Treatment of tarterazine dye wastewater by a cold atmospheric plasma process

Plasma is a subgroup of advanced oxidation technology (AOP) that has received considerable attention. It is currently being used to degrade persistent pollutants and inactivate organisms in environmental bodies. The objective of the present study is to decolorize tatrtrazine aqueous dye solution using cold atmospheric plasma technology. The main parameters selected for the study were initial dye concentration (4-20 mg/L), pH of the solution (2.2-9), input AC voltage (70-110), treatment time (10-30 minutes), and the electrode distance, which was kept at 8 mm throughout the experiment. The primary parameters investigated through the optimization tool of response surface methodology (RSM) software were color concentration, solution pH (2.2-9.4), power supply voltage (70-110 V), and detention time (10-30 minutes). The experimental reactor had a capacity of 15 ml. The color removal study of the plasma process showed that the optimal condition occurred at an initial concentration of 14 mg/L, voltage of 86 V, pH = 4.1, and plasma irradiation time of 18.7 minutes, resulting in a color removal percentage of 99.78%. According to half-life and efficiency yield calculations, the process was suitable for application in water pollution decontamination, with the lowest half-life achieved at the optimum condition (1.18) and the highest efficiency yield (108.3 mg/Kwh). The results extracted from the quadratic model illustrate the direct effect of retention time and initial voltage and the inverse effect of pH and initial concentration of industrial dye on the removal efficiency. The contact time had the major influence on efficiency via its coefficient in the model equation, while among interactive parameters, pH and contact time had the most interactive influence on the process. The reaction rate could also be described by the first-order kinetic model with an R2 value of over 95%.