Efficient activation of peroxymonosulfate via Cu2+/Cu+ cycle enhanced by hydroxylamine for the degradation of Rhodamine B

The application of Cu2+/peroxymonosulfate (PMS) process for the elimination of refractory pollutants in industrial wastewater is limited by the slow transformation from Cu2+ to Cu+. In this research, hydroxylamine (HA) was employed to improve the degradation capacity of the Cu2+/PMS process. Rhodamine B (RhB) was selected as the target compound to indicate the performance of HA/Cu2+/PMS process. Compared with the Cu2+/ PMS process, the reduction of Cu2+ to Cu+ was effectively promoted by HA in the HA/Cu2+/PMS process, which increased the decomposition rate of PMS by 29.2%, correspondingly, promoted the removal rate of RhB by 77.6%. The degradation of RhB followed pseudo-second-order kinetics in the proposed process. The active species analysis subsequently indicated hydroxyl radicals (center dot OH) and sulfate radicals (SO4 center dot-) played important roles for degrading RhB with center dot OH as the dominant active radical. The effects including initial pH, RhB concentration, PMS concentration, and Cu2+ concentration on the degradation of RhB were further investigated and discussed in detail. Additionally, the HA/Cu2+/PMS process exhibited effective RhB removal in simulated wastewater. From the perspective of waste utilization (Cu2+) and the remediation of organic contamination, the work would provide a valuable and promising process.

Automated summary

In this study, hydroxylamine (HA) was used to enhance the degradation capacity of Cu2+/PMS process for refractory pollutants in industrial wastewater. Compared to Cu2+/PMS process, HA/Cu2+/PMS process effectively facilitated the reduction of Cu2+ to Cu+, leading to improved decomposition rate of PMS by 29.2% and removal rate of RhB by 77.6%. The study also investigated the effects of various factors on RhB degradation and demonstrated the effectiveness of the HA/Cu2+/PMS process in simulated wastewater.