Electronic Theses and Dissertation

Green synthesis nanopartikel α-Fe₂O₃ menggunakan ekstrak etanol daun pala
(Myristica fragrans) telah berhasil dilakukan dan uji aktivitas fotokatalitiknya pada
degradasi zat warna Naphthol Blue Black (NBB). Ekstrak etanol daun pala memiliki
kandungan metabolit sekunder berupa fenolik, saponin, steroid, dan tanin yang
berperan sebagai agen pereduksi dan penstabil (capping agent). Kandungan fenolik
total (total phenolic content, TPC) ekstrak etanol daun pala sebesar 126,21 mg GAE/g,
sedangkan kandungan flavonoid total (total flavonoid content, TFC) sebesar 10,562
mg QE/g. Sintesis nanopartikel α-Fe₂O₃ dilakukan menggunakan prekursor
Fe(NO₃)₃·9H₂O melalui metode green synthesis yang dikombinasikan dengan proses
hidrotermal. Karakterisasi nanopartikel α-Fe₂O₃ dilakukan menggunakan X-Ray
Diffraction (XRD), Fourier Transform Infrared (FTIR). UV-Vis Diffuse Reflectance
Spectroscopy (UV-Vis DRS), Scanning Electron Microscopy (SEM). Hasil
karakterisasi menunjukkan bahwa nanopartikel yang dihasilkan memiliki struktur
hematit (α-Fe₂O₃) berfase rhombohedral dengan ukuran kristalit rata-rata 60,44 nm,
menunjukkan pita serapan khas ikatan Fe–O pada spektrum FTIR, dengan nilai band
gap sebesar 2,08 eV. Sedangkan hasil karakterisasi sem menunjukkan nanopartikel αFe₂O₃ memiliki bentuk bulat (sferis) dengan distribusi partikel yang homogen. Hasil
uji aktivitas fotokatalitik menunjukkan bahwa nanopartikel α-Fe₂O₃ mampu
mendegradasi zat warna Naphthol Blue Black di bawah radiasi sinar UV maupun sinar
matahari. Persen degradasi Naphthol Blue Black menggunakan sinar matahari lebih
tinggi yaitu sebesar 96% selama 90 menit, dibandingkan menggunakan sinar UV
dengan persen degradasi sebesar 90% selama 150 menit. Nanopartikel α-Fe₂O₃ hasil
green synthesis menggunakan ekstrak etanol daun pala berpotensi diaplikasikan
sebagai fotokatalis ramah lingkungan untuk pengolahan limbah zat warna.
Kata kunci: Green synthesis, Myristica fragrans, α-Fe₂O₃, nanopartikel, fotokatalisis,
Naphthol Blue Black.

Green synthesis of α-Fe₂O₃ nanoparticles using ethanolic extract of nutmeg (Myristica fragrans) leaves was successfully carried out, and evaluation of their photocatalytic activity on degradation of Naphthol Blue Black (NBB) dye. The ethanolic extract of nutmeg leaves contained secondary metabolites, including phenolics, saponins, steroids, and tannins which played a role as reducing and stabilizing agent (capping agent). The total phenolic content (TPC) and total flavonoid content (TFC) values of ethanolic extract of nutmeg leaves are 126,21 mg GAE/g and 10.562 mg QE/g, respectively. α-Fe₂O₃ nanoparticles were synthesized using Fe(NO₃)₃·9H₂O as the precursor through a green synthesis method that was combined with hydrothermal process. The synthesized nanoparticles were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS), and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS). The characterization results confirmed the formation of hematite (α-Fe₂O₃) phase, rhombohedral structure with the averages crystallite size of of 60,44 nm, characteristic Fe–O absorption bands in the FTIR spectrum, and the band gap energy is 2.08 eV. The α-Fe₂O₃ nanoparticles are in spherical shape with homogeneous distribution. The photocatalytic study demonstrated that the synthesized α-Fe₂O₃ nanoparticles effectively degraded Naphthol Blue Black under UV light and sunlight irradiation. The degradation efficiency of NBB was higher under sunlight irradiation (96%) for 90 minutes than that of UV irradiation (90%) for 150 minutes. The green-synthesized α-Fe₂O₃ nanoparticles have considerable potential as environmentally friendly photocatalysts for dye wastewater treatment. Keywords: green synthesis, Myristica fragrans, α-Fe₂O₃, nanoparticles, photocatalysis, Naphthol Blue Black.