Liquid membrane technique is introduced as subset of membrane science. This technique has attracted increasing attention for its potential capability field of separation and demonstrated as an effective tool in many applications. The present book reports the first application in Iraq ,by using macro cyclic compounds (crown ethers) as carrier in Liquid Membrane techniques as well as the matching size model of crown ethers with various ionic radius of metal ions, from evaluation of dibenzo 18-Crown-6, dicyclohexyl 18-crown-6 Kryptofix 2.2.2 and diaza 18-crowwn-6 as carrier molecule and study the transport behavior of Pb2+, Cd2+, Zn2+ and ReO4- across (1,2-dichloroethane, chloroform and carbon tetrachloride) as Bulk Liquid Membrane. In the present work transport experiments were performed across Bulk Liquid Membranes(BLMs) using U-Shape Setup from source phase which consist of 10-3M of metal ions dissolved in 10 mL of double distilled deionized water at pH=5.2-5.5 for Pb2+, Cd2+, Zn2+ metal cations and at PH= 6.2-6.5 for ReO4- metal anion to receiving phase consist of 10ml of double distilled deionized water at pH= 3.2-3.7 across organic phase consisting 0.001M of dibenzo18-crown-6,