Search Results

You are looking at 1 - 10 of 19 items for

  • Author: Małgorzata Rajfur x
Clear All Modify Search
Open access

Małgorzata Rajfur

Abstract

The influence of the preparation method of samples on the zinc ions sorption parameters in Spirogyra sp. algae was analysed. The Zn2+ sorption process from the salt solutions of this analyte was carried out in static conditions. The carried out analyses results show that the method of algae samples preparation for analyses (thermal drying, freeze drying, samples conditioning in demineralised water) and storage period influence their sorption capacity. On the basis of the carried out research of the metal sorption kinetics in live and prepared algae samples, it was found that the equilibrium is achieved after approximately 30 min. In the experiment conditions, 56% of metals are sorbed in live algae during the first 15 min. Approximately 17 and 65% of zinc ions present in the dilution accumulated in thermally dried and freeze dried algae samples respectively after 30 min of the process. It was confirmed that conditioning of the algae samples in demineralised water, prior to the sorption process, increases its efficiency. In order to define sorption capacity of freeze dried Spirogyra sp. algae, the Langmuir isotherm model was applied. It was found out that algae absorb heavy metals in proportion to their content in a solution, in which they were immersed. The sorption capacity of freeze dried Spirogyra sp. algae and zinc, defined with the use of the Langmuir isotherm, shows considerable imprecise result. Evident influence of hydrogen cations on zinc concentrations in algae and in the solution in the state of equilibrium was found out.

Open access

Małgorzata Rajfur

Abstract

The publication is a synthetic collection of information on the sorption properties of marine and freshwater algae. Kinetics and sorption equilibrium of heavy metals in algae-solution system, influence of abiotic factors on the process of sorption and desorption of analytes from biomass are discussed. In paper the results of laboratory tests conducted using different species and types of algae, which purpose was to assess their usefulness as natural sorbents, are described. The conclusions drawn from current research confirm the results from literature.

Open access

Tadeusz Rodziewicz, Małgorzata Rajfur and Maria Wacławek

Abstract

The article presents theoretical foundations of a two-diode equivalent model of a photovoltaic cell/module (PV), together with calculation procedures. A physical interpretation of individual components of an equivalent model was presented. Its practical application in predicting efficiency of operation of various PV cells and modules in low insulation conditions was demonstrated. The obtained predictions were verified with the actual results of their operation in open space (outdoor). The practical suitability of the “model” in early detection of ageing phenomena, such as, for example, absorber degradation taking place in PV modules, was demonstrated. The article was prepared on the basis of the results of testing five different PV modules with various constructions, made of different materials and absorbers, such as: c-Si, mc-Si, CIS, a-Si_SJ, a-Si_TJ. The used measurement data were collected during the 16-year period of the experimental PV modules testing system operation in University of Opole, equipped with a data acquisition system.

Open access

Małgorzata Rajfur and Andrzej Kłos

Abstract

Biomonitoring studies have been carried out in three retention reservoirs located in the Opole Province (southern Poland): Turawa reservoir, Nysa reservoir and Otmuchow reservoir. The increases of concentrations of Mn, Fe, Cu, Zn, Cd and Pb in fresh water algae Spirogyra sp. and sea water Palmaria palmata (Linnaeus) Weber & Mohr, exposed in the analysed waters, were determined by the atomic absorption spectrometry method (AAS). Also the waters pH, conductivity and Mn and Fe concentrations were determined. The concentrations of Cu, Zn, Cd and Pb in the analysed waters were lower than the method limit of determination. The analyses were carried out during the period from June to July 2014. The differences between the increases of heavy metal concentrations in the samples of algae found along the coastline were indicated; they result from different distances from the pollution sources, such as sediments or drainage from the areas adjacent to the reservoirs. Better sorption characteristics of Palmaria palmata in comparison to Spirogyra sp. were indicated. An empirical interrelation was also tested, the application of which after modification may enable the quantitative assessment of waters pollution with heavy metals, based on the analysis of the concentration of the element in the algae thallus.

