Ion exchanger

A method for manufacturing a porous ion exchanger having many macropores therein, comprising the steps of:

• mixing an oil-soluble monomer, a precipitant which is a poor solvent with respect to a polymer obtained by polymerizing the oil-soluble monomer and which dissolves the oil-soluble monomer, a surface-active agent, and water to form a water-in-oil type emulsion in which water droplets are dispersed in an oil phase;
• polymerizing the monomer in the water-in-oil type emulsion to form a porous material;
• and
• introducing an ion exchange group into the formed porous material to manufacture the ion exchanger including an open cell structure in which the macropores are interconnected via mesopores and an average diameter of the mesopores is in a range of 1 to 1000 μm, and further including micropores as a non-continuous pores having an average pore diameter of 5 to 800 nm and existing on inner walls which define the respective pores.