Preparation of Bioactive Polyamide Fibres Modified with Acetanilide and Copper Sulphate.

This paper presents a simple method of obtaining polyamide 6 fibres modified with acetanilide and copper ions. During the spinning of the fibres with the additives applied, a partial reduction of CuSO4 to Cu2+ and Cu+ ions occurs, which is observed as a change in the blue colour of the prepared polyamide granulate to the grey-brown colour of the formed fibres. CuMPs obtained as a result of the salt reduction should give the obtained fibres bioactive properties. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against Gram-positive and Gram-negative bacteria. The largest inhibition zones were obtained for the Gram-positive bacteria Staphylococcus aureus, ranging from 1.5 to 4.5 mm, depending on the concentration of CuMPs. The morphology of the fibres' surfaces was examined by means of scanning electron microscopy (SEM) and optical microscopy (OM). The changes in the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray structure studies (WAXS and SAXS) and an energy-dispersive spectroscopy (EDS) analysis. The newly obtained bioactive polyamide fibres can be used in many areas, including medicine, clothing and environmental protection for the production of filters.

The effect of pre-treatment and anaerobic digestion for pathogens reduction in agricultural utilization of sewage sludge.

The aim of the research work was to explain the possibilities of application of waste activated sludge (WAS) pretreatment processes prior to anaerobic digestion (mesophilic fermentation). Hydrodynamic disintegration and freezing/thawing disintegration methods were used. Based on the microbiological and parasitological analyses, a significant decrease in pathogenic bacteria, coliphages, and parasite eggs was observed. The number of bacteria analyzed (Salmonella sp., Escherichia coli, Clostridium perfringens) and coliphages were reduced from 19.3to 42.3% after hydrodynamic cavitation. A similar effect was achieved for destruction by freezing/thawing with dry ice between 7.8 and 14.9%. The effectiveness of parasite eggs reduction (Ascaris sp., Trichuris sp., Toxocara sp.) for these disintegration methods ranged from 10.7 to 29.3%. The highest results were observed for the hybrid disintegration method (hydrodynamic cavitation + dry ice disintegration) caused by a synergistic effect. Salmonella sp. in 1 gd.w. decrease about 69.7%, E. coli by 70.0%, Clostridium perfringens by 38.4%, and coliphages by 48.2%. Disruption of WAS by a hybrid method led to a reduction in the number of helminth eggs Ascaris sp. (63.8%), Trichuris sp. (64.3%), and Toxocara sp. (66.4%). After anaerobic digestion under mesophilic conditions, an additional reduction of analyzed bacterial pathogens and helminth eggs were observed. The introduction of hybrid disintegrated WAS to the fermentation chamber resulted in higher efficiency in decrease (from 1 to 23%) in comparison to the control sample (70%WAS + 30%DS (inoculum-digested sludge)).

Graphene Oxide and Stabilized Ortho-Silicic Acid as Modifiers of Amnion and Burn Affected Skin: A Comparative Study.

INTRODUCTION: Oxidative tissue damage caused by reactive oxygen species results in a significant decrease in the total antioxidant capacity of the biological system. The aim of this interdisciplinary study was to answer the question of whether active antioxidants modify, at a molecular and supramolecular level, the tissue of pathological amnion and the necrotic eschar degraded in thermal burn. METHODS: A Nicolet 6700 Fourier-transform spectrophotometer with OMNIC software and the EasiDiff diffusion accessory were used in the FTIR spectroscopic analysis. A NICOLET MAGNA-IR 860 spectrometer with FT-Raman accessory was used to record the Raman spectra of the samples. The samples were exposed to bacteria capable of causing nosocomial infections, ie Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa. Whereas samples of hypotrophic amnion interacted with Staphylococcus aureus, Escherichia coli and Enterococcus faecalis. The obtained flame retardant effect of placentas was evaluated using the method of the limiting oxygen index (LOI). RESULTS: The infrared spectroscopy analysis proved that after modification of the amniotic samples in graphene oxide and ortho-silicic acid, the amide II band is split into two components. Incubation of samples in modifier solutions: graphene oxide, sodium ascorbate and L-ascorbic acid results in shifts and changes of intensity within the broadly understood lipid band 1743-1745-1747 cm-1. The oxidising changes observed within the lipid and amide bands are affected by the incubation effect of graphene oxide as a modifier, possibly adsorbing on the surface of the amniotic membrane. On the basis of microbiological studies, pathogenic bacteria commonly causing amniotic infections and growing in burn wounds were found to have particularly good resistance to stabilized ortho-silicic acid (E. coli) and lactoferrin (S.aureus). CONCLUSION: This thermogravimetric study found the highest stability of the analysed tissues (hypotrophic amnion and burnt epidermis) after modification with graphene oxide and sodium ascorbate.

