Design and Evaluation of a Continuous Photocatalytic Ozonation Reactor: Application on the Degradation of Amido Black 10B

A continuous photocatalytic ozonation reactor was developed at a laboratory scale for wastewater treatment. It was evaluated by using Amido Black (AB) in aqueous solution as a model pollutant. The TiO2 nano-catalysts presented as rutile phase were coated on stainless steel grids by the atomic layer deposition technique (ALD). The efficiency of ozonation (O3), photolytic ozonation (O3/UV), and combined photocatalytic ozonation process (TiO2/UV/O3) has been investigated and compared for AB removal. The effects of the initial dye concentration, pH, and radical scavenger (tert-butanol) have been examined using the designed reactor. Under the optimal operating parameters (C0 = 300 mg L−1, pH = 9 and ozone dose = 22 mg min−1), the results showed that about 64% of the initial TOC and 100% of AB color removal (at a concentration of 300 mg L−1) were achieved within 30 min. The overall reaction pseudo-first-order rate was significantly enhanced using the O3/UV/TiO2 process (kapp = 0.663 min−1), which allows achieving 100% of color removal in comparison with single ozonation (kapp = 0.589 min−1) and photolytic ozonation (kapp = 0.438 min−1) after 30 min of reaction time. Under the optimal conditions, the O3/UV/TiO2 oxidation process was the most effective process for AB removal from water.