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 (k_app = 0.663 min⁻¹), which allows achieving 100% of color removal in comparison with single ozonation (k_app = 0.589 min⁻¹) and photolytic ozonation (k_app = 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.