Nitrilotriacetic acid enhanced UV/Fe0/H2O2 process for salty wastewater treatment at neutral pH

In this study, nitrilotriacetic acid (NTA) was used to enhance UV/Fe 0 /H 2 O 2 process for highly salty wastewater at neutral pH. The addition of Fe 0 could not accelerate the UV/H 2 O 2 process for salty wastewater treatment at neutral pH due to the precipitation of Fe ions. While NTA added into UV/Fe 0 /H 2 O 2 process which could form complex with Fe ion, the tartrazine removal could increase from 45.7% to 84.7% within 60 ​min. The k -value of the UV/Fe 0 -NTA/H 2 O 2 system to remove tartrazine is also 2.2 times higher than that in UV/Fe 0 /H 2 O 2 system. Meanwhile, the UV/Fe 0 -NTA/H 2 O 2 process could obtain good performance for salt wastewater treatment under a wide salt concentration level of 0–0.2 ​M. It can also expand the application range of pH to neutral pH. SEM and XPS characterization showed that the corrosion rate of Fe 0 in salty system was faster, and the presence of NTA could accelerate the recirculation of Fe 3+ /Fe 2+ on the Fe 0 surface. EPR spectroscopic analysis and scavenge experiments showed that • OH was the main reactive radical for the removal of tartrazine in the UV/Fe 0 -NTA/H 2 O 2 system. In addition, the k -value for removing tartrazine in various types of salt systems in the UV/Fe 0 -NTA/H 2 O 2 system was 3.2–4.2 times that of the UV/Fe 0 /H 2 O 2 system. It demonstrated UV/Fe 0 -NTA/H 2 O 2 processes fits to different types of salt system. Therefore, this study will provide a new method for the treatment of saline wastewater at neutral pH.