Efficient removal of endosulfan from aqueous solution by UV-C/peroxides: a comparative study

Area of Science:

• Environmental Chemistry
• Water Treatment Technologies
• Advanced Oxidation Processes

Background:

• Endosulfan is a persistent organochlorine insecticide posing risks to water resources.
• Emerging water pollutants necessitate efficient removal strategies.
• Advanced Oxidation Processes (AOPs) offer promising solutions for contaminant degradation.

Purpose of the Study:

• To evaluate the efficacy of UV-C-based AOPs (UV/S2O8(2-), UV/HSO5(-), UV/H2O2) for endosulfan degradation.
• To investigate the influence of radical scavengers on AOP efficiency.
• To elucidate the degradation pathway and identify by-products.

Main Methods:

• Degradation of endosulfan using UV/S2O8(2-), UV/HSO5(-), and UV/H2O2.
• Varying initial endosulfan concentrations and UV fluence.
• Assessing the impact of alcohols, natural organic matter, and inorganic anions.
• Identifying degradation by-products.

Main Results:

• UV/S2O8(2-) achieved 91% endosulfan removal, followed by UV/HSO5(-) (86%) and UV/H2O2 (64%).
• Process efficiency was reduced by radical scavengers like alcohols and natural organic matter.
• Inorganic anions inhibited degradation in the order: nitrite > bicarbonate > chloride > nitrate ≈ sulfate.
• Endosulfan ether was identified as the primary by-product.

Conclusions:

• UV-C-based AOPs are effective for removing endosulfan from contaminated water.
• Process performance is sensitive to water matrix composition, particularly scavengers.
• Further research into optimizing AOPs for real-world applications is warranted.