Periodic mesoporous organosilicas containing naphthalenediimides as organic sensitizers for sulfadiazine photodegradation

Author(s)

Castanheira, Bruna ; Brochsztain, Sergio ; Otubo, Larissa ; Teixeira, Antonio Carlos S. C.

• Document type: Journal article
• Source: JOURNAL OF HAZARDOUS MATERIALS; v. 443, p. 9-pg., 2023-02-05.

Abstract

In this work, periodic mesoporous organosilicas (PMO) functionalized with the organic sentisizer naph-thalenediimide (NDI) were employed as heterogeneous catalysts for the photodegradation of the antibiotic sulfadiazine (SDZ), taken as a model for contaminants of emerging concern (CECs). The catalysts, designated as PMONDI, were prepared by surfactant-directed co-condensation of the precursor N,N '-bis(3- triethoxysilylpropyl)-1,4,5,8-naphthalenediimide with tetraethoxysilane. The synthesized PMONDI were characterized using transmission electron microscopy, nitrogen adsorption isotherms and small and large angle x-ray scattering. The performance of PMONDI catalysts in the photodegradation of SDZ was compared to that of TiO2 nanoparticles impregnated into SBA-15 mesoporous silica (TiO2/SBA-15), under irradiation with a Hg lamp with a bandpass filter of 320-500 nm. Under optimal conditions, PMONDI degraded 100% of the SDZ in 45 min, while the total degradation of SDZ was achieved only after 150 min with TiO2/SBA-15. PMONDI also performed better than TiO2/SBA-15 in reuse tests. The mechanism of photodegradation with PMONDI involves the for-mation of excited triplet states of NDI (3NDI*) upon irradiation, which can then react with molecular oxygen to form reactive oxygen species, which degrade SDZ. Analysis of the SDZ degradation products indicated two main pathways: (1) hydroxylation of the aniline ring and (2) SO2 extrusion and rearrangement, followed by oxidation of the aniline ring to nitrobenzene. In conclusion, the great potential of the PMONDI materials as photocatalysts for CECs degradation was demonstrated in this work, encouraging further research on these materials for the degradation of pollutants. (AU)

• FAPESP's process: 18/21271-6 - SOLAR DEGRADATION OF POLLUTANTS OF EMERGING CONCERN: PHOTOREACTORS AND INNOVATIVE TREATMENTS
• Grantee: Antonio Carlos Silva Costa Teixeira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/05496-2 - Synthesis and characterization of periodic mesoporous organosilicas containing aromatic imides for applications in the energy sector
• Grantee: Sergio Brochsztain
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/24158-9 - Environmental fate of emerging pollutants in surface waters and sustainable alternatives for their mitigation: a hybrid experimental & theoretical approach
• Grantee: Antonio Carlos Silva Costa Teixeira
• Support Opportunities: Regular Research Grants