Photocatalytic membranes

Moziaa S, Morawskia AW, Toyodab M et al (2009) Application of anatase-phase Ti02 for decomposition of azo dye in a photocatalytic membrane reactor. Desalination 24 97-105... 

Several studies have investigated the use of photosensitized reactions to remove triazines from water. For example, complete mineralization of several triazine herbicides was observed when aqueous solutions of these herbicides were photolyzed in the presence of titanium dioxide immobilized in a photocatalytic membrane. 

The effectiveness of photocatalytic membranes - in which Ti02 alone or together with tri-(ferf-butyl)- and tri-(isopropyl)vanadate were co-immobilized - were compared (Gianturco et al, 1997 Bellobono et al, 1998) for the... 

Gianturco, F., C.M. Chiodaroli, I.R. Bellobono, M.L. Raimondi, A. Moroni, and B. Gawlik (1997). Pilot-plant photomineralization of atrazine in aqueous solution, by photocatalytic membranes immobilising titanium dioxide and promoting photocatalysts. Fresenius Environ. Bull., 6 461 -68. 

Novel photocatalytic membranes have been prepared by the heterogenization in PVDF membrane ofthe decatungstate (W10O324 ), a polyanionic metal-oxide cluster used as photocatalysts for oxidation reactions. 

These catalytic membranes have been successfully used in a photocatalytic membrane reactor for the mineralization of the phenol, one of the main organic pollutants in wastewater, demonstrating that these catalytic membranes are stable and recyclable [42]. 

Bonchio, M., Carraro, M., Gardan, M., Scorrano, G., Drioli, E. and Fontananova, E. (2006) Hybrid photocatalytic membranes embedding decatungstate for heterogeneous photooxygenation. Topics in Catalysis, 40 (1 1), 133-140. 

Photocatalytic Membrane Reactors in the Conversion or Degradation of Organic Compounds... 

The photocatalytic membrane reactors (PMRs) combine the advantages of classical photoreactors (catalyst in suspension) and those of membrane processes (separation at molecular level) with a synergy for both technologies. 

Various types of photocatalytic membrane reactors in which the catalyst was used in different modes have been built with the purpose to have an easy separation of the catalyst from the reaction environment a photocatalyst in suspension in magnetically or mechanically agitated slurries confined by means of a membrane, fixed bed, catalyst deposited or entrapped on an inert support or in a membrane, and so on. 

Molinari et at. [73] reported a study on various configurations of photocatalytic membrane reactors for the degradation of 4-nitrophenol using Ti02 as catalyst. Two configurations have been studied irradiation of a recirculation tank, with the suspended catalyst confined by means of the membrane, and irradiation of the cell containing the membrane with three sub-cases catalyst deposited on the membrane, catalyst suspended, and catalyst included in a membrane during its preparation. 

Parameters Influencing the Photocatalytic Membrane Reactors (PMRs) Performance... 

In the development of a photocatalytic membrane reactor it is important to take into account some parameters that influence the performance of the system and its applicability to the industrial level. 

The possibility to use sunlight makes the photocatalytic membrane reactors promising in industrial and environmental fields, although very few studies have yet been performed in this area. 

In this section some experimental results obtained in our laboratories on PM Rs are reported. In particular two different photocatalytic membrane reactors, used in total and partial photocatalytic oxidations are described. 

In addition, the maximum benefit when a photocatalytic membrane reactor is used for water purification consists in retaining not only the pollutants but also their intermediates. 

Photocatalytic membrane reactors represent a very promising technology of great research and industrial interest. 

Photocatalytic membrane reactor Ti02-UV/VIS Laboratory Molinari et al. (2001)... 

Molinari R, Grande C, Drioli E, Palmisa-NO L, ScHiAVELLO M (2001) Photocatalytic Membrane Reactors for the Degradation of... 

Photocatalytic membranes are mentioned in the literature as potentially interesting for a number of applications. Here, the membrane acts in the first place as a transparent storage medium for reactants, i.e., as a transparent microreactor system. 

Bonchio M, Carraro M, Scorrano G, Fontananova E, and Drioli E, Heterogeneous photooxidation of alcohols in water by photocatalytic membranes incorporating decatungstate, Adv. Synth. Catal. 2003 345 1119. 

Barni, B., Cavicchioli, A., Riva, E., Zanoni, L., Bignoli, F, Bellobono, R., Gianturco, F., De Giorgi, A., Muntau, H., Montanarella, L., Facchetti, S., and Castellano, L., 1995, Laboratoiy-scale photodegradation of chloroaliphatics in aqueous solutions by photocatalytic membranes immobilizing Ti02, Chemosphere, 30(10) 1847-1860. 

Bellobono, I. R., Canara, A., Banii B., and Gazzotti, A., 1994, Laboratory-and pilot-plant-scale photodegradation of chloroaliphatics in aqueous solution by photocatalytic membranes immobilizing TiOi. J- Pho-tochem. Photob. A Chem., 84 83-90. 

Giaturco, F., Vianelly, L., Tatti, L., Rota, F., Brtrzzi, P, Rivas, L., Bellobono, L. R Bianchi, M., and Muntau, H., 1996, Pilot-plat photomineralization of dichloromethane and tetrachloroethane in aqtreotts solution, by photocatalytic membranes immobilizing TiOa and photopromoters. Chemosphere., 33(8) 1531-1542. 

Molinari R., Caruso A., Poerio T. 2009. Direct benzene conversion to phenol in a hybrid photocatalytic membrane reactor. Catalysis Today 144 81-86. 

Kumakiri I, Diplas S, Simon C, and Nowak P. Photocatalytic membrane contactors for water treatment. Ind. Eng. Chem. Res. 2011 50 6000-6008. 

Photocatalytic membranes incorporating titanium dioxide (Ti02) improve the self-cleaning performance and reduce streaking of tensile surface structures. In the case of PTFE T1O2 coated membranes, the surface has also been proven to remove exhaust pollutants from the atmosphere, effectively cleaning pollution from the urban environment (Mak Max, 2009b). 

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