Catalytic Potential of Green-Synthesized IronNanoparticles from Psidium guajava for 4-Nitrophenol Reduction

Abstract

This study presents a sustainable approach for thegreen synthesis of iron nanoparticles (Fe(NPs)) using an aqueous extract of Psidiumguajava (guava leaves) as a reducing and stabilizing agent. The FeNPs wereapplied in the catalytic reduction of 4-nitrophenol. To minimize the use ofsodium borohydride (NaBH₄), different volumetric ratios of plantextract and NaBH₄ were tested. The influence of these ratios on thephysicochemical and morphological properties of the FeNPs was evaluated usingX-ray diffraction (XRD), scanning electron microscopy with energy-dispersiveX-ray spectroscopy (SEM/EDS), high-resolution field-emission SEM (HR-FESEM),Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis(TGA), and N₂ physisorption. Increasing the proportion of plant extract led toreduced crystallinity, larger particle sizes, and lower surface areas. Despitethese changes, using up to 40% extract improved catalytic performance,achieving over 90% reduction of 4-nitrophenol. Ecotoxicological assessmentsconfirmed the biocompatibility of the FeNPs, the effective neutralization of4-nitrophenol toxicity post-reduction, and highlighted the inherent toxicity ofNaBH₄. These findings demonstrate the potential of Psidiumguajava-mediated FeNPs as eco-friendly catalysts for pollutant reduction,combining efficiency with reduced environmental impact.

Keywords

Iron oxides / Stabilization / Vegetable coating / Sodium borohydride / Ecotoxicological tests

Supplementary Materials

The following supporting information can be found at: https://www.sciepublish.com/article/pii/714, Figure S1: Elemental mapping and EDS spectrum of Fe(NPs) synthesized with different volumetric proportions of plant extract: (a) Fe(NPs) 25%, (b) Fe(NPs) 40%, and (c) Fe(NPs) 50%; Figure S2: UV-VIS absorption spectra of catalytic reduction reactions using Fe(NPs) synthesized with: (a) Fe(NPs) 25%, (b) Fe(NPs) 40%, and (c) Fe(NPs) 50% plant extract.

Acknowledgments

The authors thank the Federal University of Technology—Paraná (UTFPR campus Pato Branco), Laboratory Central de Análises (CA), and C²MMa—Centro de Caracterização Multiusuário em Pesquisa e Desenvolvimento de Materiais for the use of facilities. The authors also acknowledge the Coordination for the Improvement of Higher Education Personnel (CAPES)—Financing Code 001 for financial support.

Author Contributions

Conceptualization, F.K.d.S.N.; Methodology, F.K.d.S.N., M.B.R. and R.B.; Experimental Activities, F.K.d.S.N., M.B.R., R.B., G.G.L., Y.M.L.B. and M.A.C.d.A.; Investigation, F.K.d.S.N., M.A.C.d.A., G.G.L. and Y.M.L.B.; Resources, M.B.R. and R.B.; Data Processing and Analysis, F.K.d.S.N. and Y.M.L.B.; Writing—Original Draft Preparation, F.K.d.S.N.; Writing—Review & Editing, F.K.d.S.N., Y.M.L.B., M.B.R. and R.B.; Visualization, F.K.d.S.N.; Supervision, M.B.R. and R.B.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author, Filipe Kalil da Silva Naves, upon reasonable request.

Funding

This research was funded by the Coordination for the Improvement of Higher Education Personnel (CAPES)—Finance Code 001.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

[1] Mukherjee R, Kumar R, Sinha A, Lama Y, Saha AK. A review on synthesis, characterization, and applications of nano zero valent iron (nZVI) for environmental remediation. Crit. Rev. Environ. Sci. Technol. 2016, 46, 443-466. doi: 10.1080/10643389.2015.1103832.

[2] Nkosi NC, Basson AK, Ntombela ZG, Dlamini NG, Pullabhotla RV. Green synthesis and characterization of iron nanoparticles synthesized from bioflocculant for wastewater treatment: a review. Biotechnol. Notes 2025, 6, 10-31.

[3] Chaudhari DS, Upadhyay RP, Shinde GY, Gawande MB, Filip J, Varma RS, et al. A review on sustainable iron oxide nanoparticles: Syntheses and applications in organic catalysis and environmental remediation. Green Chem. 2024, 26, 7579-7655. doi: 10.1039/D4GC01234A.