Nanocomposite Cellulose Fibres Doped with Graphene Oxide and Their Biocidal Properties.

The paper presents a method of obtaining composite cellulose fibres (CEL) doped with graphene oxide (GO) and the influence of GO nanoparticles on the structure and properties of the obtained fibres. Composite fibres (GO/CEL) were prepared using wet method from 5% CEL solutions in 1-ethyl-3-methylimidazolium acetate (EMIMAc) containing GO (0; 0.21; 0.50; 0.98; 1.97% w/w) dispersion in N,N-dimethylformamide (DMF). The fibres were coagulated in distilled water and methanol. Optical microscopy allowed us to demonstrate a good degree of GO additive dispersion in the CEL matrix. Surface morphology was examined by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR), which indicated interactions between the matrix and the additive. Strength tests have shown that GO/CEL fibres are characterised by high values of elongation at break (7.7-19.5%) and tenacity (~133-287 [MPa]). The obtained composite fibres are characterized by good biocidal properties against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphilococcus aureus), and fungi Candida albicans, and the resistance to microorganisms depends on the surface zeta potential value and the isoelectric point (IEP) of GO/CEL fibres.

Stabilized Ortho-Silicic Acid as a Modifier of Tissue-Preliminary Comparative Biomaterial Studies.

The ortho-silicic acid (H4SiO4) plays an essential role in delivering silicon to body cells and the monomeric ortho-silicic acid is the most bioavailable source of silicon for humans. This study reveals that the ortho-silicic acid (OSA) modifies the tissue of a healthy and pathological hypotrophic amnion, thermal burn skin and, additionally, the OSA-incubated serum. Changes in the tissue modified by the ortho-silicic acid were traced on the molecular level with the use of FTIR spectroscopy. The most interesting area of tissue modification with the use of OSA acid solutions is the appearance of the 1085 cm-1 Si-O-Si band which is optimal for the 1:6000 OSA concentration. Microbiological studies aiming at anticipating anti-inflammatory and antibacterial bioactivity revealed that the skin samples and amniotic samples were characterised by good resistance to the following bacteria: Enterococcus faecalis, Staphylococcus aureus and Escherichia coli (medium growth inhibition zone: 0.5-4 mm). The present study determined the concentration and the composition of the solutions to be used in the future to create innovative modifiers (active dressings or new dietary supplements) enhancing tissue regeneration.

Preparation of Antimicrobial Fibres from the EVOH/EPC Blend Containing Silver Nanoparticles.

The article presents a new fabrication method for bioactive fibres with a microporous structure of ethylene-vinyl alcohol copolymers (EVOH)/ethylene-propylene copolymer (EPC) blends. The experimental work carried out resulted in obtaining EVOH/EPC polymer blends fibres with the addition of glycerol and sodium stearate. Different concentrations of glycerol (38%, 32%) and sodium stearate (2%, 8%) were used to prepare the fibres. The purpose of using different concentrations of stearate and glycerol was to evaluate the effect of additives on the structure and properties of the fibres. A significant influence of the additives used on the morphological structure of the fibres was found. The resulting fibres were modified with an AgNO3 solution and reduced to silver nanoparticles (AgNPs), to give the fibres bioactive properties. The fibres obtained with the addition of 8% stearate have a more developed surface, which may influence the amount of adsorbed silver particles inside the fibre. However, the durability of depositing silver particles after multiple washes has not been tested. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against gram positive and negative bacteria. The largest inhibition zones were obtained for gram-positive bacteria Staphylococcus aureus, ranging from 3 to 10 mm depending on the concentration of AgNPs. The morphology of the blends fibres was characterized by scanning electron microscopy (SEM) and optical microscopy (OM). The occurrence of elemental silver was analysed by energy dispersive spectroscopy (EDS) analysis. The changes of the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR).

