{"title":"Highly efficient photocatalytic degradation of ofloxacin coupling with Cr(VI) reduction by m-PDI/BiOI organic–inorganic S-scheme heterojunction catalysts","authors":"Haoruo Xu , Chenxi Huang , Weili Yu , Ningjie Fang , Yinghao Chu , Jinhui Li","doi":"10.1016/j.seppur.2025.134477","DOIUrl":null,"url":null,"abstract":"<div><div>The combined pollution toxicity of hexavalent chromium heavy metal (Cr(VI)) and antibiotics (such as ofloxacin, OFL) is much higher than that of a single pollutant, posing a serious challenge to the ecological environment. Photocatalytic technology can achieve the removal of both single pollutants and composite pollutants. It is urgent to develop catalysts with high carrier separation efficiency and photocatalytic degradation performance. In this work, we successfully prepared m-PDI/BiOI heterojunction catalysts (mPB-3) with tight contact interfaces using the continuous ion layer adsorption and reaction method, and applied them to the synergistic removal of OFL and Cr(VI). The results showed that mPB-3 exhibited a bidirectional enhancement effect. The degradation rate of OFL reached more than 99.5 % within 40 min, the corresponding reduction efficiency of Cr(Ⅵ) reached 63.7 % at pH = 9. Furthermore, the influence of different environmental factors on the degradation process have also been clarified, indicating that mPB-3 has good stability and adaptability. The system characterization results confirmed that a S-scheme heterojunction has been formed. This can accelerate the rapid migration of electrons from m-PDI to BiOI, achieving efficient charge separation, and ultimately enhancing the photocatalytic activity. Finally, the degradation intermediate products and degradation mechanism were analyzed. This study provides a feasible solution for the design of efficient photocatalytic materials and their application in the combined pollution treatment of OFL and Cr(VI).</div></div><div><h3>Environmental implication</h3><div>Cr(VI) and OFL coexisting in water bodies pose significant ecological risks due to their enhanced combined toxicity. Traditional treatment techniques often struggle to effectively address such complex pollution systems. This study demonstrates that the m-PDI/BiOI heterojunction photocatalyst can efficiently synergistically remove both contaminants under environmentally relevant conditions (e.g., pH = 9), providing a practical strategy to mitigate composite pollution challenges. The S-scheme charge separation mechanism offers insights for designing advanced catalysts to tackle emerging multi-pollutant threats in aquatic ecosystems, supporting sustainable water treatment solutions.</div></div>","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":"377 ","pages":"Article 134477"},"PeriodicalIF":9.0000,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Separation and Purification Technology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1383586625030746","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The combined pollution toxicity of hexavalent chromium heavy metal (Cr(VI)) and antibiotics (such as ofloxacin, OFL) is much higher than that of a single pollutant, posing a serious challenge to the ecological environment. Photocatalytic technology can achieve the removal of both single pollutants and composite pollutants. It is urgent to develop catalysts with high carrier separation efficiency and photocatalytic degradation performance. In this work, we successfully prepared m-PDI/BiOI heterojunction catalysts (mPB-3) with tight contact interfaces using the continuous ion layer adsorption and reaction method, and applied them to the synergistic removal of OFL and Cr(VI). The results showed that mPB-3 exhibited a bidirectional enhancement effect. The degradation rate of OFL reached more than 99.5 % within 40 min, the corresponding reduction efficiency of Cr(Ⅵ) reached 63.7 % at pH = 9. Furthermore, the influence of different environmental factors on the degradation process have also been clarified, indicating that mPB-3 has good stability and adaptability. The system characterization results confirmed that a S-scheme heterojunction has been formed. This can accelerate the rapid migration of electrons from m-PDI to BiOI, achieving efficient charge separation, and ultimately enhancing the photocatalytic activity. Finally, the degradation intermediate products and degradation mechanism were analyzed. This study provides a feasible solution for the design of efficient photocatalytic materials and their application in the combined pollution treatment of OFL and Cr(VI).
Environmental implication
Cr(VI) and OFL coexisting in water bodies pose significant ecological risks due to their enhanced combined toxicity. Traditional treatment techniques often struggle to effectively address such complex pollution systems. This study demonstrates that the m-PDI/BiOI heterojunction photocatalyst can efficiently synergistically remove both contaminants under environmentally relevant conditions (e.g., pH = 9), providing a practical strategy to mitigate composite pollution challenges. The S-scheme charge separation mechanism offers insights for designing advanced catalysts to tackle emerging multi-pollutant threats in aquatic ecosystems, supporting sustainable water treatment solutions.
期刊介绍:
Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.