[4] Shahzadi S, Fatima S, Shafiq Z, Janjua MR. A review on green synthesis of silver nanoparticles (SNPs) using plant extracts: A multifaceted approach in photocatalysis, environmental remediation, and biomedicine. RSC Adv. 2025, 15, 3858-3903. doi: 10.1039/d4ra07519f.

[5] Ahmad S, Ni H, Al-Mubaddel FS, Rizk MA, Ammar MB, Khan AU, et al. Magnetic properties of different phases of iron oxide nanoparticles prepared by microemulsion-hydrothermal method. Sci. Rep. 2025, 15, 878. doi: 10.1038/s41598-025-85145-5.

[6] Al-Harbi N, Abd-Elrahman NK. Physical methods for preparation of nanomaterials, their characterization and applications: a review. J. Umm Al-Qura Univ. Appl. Sci. 2025, 11, 356-377. doi: 10.1007/s43994-024-00165-7.

[7] Rana A, Kumari N, Tyagi M, Jagadevan S. Leaf-extract mediated zero-valent iron for oxidation of Arsenic (III): Preparation, characterization and kinetics. Chem. Eng. J. 2018, 347, 91-100. doi: 10.1016/j.cej.2018.04.075.

[8] Bachhar V, Joshi V, Bhatia A, Rom T, Duseja M, Shukla RK. Green synthesis of AgFe bimetallic nanoparticles from Calyptocarpus vialis plant extract for enhanced catalytic reduction of 4-nitrophenol, antioxidant, and antibacterial activities. J. Environ. Chem. Eng. 2025, 13, 116829. doi: 10.1016/j.jece.2025.116829.

[9] Uncu Kirtiş EB, Yiğit Koçak D, Elderviş U, Tuna S, Bayraç C. Green synthesis of iron oxide nanoparticles from extracts of Daucus carota subsp. sativus whole vegetable, peel, pomace, and juice and their application as antibacterial agents and Fenton-like catalysts. Int. J. Food Sci. Technol. 2025, 60, vvae035.

[10] Joga SB, Korabandi D, Lakkaboyana SK, Kumar V. Synthesis of iron nanoparticles on lemon peel carbon dots (LP-CDs@Fe₃O₄) applied in photocatalysis, antioxidant, antidiabetic, and hemolytic activity. Inorg. Chem. Commun. 2025, 174 P1, 113960. doi: 10.1016/j.inoche.2025.113960.

[11] Archana V, Joseph PJ, Kalainathan S. Simple One-Step Leaf Extract-Assisted Preparation of α-Fe₂O₃ Nanoparticles, Physicochemical Properties, and Its Sunlight-Driven Photocatalytic Activity on Methylene Blue Dye Degradation. J. Nanomater. 2021, 2021, 8570351. doi: 10.1155/2021/8570351.

[12] Puthukkara AR, Jose TS, Dinoop S. Plant mediated synthesis of zero valent iron nanoparticles and its application in water treatment. J. Environ. Chem. Eng. 2021, 9, 104569. doi: 10.1016/j.jece.2020.104569.

[13] Naves FKS, Bueno YML, Rocha RDC, Brackmann R, Rodrigues MB. Green synthesis of iron nanoparticles (Fe(NPs)) using plant extract from Eucalyptus grandis: characterization and determination of the catalytic potential for reduction of 4-nitrophenol. Rev. Ambient. Água. 2024, 19, e2978. doi: 10.4136/ambi-agua.2978.

[14] Shahid A, Muhamma I, Muhammad R, Beenish I. Phytochemical screening and in vitro radical scavenging activities of “Gola” guava fruit and leaf extracts. J. Food Process. Preserv. 2022, 46, e16989. doi: 10.1111/jfpp.16989.

[15] Samari F, Salehipoor H, Eftekharb E, Yousefinejad S. Low-temperature biosynthesis of silver nanoparticles using mango leaf extract: Catalytic effect, antioxidant properties, anticancer activity and application for colorimetric sensing. New J. Chem. 2018, 42, 15905-15916. doi: 10.1039/c8nj03156h.

