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.
alireza ziapour; zahra Kazemi Karchegini; negin Kazemi Karchegini
Abstract
The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices ...
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The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers are trying to find available low-cost materials with high adsorption. In this research, soybean lignocellulosic waste has been investigated for absorption of Rimosol Black B (RBB) dye. First, the effect of dye RBB concentration, pH, temperature and contact time on the absorption value was investigated, and then the adherence of the adsorption isotherm to the Langmuir and Freundlich models was investigated. The results showed that the absorption efficiency depended strongly on pH and slightly on the temperature. The absorption rate of RBB dye with soybean residue is high and the absorption is complete in a short period of time. The results of the adsorption isotherm analysis showed that both models are suitable for describing the adsorption of RBB dye with soybean. The maximum absorption capacity of RBB dye by soybean waste was calculated 90.9 mg/g, which is more than some cheap absorbents studied and less than others such as rapeseed lignocellulosic waste.
