Recent technological developments have led to a significant increase in energy consumption in daily life. The search for alternative means of energy production has become an important task for ...applied sciences and modern technology. Hydrogen technology has great potential as a source of clean energy. The production of green hydrogen is a desirable and beneficial way to contribute to the decarbonization of the energy sector. In response to the demand for environmentally friendly and economically feasible approaches, biohydrogen production from waste materials has recently attracted interest. Waste materials from industrial or municipal production can be used as low-cost substrates for biohydrogen production through microbial degradation. Green energy needs could be met through a form of sustainable development that moves hand in hand with the harnessing of the microbial potential of waste biomass. Reuse of waste materials leads to pollution reductions and energy recycling. The aim of this review is to provide informative insights for researchers and engineers to help them better understand microbial biohydrogen production from low-cost waste substrates, such as industrial wastewater and waste activated sludge.
Silver nanowires were prepared by the polyol process with ethylene glycol as a solvent and reducing agent, silver nitrate as a silver source, polyvinylpyrrolidone as a growth-directing agent, ...stabilizer and agglomeration prevention agent, and copper chloride as a growth control agent. The product was characterized by UV–Vis spectroscopy, scanning electron microscopy, and X-ray diffraction. The biocidal activity of silver nanowires was investigated using the disc diffusion method on the bacteria Bacillus subtilis and Pseudomonas aeruginosa and the fungi Aspergillus niger and Candida albicans. X-ray diffraction and scanning electron microscopy showed that, in addition to silver nanowires, the product also contains quasi-spherical silver nanoparticles and some silver chloride. Based on the results of UV–Vis spectroscopy and scanning electron microscopy, it was estimated that the diameter of the nanowires is 200–300 nm. Nanowires have shown weak bactericidal and good fungicidal activity. Silver nanowires showed particularly good activity in inhibiting the growth of Candida albicans.
Nanoparticles are capable of making more durable and stronger materials with better chemical resistance. They are used for a wide range of applications. Likewise, the potential of metal nanoparticles ...as antimicrobial agents has been widely studied. In this work, we investigate various nanoparticles (Al, Ni, Ag) incorporated into epoxy coating. The anticorrosion and antibacterial properties of the unmodified and modified coatings were evaluated. According to the SEM and EDS analyses, the coating did not contain agglomerates, which confirms the quality of the dispersion of inorganic nanoparticles in the coating. After 24 h and 10days immersions in a 3.5 wt.% NaCl solution, the corrosion behaviour for all nanocomposite was studied by means of EIS investigations. The study included the evaluation of the inhibition zone of the nanoparticles and the antimicrobial properties of the nanocomposite. It was found that the nanoparticles of Al and Ag provide excellent antibacterial properties. The epoxy nanocomposite with Al NP showed the migration of ions in the range from 0.75 to 1 mg/L in a wastewater solution for 30 days, indicating a potential for antimicrobe activity. The 1% Al NP epoxy nanocomposite showed good anticorrosion and antibacterial properties and demonstrated great potential for applications in pipelines.
Biosorption is becoming increasingly important for the treatment of pollutants due to its cost-effectiveness, environmental friendliness and efficiency. For a more sustainable environment, more ...studies need to focus on the application of real industrial effluents. Increasing the initial concentration of activated sludge increases the specific surface area of the sludge, which allows for greater sorption of sorbates. The optimal initial concentration of activated sludge in the process of biosorption of pollutants from pharmaceutical effluent was 5.12±0.13 g/L. The biosorption process can be described by the Temkin model, where the estimated values of B
T
and A
T
ranged from 29.11 to 76.08 and from 1.10 to 1.48 L/g, respectively. The overall efficiency of the biosorption process ranged from 9.5 to 40.2%. The removed toxicity averaged 41.1±7.88% for all experiments.
The manufacture of pharmaceutical products generates wastewater that contains a variety of specific pollutants. The application of biological treatment with activated sludge is a commonly used ...process in industrial wastewater treatment with the aim of removing organic compounds by combining biosorption with biodegradation as a metabolic reaction of microorganisms, which are environmentally friendly processes. The efficiency of biosorption process ranged from 9.5 to 40.2%, with the values removal efficiency of toxic compounds ranging from 22.61 to 60.33%, while the overall biodegradation efficiency of organic pollutants ranged from 51.30 to 60.60%. By combining the process of biosorption and biodegradation, the optimal concentration of activated sludge was 4.96 ± 0.23 g dm
−3
for treating real pharmaceutical industrial wastewater. The morphology of the activated sludge maintained its structure, indicating that the activated sludge is resistant to changes in the pharmaceutical industrial wastewater treatment system.
