PILOT-PLANT-SCALE PHOTODEGRADATION OF PHENOL IN AQUEOUS-SOLUTION BY PHOTOCATALYTIC MEMBRANES IMMOBILIZING TITANIUM-DIOXIDE (PHOTOPERM(R) PROCESS)

The TiO2-mediated photodegradation of phenol was studied at 298 +/- 2 K or at 315 +/- 5 K (with the ratio between the hydrogen peroxide adde d and the stoichiometric amount (N) in the range 0 - 3), using PHOTOPE RM(R) CPP/313 membranes containing immobilized 30 +/- 3 wt.% TiO2. The rate of photodegradation was studied as a function of: i) initial con centration of substrate (8.76x10(-6) - 0.01 M), ii) flow rate (0.4 - 5 m(3)/h), iii) apparent (geometrical) membrane surface (30 - 190 cm2/c m of central axis of radiation field), iv) kind of radiation source (l ow and high pressure mercury are lamps, with fixed or variable radiant power, in the absorption range of semiconductor, of 31 W and 136-680 W respectively), v) radiation intensity. Disappearance of both phenol and total organic carbon (TOC) was examined. The operations of two pil ot-plants, differing in range of flow rates, and membrane arrangement, are critically compared. The apparent reaction orders as a function o f concentration are also compared and discussed,