Lippi Martina, Riva Laura, Caruso Manfredi, Punta Carlo
Department of Chemistry, Materials, and Chemical Engineering "G. Natta" and INSTM Local Unit, Politecnico di Milano, 20131 Milano, Italy.
Materials (Basel). 2022 Jan 27;15(3):976. doi: 10.3390/ma15030976.
The control of airborne contaminants is of great interest in improving air quality, which has deteriorated more and more in recent years due to strong industrial growth. In the last decades, cellulose has been largely proposed as suitable feedstock to build up eco-friendly materials for a wide range of applications. Herein, the issue regarding the use of cellulose to develop air-filtering systems is addressed. The review covers different cellulose-based solutions, ranging from aerogels and foams to membranes and films, and to composites, considering either particulate filtration (PM, PM, and PM) or gas and water permeation. The proposed solutions were evaluated on the bases of their quality factor (QF), whose high value (at least of 0.01 Pa referred to commercial HEPA (high-efficiency particulate air) filters) guarantees the best compromise between high filtration efficiency (>99%) and low pressure drop (<1 kPa/g). To face this aspect, we first analyzed the different morphological aspects which can improve the final filtration performance, outlining the importance on using nanofibers not only to increase surface area and to modulate porosity in final solutions, but also as reinforcement of filters made of different materials. Besides the description of technological approaches to improve the mechanical filtration, selected examples show the importance of the chemical interaction, promoted by the introduction of active functional groups on cellulose (nano)fibers backbone, to improve filtration efficiency without reducing filter porosity.
控制空气中的污染物对于改善空气质量至关重要，近年来，由于工业的强劲增长，空气质量日益恶化。在过去几十年中，纤维素被广泛提议作为合适的原料，用于制造适用于广泛应用的环保材料。本文探讨了使用纤维素开发空气过滤系统的问题。该综述涵盖了不同的基于纤维素的解决方案，从气凝胶、泡沫到膜和薄膜，再到复合材料，涉及颗粒过滤（PM、PM和PM）以及气体和水的渗透。所提出的解决方案根据其质量因子（QF）进行评估，其高值（相对于商用高效空气过滤器（HEPA）至少为0.01 Pa）保证了在高过滤效率（>99%）和低压降（<1 kPa/g）之间的最佳折衷。为了解决这一问题，我们首先分析了可以改善最终过滤性能的不同形态学方面，强调了使用纳米纤维的重要性，不仅是为了增加最终解决方案的表面积和调节孔隙率，还作为不同材料制成的过滤器的增强材料。除了描述改善机械过滤的技术方法外，所选示例还展示了通过在纤维素（纳米）纤维主链上引入活性官能团促进化学相互作用的重要性，以在不降低过滤器孔隙率的情况下提高过滤效率。