The Influence of Graphene Addition on the Properties of Composite rGO/PAN Membranes and Their Potential Application for Water Disinfection.

The paper presents a method of obtaining composite polyacrylonitrile-based (PAN) membranes with the addition of reduced graphene oxide (rGO). The membranes were obtained using phase inversion method from a homogeneous rGO dispersion in a solution of PAN dissolved in N, N-dimethylformamide (DMF). The impact of the amount of rGO addition to the PAN matrix on the physicochemical, structural, transport, and separation properties and on fouling resistance was studied. Composite membranes, due to the method of preparation used and the addition of rGO, are characterized by very good transport properties (~390 L/m2 h) and by a high degree of protein retention (85%). Reduced graphene oxide has biocidal properties, which, as we have shown, depend on the size of nanoparticles and the type of microorganism. rGO/PAN membranes, on the other hand, show biostatic properties against Gram-negative bacteria (Escherichia coli), Gram-positive bacteria (Staphylococcuc aureus) and fungi (Candida albicans). Thus, the obtained composite membranes can be potentially used in water disinfection.

Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations.

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.

Synergetic disintegration of waste activated sludge: improvement of the anaerobic digestion and hygienization of sludge.

The main aim of this study was to investigate the impact of a hybrid disintegration process with the use of alkalization and freezing by dry ice on waste activated sludge (WAS) and on the course of the process of mesophilic methane fermentation. In order to achieve the mentioned goal, various analytical techniques were used for assessment of the sludge disintegration and its influence on the further biogas production. As a result of the investigation, it was found that the chemical-thermal process of destruction of WAS results in an increased concentration of organic compounds in the supernatant (expressed as a change in the value of the soluble chemical oxygen demand - SCOD). The use of disintegrated WAS and feeding of the material into the fermentation digester influences, depending on its proportion by volume, the production of biogas and the biogas yield (higher biogas production by ca. 39% in comparison to blank sample was achieved with the appropriately disintegrated sludge). The hybrid process is simple and easy to implement in the full technical scale and does not influence or change the pH value of the sludge feed into the fermentation chambers (the dry ice neutralizes the high pH of the sludge). Additionally, it was determined that the herein developed process, can improve hygienization of the digested sludge.

Investigation of the effectiveness of nutrient release from sludge foam after hybrid pretreatment processes by IR analysis and EDX Quantification.

One of the problems in wastewater treatment technologies is the formation of foam/scum. It is thought that filamentous microorganisms are responsible for foam formation and foam elimination/destruction can be carried out by various methods, among which disintegration is included. Hybrid disintegration (chemical decomposition and hydrodynamic cavitation) of foam microorganisms results in the transfer of phosphates, ammonium nitrogen, magnesium and potassium from the foam solids into the liquid phase. Application of both methods as a hybrid pretreatment process caused an increase in the concentration of phosphates of about 650 mg [Formula: see text] L(-1) and ammonium nitrogen of about 30 mg [Formula: see text] L(-1). The concentration of Mg(2+) and K(+) in the solution increased from 6.8 and 26.1 mg Mg(2+) L(-1) to 32.2 and 82.2 mg K(+) L(-1), respectively. The presence of nutrients and metal cations in the solid phase of foam was acknowledged by EDX Quantification. The confirmation of physico-chemical changes and release of cellular matter as a result of cellular lysis (hybrid disintegration) was done by infrared analysis. It was demonstrated that the disintegration of foam permits the removal of a part of nutrients in the form of struvite.

Inhibitors of thermally induced burn incidents ­ characterization by microbiological procedure, electrophoresis, SEM, DSC and IR spectroscopy.

