https://www.mdu.se/

This study primarily focuses on evaluating the effects of solution matrix and pH for the generation of reactive oxygen species (ROSs) in Z-nZVI-catalyzed sodium percarbonate (SPC) system to degrade 1,1,1-trichloroethane (1,1,1-TCA) in the absence and presence of reducing agent (RA) i.e. hydroxylamine. 1,1,1-TCA degradation was 49.5% and 95% in the absence and presence of RA. Probe tests confirmed the generation of major hydroxyl radicals (OH•) and minor superoxide species (O2–•), and scavenger tests verified the key role of OH• and less of O2–• radicals. 1,1,1-TCA degradation decreased significantly in the presence of Cl− and HCO3–, while NO3– and SO42– have negligible effects in absence of RA. Addition of RA significantly enhanced 1,1,1-TCA degradation by generating more OH• and O2–• radicals in presence of anions. 1,1,1-TCA degradation increased in acidic range (1–5) while, an inhibitive trend from neutral to basic (7–9) was observed. On the contrary, a significant increase in 1,1,1-TCA degradation was observed with addition of RA in all pH values (1–9). In conclusion, the anions and pH significantly influenced the generation and intensity of ROSs and 1,1,1-TCA was effectively degraded in Z-nZVI-catalyzed SPC system in the presence of RA.