Photocatalytic membrane reactors suspended photocatalyst

Photocatalytic membrane reactors with suspended photocatalyst... 

Abstract The configurations and performance of photocatalytic membrane reactors (PMRs) assembled with membranes (also photocatalytic type) and/or suspended photocatalyst are described. Examples of the application of PMRs in water/wastewater treatment as well as in photocatalytic synthesis are shown. An outUne of the modeling of PMRs is presented with a brief economic analysis future trends in PMRs are also discussed. 

More common configurations of PMRs are systems with suspended photocatalyst. In these PMRs various membrane techniques are utilized MF, UF, NF, dialysis, PV, or MD. The photocatalytic reaction in PMRs with suspended photocatalyst might be conducted in (a) a feed tank, (b) a membrane module or (c) an additional reservoir (photoreactor) which is located between the feed tank and the membrane module. Thus, the danger of polymer membrane destruction by UV light could be avoided by a proper selection of reactor configuration. 

There are two types of PMRs (i) PMRs with photocatalytic membranes, and (ii) PMRs with suspended photocatalysts. In the former, membrane fouling due to photocatalyst particles can be avoided and, moreover, the photocatalytic reaction can be conducted either in the feed or in the permeate. However, when the photocatalytic reaction takes place in an aqueous phase the efficiency of photodegradation is found to be lower than in case of the latter configuration. On the other hand, when gaseous phase reactions are considered, the reaction rate is found to be faster when using PMRs with suspended photocatalysts than when using reactors with photocatalysts fixed on a non-porous support. 

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