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. 2025 Jan 11;10(3):2858-2870.
doi: 10.1021/acsomega.4c08813. eCollection 2025 Jan 28.

Facile Sol-Gel Synthesis of C, N Codoped-TiO2 for Efficient Degradation of Palm Oil Mill Effluent

Benjamin Tze-Wei Tan  1 , Nor Ashikin Mohd Rashid  1 , Nurul Hidayah Mohamad Idris  1 , Wee Long Wun  2 , Hooi Ling Lee  1
Affiliations

Facile Sol-Gel Synthesis of C, N Codoped-TiO2 for Efficient Degradation of Palm Oil Mill Effluent

Benjamin Tze-Wei Tan et al. ACS Omega. .

Abstract

Wastewater treatment has been regarded as an effective solution in lowering the potential environmental hazards caused by palm oil mill effluent (POME). To ensure the efficient remediation of POME, the implementation of a promising strategy is necessary to overcome the limitations of conventional water treatment methods for the treatment of this pollutant. In this study, the synthesis of carbon, nitrogen codoped titanium dioxide nanoparticles (C, N-TiO2 NPs) was successfully performed by a sol-gel approach for the treatment of POME as a model pollutant under solar light irradiation. The synthesized C, N-TiO2 NPs displayed unique characteristics including an anatase phase with an average crystallite size of 11.35 nm and irregular spherical structures. Additionally, C, N-TiO2 possessed a lower band gap energy of 2.95 eV than 3.2 V of bulk anatase TiO2 and slower electron-hole (e--h+) pair recombination rate as evidenced by photoluminescence (PL) studies. The adsorption isotherm study of POME was most compatible with the Langmuir isotherm model, and the POME degradation kinetics proceeded according to first-order kinetics. Accordingly, the photocatalytic degradation of POME displayed a maximum degradation efficiency of 100% under the optimum condition of pH 7 in the presence of 0.12 g of the C, N-TiO2 photocatalyst within 150 min. The scavenging study showed that the superoxide radical (•O2 -) was the primary active species in the POME photodegradation. Finally, the reusability analysis confirmed that the C, N-TiO2 NPs could be reused for a maximum of five cycles, making them promising photocatalysts for wastewater treatment.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Photocatalytic degradation process utilizing TiO2.
Figure 2
Figure 2
XRD for the synthesized C, N-TiO2 NPs with the Miller indices of the reflections (COD file no. 5000223). Adapted with permission from Mohamad Idris et al., (2024). C, N-Codoped TiO2 Nanoparticles Immobilized on Floating Alginate Beads for Diazinon Removal under Solar Light Irradiation. ACS Appl. Nano Mater.2024, 7(16), 18273–18286. Copyright 2024, American Chemical Society. 10.1021/acsanm.3c03622.
Figure 3
Figure 3
FTIR spectrum of anatase TiO2 and synthesized C, N-TiO2 NPs.
Figure 4
Figure 4
HRTEM images of synthesized C, N-TiO2 NPs at (a) low magnification of 50 nm and (b) 20 nm and at (c) high magnification of 5 nm with inlay displayed. The FFT image corresponds to the specified area. (d) Particle size distribution of C, N-TiO2 NPs.
Figure 5
Figure 5
High-resolution deconvoluted (a) Ti 2p, (b) O 1s, (c) C 1s, and (d) N 1s XPS spectra of C, N-TiO2 NPs.
Figure 6
Figure 6
(a) Band gap spectrum of C, N-TiO2 NPs and anatase TiO2 with the inset showing the absorption of C, N-TiO2 NPs and anatase TiO2. (b) PL spectra of the synthesized C, N-TiO2 NPs and anatase TiO2.
Figure 7
Figure 7
Adsorption capacity of C, N-TiO2 NPs for the (a) Langmuir isotherm of variation adsorption (Ce/qm) against the equilibrium concentration (Ce) and (b) Freundlich isotherm of variation adsorption (ln qe) against the equilibrium concentration (ln Ce).
Figure 8
Figure 8
Catalyst dosages of 0.08, 0.10, and 0.12 g for the degradation efficiency of POME (a) by anatase TiO2 and (b) by C, N-TiO2 NPs under solar light irradiation. (c) First-order kinetics for the degradation of POME by C, N-TiO2NPs with catalyst dosages of 0.08, 0.10, and 0.12 g.
Figure 9
Figure 9
(a) Degradation efficiencies of POME and (b) their first-order kinetics with various initial pH values of POME by optimized C, N-TiO2 NPs under solar light irradiation.
Figure 10
Figure 10
Radical scavenging test of the optimized C, N-TiO2 NPs.
Figure 11
Figure 11
Proposed mechanism scheme for the photocatalytic degradation of POME.
Figure 12
Figure 12
Reusability test of optimized C, N-TiO2 NPs for five cycles (n = 2).
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References

    1. Madhav S.; Ahamad A.; Singh A. K.; Kushawaha J.; Chauhan J. S.; Sharma S.; Singh P.. Water Pollutants: Sources and Impact on the Environment and Human Health. In Sensors in Water Pollutants Monitoring: Role of Material Pooja D.; Kumar P.; Singh P., Patil S. (Eds.); Springer: Singapore, 2020; pp 43–62.
    1. Saad M. S.; Wirzal M. D. H.; Putra Z. A. Review on current approach for treatment of palm oil mill effluent: Integrated system. J. Environ. Manage. 2021, 286, 11220910.1016/j.jenvman.2021.112209. - DOI - PubMed
    1. Lok X.; Chan Y. J.; Foo D. C. Y. Simulation and optimization of full-scale palm oil mill effluent (POME) treatment plant with biogas production. J. Water Process Eng. 2020, 38, 10155810.1016/j.jwpe.2020.101558. - DOI
    1. Anuar M. A. M.; Amran N. A.; Ruslan M. S. H. Optimization of Progressive Freezing for Residual Oil Recovery from a Palm Oil-Water Mixture (POME Model). ACS Omega 2021, 6 (4), 2707–2716. 10.1021/acsomega.0c04897. - DOI - PMC - PubMed
    1. Mohd Yusof M. A. B.; Chan Y. J.; Chong C. H.; Chew C. L. Effects of operational processes and equipment in palm oil mills on characteristics of raw Palm Oil Mill Effluent (POME): A comparative study of four mills. Clean. Waste Syst. 2023, 5, 10010110.1016/j.clwas.2023.100101. - DOI

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