Photodegradation of the Volatile Organic Compounds in the Gas Phase: A Review

Abstract

SINGAPORE 11 7576 ~~ A review of photodegradation processes suitable for the treatment of Volatile OrganicCompounds (VOCs) present in the efluents from air-stripping and soil-vapor extraction is presented. This paper outlines and summarizes the essential factors such as kinetics and mechanism, intermediates of degradation processes, and reactor modeling which lead to the successful application of this useful technology. In addition, the effects of operating parameters such as humidity, temperature, additives and types of VOCs are discussed. The review also identijies the areas where further work is needed.

Vapor Phase Hydrogen Peroxide – Method for Decontamination of Surfaces and Working Areas from Organic Pollutants

“…The total rate of chemical degradation of contaminants by UV-C and hydrogen peroxide is dependent on the mechanism of the reaction of OH radicals with the contaminants, on the reaction rate of direct photolysis of contaminant (absorptivity of substrate), on the absorptivity of by-products and other absorbents of UV-C radiation at 254 nm (competitive absorption), on the intensity of the UV-C source and on the concentration of hydrogen peroxide (Kang & Lee, 1997). Degradation of organic substances by this effective combination proceeds by a radical oxidative reaction (Ray, 2000). There are several practical applications of the VPHP decontamination process employing the synergistic effect of UV-C (VPHP/UV-C) for the sterilization of continual filing processes of food in liquid form (milk, water, juice).…”

“…Thus, it is necessary to work with optimal concentration of hydrogen peroxide to achieve the highest efficiency of contaminant degradation in the TiO 2 /UV/H 2 O 2 system (Elmolla & Chaudhuri, 2010). Although similar properties as TiO 2 are also provided by other semiconductor materials as ZnO, ZnS, CdS, Fe 2 O 3 , WO 3 , these materials do not show the efficiency of degradation as high as TiO 2 does (Ray, 2000). There are also other possibilities to promote VPHP process, e.g.…”

Nanostructured 3D Sunflower-like Bismuth Doped BiOClxBr1–x Solid Solutions with Enhanced Visible Light Photocatalytic Activity as a Remarkably Efficient Technology for Water Purification

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 These encouraging results have prompted us to investigate the photo-oxidation processes by means of monitoring the Chemical Oxygen Demand (COD). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 For comparison, Figure 6 illustrates Interestingly it is apparent that the peaks at around 220nm, corresponding to typical chromophores 33 in aromatic rings such as of Toluene, are not affected by visible light in These results shown above, which are in an excel...…”

Conversion characteristics and kinetic analysis of gaseous α-pinene degraded by a VUV light in various reaction media

“…(1) the precursor of ozone, which was electronically excited oxygen atoms formed by photolysis of oxygen, could react with water molecule [33], and (2) H • generated by photolysis of water molecule could also consume ozone [4]:…”