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Destruction of pharmaceuticals excreted in urine can be an efficient approach to eliminate these environmental pollutants. However, urine contains high concentrations of chloride, ammonium, and bicarbonate, which may hinder treatment processes. This study evaluated the application of ferrate(VI) (Fe VI O 4 2− , Fe(VI)) to oxidize pharmaceuticals (carbamazepine (CBZ), naproxen (NAP), trimethoprim (TMP), and sulfonamide antibiotics (SAs)) in synthetic hydrolyzed human urine and uncovered new effects from urine's major inorganic constituents. Chloride slightly decreased pharmaceuticals' removal rate by Fe(VI) due to the ionic strength effect. Ammonium (0.5 M) in undiluted hydrolyzed urine posed a strong scavenging effect, but lower concentrations (≤0.25 M) of ammonium enhanced the pharmaceuticals' degradation by 300 μM Fe(VI), likely due to the reactive ammonium complex form of Fe(V)/Fe(IV). For the first time, bicarbonate was found to significantly promote the oxidation of aniline-containing SAs by Fe(VI) and alter the reaction stoichiometry of Fe(VI) and SA from 4:1 to 3:1. In depth investigation indicated that bicarbonate not only changed the Fe(VI)/SA complexation ratio from 1:2 to 1:1 but provided a stabilizing effect for Fe(V) intermediate formed in situ, enabling its degradation of SAs. Overall, the results of this study suggested that Fe(VI) is a promising oxidant for the removal of pharmaceuticals in hydrolyzed urine.

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This paper presents an accelerated ferrate(VI) (FeO, Fe) oxidation of contaminants in 30 s by adding one-electron and two-electron transfer reductants (R and R). An addition of R (e.g., NHOH, As, Se, P, and NO, and SO) results in Fe initially, while Fe is generated with the addition of R (e.g., SO). R additives, except SO, show the enhanced oxidation of 20-40% of target contaminant, trimethoprim (TMP). Comparatively, enhanced oxidation of TMP was up to 100% with the addition of R to Fe. Interestingly, addition of SO (i.e., R) also achieves the enhanced oxidation to 100%. Removal efficiency of TMP depends on the molar ratio ([R]:[Fe] or [R]:[Fe]). Most of the reductants have the highest removal at molar ratio of ∼0.125. A Fe-SO system also oxidizes rapidly a wide range of organic contaminants (pharmaceuticals, pesticides, artificial sweetener, and X-ray contrast media) in water and real water matrices. Fe and Fe as the oxidative species in the Fe-SO-contaminant system are elucidated by determining removal of contaminants in oxygenated and deoxygenated water, applying probing agent, and identifying oxidized products of TMP and sulfadimethoxine (SDM) by Fe-SO systems. Significantly, elimination of SO from sulfonamide (i.e., SDM) is observed for the first time.

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