Pulp and paper
Amir Hosein Ghasemi; Noureddin Nazarnezhad; Shaghaygh Rezanezhad; Seed Hasan Sharifi
Abstract
Background and objectives: Some medicinal herb extracts have the antibacterial capability. On the other hand, herb extract is one of the organic, natural, and environmentally friendly substances. In recent years, the production of environmental and safe packaging materials has attracted the attention ...
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Background and objectives: Some medicinal herb extracts have the antibacterial capability. On the other hand, herb extract is one of the organic, natural, and environmentally friendly substances. In recent years, the production of environmental and safe packaging materials has attracted the attention of scientists and industrialists. Paper is one of the biodegradable and less cost options for packaging in various industries, including the food industry. Also, the raw materials of paper can be modified and changed with different materials. As a result, paper fibers can be treated with herb extracts and used in the production of renewable papers with antibacterial properties.Methodology: In this research, thyme (Zataria Multiflora) was used for extraction. The thyme obtained from the research farm was dried and then powdered. Powdered thyme was treated via ultrasonication. In this method, two amplitudes of 40 and 60 amplitudes and three time levels of 3, 6, and 9 minutes were used for extraction. Then the papers were treated with herbal extract prepared in two amounts of 15 and 20% based on the dry weight of the paper by spraying. The antibacterial properties of the papers were investigated with Escherichia coli and Staphylococcus aureus bacteria. The chemical structure of materials extracted from the thyme extract investigated by fourier transform infrared spectrum (FTIR) analysis. Also, gas chromatography (GC-MASS) analysis was used to investigate the components of thyme extract. The optical properties of the paper, including brightness and opacity, and the strengths properties of the produced papers were measured by tensile, tear, and burst strengths.Results: The highest inhibition zone diameter in the treated paper with the thyme extracted by ultrasonic method was 20 mm in 40 amplitude and 9 minutes for Escherichia coli bacteria. Also, the highest inhibition zone diameter for Staphylococcus aureus bacteria was 14 mm in 60 amplitude and 6 minutes. According to the results of the papers analysis, the papers showed better antibacterial properties and higher inhibition zone against the Escherichia coli bacteria. The chemical compounds in the thyme extract including various substances such as hexane and furans. The most important chemical components that caused the antibacterial properties of the papers is carvenone, which was observed in the thyme extract. The results of the strength test of the treated papers showed that the sample of the thyme extracted by the ultrasonic method at 40 amplitudes, 3 minutes, and the 20% consumption amount based on the dry weight of the paper has the highest tensile and burst index. As well as, the highest tear index of the treated papers was in the treated sample with the thyme extracted at 60 amplitudes, 3 minutes, and 15% consumption amount based on the dry weight of the paper. The results of the optical tests showed that the opacity of the papers decreased and the brightness increased.Conclusion: The results of this research showed that the paper as a biodegradable and environmentally friendly material has the ability to be treated with herbal and natural antibacterial materials such as the thyme extract. Also, the herbal extracts are a suitable alternative to inorganic and metallic materials in the production of materials with antibacterial properties due to the herbal extracts are cheap, available and natural materials.
Pulp and paper
Zahra Kazemi Karchangi; Noureddin Nazarnezhad; Hasan Sharifi
Abstract
Background and purpose: Today, with the rapid development of human society, the pollution of particles matter (PM) in the atmosphere has increased. Suspended particles easily enter the human respiratory system and have serious effects on health, they are considered as one of the critical and risky issues ...
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Background and purpose: Today, with the rapid development of human society, the pollution of particles matter (PM) in the atmosphere has increased. Suspended particles easily enter the human respiratory system and have serious effects on health, they are considered as one of the critical and risky issues in modern urban societies. Air filters play a key role in reducing the emission of these particles and preventing their harmful effects on human health. Due to the growing importance of air pollution and its harmful effects on human health and the environment, the use of effective and environmentally friendly filters has received more attention. In this regard, natural and biodegradable materials such as bamboo fibers are considered a suitable alternative to synthetic polymer materials in making filters. This research focuses on the preparation and evaluation of cellulose air filter using bamboo fibers to deal with air pollution.Materials and methods: To prepare the filter, bamboo fibers were first pulped through the process of soda anthraquinone with 25% sodium hydroxide, pulping time 2 hours and temperature 175 degrees Celsius with 0.2% anthraquinone (AQ), then during D0ED1 sequence was bleached by chlorine dioxide and soda. In the next step, the oxidation process was carried out with 3% hydrogen peroxide, 3% sodium silicate and the ratio of sodium hydroxide to hydrogen peroxide 0.8. Then 3% polyvinyl alcohol was added to the resulting suspension and stirred for 10 minutes with the same retention time for all treatments. The suspension was homogenized with an Ultra Thorax homogenizer and dried in a freeze dryer at -110°C for 72 hours to prepare the cellulose filter.Results: The results showed that oxidation and addition of PVA have a positive effect on the mechanical and structural characteristics of the filter. The tensile strength of filters improved significantly after oxidation and adding PVA and increased from 0.236 Nm/g to 0.528 Nm/g. The amount of porosity and air permeability were also affected by oxidation and PVA addition, after oxidation, the porosity and air permeability increased by increasing the number of carboxyl groups and improving the dispersion of cellulose fibers. While the addition of PVA created strong hydrogen bonds and reduced porosity and air permeability. Electron microscopic images (SEM) also clearly showed the structural changes caused by oxidation. After oxidation and adding PVA, the density of the fiber network increased and improved the uniform dispersion of fibers and created a more coherent structure while small pores between fibers still existed. The specific surface area and the average pore size of the filters were checked using the BET method, which shows that the specific surface area increased in the oxidized and PVA-containing filters, and the pore size was maintained in the nano scale in all filters.Conclusion: These results show that the combination of oxidized bamboo fibers containing PVA leads to the production of efficient air filters with improved characteristics that can help reduce air pollution because these filters are able to prevent the passage of PM suspended particles by having pores at the nanoscale.
