Degradation of amaranth by persulfate activated with zero-valent iron: influencing factors, response surface modeling

Abstract In this study, zero-valent iron (ZVI) is applied to activate persulfate (PDS) for the degradation of amaranth (AMR). The effects PDS concentration, ZVI solution pH , temperature, and reaction time on AMR by ZVI/PDS advance oxidation process are investigated. Sulfate hydroxyl radicals involved in main pathway sulfate radical acts as a dominant oxidant. CCD (central composite design) plan chosen build RSM model prediction degradation. ANOVA analysis shows that secondary fitting had great fitness with R 2 = 0.997, $$R_{{{\text{adj}}}}^{2}$$ R adj 2 0.936, p -value lack fit 0.107. Optimum conditions 98% removal given concentration 7.33 mM, dosage 17.79 initial 4.62, temperature 59.49 °C, 9.88 min which proved be very closed real rate 96.78%. Sensitivity indicates relative importance influencing parameters following order: dosage, time. PDS/ZVI system an acceptable RSE about 75% TOC 85% oxidation. Finally, possible proposed.