Due to the superior ability of photocatalysis to inactivate a wide range of harmful microorganisms, it is being examined as a viable alternative to traditional disinfection methods such as chlorination, which can produce harmful byproducts. Photocatalysis is a versatile and effective process that can be adapted for use in many applications for disinfection in both air and water matrices. Additionally, photocatalytic surfaces are being developed and tested for use in the context of “self-disinfecting” materials. Studies on the photocatalytic technique for disinfection demonstrate this process to have potential for widespread applications in indoor air and environmental health, biological, and medical applications, laboratory and hospital applications, pharmaceutical and food industry, plant protection applications, wastewater and effluents treatment, and drinking water disinfection. Studies on photocatalytic disinfection using a variety of techniques and test organisms are reviewed, with an emphasis on the end-use application of developed technologies and methods.

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A novel photoreactor system consisting of a TiO2-coated corrugated drum and a UV light source is experimentally characterized for the treatment of phenol-polluted wastewaters. The design incorporates periodic illumination and increased agitation through the introduction of rotation. The effects ofrent degrees and flat fins to increase surface area, varying rotational speed, initial pollutant concentration, and illumination intensities were studied. The corrugated and finned drums did not exhibit a critical rotational speed, indicating that there is excellent mass transfer in the system. A Langmuir-Hinshelwood kinetic analysis was applied to the degradation, and an average adsorption coefficient ofK=0.120 L/mg was observed. The overall reaction rate increased with increasing surface area from 0.046 mg/L/min for the annular drum to 0.16 mg/L/min for the 40-fin drum. The apparent photonic efficiency was found to increase with increasing surface area at a faster rate for the corrugations than for the fin additions. The energy efficiency (EE/O) found for the drums varied from 380–550 kWh/m3, which is up to 490% more energy-efficient than the annular drum.

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Advanced oxidation processes have been investigated as a viable means of treatment for the degradation and removal of dye-containing effluents. In this work, the degradation of an azo dye, Eriochrome black, was studied using a novel photocatalytic reactor in which TiO 2 is immobilized on a rotating corrugated drum. The degradation of the dye via the photocatalytic method was confirmed, and degradation rates were compared using different drum designs. Catalyst deactivation was observed, and this process of irreversibility was found to increase with increasing initial dye concentration in the water. A Langmuir-Hinshelwood kinetic analysis was applied, and it was found to agree well with the data in the initial parts of the reaction but diverged with increasing time. The discrepancy was thought to be due to the presence of unquantified reaction intermediates which may only be broken down slowly by the photocatalytic process.