Trace Cu(II) can enhance the degradation of Orange II in Fe(II)/ hydroxylamine/persulfate system

This paper explored the effect of trace Cu(II) (5 mu M) on the degradation of Orange II by Fe(II)/Hydroxylamine (HA)/Persulfate (PS) system. The results showed that the addition of trace Cu(II) not only improved the degradation efficiency of Fe(II)/HA/PS system, but also broadened the pH range of Fe(II)/HA/PS degradation Orange II (2-10). Increasing the dosage of Fe(II), Cu(II) and PS will promote the degradation of Orange II by the Cu(II)/Fe(II)/HA/PS system. However, the optimal dosage of HA is 0.03 mM. Lower or excessive HA dosage is not conducive to the degradation of Orange II by the Cu(II)/Fe(II)/HA/PS system. Scavenger experiments show that SO4 center dot- is the main reactive oxygen species (ROS) in the Cu(II)/Fe(II)/HA/PS system. In both acidic and alkaline environments, Cu(I) reduced by hydroxylamine can promote the conversion of Fe(III) to Fe(II). In acidic environment, Fe(II) reduced by Cu(I) is the reason why trace Cu(II) can enhance the efficiency of Fe(II)/HA/PS system to degrade Orange II. However, in alkaline environment, Cu(I) reduced by hydroxylamine is the main participant in the production of SO4 center dot- by activating persulfate, which is also the main reason for broadening the applicable pH of Fe(II)/HA/PS for Orange II degradation to alkaline environment.

Automated summary

The addition of trace Cu(II) enhances the degradation efficiency of Fe(II)/HA/PS system and broadens the applicable pH range. Optimal dosages of Fe(II), Cu(II), and PS promote the degradation of Orange II, while excessive or inadequate HA dosage is not conducive. Scavenger experiments indicate that SO4 center dot- is the main reactive oxygen species (ROS) in the system.