Insight into the high-efficiency adsorption of pyrene by Schiff base porous polymers: Modelling and mechanism

ABSTRACT Pyrene (PYR) as one of polycyclic aromatic hydrocarbons (PAHs) has attracted increasing attention due to their carcinogenicity, mutagenicity and toxicity. A novel Schiff base porous organic nanocomposite is successfully synthesized via the encapsulating and etching processes. Nano-scale calcium carbonate was used as the solid core in Schiff base derived by condensation of 1, 4-Diaminobenzene and Benzene-1, 4-dicarboxaldehyde. After that, the solid state calcium carbonate was etched by low concentration hydrochloric acid. Finally, Schiff base polymer with porous structure was obtained through filtration, rinsing and drying. XRD, SEM, BET, XPS, Raman, FTIR and TGA technologies were used to characterize the samples. As expected, the novel Schiff base porous organic polymer (SBPP-0.5) exhibited excellent adsorption capacity for PYR. Based on adsorption isotherms and kinetics investigation, PYR adsorption on Schiff base porous organic polymer is mainly affected by chemical interactions. The adsorption sites are uniform and the aromatic structure of planer PYR molecules could inevitably present intense π-π interactions with the aromatic nucleus of Schiff base porous organic polymer. The adsorption process is multi-stage and film diffusion dominated the adsorption process, which is mainly occurred in the initial adsorption stage. This work shows that Schiff base polymer with complicated microstructure can be used for PAHs removing.