[16] Amezquita-Garcia HJ, Rangel-Mendez JR, Cervantes FJ, Razo-Flores E. Bioreactors packed with activated carbon fibers as redox mediators in the anaerobic biotransformation of 4-Nitrophenol to 4-Aminophenol. Bol. Grupo Esp. Carbón 2017, 3, 15-17.

[17] Sravanthi K, Ayodhya D, Swamy PY. Green synthesis, characterization and catalytic activity of 4-nitrophenol reduction and formation of benzimidazoles using bentonite supported zero valent iron nanoparticles. Mater. Sci. Energy Technol. 2019, 2, 298-307. doi: 10.1016/j.mset.2019.02.003.

[18] Díaz-de-Cerio E, Vito V, Ana María G, Alberto F, Antonio S. Determination of polar compounds in guava leaves infusions and ultrasound aqueous extract by HPLC-ESI-MS. J. Chem. 2015, 2015, 250919. doi: 10.1155/2015/250919.

[19] Dong H, Zhao F, Zeng G, Tang L, Fan C, Zhang L, et al. Aging study on carboxymethyl cellulose-coated zero-valent iron nanoparticles in water: Chemical transformation and structural evolution. J. Hazard. Mater. 2016, 312, 234-242. doi: 10.1016/j.jhazmat.2016.03.069.

[20] Dong H, Zhao F, He Q, Xie Y, Zeng Y, Zhang L, et al. Physicochemical transformation of carboxymethyl cellulose-coated zero-valent iron nanoparticles (nZVI) in simulated groundwater under anaerobic conditions. Sep. Purif. Technol. 2017, 175, 376-383. doi: 10.1016/j.seppur.2016.11.053.

[21] Singh H, Desimone MF, Pandya S, Jasani S, George N, Adnan M, et al. Revisiting the green synthesis of nanoparticles: uncovering influences of plant extracts as reducing agents for enhanced synthesis efficiency and its biomedical applications. Int. J. Nanomed. 2023, 18, 4727-4750. doi: 10.2147/IJN.S419369.

[22] Bibi I, Nazar N, Ata S, Sultan M, Ali A, Abbas A, et al. Green synthesis of iron oxide nanoparticles using pomegranate seeds extract and photocatalytic activity evaluation for the degradation of textile dye. J. Mater. Res. Technol. 2019, 8, 6115-6124. doi: 10.1016/j.jmrt.2019.10.006.

[23] Adhikari A, Chhetri K, Acharya D, Pant B. Adhikari A. Green Synthesis of Iron Oxide Nanoparticles Using Psidium. Catalysts 2022, 12, 1188. doi: 10.3390/catal12101188.

[24] Sun Y, Li X, Zhang W, Wang HP. A method for the preparation of stable dispersion of zero-valent iron nanoparticles. Colloids Surf. A Physicochem. Eng. Asp. 2007, 308, 60-66. doi: 10.1016/j.colsurfa.2007.05.029.

[25] Singh G, Jalandhara D, Yadav K. Effect of grain size on optical properties of iron oxide nanoparticles. AIP Conf. Proc. 2016, 1728, 020409. doi: 10.1063/1.4946460.

[26] Casassa-Padrón AM, Portillo E, González C. FTIR-ATR for the identification of Psidium guajava plants infested with Meloidogyne enterolobii. Rev. Fac. Agron. 2022, 39, 2. doi: 10.47280/RevFacAgron(LUZ).v39.n3.03.

[27] Karu E, Magaji B, Mohammed Bello A. Green synthesis, spectroscopic analysis and stabilization energy of iron oxide nanoparticles from aqueous Ziziphus leaf extract. Bima J. Sci. Technol. 2022, 6, 40-49.

[28] Kumari T, Phogat D, Shukla V. Exploring the multipotentiality of plant extracts for the green synthesis of iron nanoparticles: A study of adsorption capacity and dye degradation efficiency. Environ. Res. 2023, 229, 116025. doi: 10.1016/j.envres.2023.116025.

[29] Mokshith DG, Kalpashree MM, Krishna DK. Natural Synthesis of Nanoparticles using Flower Extract of Hymenocallis littoralis (Jacq) Salisb and Evaluation of its Antimicrobial activity. Int. J. Res. Appl. Sci. Eng. Technol. 2022, 10, 1199-1207. doi: 10.22214/ijraset.2022.47158.