Open access

Małgorzata Rajfur, Andrzej Kłos and Jan Kříž

Abstract

Kinetics of the sorption of copper cations in Spirogyra sp. algae was analysed, together with the accompanying processes of hydrogen cations sorption and releasing to the solution the cations bonded in the algae: Na+, Mg2+, K+ and Ca2+. It was established that, in a static system, at the fixed proportion of algae mass to the solution volume, these processes occur simultaneously, however presumably the quantity of the released salts influences the parameters of heterophase equilibrium of ion exchange. In the experiment conditions, the quantity of the released cations was nearly 10 times larger than the quantity of the sorbed cations. The equilibrium parameters, determined from the model of pseudo second order reaction, were compared with the parameters obtained after 30 min of the process duration, ie at relatively stable indications of measuring equipment. On the example of the sorbed copper, the difference is approximately 8%. It was confirmed that the solution conductivity is a good parameter for the estimation of the state close to equilibrium.

Open access

Małgorzata Rajfur, Małgorzata Anna Jóźwiak and Andrzej Kłos

Abstract

Due to their occurrence in very different conditions and high resistance to physical and chemical factors, algae are pioneers colonising new environments and their sorption properties are used in biomonitoring and water remediation. The efficiency of the process of heavy metal sorption in algae used for in situ tests depends on abiotic factors, such as the chemical composition of water. Freshwater algae Spirogyra sp. were used in tests. Algae were exposed in the laboratory in manganese chloride solutions with various contents of other cations, including heavy metals and macronutrients. It has been shown that some heavy metals may desorb manganese bound to the surface of algae as a result of ion exchange in the following sequence: Cd2+ < Mn2+ ≈ Zn2+ < Cu2+. It has been also found that the competitiveness of sorption of cations naturally present in the alga environment versus Mn2+ cations changes in the sequence Na+ < Ca2+ < H+, defined for the concentrations referring to the cation unit charge. The results of tests were compared to the results of dried sea algae Palmaria palmata analyses.

Open access

Agnieszka Rombel-Bryzek, Małgorzata Rajfur, Olga Żuk and Patryk Zając

Abstract

As a heavy metal, cadmium has strongly toxic effects on plants and can induce oxidative stress. It is absorbed by the roots and transported to the stems and leaves. The aim of the study was to evaluate the effect of various concentrations of cadmium on the metabolic activity of Beta vulgaris and assess the dependence of these processes on the content of metal in the plants. To demonstrate the effect of cadmium on metabolism, protein and photosynthetic pigment content, lipid peroxidation, and the activity of enzymes specific for oxidative stress in roots and shoots were measured. Seeds of B. vulgaris were treated with different concentrations of Cd supplied via a CdCl2 solution: 0 (control), 200, 300 and 400 mg/dm3. Results of the present study revealed increased GPOX activity as cadmium concentration rose, while SOD activity was stimulated by a low Cd concentration (200 mg/dm3) and reduced by high levels of Cd. Based on the present findings, it can be concluded that GPOX in B. vulgaris played a more important role in ROS scavenging than SOD did and was able to reduce the level of lipid peroxidation in plants. Cadmium, in the concentration range used, did not show any significant effect on protein or photosynthetic pigment content.

Open access

Paweł Świsłowski and Małgorzata Rajfur

Abstract

The aim of the research was to assess the level of contamination with heavy metals (manganese, iron, nickel, copper, zinc, cadmium and lead) in two forest areas selected in different places in Poland: the first one in the Swietokrzyskie Province (forests of the Staporkow Forest Division) and the second one in the Opolskie Province (forests of the Kup Forest Division). The degree of contamination of these forest areas with analytes was found using edible large-fruited mushrooms naturally occurring there - the research was carried out using passive biomonitoring method. Heavy metals in mushrooms (separately in stems and hats) as well as in soil samples were determined by atomic absorption spectrometry with excitation in flame (F-AAS). The obtained results were interpreted by assessing the degree of contamination of forest areas on the basis of concentrations of heavy metals in mushrooms. The obtained results indicate an increased accumulation of heavy metals in hats than in mushrooms stems. On the basis of the obtained data, significant contamination of forest areas with selected heavy metals was also found. This is confirmed by the possibility of using mushrooms as biomonitors in passive biomonitoring of forest areas, which are heavy metal accumulators. In the interpretation of the test results, the phytocumuling factor (PF) was also used. The degree of accumulation of heavy metals, from given forest areas - from soil to mushrooms - was assessed on the basis of determined PF coefficients. In addition, good bioavailability of the analysed analytes by mushrooms was found. Additionally, on the basis of the conducted studies, the possibility of mushroom consumption was assessed - they are not suitable for consumption due to the fact that the permissible concentration standards of heavy metals contained in mushrooms were exceeded.

