Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 9
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Conventional membranes used in the process of premix membrane emulsification are prone to fouling, especially when biopolymers are employed as surfactants. An alternative to conventional membranes are dynamic membranes consisting of an unconsolidated porous medium. Dynamic membranes have the advantage of enabling easy cleaning of the inside of the pores. Experimental research carried out to date has focused on the application of hydrophilic dynamic membranes composed of glass microbeads for producing o/w emulsions. The aims of this study were to determine the efficiency of droplet size reduction in a w/o emulsion when passed through a dynamic hydrophobic membrane consisting of a bed of irregular polymer particles, and to assess the effect of multiple membrane passes on the properties of the w/o emulsion. The dynamic membranes evaluated in the tests were found to reduce the diameters of premix droplets when an appropriate pressure level was reached. Higher bed porosity was associated with greater fluxes achieved across the packed bed, but the resulting emulsions were less homogeneous. Multiple passes of the emulsion through the dynamic polypropylene membrane led to a further reduction in droplet size, but it was accompanied by a decline in emulsion homogeneity.
Go to article

Authors and Affiliations

Adrianna Frankiewicz
1
ORCID: ORCID
Jacek Różański
1
ORCID: ORCID

  1. Poznan University of Technology, Institute of Chemical Technology and Engineering, ul. Berdychowo 4, 60-965 Poznan, Poland
Download PDF Download RIS Download Bibtex

Abstract

Due to the increasing problem resulting from environmental pollution with heavy metals, great emphasis is placed on the development of removal methods of these pollutants from the environment. This study presents a literature review on the methods for the removal of nickel ions from aqueous solutions such as sorption, especially using low-cost sorbents which are very popular in 21���� century, electrochemical processes and membrane techniques. It is often impossible to use a single technique for efficient removal of heavy metals from wastewater as the process depends on many factors, such as wastewater composition, pH, temperature and many others. The aim of this review is to present some selected removal techniques of nickel(II) from wastewater from the point of view of their efficiency and applicability.
Go to article

Authors and Affiliations

Izabela Kruszelnicka
1
ORCID: ORCID
Dobrochna Ginter-Kramarczyk
1
ORCID: ORCID
Wojciech Góra
1
ORCID: ORCID
Katarzyna Staszak
2
ORCID: ORCID
Marek Baraniak
3
Grzegorz Lota
3
ORCID: ORCID
Magdalena Regel-Rosocka
2
ORCID: ORCID

  1. Poznan University of Technology, Faculty of Energy and Environmental Engineering, Institute of Environmental Engineering and Building Installations, Berdychowo 4, 60-965 Poznan
  2. Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, 60-965 Poznan
  3. Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemistry and Technical Electrochemistry, Berdychowo 4, 60-965 Poznan
Download PDF Download RIS Download Bibtex

Abstract

Bacteriophages, viruses that can infect bacteria, are promising alternatives for antibiotic treatment caused by antibiotic-resistant bacteria strains. For that reason, the production of bacteriophages is extensively studied. Mathematical modelling can lead to the improvement of bioprocess by identification of critical process parameters and their impact on the demanded product. Dynamic modelling considers a system (i.e. bioreactor or bioprocess) as a dynamic object focusing on changes in the initial and final parameters (such as biomass concentration and product formation) in time, so-called signals and treats the studied system as a “black box” that processes signals. This work aimed to develop a mathematical model that describes bacteriophage production process. As result, we created a dynamic model that can estimate the number of bacteriophages released from cells as plaque-forming units at specific time points based on the changes in the bacteria host-cell concentration. Moreover, the proposed model allowed us to analyze the impact of the initial virus concentration given by multiplicity of infection (MOI) on the amount of produced bacteriophages.
Go to article

Authors and Affiliations

Maciej Konopacki
1 2
ORCID: ORCID
Bartłomiej Grygorcewicz
1 2
ORCID: ORCID
Marta Gliźniewicz
2
ORCID: ORCID
Dominika Miłek
2
ORCID: ORCID
Marian Kordas
1
ORCID: ORCID
Rafał Rakoczy
1
ORCID: ORCID

  1. West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical and Process Engineering, al. Piastów 42, 71-065 Szczecin, Poland
  2. Pomeranian Medical University in Szczecin, Chair of Microbiology, Immunology and Laboratory Medicine, Department of Laboratory Medicine, al. Powstanców Wielkopolskich 72, 70-111 Szczecin, Poland
Download PDF Download RIS Download Bibtex

