N-doped porous carbon modified by polyacrylic acid for efficient removal of disinfection products in environmental waters under extensive conditions

Abstract

In this work, a novel porous carbon nanocomposite was successfully prepared by creatively using polyacrylic acid to modify N-doped porous carbon, which was used to adsorb and remove new cyclic chlorine disinfection by-products in various water environments. The high-temperature calcination process at 1000 °C created a hierarchical pore structure that contained both micropores and mesopores. This structure significantly increased the mass transfer efficiency of the target on the adsorbent. The incorporation of N atoms enhanced NC's binding affinity and furnished target adsorption sites. The dispersion of N-doped porous carbon was significantly improved after polyacrylic acid modification. Moreover, the surface charge of NC-1000 was also altered, facilitating easier electrostatic interaction with DBPs. Subsequently, faster adsorption kinetics was obtained within 2 min, and the removal efficiency of 2,4-dichlorophenol (2,4-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) were promoted to 94.10 % and 98.71 %, respectively. Characterization and data analysis revealed that the primary adsorption mechanism was chemical (electrostatic interaction, hydrophobic interaction, π-π interaction, and hydrogen bond). Surprisingly, factors such as ionic strength, natural organic matter and pH had minimal impact on the adsorption process, indicating that NC-1000@PAA had excellent anti-interference performance. Despite undergoing four adsorption–desorption cycles, NC-1000@PAA upheld a steady composition along with a remarkable adsorption capability. Furthermore, NC-1000@PAA had negligible cytotoxicity, which was assessed by cell experiments. The application of NC-1000@PAA was attested in various environmental waters. The proposed method provided a new strategy to pollutant removal by NC-1000@PAA under extensive conditions, which had wide perspective and practicability on the purification treatment of environmental water.