In this study, different concentrations of aluminium nanoparticles (Al NP) were incorporated into epoxy resin and epoxy paint. Here, we present a detailed systematic study of different methods of ...incorporating inorganic nanoparticles into epoxy coating. This work aims to obtain an epoxy coating with anticorrosion and antibacterial properties. The physical properties of coatings such as thickness, hardness, colour, and adhesion did not change with the addition of nanoparticles. According to the SEM and EDS analyses, the distribution effect of Al NPs in epoxy coating was better with ultrasonic homogenisation than with mechanical stirring. The EIS and SECM measurements were used to investigate corrosion resistance. The coating with 1.0 wt.% Al NP showed the best physical and chemical properties. SECM examination indicated that nanoparticles in epoxy resin increase the protection efficiency by 25.75% and in the epoxy paint by 40.89%. The results also showed the antibacterial activity of aluminium nanoparticles by inhibiting the growth of biofilm-forming bacteria such as P. aeruginosa and B. subtilis.
Diuron is a selective and the most persistent herbicide. Widespread use of this compound has led to the elevated concentrations of diuron in groundwater and wastewater. The main objectives of this ...study were to investigate biodegradation of diuron by Pseudomonas aeruginosa FN and evolved degradation product, 3,4‐dichloroanilines (3,4‐DCA). The influence of temperature, initial optical density of Pseudomonas aeruginosa FN and initial diuron concentration were examined to further optimize biodegradation of diuron, and the effect of these factors were investigated by the response surface methodology (RSM) and full factorial design (FFD). The optimal biodegradation conditions were obtained at T = 25°C, γ (diuron) = 0.5 mg/L and initial optical density of 0.2. The biodegradation kinetic of diuron was described by Monod model and the obtained value of F‐test was grater that 0.96 which showed good correlation between Monod model and experimental results.
Biowaste, which often accounts for more than 50% of municipal waste, is an environmental problem if disposed of improperly in landfills but has great potential to achieve the recycling targets set ...out in Directive (EU) 2018/851. Despite the knowledge in theory and practice about the processing of biowaste and the benefits of recycling, there is a lack of methodological approaches in describing the process of aerobic biodegradation in a concise and suitable way for decision makers, environmental engineers, and project designers. This paper presents how basic data on the properties of biowaste can be used, using theoretical models, to determine basic indicators of the dynamics and material balance of the process. The maximum rate of CO2 generation on the 4th day was Rm = 45.3 g/d, with the potential of available, readily biodegradable components of the biowaste sample of P = 526 g CO2/kg VS. A substrate conversion of 51.7% was achieved in the bioreactor by the 17th day of treatment. The results of this analysis, together with future analyses of sensitivity and boundary conditions of the process, are useful for rapidly sizing a biological treatment system for municipal solid waste in a given area.
•Apple and tobacco waste mixture was efficiently composted during 22days.•Physical–chemical and microbiological properties of the mixture were suitable the process.•Evaluation of selected ...mathematical model showed good prediction of the temperature.•The temperature curve was a “mirror image” of the oxygen concentration curve.•The peak values of the temperature were occurred 9.5h after the peak oxygen consumption.
Efficient composting process requires set of adequate parameters among which physical–chemical properties of the composting substrate play the key-role. Combining different types of biodegradable solid waste it is possible to obtain a substrate eligible to microorganisms in the composting process. In this work the composting of apple and tobacco solid waste mixture (1:7, dry weight) was explored. The aim of the work was to investigate an efficiency of biodegradation of the given mixture and to characterize incurred raw compost. Composting was conducted in 24L thermally insulated column reactor at airflow rate of 1.1Lmin−1. During 22days several parameters were closely monitored: temperature and mass of the substrate, volatile solids content, C/N ratio and pH-value of the mixture and oxygen consumption. The composting of the apple and tobacco waste resulted with high degradation of the volatile solids (53.1%). During the experiment 1.76kg of oxygen was consumed and the C/N ratio of the product was 11.6. The obtained temperature curve was almost a “mirror image” of the oxygen concentration curve while the peak values of the temperature were occurred 9.5h after the peak oxygen consumption.
