The material at the heart of the study, published in the Journal of Nanoparticle Research, is a molecularly imprinted form of bismuth ferrite, abbreviated I-BFO. Bismuth ferrite, or BiFeO3, is a perovskite-type semiconductor that has long attracted attention in photocatalysis because it absorbs a substantial portion of visible light, making it suitable for solar-driven chemistry. Its weakness, shared by most conventional photocatalysts, is a lack of discrimination. In a real wastewater stream, dozens of organic compounds compete for the catalyst’s surface, and a non-selective material wastes its oxidative power on whatever happens to be nearby. The Chinese team’s solution was borrowed from a technique that immunology and analytical chemistry have used for decades: molecular imprinting, in which a template molecule is used to cast custom-shaped recognition cavities into a surrounding matrix.

The imprinting process works much like making a key mold. Ciprofloxacin molecules are introduced during the synthesis of the catalyst, and as the bismuth ferrite framework forms around them, it develops cavities whose size, shape and chemical functionality complement the antibiotic. When the template molecules are subsequently removed, they leave behind a landscape of molecular footprints on the catalyst surface. These cavities preferentially re-adsorb ciprofloxacin, positioning the target molecule in intimate contact with the catalytically active sites before light-driven degradation begins. The result is a catalyst that concentrates its chosen substrate at the very locations where reactive oxygen species are generated, rather than letting those powerful oxidants dissipate on irrelevant organic matter.

The performance gains reported by the team, led by corresponding authors Jie Jin and Ziyang Lu, are substantial. Compared with pristine, non-imprinted bismuth ferrite, the imprinted catalyst achieved a 2.52-fold increase in the degradation rate of ciprofloxacin. That acceleration is not merely a matter of faster adsorption; it reflects the tighter coupling between molecular recognition and photocatalytic oxidation. When the target molecule is held within a complementary cavity, the photogenerated oxidants that break it apart are produced in its immediate vicinity, shortening the diffusion pathways that normally limit reaction rates and reducing the chance that intermediates escape into solution before complete mineralization.

Selectivity was tested directly in competitive degradation experiments, where ciprofloxacin had to contend with tetracycline, another common antibiotic with a very different molecular architecture. The imprinted catalyst consistently favored ciprofloxacin, degrading it preferentially over tetracycline and registering a selectivity coefficient of 1.79 relative to the pristine material. In practical terms, this means the catalyst can operate in a mixed-pollutant environment and still direct its oxidative capacity toward the compound it was designed to recognize. For treatment engineers, that kind of discrimination is invaluable: it allows a targeted catalyst to be deployed against a specific problematic contaminant without being poisoned or distracted by the chemical noise that characterizes real municipal and industrial effluents.

Durability is the other half of the story, and here too the imprinted material performed well. Across five successive degradation cycles, the catalyst retained approximately 90.0 percent of its initial efficiency, a figure that speaks to both the robustness of the bismuth ferrite framework and the stability of the imprinted cavities. Recyclability has long been a stumbling block for advanced photocatalysts, many of which suffer from photocorrosion, leaching of metal ions, or fouling of their active surfaces after only a few uses. A catalyst that can be recovered and reused with minimal loss of activity is far more attractive for continuous water treatment operations, where replacement costs and material losses quickly erode any laboratory-scale advantage.

To understand which chemical species were actually doing the work of destruction, the researchers carried out radical scavenging experiments, in which specific quenchers are added to intercept particular reactive intermediates. The results pointed to photogenerated holes and hydroxyl radicals as the primary reactive species governing ciprofloxacin degradation. Photogenerated holes are the positively charged vacancies left behind when a semiconductor absorbs light and promotes electrons to its conduction band; they are powerful oxidants in their own right and can directly attack organic molecules adsorbed on the catalyst surface. Hydroxyl radicals, meanwhile, are among the most aggressive oxidants known in aqueous chemistry, capable of stripping hydrogen atoms and adding across double bonds in organic pollutants. The identification of these two species as the dominant actors provides a mechanistic picture that future researchers can build upon when optimizing related systems.

The broader significance of the work lies in how it addresses two chronic limitations of photocatalytic water treatment at once: selectivity and charge dynamics. The authors frame the enhancement of charge separation efficiency as a central objective in the field, because when electrons and holes recombine inside a semiconductor instead of reaching the surface, their oxidative and reductive potential is simply lost as heat. Molecular imprinting contributes indirectly to this challenge as well, by ensuring that adsorbed target molecules are positioned to consume the charge carriers as soon as they arrive at the surface, effectively giving the photogenerated holes and radicals something productive to do before recombination can occur. The study thus sits within a wider research effort, visible across the team’s own recent publications, to engineer photocatalytic materials whose surfaces are as thoughtfully designed as their bulk electronic structures.

The environmental context makes the advance timely. Global ecological analyses have shown that concentrations of ciprofloxacin in the world’s rivers correlate with the prevalence of fluoroquinolone resistance in Escherichia coli, tying water quality directly to the trajectory of the antimicrobial resistance crisis. Conventional approaches, from adsorptive membranes to advanced oxidation processes, can remove or destroy antibiotics, but they typically do so without preference, consuming energy and reagents on the full cocktail of contaminants present. A selective photocatalyst that runs on light and targets the most problematic compound in the mixture represents a more surgical intervention, one that could be combined with existing treatment trains to polish effluents before discharge or to treat concentrated waste streams at their source, such as hospital effluent and pharmaceutical manufacturing wastewater.

Challenges remain before imprinted photocatalysts like I-BFO reach real-world deployment. Scaling up the imprinting synthesis while maintaining uniform cavity quality, demonstrating performance in genuinely complex environmental water matrices with their humic substances and competing ions, and integrating the catalyst into continuous-flow reactors are all steps that lie ahead. Yet the experimental foundation laid by the Jiangsu University team is a meaningful one. By fusing the molecular recognition of imprinting with the visible-light activity of bismuth ferrite, and by demonstrating both a 2.52-fold rate enhancement and a clear selectivity advantage in competitive settings, the researchers have shown that photocatalysis can be taught to tell its targets apart. In a world where the smallest concentrations of a single drug can reshape microbial ecosystems, that ability to aim, rather than simply blast, may prove to be exactly what environmental remediation has been waiting for.

Subject of Research: Molecularly imprinted bismuth ferrite photocatalysis for selective degradation of ciprofloxacin in wastewater

Article Title: Targeted photodegradation of ciprofloxacin on imprinted bismuth ferrite with improved catalytic performance

Article References: Onwubiko, J. S., Xu, Y., Li, X., Cheng, Y., Tang, L., Liu, X., Jin, J., & Lu, Z. (2026). Targeted photodegradation of ciprofloxacin on imprinted bismuth ferrite with improved catalytic performance. Journal of Nanoparticle Research, 28(10), Article 258. https://doi.org/10.1007/s11051-026-06781-0

Image Credits: AI Generated

DOI: 10.1007/s11051-026-06781-0

Keywords: photocatalysis, bismuth ferrite, molecular imprinting, ciprofloxacin, antibiotic pollution, wastewater treatment, selective degradation, hydroxyl radicals, charge separation, environmental remediation, nanomaterials, water purification