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EN
The objective of this work was the application of innovative method for metals recovery from metalliferous mine water released from the flooded siderite ore deposit Nižná Slaná. Although the metals contained in mine drainage are considered environmental pollutants, they may also be recognised as valuable resources. Several techniques can be used to obtain them by precipitation. Conventional processes using alkaline reagents produce huge amounts of mixed sludge with appropriate storage and management requirement, void of possibility of individual metals subsequent processing. This study examined the feasibility of Fe and Mn selective retrieval from real mine water. After oxidation and partial precipitation of iron using hydrogen peroxide, precipitation by sodium hydroxide was applied to the residue iron removal from mine water. In the next step potassium permanganate was used to eliminate manganese by oxidative precipitation. ORP and pH values of processed mine water was recorded in the course of oxidation/precipitation processes. The morphology and elemental composition of obtained products were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The recovery efficiencies of Fe and Mn from mine water reached 99.87 % and 99.25%, respectively. Target metals were removed with high selectivity to levels that comply with environmental requirements.
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EN
High concentration of sulphates and metals in waters is often as a consequence of anthropogenic activity and industry. The principles of the biological-chemical methods for pollution removal include various processes. The most widely metabolic pathway of sulphate-reducing bacteria - overall dissimilatory reduction - is the complete reduction of sulphate to hydrogen sulphide. Two major metabolic groups are known, depending on whether or not they can oxidize acetate. One group utilizes lactate, fumarate, propionate, butyrate, pyruvate, and aromatic compounds, which they typically oxidize to acetate, while the other group oxidizes acetate to CO₂ and H₂O. Sulphate is reduced to H₂S through a series of intermediate reactions. The end product of this reaction, hydrogen sulphide, can react with metal ions to form insoluble metal sulphides or reduce soluble toxic metals, often to less toxic or less soluble forms. This way, sulphate-reducing bacteria are utilizable in bio-elimination of sulphate and metal from water.
PL
Wysokie stężenie siarczanów i metali w wodach jest często konsekwencją działalności antropogenicznej i przemysłu. Zasady biologiczno-chemicznych metod usuwania zanieczyszczeń obejmują różne procesy. Najszerzej szlakiem metabolicznym bakterii redukujących siarczany – ogólna redukcja dyssymilacyjna – jest całkowita redukcja siarczanu do siarkowodoru. Znane są dwie główne grupy metaboliczne, w zależności od tego, czy mogą utleniać octan. Jedna grupa wykorzystuje mleczan, fumaran, propionian, maślan, pirogronian i związki aromatyczne, które zwykle utleniają do octanu, podczas gdy druga grupa utlenia octan do CO2 i H2O.Siarczan jest redukowany do H2S poprzez szereg reakcji pośrednich. Produkt końcowy tej reakcji - siarkowodór - może reagować z jonami metali, tworząc nierozpuszczalne siarczki metali lub redukować rozpuszczalne metale toksyczne, często do postaci mniej toksycznych lub mniej rozpuszczalnych. W ten sposób bakterie redukujące siarczany są wykorzystywane do bio-eliminacji siarczanu i metalu z wody.
EN
Steel production processes generate the coke wastewaters contaminated predominantly by highly toxic phenol. Numbers of physical, chemical and physicochemical methods have been developed for the removal of phenol from coke wastewaters. Biological methods are eco-friendly and present appropriate alternative of conventional processes. Various microorganisms are able to degrade phenolic compounds including sulphate-reducing bacteria (SRB). In this work, we study the adaptation of SRB isolated from natural source to phenol and consequently the application of the adapted bacterial cultures for the biodegradation of phenol from model solutions. Two types of bacterial culture were used (monoculture containing SRB genera Desulfovibrio and mixed bacterial consortium containing SRB genera Desulfovibrio). In experiments the modified Postgate’s medium C was used - sodium lactate as the original energy and carbon source was replaced by phenol with concentration 10 mg/dm3 for adaptation and 50 mg/dm3 for biodegradation. The mixed bacterial consortium has been shown as more capable to be adapted and grow on phenol and it has the better potential for phenol biodegradation as the bacterial monoculture of SRB genera Desulfovibrio.
EN
The water contamination by toxic metal ions is a worldwide environmental problem. High concentrations are hazardous for all living organisms, causing many disorders and diseases and ecological damages to the surroundings. Biosorption is an innovative technology that employs inactive and dead biomass (bacteria, fungi, algae, biowaste) for the recovery of metals from aqueous solutions. Sulphate-reducing bacteria utilization is one of the options how to prepare applicable sorbent which removes metal ions from water. This material is created as a consequence of bacteria metabolism in anaerobic environment. The use of freely suspended biomass is often impractical and has some disadvantages. In contrast to this, application of immobilized biomass shows more benefits including increased mechanical strength, resistance to chemical environment, easy separation of cells and effluents, high biomass performance and repeated use in many adsorption/desorption cycles. Cell entrapment is the most widely used method for immobilization. In this technique, the cells are enclosed in a polymeric matrix which is porous enough to allow diffusion of substrate to the cells. The aim of this work was to examine and compare the sorption ability of biogenic iron sulphides created by sulphate-reducing bacteria in “free” and “entrapped” form. Precipitates were synthesized in reagent bottles with bacteria culture and growth media Postgate C, at 30 °C during 60 days, subsequently dried and analysed. Prepared samples were immobilized using sodium alginate. Sorption of cadmium from model solutions was realized in 100 ml Erlenmeyer flasks, with sorbent dose 1 g/l, during 24 hours. During experiments, the samples showed a satisfying stability and maximum adsorption capacity achieved 38 mg/g. The results refer to good sorption properties of immobilized samples and their potential for further practical use.
