The presence of hundreds of pharmaceuticals in water bodies and drinking water adversely affects the health and behavior of humans and wildlife. While conventional wastewater treatment plants would typically take care of such a situation but pharmaceuticals, in general, pass through. In this regard, extensive research efforts have been focused on improving existing water treatment technologies and developing new advanced oxidation technologies. Although conventional semiconductor photocatalysts, e.g., titania, proving potential for such purpose1, however, it has intrinsic limitations, viz., i) high e−h recombination rate; ii) low surface area; iii) limited light absorption (only under UV). In this context, ordered mesoporous titania materials show promise with their unique textural, electronic, and optical properties2,3. In this context, we have developed a series of high-quality 2D-hexagonal ordered mesoporous titania (OMT) using P-123 and CTAB as structure-directing agents. Interestingly, these materials exhibit significant amounts of intrinsic defects such as Ti3+ centers, which promote charge separation of photogenerated excitons, and therefore exhibit excellent degradation efficiency (DE) for pharmaceutical pollutant like famotidine (FAM)3.
Further, integration of ordered mesoporous carbon (OMC), as an electron-sink, and OMT with chemically bonded interface, i.e., OMT-OMC composite, show a remarkable DE of FAM as well as its intermediate or partial degradation products. On the other hand, the limited light absorption efficienty of both pristine OMT and OMT-OMC has been overcome by functionalizing OMT with tetra(4-carboxyphenyl)porphyrin (TCPP), a chlorophyll synonym. The resulting TCPP-OMT hybrid in-turn extend the light absorption in the visible region, which displayed an excellent 100% DE of FAM indicating a complete mineraliazation of the pollutant as compared with the commercial titania photocatalyst such as Degussa/Aeroxide P-25. Finally, the experimants were also performed with both solar-simulated and natural sun-light. and the results suggest excellent applicability and versatility of OMT-based hybrid materials for the photocatalytic degradation of pharmaceutical pollutant in aqueous solution.
References
1.Chen X.; Selloni, A. Chem. Rev. 2014, 114, 9281-9282.2. Selvam, P.; Vatti, S.K. Indian Patent Application Numbers: 201841003631; 201941008110.3.Vatti, S.K.; Gupta, S.; Raj, R.P.; Selvam, P. New J. Chem. 2020, 44, 16269-16284.