Adsorption promoted heterogeneous catalytic ozonation for removing emerging contaminations: The intrinsic correlations with biochar properties and complementary effect of adsorption and ozonation processes

Abstract

The increasingly strict standards for petrochemical wastewater treatment and the increasing attention to emerging contaminations (ECs) have exacerbated the problems of limited activity, insufficient mass transfer power and poor pH stability faced by ozonation processes. Adsorption promoted heterologous catalytic ozonation (HCOAP) based on Enteromorpha prolifera-based biochar (EpC) is a clean and efficient technology to overcome the above problems. By exploring the detailed conversion pathways of N, O functional groups during pyrolysis, EpC2-650 with optimal HCOAP activity is obtained, which has the best complementary effect during ECs removal due to the alternating change between adsorption and heterogeneous ozonation processes under different conditions. Besides dominant functional groups, the HCOAP reactivity is also influenced by surface electrostatic potential, CDD (atomic reactivity), and frontier molecular orbital of ECs. Among the representative advantageous structure, the 2p orbitals hybridization on the bonding states orbital and the close charge exchange between pyrrolic-N and *O3 (EA-O3 = -2.9 eV) promote the formation of *O and reduce ROS generation barrier. Specifically, EpC2-650-HCOAP system has the highest production of ⋅OH and ⋅O2-, and maintaining a stable ECs removal rate with only a 3.17 % variation for TC and a 2.93 % variation for PNP across a pH range of 6.5 to 9. Additionally, it achieves higher treatment efficiency for petrochemical wastewater than ozonation and adsorption systems. This study provides reference for the activity prediction of biomass materials, and highlights the potential of ozonation progress in the efficient and stable application for treating ECs.