Electroosmotic flow (EOF) is an electrokinetic phenomenon that occurs when an ionic current is passed through a channel or porous material that contains excess surface charge. We have found that net flow through a conical-pore membrane can be achieved by applying a symmetrical sinusoidal voltage waveform across the membrane. This is possible because the alternating current (AC) carried by ions through the nanopore is rectified. Here, the EOF pump based on polyethylene terephthalate (PET) membranes were modified with 18-crown-6 to selectively pump solution without lead ions. As more lead ions bound with 18-crown-6 on the surface, the surface charge was more neutral. Thus, the electroosmotic flow was less rectified. Finally, the net flow was zero meaning the pump was turned off if the lead concentration is high enough. The flow rate of EOF pump in a series of lead ions aqueous solution was investigated. We also reported the selectivity of this EOF pump in the aqueous solution with different metal ions.