Rapid effectual entrapment of pesticide pollutant by phosphorus-doped biochar: Effects and response sequence of functional groups

The purpose of this study is to clarify the mechanism of P-doped biochar adsorbing pesticide pollutants such as 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution. Through environmental interference, adsorption isotherms and kinetic experiments, the mechanism evolution of 2,4-D adsorption by the inherent structure of biochar and the species difference of phosphorus-oxygen groups was investigated. Under controlled nitrogen flow, among the P-doped biochar produced at different pyrolysis temperatures (300, 500 and 700celcius), the P-doped biochar produced at 700celcius (PBC-700) showed the best 2,4-D adsorption capacity (146.41 mg g-1). The adsorption of 2,4-D largely depends on the characteristic surface functional groups, specific surface area and porosity of biochar. In the adsorption process, hydrogen bonding and p- p EDA interaction dominate, and electrostatic force and pore filling play an auxiliary role. The chemisorp-tion function of PBC-700 was weaker than that of PBC-300. The density functional theory (DFT) calcula-tion results showed that the incorporation of P species regulated the electronic structure and surface charge distribution of the biochar. The two-dimensional correlation spectroscopy (2D COS) analysis revealed the order of the main functional groups involved in the adsorption process. Furthermore, the good recovery capacity improved the feasibility of P-doped biochar to repair surface water polluted by pesticides such as 2,4-D.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The purpose of this study is to clarify the mechanism of P-doped biochar adsorbing pesticide pollutants such as 2,4-D in aqueous solution. The characteristics of biochar, including surface functional groups, specific surface area and porosity, play a crucial role in the adsorption of 2,4-D. The incorporation of P species in biochar regulates its electronic structure and surface charge distribution.