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Pawlik-Skowronska B.,Joseph W. Jones Ecological Research Center | Pawlik-Skowronska B.,Lublin University of Life Sciences | Kornijow R.,Lublin University of Life Sciences | Kornijow R.,Polish National Marine Fisheries Research Institute | And 2 more authors.
Polish Journal of Ecology | Year: 2010

Recent history of numerous lakes is, among others, a consequence of anthropogenic activity that led to water eutrophication and excessive phytoplankton development. In nutrient- rich lakes both biomass of cyanobacteria and cyanotoxins, that may have a substantial impact on aquatic biocenoses, are present not only in water column but also in the bottom sediments. This study demonstrates vertical distribution of microcystins (MC) traces in sediments of two eutrophic lakes. one phytoplankton/macrophyte-dominated and the other phytoplankton-dominated. The sediments (1-40/50 cm depth) were sampled from central part of lakes and content of MC traces was determined by means of GC-MS in 1cm core slices. In the sediment profile (1-40 cm depth) of the phytoplankton/ macrophyte-dominated lake the MC contents ranged from 0.011 in deep layer (35 cm) to 0.910 μg equival. MC-LR g-1 d.w. in the surface layer (1 cm) and indicated gradual increase in eutrophication. connected with mass development of cyanobacteria over time. In phytoplanktondominated lake, MC contents (0.0-0.335 μg equival. MC-LR g-1 d.w.) oscillated through the core (1- 50 cm depth) and were relatively similar in older, deeper (20-50 cm) and younger (1-20 cm) layers what suggests long-lasting but variable intensity of cyanobacteria mass development. The obtained results indicate that traces of microcystins persist and are detectable for several dozens years not only in surface but also in deep sediment layers of lakes affected by former cyanobacterial blooms. They seem to be a reliable tool to follow eutrophication and its consequence. excessive development of cyanobacteria in the past time. Source

Bratek W.,Wroclaw University of Technology | Swiatkowski A.,Military University of Technology | Pakula M.,Naval University of Gdynia | Biniak S.,Nicolaus Copernicus University | And 2 more authors.
Journal of Analytical and Applied Pyrolysis | Year: 2013

Poly(ethylene)terephthalate (PET) waste was subjected to carbonization in a nitrogen stream at 1098 K. The coke was then activated in a carbon dioxide stream under various conditions: temperatures of 1173, 1198 and 1213 K as well as process times of 4, 5, 6 and 8 h. The activated carbons were characterized using various methods: the structure from Raman and XRD measurements, the porosity from low temperature nitrogen adsorption, the surface properties from cyclic voltammetry and the hydrogen storage capacity from the low temperature adsorption isotherm of H2. The results demonstrated the importance of the temperature and the duration of the process. Higher temperatures result in the etching of graphitic domains of better crystallinity. A relatively small increase in activation time at the highest temperature used yielded a significant increase in the degree of burn-off and porous structure development. The microporosity of these carbons is similar to that of commercial activated carbons. They also have a similar capacity to adsorb water pollutants (e.g. 4-chlorophenol). The PET carbon sample with maximum burn-off exhibited higher values of the microporous structure parameters and the electric double layer capacity in electrolyte solution than the other three samples. The same sample exhibits a sufficient hydrogen storage capacity, which after optimization of the activation conditions should yield an effective storage material. This confirms the possibility of producing activated carbon from waste PET with satisfactory properties by the simple processes of carbonization and activation. The activated carbons obtained have potential use as water pollutant adsorbents, low-cost materials for hydrogen storage and electrode materials in supercapacitors or fuel cells. © 2012 Elsevier B.V. Source

Dziura A.,Military University of Technology | Marszewski M.,Kent State University | Choma J.,Military University of Technology | De Souza L.K.C.,Kent State University | And 3 more authors.
Industrial and Engineering Chemistry Research | Year: 2014

A series of microporous carbons was obtained through carbonization of Saran polymer (poly(vinylidene chloride-co-vinyl chloride)) at various temperatures. The resulting carbons were also activated with KOH to obtain highly microporous carbons. The activated carbons possessed well-developed porous structures: specific surface area in the range 1460-2200 m2/g, micropore volume in the range of 0.65-0.96 cm3/g, and ultramicropore volume in the range of 0.18-0.25 cm3/g. The well-developed porous structure of these carbons resulted in high CO2 and benzene uptakes: CO2 uptake of 6.7 mmol/g at 0 °C and 3.9 mmol/g at 25 °C (both at ca. 800 mmHg) and benzene uptake of 11.6 mmol/g at 20 °C (at a pressure close to the saturation vapor pressure). This study shows that simple but controlled carbonization and activation of commercially available polymers such as Saran can afford high surface area carbon sorbents for CO2 and benzene adsorption and for related environment remediation applications. © 2014 American Chemical Society. Source

Choma J.,Military University of Technology | Marszewski M.,Kent State University | Osuchowski L.,Military Institute of Chemistry and Radiometry | Jagiello J.,Micromeritics Instrument Co. | And 2 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2015

Two sets of activated carbons have been prepared from waste CDs and DVDs by carbonization and subsequent activation with either KOH or CO2. The resulting activated carbons had specific surface area in the range of 500-2240 m2 g-1, total pore volume in the range of 0.18-1.36 cm3 g-1, volume of micropores and small mesopores (w < ∼2.9 nm) in the range of 0.17-1.25 cm3 g-1, and volume of small micropores (w < ∼1.2 nm) in the range of 0.14-0.71 cm3 g-1. Both KOH and CO2 activation resulted in 5-45-fold improvement in the structural properties, depending on the conditions used. The resulting carbons showed good adsorption properties toward carbon dioxide, hydrogen, and benzene. The best uptakes for these adsorptives were 5.8 mmol g-1 of CO2 at 0 °C and 800 mmHg, 3.3 mmol g-1 of CO2 at 25 °C and 850 mmHg, 13.9 mmol g-1 of H2 at -196 °C and 850 mmHg, and 15.4 mmol g-1 of C6H6 at 20 °C and saturation pressure. The excellent adsorption properties of the prepared carbons render them as potential adsorbents in CO2 capture and storage, VOCs adsorption/separation, and hydrogen storage. © 2015 American Chemical Society. Source

Sobczak M.,Medical University of Warsaw | Kamysz W.,Medical University of Gdansk | Kamysz W.,Research and Development Laboratory | Tyszkiewicz W.,Military Institute of Chemistry and Radiometry | And 8 more authors.
Reactive and Functional Polymers | Year: 2014

The effective synthesis of citropin-polymer conjugates was described in this paper. The obtained biodegradable polymeric matrices and polymeric conjugates were characterized using 1H or 13C NMR and Fourier transform infrared spectroscopies, gel permeation chromatography and scanning electron microscopy. Toxicity of polymers was evaluated with bacterial luminescence test and two protozoan assays. The in vitro release study of citropin from the obtained conjugates was investigated. The preliminary results of antimicrobial activity of the obtained macromolecular conjugates against Bacillus anthracis, Enterococcus hirae and Staphylococcus aureus were also discussed. The peptide had a high level of antimicrobial activity during 3-5 weeks of the degradation process. The development of biodegradable citropin systems should be of a great interest in the delivery systems of antimicrobial agents. © 2014 Published by Elsevier B.V. Source

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