Open access

Harold Walter Kroto, Maria Zielińska, Małgorzata Rajfur and Maria Wacławek

Abstract

A necessary (though probably not sufficient) condition for creativity in the sciences and the arts to flourish is a liberal/democratic socio-political environment. In Europe this was manifested in the Enlightenment as Galileo, Copernicus and others laid the foundations for the evidence-based natural philosophy which signaled the birth of “The Enlightenment”. The importance of intellectual and personal freedom for humanitarian advance is clearly manifested in the exponential success of the sciences in conquering many humanitarian problems from starvation and disease to the more obvious technologies that make modern life relatively pleasant for many - especially in the developed world. On the down side however has been the reckless thirst of a plethora of governments to exploit the vast powers of the sciences to construct ever more powerful destructive weapons. Since then, the great thinkers from Kant to Russell, scientists from Einstein to Feynman and writers from Whitman to Shaw have repeatedly pointed to the importance of the doubt-based philosophy that is the crucial antidote to the stultifying effect of dogmas of all kinds. Indeed it is only doubt that leaves the road open for all advances in human endeavour. In the 21st Century we have reached a watershed in that the human race now confronts a set of crises significantly more serious than any previously. These threats can only be overcome by an open minded liberal education of the next generation of young people. Before the name “Science” was coined it had another name, “Natural Philosophy” which more adequately describes its primary place in the spectrum of human culture. More important than any other aspect is the fact that Natural Philosophy is the only philosophical construct we have devised to determine Truth with any degree of reliability. As such it should be a primary ethical focus for the education of every child, student and citizen so at the very least they can decide whether what they are being told is actually true. This is also a strong intellectual basis for fostering creativity. For a truly humanitarian global society to evolve, equality of opportunity and personal freedom will be a necessary for all young people whatever their race, colour, nationality and most importantly sex. All technologies have the capacity to benefit society or to be detrimental and so as powerful new technical advances arise there is an onus on everyone to understand some important SET factors. As our modern world is so completely - and precariously - balanced on SET, an understanding of these disciplines by all in positions of responsibility is vital. Although wise decision-making may not be guaranteed by knowledge, common sense suggests that wisdom is an unlikely consequence of ignorance. Education is certainly a key factor and the Internet must be harnessed to improve matters. With the Vega Science Trust (www.vega.org.uk) an exciting new Global Educational Outreach for Science Engineering and Technology initiative GeoSet (www.geoset.info) and (www.geoset.fsu.edu) we are now working with other Universities to make outstanding educational material available on the Internet in any part of the world.

Open access

Paweł Krems, Małgorzata Rajfur, Maria Wacławek and Andrzej Kłos

Abstract

The publication is a synthetic review of many years of research on the possibility of using water plants (macrophytes) to assess pollution of surface waters and the possibility of using the biomass in phytoremediation processes. The results of the research of kinetics and equilibria of heavy metals sorption and desorption conditions were presented in order to repeatedly use the biomass, as well as the research on the influence of abiotic factors on sorption processes. Defence mechanisms of macrophytes, which enable them to vegetate in considerably polluted waters, have been discussed. The results presented herein and carried out in many countries demonstrate that macrophytes can be successfully used in the biomonitoring of water environments and phytoremediation of waters and sewage; however, validation of these procedures requires more detailed research of the mechanisms, which accompany them.