Effect of the presence of inorganic ions and operational parameters on free cyanide degradation by ultraviolet C activation of persulfate in synthetic mining wastewater

This work studied the influence of several parameters on free cyanide (CN?) degradation (50 mg L?1) by UVC-activated persulfate (PS) at alkaline conditions (UVC/PS). Firstly, photolysis and activation PS were evaluated. Then, effect initial concentration (0.2, 0.4, 0.6 g dissolved oxygen in solution (absence/presence) studied. Lastly, phosphate, carbonate, nitrate presence different concentrations (50, 150, 350, 500 CN? elimination was tested. Additionally, electric energy per order (EEO), a measure consumption process determined, mechanistic view proposed. The results show that degraded 8 11% CN?, respectively, whereas their combination presented synergistic pollutant elimination. While had vital role due to formation 1O2 oxidize CNO?, HO• SO4•? primarily responsible for UVC/PS. It also found removal followed pseudo-first-order kinetics whose apparent reaction rate constant (k) increased from 0.0104 0.0297 min?1 as 0.2 L?1, indicating strong dependency efficiency amount. Remarkably, combined UVC/PS showed high conversion selectivity even ions (500 L?1), which resulted removals higher than 80% after 60 min treatment. Furthermore, EEO values similar absence phosphate or carbonate; however, they decreased slightly with presence. All these suggest feasibility such mining wastewater.