Kinetic degradation of reactive dye RED 243 using potassium peroxymonosulfate with zero-valent iron particles

The degradation of persistent organic pollutants reduces their harmful effects on the environment. Various treatment techniques are employed to remediate these pollutants, and among them, advanced oxidative processes are effective for breaking down recalcitrant compounds. This manuscript investigated the degradation of the dye RED 243 using PMS in combination with zero-valent iron particles of different sizes. The reduction in the dye's colorimetric intensity occurred rapidly, within a few seconds. The results indicated that the reduction in colorimetric intensity ranged from 62 to 83% by the end of the tests when PMS was used with ZVI at various temperatures. It examined several types of acids to assess the impact of anions on the degradation process and found that organic acids were more efficient. The optimal reaction conditions, which minimized reagent usage, occurred at the original sample pH, 313 K, 25 mg L^-1 PMS, and 100 mg L^-1 micrometric zero-valent iron. Under these conditions, we achieved a degradation efficiency of 83% in colorimetric intensity. The dye degradation reaction followed pseudo-first-order kinetics with respect to dye concentration, yielding activation energies of 39.77 kJ mol^-1 for micro-sized iron and 55.67 kJ mol^-1 for nano-sized iron particles.