Hydroxylamine driven advanced oxidation processes for water treatment: A review

Area of Science:

• Environmental Science
• Water Treatment Technologies
• Advanced Oxidation Processes

Background:

• Hydroxylamine (HA) driven advanced oxidation processes (HAOPs) are gaining attention for water treatment.
• HAOPs accelerate reactive intermediate generation, improving contaminant elimination effectiveness.
• Existing research necessitates a comprehensive review of HAOPs' mechanisms and applications.

Purpose of the Study:

• To categorize and review hydroxylamine (HA) driven advanced oxidation processes (HAOPs) for water treatment.
• To summarize degradation efficiency, reactive intermediates, and effective pH ranges of various HAOPs.
• To elaborate on reaction mechanisms and compare different HAOP system configurations.

Main Methods:

• Categorization of HAOPs into direct reactions with oxidants, homogeneous Fenton/Fenton-like systems, and heterogeneous Fe/Cu-Fenton/Fenton-like systems.
• Review and summarization of experimental data on pollutant degradation efficiency and reactive intermediates.
• Elaboration of reaction mechanisms, including oxidant interactions and metal ion redox cycling.

Main Results:

• Direct HA reactions with oxidants generate highly reactive secondary intermediates, enhancing pollutant degradation.
• HA-driven Fenton/Fenton-like systems (homogeneous and heterogeneous) accelerate metal ion redox cycles, improving contaminant removal.
• HAOPs offer broader effective pH ranges and improved degradation efficiencies compared to traditional methods.

Conclusions:

• HAOPs represent a promising approach for efficient water treatment by enhancing reactive species generation.
• Understanding the mechanisms of HAOPs is crucial for optimizing their application in diverse water matrices.
• Further research into HA oxidation products and process scale-up is needed to address current challenges and future prospects.