Differential scanning calorimetry (DSC) and thermogravimetric (TGA) investigations, acetate electrophoresis (CAE), Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) analysis and microbiological procedures were all carried out after heating the samples to a temperature sufficient for simulating a burn incident. In particular, the purpose of the present study was to analyze the effect of antioxidants, such as fucoidan from brown seaweed and flame-retardant cyclic organophosphates and phosphonates, on an organic chicken skin that gets changed by a burn incident. DSC was considered to be a useful tool in assessing in vitro temperature-mediated cross-linking; an innovative analytical conclusion was obtained from the experimentation described in the paper. FTIR tests revealed that heating a dry organic chicken skin to the boiling point leads to the disappearance of a wide band in the 1650-1550 cm(-1) area or the conversion of a band, which may be attributed to the intermolecular ß-sheet aggregates. Fucoidan from brown seaweed and flame-retardant cyclic organophosphates and phosphonates probably bind with the collagen that is changed by the burn (in addition to the influence of antioxidant solutions on samples of a blank or not boiled organic chicken skin) incident forming a polymer film with the collagen of the chicken skin surface (SEM analysis), decreasing the aggregation process and native collagen recovery. Good bacteriostatic properties were determined for fucoidan samples from brown seaweed and flame-retardant cyclic organophosphates and phosphonates against the pathogenic bacteria Escherichia coli and Staphylococcus aureus. Thus, it was observed that the fucoidan incorporated into collagen films can be used as a therapeutically active biomaterial that speeds up the wound-healing process.

Infrared wave analysis after hydrodynamic and acoustic cavitation as effective method of confirming sewage sludge destruction.

The efficiency of disintegration of sewage sludge cells microorganisms were characterized using biochemical parameters such as COD, phosphate, ammonium nitrogen and proteins. The investigated process was additionally assessed using the coefficient DD (Degree of Disintegration). It has been demonstrated that a 30-min of hydrodynamic and ultrasonic disintegration causes the soluble COD value increased about 300 mg /L and 190 mg /L (average), while the degree of disintegration reached 24% and 21%, respectively. The efficiency of sewage sludge hydrodynamic and ultrasonic disintegration was confirmed by increased release of phosphate (V) (from 4 to 54 mg PO4(3-) /L and to 50 mg PO4(3-) /L, respectively), ammonium nitrogen (from 1.5 to 4 mg N-NH4(+) /L and to 3.5 mg N-NH4(+) /L, respectively) and proteins (from 5 to 70 mg/L and to 60 mg/L, respectively). The effectiveness of surplus activated sludge disintegration was tested in the infrared spectrum. Changes in absorbance at the specified wavelength attest to a release of i.e., amines, amino acids, amide groups (proteins), phosphates, ammonium salts of carboxylic acid, etc. during disintegration time. Revealing these chemical groups in over-sludge liquids attests to a destructive influence of hydrodynamic and ultrasonic cavitation on activated sludge microorganisms and effective cells lysis.

Use of hydrodynamic disintegration to accelerate anaerobic digestion of surplus activated sludge.

Hydrodynamic disintegration of activated sludge resulted in organic matter and polymers transfer from the solid phase into the liquid phase. Disintegration by hydrodynamic cavitation had a positive effect on the degree and rate of excess sludge anaerobic digestion. Also, addition of a part of anaerobic digested sludge containing adapted microorganisms resulted in acceleration of the process. The disruption of cells of foam microorganisms and addition to the digestion process led to an increase of biogas production.

Enhanced biological phosphorus removal and recovery.

Activated sludge systems designed for enhanced nutrient removal are based on the principle of altering anaerobic and aerobic conditions for growth of microorganisms with a high capacity of phosphorus accumulation. Most often, filamentous bacteria constitute a component of the activated sludge microflora. The filamentous microorganisms are responsible for foam formation and activated sludge bulking. The results obtained confirm unanimously that the filamentous bacteria have the ability of phosphorus uptake and accumulation as polyphosphates. Hydrodynamic disintegration of the foam microorganisms results in the transfer of phosphorus and metal cations and ammonium-nitrogen into the liquid phase. It was demonstrated that the disintegration of foam permits the removal of a portion of the nutrients in the form of struvite.