Dynamics of Humic Acid and Its Interaction with Uranyl in the Presence of Hydrophobic Surface Implicated by Molecular Dynamics Simulations.
This work targeted a molecular level of understanding on the dynamics of humic acid (HA) and its interaction with uranyl in the presence of hydrophobic surface mimicked by a carbon nanotube (CNT), which also represents a potential intruder in the environment accompanying with the development of nanotechnology. In aqueous phase, uranyl and HA were observed to build close contact spontaneously, driven by electrostatic interaction, leading to a more compact conformation of HA. The presence of CNT unfolds HA via π-π interactions with the aromatic rings of HA without significant perturbation on the interaction strength between HA and uranyl. These results show that the hydrophilic uranyl and the hydrophobic CNT influence the folding behavior of HA in distinct manners, which represents two fundamental mechanisms that the folding behavior of HA may be modulated in the environment, that is, uranyl enhances the folding of HA via electrostatic interactions, whereas CNT impedes its spontaneous folding via van der Waals (vdW) interactions. The work also provides molecular level of evidence on the transformation of a hydrophobic surface into a hydrophilic one via noncovalent functionalization by HA, which in turn affects the migration of HA and the cations it binds to.
Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education; Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064, P.R.China.|CAS Key Laboratory of Nuclear Radiation and Nuclear Techniques, Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, P.R.China.
Tu
T
Lan
CAS Key Laboratory of Nuclear Radiation and Nuclear Techniques, Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, P.R.China.
Hui
H
Wang
Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education; Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064, P.R.China.
Jiali
J
Liao
Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education; Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064, P.R.China.
Yuanyou
Y
Yang
CAS Key Laboratory of Nuclear Radiation and Nuclear Techniques, Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, P.R.China.|School of Radiation Medicine and Interdisciplinary Sciences (RAD-X), Soochow University , Suzhou 215123, P.R.China.
Zhifang
Z
Chai
Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education; Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064, P.R.China.
Ning
N
Liu
CAS Key Laboratory of Nuclear Radiation and Nuclear Techniques, Multidisciplinary Initiative Center, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, P.R.China.
Dongqi
D
Wang