Functional copolymers obtained by modification of existing polymers using radiation induced graft copolymerization are attractive materials due to their enhanced separation properties. For further progress, however, copolymers with favorable properties and geometries must be developed to address the growing demands in the field of separation and purification. In this review, the current status of research on the development and applications of radiation-grafted copolymers for separation and purification purposes is presented without neglecting the seminal work that laid the foundation to today's progress. The basic principles of this field including classifications and description of radiation-grafted copolymers with their engineering configurations and operating systems are reviewed. A wide range of diverse separation applications is addressed, covering water production, chemical industry, environmental remediation, biotechnology and biomedicine categories. The emerging applications of the new radiation-grafted materials (membranes, brushes, nanogels and microgels, hydrogels, fibers and monoliths) in separation technology are taken into account. The challenges hindering the utilization of radiation-grafted copolymers to wider commercialization applications are discussed. Future directions in developing and promoting new and advanced radiation-grafted copolymers to address separation challenges and move to new technological fronts are also deliberated. (C) 2012 Elsevier Ltd. All rights reserved.