Rapid synthesis of graphite phase carbon nitride/zeolitic imidazolate framework-8 with hierarchical structure and its superior adsorption of polycyclic aromatic hydrocarbons from aqueous solution.

Graphite phase carbon nitride (g-C3N4) incorporating zeolitic imidazolate framework-8 (ZIF-8) nanocomposite (g-C3N4 /ZIF-8) with hierarchical structure was synthesized successfully by simple and rapid in situ growth method at room temperature. The composites were used as an adsorbent of solid-phase extraction (SPE) and the superior adsorptive removal of polycyclic aromatic hydrocarbons (PAHs) for the first time. Under several optimum conditions, the g-C3N4 /ZIF-8-SPE-HPLC-FLD method show low detection limits (0.006-3.41 µg L-1) and limit of quantification (0.02-11.3 µg L-1), wide linear ranges from 0.02 to 1000 µg L-1 for all compounds, correlation coefficients (r) of more than 0.9968, and satisfying reproducibility (relative standard deviations, RSDs < 4.0% for intra-day, RSDs < 8.3% for inter-day), the spiked recoveries at two levels of 10.0, 50.0 µg L-1 were in the range of 77.4%-114% with the RSDs less than 8.66%. In addition, the g-C3N4/ZIF-8 nanocomposites demonstrated excellent enrichment ability and extraction efficiency for PAHs compared with commercial adsorbents, which might since there were strong π-π stacking force, hydrophobic interaction, hydrogen bonding, and more adsorption sites compared with other adsorbents. Finally, the g-C3N4 /ZIF-8 based SPE method was combined with high-performance liquid chromatography (HPLC) to detect fifteen PAHs in environmental water samples successfully.