Sintesis Pigmen Geothit (α-FeOOH) dari Limbah Industri Kerajinan Besi dengan Metode Presipitasi

Choirun Nisa, Nur Aini, Lilik Miftahul Khoiroh


Iron handicraft is one of industries that process iron ore into handicraft products and produce lathe waste. Iron lathe contains 96.08% iron metal which is potential source as a precursor for synthesis of goethite pigment. The method used for synthesis was precipitation using NaHCO3 as precipitator agent. Synthesis was conducted at 70°C with variations of stirring speed such as 550, 650, 750 and 850 rpm. The products were characterized by color reader, ultraviolet-visible (UV-Vis) spectroscopy, XRD and SEM-EDX. The data from color reader showed that the highest yellowness degree and lightness obtained at a stirring speed 550 rpm were 24.1 and 42.1, respectively. UV-Vis data showed that the maximum wavelength of goethite pigment was 600-624 nm. Based on XRD data, synthesized pigment was in goethite phase (α-FeOOH) for all samples with crystallite size 63.24 nm and the highest crystallinity was achieved at 550 rpm. SEM-EDX data showed that morphology pigment (α-FeOOH) was not uniform, there were impurities such as Na and C.


Keywords: Lathe waste, precipitation, goethite, pigment



Industri kerajinan besi merupakan salah satu industri yang mengolah bijih besi menjadi produk kerajinan dan menghasilkan limbah bubut besi. Limbah bubut besi mengandung unsur besi sebesar 96,08% yang berpotensi sebagai bahan baku (prekursor) untuk sintesis pigmen geothit. Metode yang digunakan adalah metode presipitasi dengan agen pengendap NaHCO3. Sintesis dilakukan pada suhu 70°C dengan variasi kecepatan pengadukan 550, 650, 750 dan 850 rpm. Produk hasil sintesis dikarakterisasi dengan color reader, spektroskopi ultraviolet-tampak (UV-Vis), XRD, dan SEM-EDX. Data color reader menunjukkan bahwa derajat kekuningan dan derajat kecerahan tertinggi didapatkan pada kecepatan pengadukan 550 rpm yaitu berturut-turut 24,1 dan 42,1. Data UV-Vis menunjukkan panjang gelombang maksimum pigmen geothit hasil sintesis adalah 600-624 nm. Hasil karakterisasi XRD menunjukkan bahwa pigmen hasil sintesis pada semua kecepatan pengadukan berfasa geothit (α-FeOOH) dengan derajat kristalinitas tertinggi pada kecepatan pengadukan 550 rpm dengan ukuran kristal 63,24 nm. Hasil SEM-EDX pada kecepatan 550 rpm menunjukkan bahwa morfologi pigmen (α-FeOOH) hasil sintesis tidak seragam dan ditemukan adanya pengotor berupa unsur Na dan C.


Kata kunci: Limbah bubut besi, presipitasi, geothit, pigmen


Iron Lathe Waste, Goethite, Temperature, Precipitation

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