不同水性聚合物对纳米纤维素基气凝胶PM_(2.5)过滤性能的影响

Effect of different water-based polymers on PM_(2.5)filtration performance of nanocellulose based aerogel

随着现代工业的快速发展,PM_(2.5)的污染问题对人体健康造成严重威胁。旨在研究一种过滤效率高、压降低、绿色环保的空气过滤材料,用于防护PM_(2.5)的污染。通过将纳米纤维素(CNF)与3种水性聚合物聚乙烯醇(PVA)、聚乙二醇(PEG)和聚乙烯亚胺(PEI)分别进行复合,并采用低温冷冻干燥的方法制备CNF/PVA、CNF/PEG和CNF/PEI气凝胶滤片。通过简单的热化学气相沉积(CVD)疏水改性CNF复合气凝胶滤片,研究了其成型机理、疏水性能和过滤性能。结果显示,质量比为1∶0.5的CNF/PVA气凝胶滤片具有较佳过滤性能,拉伸应力可达158.4 kPa,PM_(2.5)过滤效率为90.14%。在稳定性评估中,CNF/PVA复合气凝胶滤片即使在高温(150℃)和高气流速度(5 cm/s)的条件下也表现出稳定的过滤性能。通过对CNF/PVA0.5进行疏水改性后,水接触角达137.5°,并且使用简单的水洗处理即可重复使用,5次洗涤后仍能保持较高的过滤性能(过滤效率>84%)。本研究结果证明采用CNF复合气凝胶滤片制备空气过滤用材料是可行的,可为推动PM_(2.5)过滤材料的发展以及绿色空气过滤材料的开发提供理论和技术基础。

Due to the swift advancement of modern industry,the issue of PM_(2.5)pollution caused by industrial practices,construction activities,waste incineration,and vehicular exhaust has been increasingly severe and constitutes a significant risk to human well-being.Prior to eradicating the sources of PM_(2.5),the creation of environmentally friendly and efficient air filtration materials serves as a crucial means of safeguarding human health.This paper aims at investigating an air filtration material with high filtration efficiency,low pressure drops,and green environmental protection,which can safeguard against PM_(2.5)pollution.Nano-cellulose(CNF)aerogels have the characteristics of high surface area and porosity and can be used as an excellent air filtration material.To explore the feasibility of constructing composite aerogel sheets based on CNF,CNF was compounded with polyvinyl alcohol(PVA),polyethylene glycol(PEG)and polyethylene imine(PEI),respectively.CNF/PVA,CNF/PEG,CNF/PEI aerogel sheets were prepared by freeze-drying.The CNF-based composite aerogel filter sheets were subjected to hydrophobic modification via the simple thermochemical vapor deposition(CVD)to explore their molding mechanism,hydrophobic performance,and filtration properties.The optimal mass ratio of the CNF/PVA aerogel filter sheet was found to be 1∶0.5,which displayed a remarkable tensile strength of 158.4 kPa and an outstanding PM_(2.5)filtration efficiency of 90.14%.In the stability assessment of the filter,the composite aerogel filter made of CNF/PVA0.5 demonstrated consistent filtration performance even when subjected to harsh conditions such as high temperature(150℃)and high airflow velocity(5 cm/s).After hydrophobic modification of CNF/PVA0.5,the water contact angle reached 137.5°,and it could be reused with simple water washing treatment,maintaining high filtration performance(>84%)after five washes.This research offers robust substantiation for the preparation and shaping of CNF composite aerogel filters intended for the purification of air and furnishes both the theoretical and practical groundwork to expedite the advancement of PM_(2.5)filtration resources as well as the progression of eco-friendly air filtration materials.