The retention and fate of Roxarsone(ROX)onto typical reactive soil minerals were crucial for evaluating its potential environmental risk.However,the behavior and molecular-level reaction mechanism of ROX and its subst...The retention and fate of Roxarsone(ROX)onto typical reactive soil minerals were crucial for evaluating its potential environmental risk.However,the behavior and molecular-level reaction mechanism of ROX and its substituents with iron(hydr)oxides remains unclear.Herein,the binding behavior of ROX on ferrihydrite(Fh)was investigated through batch experiments and in-situ ATR-FTIR techniques.Our results demonstrated that Fh is an effective geo-sorbent for the retention of ROX.The pseudo-second-order kinetic and the Langmuir model successfully described the sorption process.The driving force for the binding of ROX on Fh was ascribed to the chemical adsorption,and the rate-limiting step is simultaneously dominated by intraparticle and film diffusion.Isotherms results revealed that the sorption of ROX onto Fh appeared in uniformly distributed monolayer adsorption sites.The twodimensional correlation spectroscopy and XPS results implied that the nitro,hydroxyl,and arsenate moiety of ROX molecules have participated in binding ROX onto Fh,signifying that the predominated mechanisms were attributed to the hydrogen bonding and surface complexation.Our results can help to better understand the ROX-mineral interactions at the molecular level and lay the foundation for exploring the degradation,transformation,and remediation technologies of ROX and structural analog pollutants in the environment.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.42207043 and 41671475)the Ministry of Science and Technology of China(Nos.2022YFD1700101 and 2018YFD0800700)the Excellent Doctoral Dissertation Cultivation Fund of Hunan Agricultural University(No.YB2018004).
文摘The retention and fate of Roxarsone(ROX)onto typical reactive soil minerals were crucial for evaluating its potential environmental risk.However,the behavior and molecular-level reaction mechanism of ROX and its substituents with iron(hydr)oxides remains unclear.Herein,the binding behavior of ROX on ferrihydrite(Fh)was investigated through batch experiments and in-situ ATR-FTIR techniques.Our results demonstrated that Fh is an effective geo-sorbent for the retention of ROX.The pseudo-second-order kinetic and the Langmuir model successfully described the sorption process.The driving force for the binding of ROX on Fh was ascribed to the chemical adsorption,and the rate-limiting step is simultaneously dominated by intraparticle and film diffusion.Isotherms results revealed that the sorption of ROX onto Fh appeared in uniformly distributed monolayer adsorption sites.The twodimensional correlation spectroscopy and XPS results implied that the nitro,hydroxyl,and arsenate moiety of ROX molecules have participated in binding ROX onto Fh,signifying that the predominated mechanisms were attributed to the hydrogen bonding and surface complexation.Our results can help to better understand the ROX-mineral interactions at the molecular level and lay the foundation for exploring the degradation,transformation,and remediation technologies of ROX and structural analog pollutants in the environment.
