Research Papers - School of Natural Sciences

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Author: search.filters.author.Thambiliyagodage, CSubject: search.filters.subject.g-C3N4

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    PublicationOpen Access
    Efficient photocatalysis of Cu doped TiO2/g-C3N4 for the photodegradation of methylene blue
    (Elsevier, 2023-03-06) Liyanaarachchi, H; Thambiliyagodage, C; Liyanaarachchi, C; Samarakoon, U
    The release of dyes into normal water reservoirs has become a tremendous environmental problem and the development of methods to remove such dyes is essential. A novel photocatalyst was fabricated in which Cu doped to TiO2 was coupled with g-C3N4 (Cu-TiO2/g-C3N4) in different weight percentages as 10, 30 and 50%, hydrothermally. Pure TiO2 consisted of both Anatase and Rutile phases where slight lattice distortions were observed in the Cu-doped TiO2 as evidenced by the XRD and Raman analysis. Cu was present at 1.7% by weight respective to TiO2 according to the XRF analysis. Spherical and irregularly shaped aggregated Cu-doped TiO2 nanoparticles in the range of 15–55 nm were heterogeneously distributed on the g-C3N4 matrix as observed by TEM and SEM. The band gap of TiO2 (3.0 eV) was reduced to 2.67 upon doping with Cu. The band gap of g-C3N4 was found to be 2.81 eV and that of Cu-TiO2/g-C3N4 in different weight percentages were in the range of 2.82 to 2.88 eV. Synthesized photocatalysts were tested on the ability to degrade methylene blue under UV and Visible light. Cu-TiO2/50% g-C3N4 showed the highest rate constant (4.4 × 10-3 min−1) which is 5 and 9.8 times greater than TiO2 and g-C3N4, respectively. The rate constant decreased with the introduction of EDTA and Isopropyl alcohol as they scavenge holes and hydroxyl radicals, respectively. The photocatalytic activity of all the nanomaterials increased with the increasing concentration of persulfate due to the increasing concentration of SO4●- and OH● produced. Synthesized nanomaterials effectively adsorb methylene blue under dark conditions following the pseudo-second-order kinetics suggesting that methylene blue molecules were chemisorbed to the adsorbents. The adsorption rate constant resulting in the best-performing photocatalyst was 0.122 g mg−1 min−1. Hence, it is evident that Cu-TiO2/g-C3N4 can effectively degrade methylene blue.
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    PublicationOpen Access
    Efficient photocatalysis of carbon coupled TiO2 to degrade pollutants in wastewater – A review
    (Elsevier, 2022-08-27) Thambiliyagodage, C
    Water pollution caused by human activities is a monumental problem that the world is facing today. The use of polluted water for domestic, industrial, and agricultural applications creates severe hazardous issues. Therefore, decontamination of polluted water is greatly important. The advanced oxidation process is preferred to purify contaminated water as the pollutants are completely degraded to harmless products. TiO2 is the most widely researched photocatalyst due to its chemical stability, low cost and eco-friendliness. However, the use of TiO2 is limited as it is only sensitive to UV range due to its high band gap (3.0 eV for rutile) and the possible electron-hole pair recombination. TiO2 has been coupled with carbon-based materials to enhance photocatalytic activity by enhancing charge separation and visible light absorption. This review summarizes the recent use of TiO2 coupled to activated carbon, carbon nanotubes, graphene derivatives, and g-C3N4 to degrade different pollutants found in water including dyes, pesticides, pharmaceuticals, phenols and heavy metals. The advantages and disadvantages of using each carbon-based material are discussed. Further, the challenges and opportunities associated with all the materials are presented. Finally, recommendations and possible future outlooks are briefed in this review.
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    PublicationOpen Access
    Fabrication of dual Z-scheme g-C3N4/Fe2TiO5/Fe2O3 ternary nanocomposite using natural ilmenite for efficient photocatalysis and photosterilization under visible light
    (Elsevier, 2022-11-11) Thambiliyagodage, C; Liyanaarachchi, H; Kumar, A; Jayanetti, M; Usgodaarachchi, L; Lansakara, B
    The advanced oxidation process is a prominent method available to remove dyes released to normal water reservoirs to alleviate water scarcity. We report the fabrication of novel g-C3N4/Fe2TiO5/Fe2O3 using natural ilmenite sand as the precursor of the metallic semi-conductors exploration of a heterostructure for photodegradation of methylene blue under sunlight. Ternary composites were synthesized by varying g-C3N4 with respect to Fe2TiO5/Fe2O3 and varying Fe2TiO5/Fe2O3 with respect to g-C3N4 where the varying component was varied as 8, 24 and 40%, respect to the constant material. The hybridization of the three semi-conductors has been confirmed by the microscopic, chemical, and structural analyses. X-ray diffraction patterns show the presence of all three g-C3N4, Fe2TiO5 and α-Fe2O3 while the transmission electronic microscopic and scanning electronic microscopic images show the heterogeneous distribution of the metal oxide nanoparticles on g-C3N4 matrix forming the composite. HRTEM images further reveal the junction of Fe2TiO5 and α-Fe2O3. X-ray photoelectron spectra show the existence of s-triazine and heptazine rings in the composites with Fe3+ and Ti4+ as the only oxidation states of Fe and Ti. Fe2TiO5/Fe2O3/40% g-C3N4 with bandgap of 2.63 eV calculated by diffuse reflectance UV-Visible spectroscopy showed the highest photocatalytic activity (0.009 min−1) being 1.3 times greater than the Fe2TiO5/Fe2O3 nanoparticles. Enhanced photocatalytic activity over the fabricated composites was observed due to the increased visible light absorption, efficient charge separation and improved charge transportation. g-C3N4 coupled with 40% Fe2TiO5/Fe2O3 showed the highest antibacterial activity against gram-negative E.Coli. The synthesis of dual Z-scheme g-C3N4/Fe2TiO5/Fe2O3 ternary composite provides new sights in developing novel photocatalysts using natural ilmenite sand for environmental applications.