Hollow Nanospheres of Conjugated Microporous Polymers for the Degradation of Organic Pollutants in Water

Morphology control and hydrophilic modification are important strategies to improve the photocatalytic activity of polymers. In the present work, novel conjugated microporous polymers with hollow spherical structures (CMPs-HSs) are prepared using 1,3,5-triacetylene benzene and 2,8-dibromodibenzothiophene as monomers through Sonogashira–Hagihara cross-coupling reaction and hard template method. In order to improve the dispersibility of the as-prepared CMPs-HSs in water, the hydrophilic modification of the CMPs-HSs is performed based on the thiol-alkynes click reaction, and the corresponding hydrophilic modified polymer is denoted as CMPs-HSs-S. The band gaps of CMPs-HSs and CMPs-HSs-S are 2.15 and 1.96 eV, respectively. The photocatalytic degradation rate of CMPs-HSs-S to Rhodamine B (RhB 20 mg L–1) is 90% within 80 min, while the CMPs-HSs is only 59%. Under the same experimental conditions, the degradation rate of CMPs-HSs-S to methylene blue (MB 20 mg L–1) is 85% within 120 min, and the degradation rate of CMPs-HSs to methylene blue is only 41%. The results of photocatalytic experiments show that the photocatalytic performance of CMPs-HSs-S is significantly better than that of CMPs-HS, suggesting that hydrophilic modification is more conducive to the contact of CMPs-HSs-S with pollutants and the occurrence of a photodegradation reaction. In addition, the corresponding composite membrane materials (abbreviated as CCMPs-MHSs and CCMPs-MHSs-S) of the CMPs-HS and CMPs-HS-S were prepared by the method of carbonized treatment, and their solar-driven interfacial evaporation (SDIE) performance was also studied. Under 1 kW m–2 simulated sunlight irradiation, the solar evaporation rates of CCMPs-MHSs and CCMPs-MHSs-S are 1.38 and 1.41 kg m–2 h–1 and the photothermal conversion efficiencies are 81.5 and 84.6%, respectively. Therefore, considering the designable flexibility of CMPs, the CMPs-based novel materials have great application potential in the study of photodegradation of organic dyes, solar-driven interfacial evaporation, etc.