Browsing by Author "Wacławek, Stanisław"

Now showing 1 - 9 of 9
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    A Polymeric Composite Material (rGO/PANI) for Acid Blue 129 Adsorption
    (MDPI, 2020-05-03) Kukulski, Tomasz; Wacławek, Stanisław; Silvestri, Daniele; Krawczyk, Kamil; Padil, Vinod V. T.; Fryczkowski, Ryszard; Janicki, Jarosław; Černík, Miroslav
    Over the years, polyaniline (PANI) has received enormous attention due to its unique properties. Herein, it was chosen to develop a new polymeric composite material: reduced graphene oxide/polyaniline (rGO/PANI). The composite was prepared by a simple and cost-effective fabrication method of formation by mixing and sonication in various conditions. The obtained materials were characterized and identified using various techniques such as scanning electron microscopy (SEM), Raman and ATR–FTIR spectroscopy, and X-ray diffraction (XRD). The objective of the paper was to confirm its applicability for the removal of contaminants from water. Water could be contaminated by various types of pollutants, e.g., inorganics, heavy metals, and many other industrial compounds, including dyes. We confirmed that the Acid Blue 129 dyes can be substantially removed through adsorption on prepared rGO/PANI. The adsorption kinetic data were modeled using the pseudo-first-order and pseudo-second-order models and the adsorption isotherm model was identified.
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    Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production
    (MDPI, 2019-12-21) Wacławek, Stanisław; Grübel, Klaudiusz; Silvestri, Daniele; Padil, Vinod V. T; Wacławek, Maria; Černík, Miroslav; Varma, Rajender S
    Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegration provides the highest biogas yield (>500%) although they tend to be the most energy demanding processes (>10,000 kJ kg−1 total solids).
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    Green Synthesis of High Temperature Stable Anatase Titanium Dioxide Nanoparticles Using Gum Kondagogu: Characterization and Solar Driven Photocatalytic Degradation of Organic Dye
    (MDPI, 2019-12-04) Sivan Saranya, Kothaplamoottil; Vellora Thekkae Padil, Vinod; Senan, Chandra; Pilankatta, Rajendra; Saranya, Kunjumon; George, Bini; Wacławek, Stanisław; Černík, Miroslav
    The present study reports a green and sustainable method for the synthesis of titanium dioxide (TiO2) nanoparticles (NPs) from titanium oxysulfate solution using Kondagogu gum (Cochlospermum gossypium), a carbohydrate polymer, as the NPs formation agent. The synthesized TiO2 NPs were categorized by techniques such as X-Ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy analysis, Raman spectroscopy, scanning electron microscope- Energy-dispersive X-ray spectroscopy (SEM-EDX), Transmission electron microscopy (TEM), High-resolution transmission electron microscopy (HR-TEM), UV-visible spectroscopy, Brunauer-Emmett-Teller (BET) surface area and particle size analysis. Additionally, the photocatalytic actions of TiO2 NPs were assessed with regard to their ability to degrade an organic dye (methylene blue) from aqueous solution in the presence of solar light. Various parameters affecting the photocatalytic activity of the TiO2 NPs were examined, including catalyst loading, reaction time, pH value and calcination temperature of the aforementioned particles. This green synthesis method involving TiO2 NPs explores the advantages of inexpensive and non-toxic precursors, the TiO2 NPs themselves exhibiting excellent photocatalytic activity against dye molecules.
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    Microwave-assisted sustainable co-digestion of sewage sludge and rapeseed cakes
    (Elsevier Ltd, 2019-11-01) Grübel, Klaudiusz; Kuglarz, Mariusz; Wacławek, Stanisław; Vellora Thekkae Padil, Vinod; Černík, Miroslav; Varma, Rajender S.
    The technological concept ensuring highly efficient co-digestion of by-products from the production of biodiesel and sewage sludge was examined. Rapeseed cakes (RC) 1–5% addition to waste activated sludge (WAS) 95–99% in digesters, positively influenced the degree of biodegradation of organic matter and the quantity and quality of the biogas produced. Under the optimal conditions (HRT = 20–22 days), the co-digestion mixtures (WAS + microwave disintegration + RC) generated double the amount of biogas, containing approximately 10–12% more CH4, than the samples which had the sewage sludge only. Under these conditions, the biogas yield increased by approximately 48–82% depending on the co-substrate used and was further improved via the introduction of microwave pre-treatment. After testing at the pilot scale, this method could be considered as a sustainable alternative to conventional methods for WAS and RC treatment.
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    Stabilization of Iron (Micro)Particles with Polyhydroxybutyrate for In Situ Remediation Applications
    (MDPI, 2019-12-09) Chronopoulou, Laura; Palocci, Cleofe; Valentino, Francesco; Pettiti, Ida; Wacławek, Stanisław; Černík, Miroslav; Petrangeli Papini, Marco
    Groundwater is an extremely important resource that may, however, contain a variety of toxic and bioaccumulative contaminants. Traditional “Pump and Treat” technologies for treating contaminated groundwater are no longer time- or cost-effective; therefore, new technologies are needed. In this work, we synthesized core–shell materials of micrometric dimensions based on the interaction of iron particles (the core) and fermentable biopolymers such as polyhydroxybutyrate (PHB, the surrounding shell) to be used in permeable reactive barriers for the removal of chlorinated pollutants from contaminated groundwater. The materials were prepared by precipitation techniques that allowed stable preparations to be obtained, whose chemico-physical properties were thoroughly characterized by scanning electron microscopy, porosimetry, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyses, disc centrifuge analysis, and dynamic light scattering. The properties of the prepared materials are very promising, and may enhance the performance of permeable reactive barriers towards chlorinated compounds.
