Effect of ternary polymer composites of macroporous adsorbents on adsorption properties for heavy metal removal from aqueous solution.

This research is focused on the preparation of macroporous poly(vinyl alcohol) (PVA)/chitosan (CS)/Al2O3 adsorbents for removal of residual metal ions from wastewater. The PVA/CS/Al2O3 adsorbents were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and energy dispersive X-ray (EDX) techniques to confirm that all compositions were incorporated into the PVA/CS/Al2O3 adsorbents without chemical modification. Furthermore, a comparison of the properties of the PVA/CS/Al2O3 adsorbents suggested that PVA/CS/0.50Al2O3 was the most suitable sample for adsorption study. The adsorption properties of PVA/CS/0.50Al2O3 for the removal of metal ions such as Pb2+, Cu2+, Zn2+, and Ni2+ in aqueous solution adsorbents in both single and quaternary systems were investigated. The results show that the adsorption selectivity of the PVA/CS/0.50Al2O3 adsorbent for these metal ions was provided in the following order: Pb2+ > Cu2+ > Zn2+ > Ni2+. The adsorption isotherm was studied by equilibrium data obtained from batch experiments. It was found that the Freundlich isotherm model was suitable for explaining the adsorption process. Adsorption kinetics were studied, which indicated that the adsorption of Pb2+, Cu2+, and Zn2+ followed a pseudo-second-order kinetic model, while the adsorption of Ni2+ followed a pseudo-first-order kinetic model. In addition, adsorption-desorption cycles were studied to prove the reusability of PVA/CS/0.50Al2O3 adsorbents. The PVA/CS/0.50Al2O3 adsorbents were able to be regenerated and reused. In a continuous adsorption process, a column experiment was simulated in laboratory. The results showed that Cu2+ was the most selective for a fixed-bed column. Thus, PVA/CS/0.50Al2O3 adsorbents could be potential used for toxic metal ion removal from wastewater, in both batch and fixed-bed continuous-flow columns.

Metallopolymer-peptide hybrid materials: synthesis and self-assembly of functional, polyferrocenylsilane-tetrapeptide conjugates.

Conjugates of poly(ferrocenyldimethylsilane) (PFDMS) with Ac-(GA)(2)-OH, Ac-A(4)-OH, Ac-G(4)-OH and Ac-V(4)-OH have been prepared by reaction of the tetrapeptide units with the amino-terminated metallopolymer. The number average degree of polymerisation (DP(n)) of the PFDMS was approximately 20 and comparable materials with shorter (DP(n) ≈ 10) and/or amorphous chains have been prepared by the same procedure. Poly(ferrocenylethylmethylsilane) (PFEMS) was employed for the latter purpose. All conjugates were characterised by GPC, MALDI-TOF MS, NMR and IR spectroscopy. With the exception of Ac-V(4)-PFDMS(20), all materials exhibited some anti-parallel ß-sheet structure in the solid state. The self-assembly of the conjugates was studied in toluene by DLS. The vast majority of the materials, irrespective of peptide sequence or chain crystallinity, afforded fibres consisting of a peptidic core surrounded by a PFS corona. These fibres were found in the form of cross-linked networks by TEM and AFM. The accessibility of the chemically reducing PFS corona has been demonstrated by the localised formation of silver nanoparticles on the surface of the fibres.