Contact and demand‐release disinfectants

A new class of solid‐phase disinfectants has emerged in recent years. Certain types of these disinfectants, the iodinated strong base resins, release iodine upon demand to microorganisms in water. These triiodide and pentaiodide resins have proven effective against a large number of bacterial genera, viruses, and representative parasites such as Giardia lamblia. Although federal regulatory policies have prevented their use for large scale water purification, they have been selectively applied in the U.S. Space Program and in situations for short‐term water disinfection. They appear to hold promise as components of hybrid devices utilizing filtration and halogen scavenging to produce high quality, potable water.