Removal of PM and oil mist from automobile exhaust by a “hamburger” structured conjugated microporous polymers membrane

Abstract

The purification treatment of automobile exhaust has attracted great attention because of the severe harm of automobile exhaust to the global environment and human health. Herein, inspired by capillarity, we adopted a very simple face-to-face constrained growth method to prepare a conjugated microporous polymers membrane (C-CMPs-M) with a “Hamburger” structure through Sonogashira-Hagihara (S-H) coupling reaction for purification and filtration of gaseous, solid and liquid pollutants in automobile exhaust. Thanks to such a special structure, the C-CMPs-M−1 membrane shows an extremely high efficiency of capture and interception of PM2.5 and PM10 (greater than99.5 %) and PM0.3 (greater than95%) in the exhaust gas obtained at different engine speeds. Unlike those hydrophilic filtration materials which suffer the drawback of less tolerance in high humidity conditions, the unique superhydrophobic chemistry of the CMPs membrane makes it possible to efficiently intercept PM under high humidity conditions, and the filtration efficiency basically remains unchanged within 10 h. More interestingly, the super lipophilicity of the membrane endows it excellent oil absorption performance, e.g., high absorption of 907.61 % of its own weight for engine oil was detected and consequently good oil retention performance was also obtained. It also has a strong absorption performance for the unburned oil mist ejected from the exhaust. Based on its ideal porous structure, high interception efficiency, and good physicochemical stability at high humidity and high temperatures conditions, therefore, our C-CMPs-M−1 shows great potential in automobile exhaust purification applications.