Abstract: Based on activation, coupling and chelating processes, PP(polypropylene) microporous membranes whose surface was treated by low temperature plasma were used for preparation of affinity membranes with Fe³⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal chelating ligand respectively. Those affinity membranes have been used for adsorption desorption experiments of lysozyme. The experimental results showed that adsorption capacity of the membranes with Ni²⁺ or Cu²⁺ metal chelating ligand is higher than that with Fe³⁺ or Zn²⁺ metal chelating ligand. The adsorption capacity of affinity membrane made in Cl^- ion solution is also higher than that made in SO₂^4- ion solution. The experimental results also showed that affinity membranes with Ni²⁺ or Cu²⁺ can be reused several times while affinity membrane with Fe³⁺ ion can not. Adsorption amount of lysozyme can be partly restored by addition of metal ions on the reused affinity membranes.

Key words: Polypropylene membrane, Plasma treatment, Affinity adsorption, Metal-chelat-ing ligand, Lysozyme