Abstract

The main aim of the below presented work was to investigate the possibility of using impedance spectroscopy in the unpasteurized beer microbial contamination degree assessment. Advantages of the impedance spectroscopy method, a negligible number of similar published results as well as their practical aspect make the research important. Four different types of beerswere investigated whichwere unfit for consumption due to improper storage and were heavily microbiologically contaminated. Their impedance was measured in the frequency range from 0.1 Hz to 1 kHz before and after centrifugation. Based on the measured values, an innovative electrical equivalent circuit was proposed and the parameters of the circuit elements were fitted. The obtained results show significant differences (23 up to 35%) in the values of resistance modelling the diffusion phenomenon. Such large changes, resulting from the removal of biomass from the samples, prove the validity of impedance spectroscopy in the study of the properties of unpasteurized beer. According to the authors, it would be possible to use the proposed methodology during the production of beer.With some limitations, it should aid in the early detection of microbial contamination.
Go to article

Authors and Affiliations

Łukasz Macioszek
1
ORCID: ORCID
Sylwia Andrzejczak-Grzadko
2
ORCID: ORCID
Olga Konkol
2
Ryszard Rybski
1
ORCID: ORCID

  1. University of Zielona Góra, Institute of Metrology, Electronics and Computer Science, ul. prof. Z. Szafrana 2, 65-246 Zielona Góra, Poland
  2. University of Zielona Góra, Institute of Biological Sciences, ul. prof. Z. Szafrana 1, 65-516 Zielona Góra, Poland
Download PDF Download RIS Download Bibtex

Abstract

The practical applications of bacteriophages are associated with the problems related to the intensification, optimization of process production of this biomaterial and the search for new methods of production. The production of bacteriophages requires a fine balance between the dynamic growth of the bacteriophage and the host. The electromagnetic field (EMF) is a promising biotechnological method for the process production of bacteriophages. This study evaluates the use of various types of EMF to enhance the process. It was found that the process production of bacteriophages is divided into two stages. In the first stage, the influence of various types of EMF on the proliferation process of bacteria (host) was analyzed. Secondly, the process production of bacteriophage was implemented for the optimal infection conditions under the action of the various types of EMF. Moreover, the study demonstrated that the most effective bacteriophage production was the process with the application of the rotating magnetic field (RMF), pulsed magnetic field (PMF) and the static magnetic field (SMF) with negative polarity.
Go to article

Authors and Affiliations

Rafał Rakoczy
1
ORCID: ORCID
Maciej Konopacki
1 2
ORCID: ORCID
Marian Kordas
1
ORCID: ORCID
Bartłomiej Grygorcewicz
2
ORCID: ORCID

  1. West Pomeranian University of Technology in Szczecin, Faculty of Chemical Technology and Engineering, Department of Chemical and Process Engineering, al. Piastów 42,71-065 Szczecin, Poland
  2. Pomeranian Medical University in Szczecin, Chair of Microbiology, Immunology and Laboratory Medicine, Department of Laboratory Medicine, al. Powstanców Wielkopolskich 72, 70-111 Szczecin, Poland
Download PDF Download RIS Download Bibtex

Abstract

Titanium dioxide with its ability to be a UV light blocker is commonly used as a physical sunscreen in the cosmetic industry. However, the safety issues of TiO 2 application should be considered more in-depth, e.g., UV light-induced generation of reactive oxygen species which can cause DNA damage within skin cells. The proper modification of titanium dioxide to significantly limit its photocatalytic properties can contribute to the safety enhancement. The modification strategies including the process conditions and intrinsic properties of titanium dioxide were discussed. The selected examples of commercially available TiO 2 materials as potential components of cosmetic emulsions dedicated for sunscreens were compared in this study. Only rutile samples modified with Al 2O 3 and/or SiO 2 showed inhibition of photocatalytic activity.
Go to article

Authors and Affiliations

Marcin Janczarek
1
ORCID: ORCID
Waldemar Szaferski
1
ORCID: ORCID

  1. Poznan University of Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, 60-965 Poznan, Poland
Download PDF Download RIS Download Bibtex

