Photocatalytic Activity of Neodymium-Based Nanocomposites for Pharmaceutical Pollutant Degradation

Abstract

Pharmaceutical contaminants are incompletely removed by many conventional wastewater-treatment processes, prompting interest in advanced oxidation approaches. This review examines neodymium (Nd)-based nanocomposites as heterogeneous photocatalysts for degrading pharmaceutical pollutants in water. It considers Nd-doped semiconductors, Nd₂O₃-containing composites, neodymium ferrites and semiconductor heterojunctions, with attention to their optical, interfacial and charge-transfer characteristics. Reported applications include the photocatalytic degradation of ciprofloxacin, tetracycline, ampicillin and ceftriaxone sodium under visible light, sunlight or simulated solar irradiation in laboratory investigations. The discussion evaluates how Nd loading, catalyst dosage, initial pollutant concentration, solution pH, irradiation conditions, surface properties and charge-carrier recombination influence observed performance. Mechanistic aspects include photogenerated electron–hole pairs, reactive oxygen species, transformation pathways and the interpretation of scavenger and characterisation measurements. Reported degradation efficiencies and apparent kinetic parameters are considered alongside mineralisation, catalyst recovery, reusability and stability. The review emphasises that percentage disappearance of the parent compound does not independently establish complete mineralisation or reduced toxicity. Differences in experimental conditions also limit direct comparisons between photocatalysts. Outstanding challenges include performance assessment in complex wastewater, Nd leaching, long-term operational stability and the reporting of irradiation and reaction parameters. Further work is needed to assess stable visible- and solar-light-responsive Nd-based nanocomposites under conditions relevant to pharmaceutical wastewater treatment.