Multi-heteroatom doped graphene-like carbon nanospheres with 3D inverse opal structure: a promising bisphenol-A remediation material

Abstract

Nitrogen, phosphorus, and sulfur co-doped 3D inverse opal structured graphene-like carbon nanospheres (denoted as NPS-IOC) are reported for the first time by graphitization of highly cross-linked poly (cyclo-triphosphazene-co-4,4′-sulfonyldiphenol) (PZS). The resulting NPS-IOC possessed hierarchical interconnected spherical voids with a diameter of about 400 nm, which not only offered a short diffusion distance for mass transportation, but also aggrandized the surface area to increase active sites. NPS-IOC₄₀₀ exhibited excellent BPA capture performance with a maximum adsorption capacity of 255.39 mg g⁻¹ at 298.15 K, ultrafast removal rate, especially stable under high ionic strengths and suitable for wide pH environments. Our systematic spectroscopic characterizations and theoretical calculations demonstrated that the adsorption mechanism was mainly driven by π–π stacking interaction. Meanwhile, electrostatic interaction, hydrophobic interactions and hydrogen-bonding also played roles in the adsorption mechanism. Most importantly, the doped N, P, S heteroatoms played a synergistic effect which promoted the adsorption process. Its unique structure and excellent performance endowed NPS-IOC with a great promising future for governing organic pollutants in aquatic environments.