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Novel nitrogen (N)-doped cellulose biochar (NC1000-10) with large adsorption capacity (103.59 mg g -1 ) for atrazine (ATZ) was synthesized through the one-pot method. It has the best adsorption efficiency than N-doped biochars prepared from hemicellulose and lignin. The adsorption behaviors of ATZ by N-doped biochars with different N doping ratios (NC1000-5, NC1000-10, NC1000-20 and NC1000-30) were significantly different, which was attributed to the difference of sp 2 conjugate C (I D /I G = 0.99-1.18) and doped heteroatom N (pyridinic N, pyrrolic N and graphitic N). Adsorption performance of ATZ on NC1000-10 conformed to the pseudo-second-order kinetic and Langmuir adsorption isotherm model. Thermodynamic calculations showed that adsorption performance was favorable. Besides, wide pH adaptability (pH = 2-10), good resistance to ionic strength and excellent recycling efficiency make it have extensive practical application potential. Further material characterizations and the density functional theory (DFT) calculations indicated that good adsorption performance of NC1000-10 for ATZ mainly depended on chemisorption, and π-π electron donor-acceptor (EDA) interaction contributed the most due to high graphitization degree. Specifically, pyridinic N and graphitic N further promoted adsorption performance by hydrophobic effect and π-π EDA interaction between ATZ and NC1000-10, respectively. Pyrrolic N and other surface functional groups (-COOH, -OH) facilitated the hydrogen bond effect., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Herein, a highly dispersed catalyst (ZnO x -500) was synthesized for heterogeneous catalytic ozonation (HCO), which had a simple ZnO crystal phase but riched in oxygen vacancies (OVs). The O 3 /ZnO x -500 system exhibited both superior catalytic activity and stability after several cycles, providing a promising strategy for atrazine (ATZ) removal. The strong inhibition of phosphoric acid validated the dominant role of the hydroxyl group (−OH) from water molecule (H 2 O) dissociation on the zinc site near OVs. Density functional theory calculation further revealed that OVs on (100) and (101) planes could make more zinc sites exposed and facilitate the formation of hydrated −OH, which was easier to approach O 3 for its decomposition to generate hydroxyl radical (•OH). This work revealed the intrinsic relationship between OVs and hydrated −OH in an aqueous solution, providing new insight into the solid-liquid interface mechanism of HCO. [Display omitted] • ZnO x -500 riched in oxygen vacancies was synthesized via a one-step method. • Oxygen vacancies promoted the formation of surface –OH by dissociating water molecules. • The formed surface −OH effectively attributed to •OH production. • OH played a crucial role in O 3 /ZnO x -500 for ATZ degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synergistic effect of adsorption (24.5%) and catalytic ozonation (74.4%) by NBC700 promoted ATZ removal. • O 3 was in-situ decomposed into *O 2 and *O. • OH was the dominant ROS and surface-O 3 further strengthened ozonation. • Defects were the major active sites verified by DFT calculation. Adsorption is the first step of the interface mechanism, but the adsorption behaviors of ozone (O 3) and pollutants on the catalyst during catalytic ozonation have always been overlooked in previous works. In this study, a promising strategy for the in-situ decomposition of O 3 to trigger surface reactive oxygen species (ROS) by nitrogen (N)-doped biochar was proposed, which greatly improved the efficiency of O 3 utilization. Specifically, N -doped biochar (NBC700) with a high defect level (I D /I G = 1.165) was achieved by a one-pot method. It showed good adsorption on O 3 and atrazine (ATZ), which promoted the in-situ formation of surface ROS, as well as resists the interferences of multiple coexisting anions (NO 3 −, Cl−, PO 4 3−, SO 4 2− and HCO 3 −) on ATZ removal. In-situ Raman spectra revealed the interface catalytic mechanism of O 3 decomposition into adsorbed peroxide species (*O 2) and adsorbed atomic oxygen (*O). Additionally, OH was the dominant ROS and surface-O 3 further strengthened direct ozonation via intramolecular electron transfer. In this process, sp 2-hybridized system with delocalized π electrons, electron-rich oxygen-containing functional groups, and conjugated heteroatoms were identified as the active sites, but defective sites with free electrons played the most important part according to the lowest adsorption energy (−13.12 eV) calculated by density functional theory (DFT). The degradation of ATZ included dechlorination and non-dechlorination pathways, which made the acute and chronic toxicity of most intermediate products both decrease to not be harmful to fish and green algae. This work provides a new perspective on the interface mechanism in catalytic ozonation for ATZ removal. [ABSTRACT FROM AUTHOR]