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

This paper reports a kind of CMPs membrane named C-CMPs-M−1 that was synthesized by the Sonogashira-Hagihara cross-coupling reaction. The C-CMPs-M−1 has a special "Hamburger" structure composed of ultra-high crosslinked nanotubes and lamellar structures which allows it to be used as a filter for applications in automobile exhaust purification. The superhydrophobicity of C-CMPs-M−1 allow the CMPs-based filter to maintain high efficiency (PM 2.5 and PM 10 ≥99%, and PM 0.3 ˃90%) in harsh conditions such as high humidity (RH: 90% ± 3%). In addition, the superlipophilicity 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. [Display omitted] • Using a simple method to prepare a membrane with a special "Hamburger" structure. • The membrane exhibits high filtration efficiency in high humidity environments. • The membrane shows good oil absorption and oil retention properties. • The membrane has a good oil–water separation ability. 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 PM 2.5 and PM 10 (greater than99.5 %) and PM 0.3 (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. [ABSTRACT FROM AUTHOR]