrations) and alkalitolerant (resistant to the high pH level) bacteria belonging to the Actinobacteria class were detected. The most of bacteria shown very high level of heavy metal resistance e.g. more than 500 μg/ml for Zn2+ or Cu2+. Based on our data, waste disposal sites thus on one side represents an important environmental burden but on other side they are a source of new poly-extremotolerant bacterial strains and species possibly used in many biotechnology and bioremediation applications.

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Selective Recovery Of Copper From Solutions After Bioleaching Electronic Waste

Abstract

Research on selective extraction of copper from solution after bioleaching grounded printed circuit boards (PCBs) using LIX 860N-IC were conducted. The effect of LIX 860N-IC concentration, phase ratio and influence of initial pH value of aqueous phase on the extraction of copper and iron was examined. It was found that the extraction rate of copper increases with the LIX 860N-IC concentration. Best results of Cu extraction (98 %) were achieved with extractant concentration of 5 % and pH 1.9. Higher pH value of aqueous phase (pH=2.4) is conducive to the simultaneous effect of Fe co-extraction.

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Separation Of Methionine Enantiomers By Using Teicoplanin And Cyclofructan Columns

Abstract

Methionine is a naturally occurring amino acid. Its enantiomeric separation by using high performance liquid chromatography on various types of chiral stationary phases was studied. The effect of mobile phase composition on enantioselectivity and retention was considered. The separation of the enantiomers was attained in different separation modes – reversed phase mode for the macrocyclic antibiotic chiral stationary phases (teicoplanin, teicoplanin aglycone), normal phase and polar organic phase modes for the isopropyl carbamate cyclofructan 6 chiral stationary phase. It was shown that the hydrogen bonding, dipole interactions, steric effects between methionine molecules and stationary phases play an important role in the separation of enantiomers.

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