Improving ozonation to remove carbamazepine through ozone-assisted catalysis using different NiO concentrations

Area of Science:

• Environmental Chemistry
• Catalysis
• Water Treatment

Background:

• Carbamazepine (CBZ) is a persistent pharmaceutical pollutant in water.
• Conventional ozonation can be enhanced by catalytic processes for improved pollutant degradation.

Purpose of the Study:

• To evaluate carbamazepine (CBZ) abatement using catalytic ozonation with nickel oxide (NiO).
• To assess the impact of NiO concentration on CBZ mineralization and byproduct formation.

Main Methods:

• Catalytic ozonation of CBZ using varying NiO concentrations (100, 300, 500 mg L⁻¹).
• Analysis of total organic carbon (TOC) removal, acid intermediate formation (oxalic, formic), and oxidant species.
• X-ray Photoelectron Spectroscopy (XPS) for surface analysis.
• Toxicity bioassays using Lactuca sativa seeds.

Main Results:

• Complete CBZ destruction achieved in 5 minutes with or without NiO catalyst.
• NiO enhanced partial mineralization, increasing oxalic and formic acid formation proportionally to catalyst concentration.
• Maximum TOC removal of 79.2% achieved at 500 mg L⁻¹ NiO, surpassing conventional ozonation by 50%.
• Formation of non-toxic byproducts, indicated by similar plant germination rates compared to controls.

Conclusions:

• Catalytic ozonation with NiO effectively mineralizes CBZ and reduces TOC.
• NiO promotes the formation of organic acids and oxidant species, leading to enhanced degradation.
• The process generates non-toxic byproducts, making it a viable water treatment strategy.