Adsorption toward Cu(II) and inhibitory effect on bacterial growth occurring on molybdenum disulfide-montmorillonite hydrogel surface.

Novel molybdenum disulfide-montmorillonite (MoS@2DMMT) hydrogels for Cu(II) removal and inhibition on bacterial growth were successfully prepared. MoS was first in-situ growth onto 2DMMT platelet through hydrothermal method and then cross-linked with organic reagents to form hydrogels. The flower-like structure of synthesized MoS could be clearly observed in MoS@2DMMT by SEM. The synthesized hydrogels possessed a three-dimensional macroporous structure, offering a free access for contaminants to get inside and combine with the active sites. Adsorption tests revealed that efficient Cu(II) removal (65.75 mg/g) could be achieved within a short time (30 min) at pH 5. The pseudo-second-order kinetics model and Langmuir isotherm model indicated the existence of chemisorption and monolayer absorption for Cu(II) onto MoS@2DMMT hydrogels. Characterizations of EDS and XPS indicated that Cu(II) reacted with groups of carboxyl, hydroxyl and amidogen. Bacteriostatic tests revealed that almost a complete bacteriostatic was achieved with just small dosage (0.8 mg/mL) of MoS@2DMMT hydrogels after the Cu(II) removal under the normal illumination. The mechanism was ascribed to the destructive effect of Cu(II) to the cytomembrane and the damage of reactive oxygen species (ROS) to the DNA. Such hydrogel not only provided insights for treating co-existing contaminates, but also guides for designing novel polymer materials from two-dimensional (2D) nano-materials.