Enhanced photodegradation of antibiotics via modified graphitic carbon nitride (g-C3N4) : Effects of defect engineering and elemental doping strategies
흑연질화탄소(g-C3N4) 개질에 따른 향상된 항생제 광분해 제거: 공석 도입 및 원소 공동 도핑 전략의 효과 연구
- 주제(키워드) Photocatalysis , g-C3N4 , Antibiotics , Hydrophilicity , Elemental co-doping.
- 주제(DDC) 628
- 발행기관 아주대학교 일반대학원
- 지도교수 이창구
- 발행년도 2025
- 학위수여년월 2025. 2
- 학위명 석사
- 학과 및 전공 일반대학원 환경공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000034332
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
This study investigates various modification methods to enhance the photocatalytic per- formance of graphitic carbon nitride (g-C3N4), with a particular focus on how characteristics such as hydrophilicity and elemental constitution play a crucial role in antibiotic photodegra- dation. The surface hydrophilicity of a photocatalyst influences its interaction with organic pollutants and significantly impacts degradation efficiency. Then, alkaline solvothermal treat- ment was applied to increase the surface hydrophilicity of g-C3N4, reducing the contact angle from 61.1° to 31.8° without significantly altering its morphology, crystalline structure, or sur- face functional groups, as confirmed by SEM, XRD, and FT-IR analyses. The enhanced hy- drophilicity positively affected the degradation of oxytetracycline (OTC), while the degrada- tion of oxolinic acid (OA) showed a different trend, highlighting the importance of surface characteristics in degradation behavior. This study elucidates the impact of enhanced hydro- philicity of the catalyst on the photocatalytic degradation of antibiotics. Additionally, the pho- tocatalytic performance of g-C3N4 was further enhanced by doping with potassium (K) and phosphorus (P) using a simple one-step synthesis method with K2HPO4 as the precursor. De- spite the simplicity of the synthesis, the doped g-C3N4 exhibited fast and efficient OTC deg- radation, with the KPCN-100 sample, synthesized using 100 mg of K2HPO4, achieving the highest degradation rate of 99.43 ± 0.53 %, significantly outperforming pristine g-C3N4 (29.52 ± 0.03 %). The doping of K and P altered the band position optical, and photoelectrochemical properties of g-C3N4. According to previous results, reactive oxygen species (ROS) such as O2•− (87.25 %) and 1O2 (56.53 %) were boosted in the KPCN-100 system. In addition, several experimental parameters, including the presence of co-existing ions and humic acid, the pH level, the initial OTC concentration, and the photocatalyst dosage, were varied to better un- derstand the photodegradation mechanisms at work within the KPCN-100 system. This study highlights that even with a simple synthesis approach, elemental doping can lead to highly efficient and rapid degradation of antibiotics like OTC, offering an effective strategy for en- hancing photocatalytic performance. Keywords: Photocatalysis; g-C3N4; Antibiotics; Hydrophilicity; Elemental co-doping.
more목차
1. Introduction 1
2. Material and methods 4
2.1. Chemicals 4
2.2. Photocatalyst preparation 4
2.2.1. Synthesis of g-C3N4 (CN) 4
2.2.2. Synthesis of N-vacancy g-C3N4 (Nv-HPCN) 5
2.2.3. Synthesis of K/P co-doped g-C3N4 (KPCN) 5
2.3. Photodegradation procedure 5
2.3.1. Photodegradation experiments of Nv-HPCN 5
2.3.2. Photodegradation experiments of KPCN-100 6
2.4. Characterization 6
3. Results and discussion 8
3.1. N-vacancy g-C3N4 (Nv-HPCN) 8
3.1.1. Alkaline solvothermal treatment increased the N vacancy and hydrophilicity of photocatalysts 8
3.1.2. Different removal efficiencies of the antibiotics depend on their log Kow values 13
3.1.3. O 2•- played a significant role in the degradation of antibiotics 20
3.1.4. Effects of coexisting anions and natural organic matters on antibiotic degradation 22
3.1.5. Effects of catalyst dose, and initial antibiotic concentration on photocatalytic efficiency 26
3.2. K/P co-doped g-C3N4 (KPCN-100) 28
3.2.1. Co-doping of the g-C3N4 structure with K and P 28
3.2.2. OTC photodegradation efficiency using the co-doped photocatalyst 34
3.2.3. Optical and photoelectrochemical properties 37
3.2.4. Contribution of superoxide radicals and singlet oxygen to the photodegradation of OTC 41
3.2.5. Effects of co-existing anions and humic acid 45
3.2.6. Effects of operating parameters on the KPCN-100 system 47
4. Conclusion 50
References 53
국문 초록 61
