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Substrate-driven differential sensitivity of gram-positive and gram-negative bacteria to pine and birch liquid pyrolysis products
Comparison of the properties of birch bark tar obtained by the double-clay pot method and the laboratory method
The Influence of Hemp Fibers (Cannabis sativa L.) on the Mechanical Properties of Fiber–Gypsum Boards Reinforcing the Gypsum Matrix
The modern construction industry is looking for new ecological materials (available, cheap, recyclable) that can successfully replace materials that are not environmentally friendly. Fibers of natural origin are materials that can improve the properties of gypsum composites. This is an important issue because synthetic fibers (hardly biodegradable—glass or polypropylene fibers) are commonly used to reinforce gypsum boards. Increasing the state of knowledge regarding the possibility of replacing synthetic fibers with natural fibers is another step towards creating more environmentally friendly building materials and determining their characteristics. This paper investigates the possibility of manufacturing fiber–gypsum composites based on natural gypsum (building gypsum) and hemp (Cannabis sativa L.) fibers grown in Poland. The effect of introducing hemp fibers of different lengths and with varying proportions of mass (mass of gypsum to mass of fibers) into the gypsum matrix was investigated. The experimental data obtained indicate that adding hemp fibers to the gypsum matrix increases the static bending strength of the composites manufactured. The highest mechanical strength, at 4.19 N/mm2, was observed in fiber–gypsum composites with 4% hemp fiber content at 50 mm in length. A similar trend of increased strength was observed in longitudinal tension. Again, the composite variant with 4% fiber content within the gypsum matrix had the highest mechanical strength. Manufacturing fibers–gypsum composites with more than 4% hemp fiber content negatively affected the composites’ strength. Mixing long (50 mm) hemp fibers with the gypsum matrix is technologically problematic, but tests have shown a positive effect on the mechanical properties of the refined composites. The article indicates the length and quantity limitations of hemp fibers on the basis of which fiber–gypsum composites were produced.
Valorization of Forest Biomass Through Pyrolysis: A Study on the Energy Potential of Wood Tars
Forest biomass is a renewable source of environmentally friendly material—wood. However, wood processing generates large amounts of by-products, including branches. These byproducts are often used as firewood; however, they can be used much more effectively. In this study, the pyrolysis of two woods, namely birch and pine, was proposed. The liquid products of pyrolysis were studied by FTIR spectroscopy, and the heating value of these products was evaluated. In order to find the optimal pyrolysis temperature from the point of view of the calorific value of the product, the process was carried out at four temperatures: 450, 500, 550, and 600 °C. The liquid product yielded three fractions, from which two were analyzed, namely the dense tar fraction and light liquid fraction. FTIR analysis results clearly demonstrated that samples from different fractions differ from one another, yet the results within the same fraction are remarkably similar. The tar fraction was characterized with a higher gross calorific value between 42 to 50 MJ/kg, while the liquid fraction gross calorific value was between 29 and 39 MJ/kg; in general, pine wood yielded products with higher calorific values. The pyrolysis of small wood industry by-products is an interesting method of utilization, yielding not only a liquid product with good calorific properties, but also a solid product, namely biochar, which may be used in carbon storage or used as a soil amendment.
Activated carbon prepared from corn biomass by chemical activation with potassium hydroxide
With the depletion of fossil fuel feedstocks, the lignocellulosic biomass, including the agro-wastes, can serve as the best alternative source to produce activated carbons (ACs). Corn biomass (corn leaves, stalks, cobs without kernels, silk, and kernels) were used to produce ACs in a two-step process. Crushed plant material was carbonized at 600 °C and then the obtained carbon was activated using potassium hydroxide at 750 °C. The content and type of surface oxygen functional groups were determined by the Boehm method and infrared spectroscopy. The porous structure of the obtained AC was determined by the nitrogen adsorption/desorption method at -196 °C, and the thermal resistance by the thermogravimetric method. The iodine number was also determined. The ACs derived from corn biomass were characterized with surfaces rich in chemical groups and revealed a highly developed porous structure. The specific BET surface area ranged from 1600 m2/g to 1965 m2/g. High values of iodine number approx. 1300 mg/g, indicated an extensive system of pores and their good adsorption properties.
KOH-activated tire pyrolysis char as an adsorbent for chloroorganic water pollutants
Activated carbons (ACs) produced from end-of-life tires with different tire pyrolysis char (TPC)-to-activator (KOH) ratios of 1:2, 1:3, and 1:4 were prepared and characterized. These materials were used as adsorbents for the removal of two common chloroorganic water contaminants such as 2,4-dichlorophenol (DCP) and 2,4-dichlorophenoxyacetic acid (2,4-D). The adsorption kinetics, equilibrium adsorption, and effects of solution pH were investigated. The adsorption of both adsorbates was found to be pH-dependent and preferred in acidic environments. The adsorption kinetics was evaluated using pseudo-first-order and pseudo-second-order kinetic models and mechanism - using Weber-Morris and Boyd models. Results demonstrated that the adsorption of DCP and 2,4-D on all ACs followed the pseudo-second-order model and was controlled by film diffusion. The Langmuir isotherm described the equilibrium data better than the Freundlich isotherm model. The maximum adsorption capacity of DCP adsorbed on AC1:2, AC1:3, and AC1:4 at equilibrium was 0.582, 0.609, and 0.739 mmol/g, respectively, while the maximum adsorption capacities for 2,4-D were 0.733, 0.937, and 1.035 mmol/g, respectively. The adsorption rate and efficiency were closely correlated with the porous structure of the tested adsorbents. The results showed that the activated carbons obtained from the scrap of end-of-life tires as raw materials could be used as a low-cost and alternative adsorbent for the removal of chlorinated organic pollutants from water.
New Biodegradable Carboxymethyl Cellulose-Based Films with Liquid Products of Wood Pine Pyrolysis with Antibacterial and Antioxidant Properties
Novel carboxymethylcellulose (CMC) films with liquid products of pyrolysis (LPP) from wood pine were produced. The obtained CMC-LPP films were plasticized with 5% glycerol. CMC-LPP films were a light brown colour with a characteristic smoky scent, and showed a higher oxygen permeability when compared to control film without the addition of the LPP. CMC-LPP exhibited high antioxidant activity (5 and 18 times higher than CMC films). Furthermore, the antibacterial activity of the CMC-LPP films was tested, showing a strong inhibiting growth effect on the seven tested human pathogenic bacteria. The new material had the most substantial bacteriostatic effect on Listeria monocytogenes, Salmonella typhimurium, and Pseudomonas aeruginosa. Introduction of LPP to plasticised CMC produces an eco-friendly material with biocidal effect and favourable mechanical and structural properties, which shows its potential for possible use in many industries.