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Synergetic adsorption of polymers on montmorillonite: Insights from molecular dynamics simulations
https://orcid.org/0000-0003-2144-6039
https://orcid.org/0000-0002-2387-3571
Abstract In the treatment of industrial tailings, fine clay minerals are generally flocculated using polymer flocculants. Interestingly, applications of multiple types of polymers together were reported to enhance the flocculation, although the underlying mechanism was still unclear. In this work, a series of molecular dynamics simulations were performed to investigate the synergetic adsorption of two types of polymers on the basal surface of montmorillonite (Mt) in aqueous environments. Cationic chitosan molecules were first introduced, followed by the addition of either neutral polyacrylamide (PAM) or anionic Magnafloc (MF). A monolayer coating of chitosan was observed to form quickly on the Mt surface. The coating was stable and facilitated the subsequent adsorption of PAM or MF which by themselves did not show effective adsorption. Adsorption of PAM and MF showed different configurations. PAM could adsorb either directly on Mt or on chitosan, in the form of clusters or individual molecules. On the other hand, MF only adsorbed on chitosan, forming a two-layer structure above the Mt surface. Adding chitosan simultaneously with PAM or MF, instead of sequentially, did not change the characteristics of the adsorption. The synergetic adsorption of polymers was attributed to the interplay of electrostatic attraction between Mt and chitosan, hydrogen bonding between chitosan and PAM, as well as electrostatic attraction between chitosan and MF. Together, the simulation results allowed us to provide a mechanistic explanation for the experimentally observed synergetic flocculation enabled by adding multiple polymers.
Highlights Chitosan and polyacrylamide adsorbed on montmorillonite in different forms. Adsorption of polyacrylamide was enhanced by the co-application of chitosan. Unstable Magnafloc adsorption was stabilized by adding chitosan. Adding sequence of two types of polymers did not affect the synergetic adsorption. Better clay flocculation enabled by multiple types of polymers was explained.
Synergetic adsorption of polymers on montmorillonite: Insights from molecular dynamics simulations
https://orcid.org/0000-0003-2144-6039
https://orcid.org/0000-0002-2387-3571
Abstract In the treatment of industrial tailings, fine clay minerals are generally flocculated using polymer flocculants. Interestingly, applications of multiple types of polymers together were reported to enhance the flocculation, although the underlying mechanism was still unclear. In this work, a series of molecular dynamics simulations were performed to investigate the synergetic adsorption of two types of polymers on the basal surface of montmorillonite (Mt) in aqueous environments. Cationic chitosan molecules were first introduced, followed by the addition of either neutral polyacrylamide (PAM) or anionic Magnafloc (MF). A monolayer coating of chitosan was observed to form quickly on the Mt surface. The coating was stable and facilitated the subsequent adsorption of PAM or MF which by themselves did not show effective adsorption. Adsorption of PAM and MF showed different configurations. PAM could adsorb either directly on Mt or on chitosan, in the form of clusters or individual molecules. On the other hand, MF only adsorbed on chitosan, forming a two-layer structure above the Mt surface. Adding chitosan simultaneously with PAM or MF, instead of sequentially, did not change the characteristics of the adsorption. The synergetic adsorption of polymers was attributed to the interplay of electrostatic attraction between Mt and chitosan, hydrogen bonding between chitosan and PAM, as well as electrostatic attraction between chitosan and MF. Together, the simulation results allowed us to provide a mechanistic explanation for the experimentally observed synergetic flocculation enabled by adding multiple polymers.
Highlights Chitosan and polyacrylamide adsorbed on montmorillonite in different forms. Adsorption of polyacrylamide was enhanced by the co-application of chitosan. Unstable Magnafloc adsorption was stabilized by adding chitosan. Adding sequence of two types of polymers did not affect the synergetic adsorption. Better clay flocculation enabled by multiple types of polymers was explained.
Synergetic adsorption of polymers on montmorillonite: Insights from molecular dynamics simulations
https://orcid.org/0000-0003-2144-6039
https://orcid.org/0000-0002-2387-3571
Abstract In the treatment of industrial tailings, fine clay minerals are generally flocculated using polymer flocculants. Interestingly, applications of multiple types of polymers together were reported to enhance the flocculation, although the underlying mechanism was still unclear. In this work, a series of molecular dynamics simulations were performed to investigate the synergetic adsorption of two types of polymers on the basal surface of montmorillonite (Mt) in aqueous environments. Cationic chitosan molecules were first introduced, followed by the addition of either neutral polyacrylamide (PAM) or anionic Magnafloc (MF). A monolayer coating of chitosan was observed to form quickly on the Mt surface. The coating was stable and facilitated the subsequent adsorption of PAM or MF which by themselves did not show effective adsorption. Adsorption of PAM and MF showed different configurations. PAM could adsorb either directly on Mt or on chitosan, in the form of clusters or individual molecules. On the other hand, MF only adsorbed on chitosan, forming a two-layer structure above the Mt surface. Adding chitosan simultaneously with PAM or MF, instead of sequentially, did not change the characteristics of the adsorption. The synergetic adsorption of polymers was attributed to the interplay of electrostatic attraction between Mt and chitosan, hydrogen bonding between chitosan and PAM, as well as electrostatic attraction between chitosan and MF. Together, the simulation results allowed us to provide a mechanistic explanation for the experimentally observed synergetic flocculation enabled by adding multiple polymers.
Highlights Chitosan and polyacrylamide adsorbed on montmorillonite in different forms. Adsorption of polyacrylamide was enhanced by the co-application of chitosan. Unstable Magnafloc adsorption was stabilized by adding chitosan. Adding sequence of two types of polymers did not affect the synergetic adsorption. Better clay flocculation enabled by multiple types of polymers was explained.
Synergetic adsorption of polymers on montmorillonite: Insights from molecular dynamics simulations
Sun, Wenyuan (Autor:in) / Zeng, Hongbo (Autor:in) / Tang, Tian (Autor:in)
Applied Clay Science ; 193
30.04.2020
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
| British Library Online Contents | 2017