Fate and Transport of Molybdenum Disulfide Nanomaterials in Sand Columns.
Research and development of two-dimensional transition metal dichalcogenides (TMDC) (e.g., molybdenum disulfide [MoS2]) in electronic, optical, and catalytic applications has been growing rapidly. However, there is little known regarding the behavior of these particles once released into aquatic environments. Therefore, an in-depth study regarding the fate and transport of two popular types of MoS2nanomaterials, lithiated (MoS2-Li) and Pluronic PF-87 dispersed (MoS2-PL), was conducted in saturated porous media (quartz sand) to identify which form would be least mobile in aquatic environments. The electrokinetic properties and hydrodynamic diameters of MoS2as a function of ionic strength and pH were determined using a zeta potential analyzer and dynamic light scattering techniques. Results suggest that the stability is significantly decreased beginning at 10 and 31.6 mM KCl, for MoS2-PL and MoS2-Li, respectively. Transport study results from breakthrough curves, column dissections, and release experiments suggest that MoS2-PL exhibits a greater affinity to be irreversibly bound to quartz surfaces as compared with the MoS2-Li at a similar ionic strength. Derjaguin-Landau-Verwey-Overbeek theory was used to help explain the unique interactions between the MoS2-PL and MoS2-Li surfaces between particles and with the quartz collectors. Overall, the results suggest that the fate and transport of MoS2is dependent on the type of MoS2that enters the environment, where MoS2-PL will be least mobile and more likely be deposited in porous media from pluronic-quartz interactions, whereas MoS2-Li will travel greater distances and have a greater tendency to be remobilized in sand columns.
Department of Chemical and Environmental Engineering, University of California , Riverside, California.
Jacob D
JD
Lanphere
Department of Chemical and Environmental Engineering, University of California , Riverside, California.
Corey J
CJ
Luth
Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois.
Linda M
LM
Guiney
Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois.
Nikhita D
ND
Mansukhani
Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois.
Mark C
MC
Hersam
Department of Chemical and Environmental Engineering, University of California , Riverside, California.
Sharon L
SL
Walker
effects of pH and ionic strength; molybdenum disulfide (MoS2); nanomaterials; pluronic coating; stability; straining; transport in packed bed column