[30] Kharisov B, Kharissova OV, Dias HVR, Méndez UO, Fuente IG, Peña Y, et al. Iron-based nanomaterials in the catalysis. In Advanced Catalytic Materials—Photocatalysis and Other Current Trends; InTech: Rijeka, Croatia, 2016; pp. 1-36. doi: 10.5772/61862.

[31] Amos-Tautua BM, Fakayode OJ, Songca SP, Oluwafemi OS. Effect of synthetic conditions on the crystallinity, porosity and magnetic properties of gluconic acid capped iron oxide nanoparticles. Nano-Struct. Nano-Objects 2020, 23, 100480. doi: 10.1016/j.nanoso.2020.100480.

[32] Fekry M, Shafek SH, Soliman FS, Bakry A. Impact of poly naphthalene sulfonate on the dispersion stability of iron oxide nanoparticles. Egypt. J. Petrol. 2023, 32, 23-32. doi: 10.1016/j.ejpe.2023.01.001.

[33] Atran AA, Ibrahim FA, Awwad NS, Hamdy MS. Iron incorporated porous cerium oxide nanoparticles as an efficient photocatalyst for different hazardous elimination. J. Rare Earths 2024, 43, 726-735. doi: 10.1016/j.jre.2024.02.006.

[34] Sirdeshpande KD, Sridhar A, Cholkar KM, Selvaraj R. Structural characterization of mesoporous magnetite nanoparticles synthesized using the leaf extract of Calliandra haematocephala and their photocatalytic degradation of malachite green dye. Appl. Nanosci. 2018, 8, 675-683. doi: 10.1007/s13204-018-0698-8.

[35] Wang Q, Kanel SR, Park H, Ryu A, Choi H. Controllable synthesis, characterization, and magnetic properties of nanoscale zerovalent iron with specific high Brunauer–Emmett–Teller surface area. J. Nanopartic. Res. 2009, 11, 749-755.

[36] Ben Kouider T, Souli L, Derouiche Y, Soltani T, Maschke U. Green synthesis and characterization of Fe₃O₄ and ε-Fe₂O₃ nanoparticles using apricot kernel shell extract and study of their optical properties. Physchem 2025, 5, 33. doi: 10.3390/physchem5030033.

[37] Beheshtkhoo N, Kouhbanani MA, Savardashtaki A, Amani AM, Taghizadeh S. Green synthesis of iron oxide nanoparticles by aqueous leaf extract of Daphne mezereum as a novel dye-removing material. Appl. Phys. A Mater. Sci. Process. 2018, 124, 363. doi: 10.1007/s00339-018-1782-3.

[38] Wunder S, Lu Y, Albrecht M, Ballauff M. Kinetic analysis of catalytic reduction of 4-nitrophenol by metallic nanoparticles immobilized in spherical polyelectrolyte brushes. J. Phys. Chem. C 2010, 114, 8814-8820. doi: 10.1021/jp101125j.

[39] Chiou JR, Lai BH, Hsu KC, Chen DH. One-pot green synthesis of silver/iron oxide composite nanoparticles for 4-nitrophenol reduction. J. Hazard. Mater. 2013, 248–249, 394-400. doi: 10.1016/j.jhazmat.2013.01.030.

[40] Biswas S, Pal A. Iron oxide-loaded alginate-bentonite hydrogel beads as a green and sustainable catalyst for 4-nitrophenol reduction. Mater. Today Commun. 2021, 28, 102588. doi: 10.1016/j.mtcomm.2021.102588.

[41] Malathi S, Ezhilarasu T, Abiraman T, Balasubramanian S. One pot green synthesis of Ag, Au and Au–Ag alloy nanoparticles using isonicotinic acid hydrazide and starch. Carbohydr. Polym. 2014, 111, 734-743. doi: 10.1016/j.carbpol.2014.04.105.

[42] Bhole R, Gonsalves D, Murugesan G, Narasimhan MK, Srinivasan NR, Dave N, et al. Superparamagnetic spherical magnetite nanoparticles: synthesis, characterization and catalytic potential. Appl. Nanosci. 2023, 13, 6003-6014. doi: 10.1007/s13204-022-02532-4.