Abstract: An apparatus and method for the photocatalytic conversion of contaminants in a fluid stream. Fluid is directed through a semitransparent packed bed or an open cell, three dimensionally reticulated, fluid permeable, semiconductor unit. Within the unit, a semiconductor, when exposed to a photoactivating light source, converts the contaminants through a photocatalytic reaction. Both the substrate and the semiconductor photocatalyst are semitransparent to the activating light to allow penetration of light into the unit, thereby distributing the light, increasing the active specific surface area, and improving the net conversion performance of the unit.

Abstract: An apparatus and method for the photocatalytic purification and ultrapurification of water. Water containing organic, inorganic and/or biological contaminants is directed through an open cell, three dimensionally reticulated, fluid permeable, semiconductor unit. Within the unit, a semiconductor surface capable of promoting electrons from its valence band to its conduction band, when exposed to a photoactivating light source, removes the contaminants through a photocatalytic reaction.