Degradation of printing ink effluent and industrial predesign by UV/H2O2 treatment: A kinetic study

Advanced Oxidation Technologies (AOTs) are effective for treating non-biodegradable organic compounds. AOTs allow to degradation of these pollutants through non-selective attacks by highly reactive radicals. This work studies the reduction of the organic load in real printing ink effluents. The Chemical Oxygen Demand (COD) reduction kinetics was evaluated. The proposed treatment consists of irradiating the effluent in the presence of H2O2 with temperature control and commercial UV light lamps (254 nm). Optimal conditions were tested on a pilot scale. The effluents were characterized before and after the treatment. The irradiation, temperature, and oxidizing agent effects were evaluated. The degradations were adjusted to pseudo-first-order kinetics up to 95 % degradations. The optimal kdeg was 0.0138 min-1 at the laboratory scale (98 % COD reduction in 300 min) and 0.0058 min-1 at the pilot scale (90 % COD reduction in 360 min). The degradation rate increased with temperature. Degradation occurred at a higher rate with mean values of oxidant concentration for all temperatures (between 0.02 and 0.04 mol L-1). The reaction rate increased proportionally to the irradiation, with this effect increasing as the process temperature increased. The pilot prototype was scaled up on an industrial scale, taking into account low-cost and easy-maintenance materials.