Xiu-Zhen Wei

A NOVEL NANOFILTRATION MEMBRANE PREPARED WITH PAMAM AND TMC (I)

A series of nanofiltration (NF) membranes were prepared with poly(amido-amine) (PAMAM) and trimesoyl chloride (TMC) via in situ interfacial polymerization. The effects of the generation number and concentration of PAMAM on the properties of NF membranes were discussed. Fourier transform infrared spectroscopy (FTIR-ATR), atomic force microscopy (AFM), scanning electron microscopy (SEM) and contact angle measurements were employed to characterize the resulting membranes. The nanofiltration performances were evaluated with solutions of NaCl, Na2SO4, MgCl2 and MgSO4, respectively. FTIR-ATR spectra indicated that TMC reacted more sufficiently with the higher generation PAMAM. The salts rejection of the resulting membranes increased with increasing the generation number of PAMAM, which was mainly attributed to the concentration difference of terminal amino-groups among the different generation PAMAM. The MgCl2 (2000 mg/L) rejection of NF-G5 reached 90.3% under the pressure of 0.6 MPa in a cross-flow method measurement. The rejection of MgCl2 increased with increasing concentration of PAMAM. The salts rejection order of NF membranes with high rejection is MgCl2 > MgSO4 > Na2SO4 > NaCl. It was also found that the NF-Gx (x = 4, 5, 6, 7) membranes became more hydrophilic with increasing the generation number of PAMAM.

Preparation and Stability of Copper Particles Formed Using Amino-terminated Dendrimer as Template

Amine-terminated seventh generation dendrimers (G7-NH2) were synthesised and employed to investigate the interior and exterior template processes for the preparation of copper particles. Ultra-violet spectroscopy and transmission electron microscopy were used to characterise the absorption properties of the G7-NH2(Cu2+)n complexes and the morphology of G7-NH2(Cu)n composite particles, respectively. Unlike the case where dendrimers with hydroxyl end-groups are used, copper particles could be prepared by exterior template process. Both the size of the copper particles and their tendency to aggregation increased as the Cu2+/G7-NH2 molar ratio increased. The copper particles were stable under oxygen-free conditions and could easily be oxidised to G7-NH2(Cu2+)n complex ions in the presence of oxygen.