Abstract

This study aims at the immobilization and characterization of thermoalkalophilic lipases produced recombinantly from Bacillus thermocatenulatus BTL2 and Bacillus pumilus MBB03. For this purpose, immobilization of the produced enzymes in calcium-alginate@gelatin (Ca–Alg@gelatin) hydrogel beads, immobilization optimization and characterization measurements of the immobilized-enzyme hydrogels were conducted. Optimum temperature and pH values were determined for B. thermocatenulatus and B. pumilus MBB03 immobilized-enzyme hydrogels (60–70 °C, 55 °C and pH 9.5, pH 8.5). Thermal stability was determined between 65 °C and 60 °C of B. thermocatenulatus and B. pumilus MBB03 immobilized enzymes, respectively. The pH stability was determined between pH 7.0–11.0 at +4°C and pH 8.0–10.0 at +4 °C, respectively.
In conclusion, the entrapment technique provided controlled production of small diameter hydrogel beads (~ 0:19 and ~ 0:29) with negligible loss of enzyme. These beads retained high lipase activity at high pH and temperature. The activity of Ca–Alg@gelatin-immobilized lipase remained relatively stable for up to three cycles and then markedly decreased. With this enzyme immobilization, it may have a potential for use in esterification and transesterification reactions carried out in organic solvent environments. We can conclude that it is one of the most promising techniques for highly efficient and economically competent biotechnological processes in the field of biotransformation, diagnostics, pharmaceutical, food and detergent industries.
Go to article

Authors and Affiliations

Kezban Yildiz Dalginli
1
ORCID: ORCID
Onur Atakisi
2
ORCID: ORCID

  1. Department of Chemistry and Chemical Processing Technologies, Kars Vocational High School Kafkas University, Kars, Turkey
  2. Department of Chemistry, Faculty Science and Letter, Kafkas University, Kars, Turkey
Download PDF Download RIS Download Bibtex

Abstract

Three activated chars obtained from end-of-life tyre pyrolysis differing in activation time (AC110 – 110 min, AC130 – 130 min, and AC150 – 150 min) were successfully used as adsorbents for the removal of model dye – Rhodamine B (RhB) from aqueous solutions. The effects of solution pH, adsorption kinetics, and equilibrium adsorption were investigated. The results showed that the adsorption was strongly pH-dependent; the highest percentage of RhB dye adsorbed was obtained at pH 2.0 and the removal efficiency decreased with an increase in solution pH. Adsorption kinetics was analyzed using pseudo-first-order, pseudo-second-order, Weber-Morris, and Boyd kinetic models. It was found that the pseudo-second-order kinetic equation was the most appropriate for describing the adsorption kinetics and that the RhB adsorption process was controlled by a film diffusion mechanism. Adsorption equilibrium data were fitted to the Langmuir, Freundlich, Temkin, and Elovich isotherm models. The equilibrium data were best represented by the Langmuir model with the monolayer adsorption capacities of 69.96, 94.34, and 133.3 μmol/g for AC110, AC130, and AC150, respectively. It was concluded that the adsorption of RhB was closely correlated with the specific surface area (and activation time) of the activated chars.
Go to article

Authors and Affiliations

Krzysztof Kuśmierek
1
ORCID: ORCID
Andrzej Świątkowski
1
ORCID: ORCID
Tomasz Kotkowski
2
ORCID: ORCID
Robert Cherbański
2
ORCID: ORCID
Eugeniusz Molga
2
ORCID: ORCID

  1. Military University of Technology, Faculty of Advanced Technologies and Chemistry, ul. Kaliskiego 2, 00-908 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Chemical and Process Engineering, ul. Waryńskiego 1, 00-645 Warsaw, Poland
Download PDF Download RIS Download Bibtex

Abstract

Following the so-called “special military operation”, which was in fact an open aggression against Ukraine, Russia was expelled from the Council of Europe. This step has significant legal consequences, including for the jurisdiction of the European Court of Human Rights. Meanwhile, many individual applications were filed with the Court, and Ukraine brought an inter-State complaint against Russia. Ukraine has also triggered the International Court of Justice. The Court has already ordered provisional measures. The ICC Prosecutor has launched an investigation into the most serious international crimes, war crimes, crimes against humanity, and genocide in Ukraine and delivered arrest warrants against the Russian President and his Commissioner for Children’s Rights. There is a serious discussion going on concerning the establishment of a special tribunal for the crime of aggression. This text deals with some aspects of the Russian “special military operation” cases before international courts. It attempts to identify what role the international courts may play in the new phase of the conflict in Ukraine and the extent and effect of their intervention, given the jurisdictional limitations and the inability to enforce judgments.
Go to article

Authors and Affiliations

Anna Wyrozumska
1
ORCID: ORCID

  1. Faculty of Law and Administration, University of Łódź (Poland)

This page uses 'cookies'. Learn more