Clay minerals, consisting of octahedral Al-O and tetrahedral Si-O layers, typically exist in stacked assemblages. Inspired by the fascinating structural features of clay minerals, we explored their potential in making advanced ecomaterials for environmental purposes as following: 1) New adsorbents were successfully prepared by in-situ growing Fe3O4 nanoparticles on halloysite nanotubes (HNTs) followed by subsequent modification with silane coupling agents. Among various silane coupling agents modified HNTs/Fe3O4, anilino-methyl-triethoxysilane (KH-42) modified HNTs/Fe3O4 composite exhibits the highest capacity for Cr(VI) adsorption. Furthermore, the presence of Cr(VI) enhances the Sb(V) removal by m-HNTs/Fe3O4. Spectroscopic studies reveal the existence of N–O–Cr bonds on adsorbent surfaces in the corresponding single-solute system, while Cr–O–Sb binding forms in the bi-solute system, which is responsible for the synergistic promoting effect on simultaneous adsorption of Cr(VI) and Sb(V).[1] 2) polyacrylamide/organo-vermiculite (PAM/OVerm) was prepared via solution polymerization of acrylamide (AM) in the presence of 3-(Triethoxysilyl)propyl methacrylate (TEPM) modified vermiculite (OVerm), and then triethylene tetramine (TETA) was grafted thereon using the Mannich reaction. As-prepared polymeric composite g-PAM/OVerm was tested for Pb(II) removal. The equilibrium data of Pb(II) adsorption on g-PAM/OVerm well fits the Langmuir sorption isotherms, and the maximum adsorption capacity of Pb(II) onto g-PAM/OVerm is 219.4 mg*g-1. Additionally, adsorbed Pb(II) on g-PAM/OVerm could be effectively desorbed in hot hydrochloric acid solution, and the adsorption capacity of the regenerated adsorbents could still be maintained at 90% at the fifth cycle test. The present work evinces that polymeric clay mineral-based composites hold great potential for heavy metal removal from aqueous system.

Clay mineral-based polymeric nanocomposites for heavy metal removal

255th National Meeting (2018)

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