5
Content available Influence of Biogenic Acid on Concrete Materials
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EN
Microbial sulphur cycle in sewers evocate the serious problem in the area concrete corrosion, health related aspects and odour. These problems are primarily related to the release of bacterially produced hydrogen sulphide from wastewater to the atmosphere during sewage transports that dissolves in the condensate on the sewer crown. In the event sulphur-oxidizing bacteria oxidize the dissolved hydrogen sulphide and other sulphur compounds to sulphuric acid, which corrodes the concrete. The concrete gradually expands causing cracks and ruptures, loss of strength and overall decay of concrete. The paper is focused on the investigation of the concrete specimens surface biodegradation study. From the viewpoint of concrete materials biodeterioration, mainly the bacteria sulphur- and sulphide-oxidising bacteria and sulphate-reducing bacteria are important and interesting. The role of bacteria mentioned above has been linked to the generation of the biogenic sulphuric acid resulting in corrosion process by dissolution of calcium containing minerals from the concrete matrices. The penetration of the corrosion was manifested by structural changes of concrete samples. The surface structure changes were by stereomicroscopy and atomic force microscopy (AFM) investigated.
PL
Cykl mikrobiologiczny siarki w wywołuje poważne problemy związane z korozją betonu a także dotyczące aspektów zdrowotnych i zapachu. Problemy te związane są przede wszystkim z uwalnianiem wytwarzanego przez bakterie siarkowodoru ze ścieków do atmosfery podczas transportu ścieków, który rozpuszcza się w kondensacie w instalacji kanalizacyjnej. W takim przypadku bakterie utleniające siarkę utleniają rozpuszczony siarkowodór i inne związki siarki do kwasu siarkowego, który powoduje korozję betonu. Beton stopniowo rozszerza się, powodując pęknięcia , utratę wytrzymałości i ogólny rozkład betonu. Praca koncentruje się na badaniu badania biodegradacji powierzchni próbek betonu. Z punktu widzenia biodeterioracji właściwych materiałów, ważne są bakterie, głównie bakterie utleniające siarkę i siarczki oraz bakterie redukujące siarczany. Rola bakterii wspomnianych powyżej została powiązana z wytwarzaniem biogennego kwasu siarkowego, powodując proces korozji poprzez rozpuszczanie minerałów zawierających wapń z betonowych matryc. Penetracja korozji objawiła się zmianami strukturalnymi próbek betonu. Zmiany struktury powierzchni były badane za pomocą stereomikroskopii i mikroskopii sił atomowych (AFM).
EN
The aim of this work was to investigate of the sulfates removal from acid mine drainage (AMD) by biological method using sulfate-reducing bacteria (SRB). A sample of AMD out-flowing from the Pech shaft of the abandoned and flooded Smolník deposit in Slovak Republic was studied. The untreated AMD (with contents metals) and treated AMD i.e. after of the metals removing by the synthetic sorbent Slovakite were used. The base of the biological sulfates elimination was the sulfates bacterial reduction under influence of SRB genera Desulfovibrio. These bacteria realize the sulfates reduction to hydrogen sulfide at the simultaneously oxidation of energetic substrate. Standard selective nutrient medium DSM-63 and modified selective nutrient medium DSM-63 (without sulfates contents) with standard amount of sodium lactate (as energetic substrate) were used in the experiments with untreated AMD. Standard selective nutrient medium DSM-63 and modified selective nutrient medium DSM-63 with standard, double and triple amount of sodium lactate were used in the experiments with treated AMD. In the case of untreated AMD has been reached low removing of sulfates - 20% efficiency (standard medium) and 26% (modified medium). The formation of heterogeneous precipitates containing metals pointed to the need for treatment of AMD by the initial removal of metals by sorption on Slovakite sorbent and subsequent removal of sulfates by bacterial reduction. The results of experiments with AMD treated in this way showed 49%, 70% and 88% efficiency of sulfate removal when using sodium lactate in standard, double and triple amounts. The results of this work suggest that ratio of substrate quantity and sulfate concentration is one of the key parameter of sulfate reducing condition. However, the price of the energy substrate is also an important factor. Therefore, subsequent experiments will be focused on the use of the more affordable substrates (e.g. whey) or mixed bacterial culture of SRB, which will also be able to use the products of decomposition of basic energetic substrates.
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