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    Synthesis of Ag nanoparticles by a chitosan-poly(3-hydroxybutyrate) polymer conjugate and their superb catalytic activity
    (Elsevier Ltd, 2020-01-01) Silvestri, Daniele; Wacławek, Stanisław; Venkateshaiah, Abhilash; Krawczyk, Kamil; Sobel, Bartłomiej; Padil, Vinod V.T.; Černík, Miroslav; Varma, Rajender S.
    This work describes an eco-friendly and sustainable technique for the synthesis of silver nanoparticles (nAg), where chitosan-poly(3-hydroxybutyrate) polymer conjugate (Chit-PHB) acts as a reducing and stabilizing material. The ensuing nanoparticles show an exceptional catalytic activity in the reduction of 4-nitrophenol to 4-aminophenol. nAg were characterized by several techniques, i.e. SEM and TEM-EDX, to confirm their production, size and morphology. Furthermore, infrared spectroscopy analysis proved the presence of a Chit-PHB coating on the nAg. The excellent catalytic properties of the nAg-Chit-PHB was discernible when the activity parameter (κc) normalized by the specific surface area (SSA) of the nanoparticles was taken into consideration; normalization of κc by the SSA is a vital parameter for the assessment of the accessibility to the surface area of particles. Herein synthesized Ag nanoparticles, as far as we know, exhibited the fastest reaction kinetics of 4-nitrophenol reduction compared to the silver nanoparticles reported in the literature
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    UV-Catalyzed Persulfate Oxidation of an Anthraquinone Based Dye
    (MDPI, 2020-01-01) Krawczyk,Kamil; Wacławek, Stanisław; Kudlek, Edyta; Silvestri, Daniele; Kukulski, Tomasz; Grübel, Klaudiusz; Padil, Vinod V. T.; Černík, Miroslav
    Wastewater from the textile industry has a substantial impact on water quality. Synthetic dyes used in the textile production process are often discharged into water bodies as residues. Highly colored wastewater causes various of problems for the aquatic environment such as: reducing light penetration, inhibiting photosynthesis and being toxic to certain organisms. Since most dyes are resistant to biodegradation and are not completely removed by conventional methods (adsorption, coagulation-flocculation, activated sludge, membrane filtration) they persist in the environment. Advanced oxidation processes (AOPs) based on hydrogen peroxide (H2O2) have been proven to decolorize only some of the dyes from wastewater by photocatalysis. In this article, we compared two very different photocatalytic systems (UV/peroxydisulfate and UV/H2O2). Photocatalyzed activation of peroxydisulfate (PDS) generated sulfate radicals (SO4•−), which reacted with the selected anthraquinone dye of concern, Acid Blue 129 (AB129). Various conditions, such as pH and concentration of PDS were applied, in order to obtain an effective decolorization effect, which was significantly better than in the case of hydroxyl radicals. The kinetics of the reaction followed a pseudo-first order model. The main reaction pathway was also proposed based on quantum chemical analysis. Moreover, the toxicity of the solution after treatment was evaluated using Daphnia magna and Lemna minor, and was found to be significantly lower compared to the toxicity of the initial dye.
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    Využití persulfátu pro odbourávání organických látek
    (Technická Univerzita v Liberci, 2016-01-01) Wacławek, Stanisław
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    Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations
    (2019-01-01) Machnicka, Alicja; Grübel, Klaudiusz; Wacławek, Stanisław; Sikora, Krzysztof
    The freezing process consists of dissipating heat from the product until the final temperature is lower than the temperature of crystallisation of that product. Freezing can be used for numerous applications, including for disruption of waste-activated sludge (WAS). The aim of this study was to calculate the estimated amount of heat conveyed between the solidified carbon dioxide and the WAS, in the following ratios: 0.25:1; 0.5:1; 0.75:1 and 1:1. In heat of phase transformations, dry ice sublimation, water solidification, the amount of heat transferred by other substances and heat transferred from the sludge (dry sludge) were taken into account during the process of WAS freezing. Heat changes on the surface of WAS were registered using a thermovision camera. The effectiveness of WAS disintegration was confirmed by several biochemical parameters such as soluble chemical oxygen demand (increase over 14 times), degree of disintegration (48%), proteins (increase over 5 times), carbohydrates (increase almost 7 times), RNA (increase by 2.23 mg L−1), ammonia nitrogen (increase over 23 times), phosphates (increase almost 27 times) and turbidity (increased over 7 times). It was found that dry ice pretreatment of WAS can be an intriguing alternative for the conventional methods used.