Electronic Theses and Dissertation

Logam berat seperti besi (Fe) merupakan salah satu polutan utama dalam air limbah quarry tambang yang bersifat toksik, tidak dapat terurai secara hayati, dan mudah mengendap di dasar perairan. Teknologi membran menjadi solusi potensial dalam pengolahan air limbah secara langsung. Polieter sulfon (PES) adalah salah satu polimer yang umum digunakan dalam pembuatan membran karena stabilitas termal, ketahanan kimia, dan kekuatan mekaniknya yang tinggi, meskipun bersifat hidrofobik. Untuk mengatasi kelemahan tersebut, dilakukan modifikasi membran PES dengan penambahan polivinil alkohol (PVA) dan silika hasil ekstraksi dari abu sekam padi melalui metode sol-gel. Silika hasil ekstraksi memiliki kemurnian sebesar 92,52% dan bersifat amorf dengan ukuran kristal sebesar 0,15 nm, yang dikonfirmasi melalui uji XRF, FTIR, dan XRD. Membran dipreparasi dengan metode inversi fasa, menggunakan variasi komposisi PES murni, PES/silika 1%, PES/PVA 1%/silika 1%, PES/PVA 3%/silika 3% (N3), dan PES/silika 3%. Hasil karakterisasi menunjukkan bahwa penambahan PVA dan silika secara signifikan meningkatkan sifat hidrofilik, morfologi pori, kekuatan tarik, dan porositas membran. Membran N3 memiliki porositas tertinggi sebesar 39,99%, ukuran pori rata-rata 69,27 µm, dan fluks air murni tertinggi sebesar 37,77 L/m²·jam. Pada uji performa filtrasi, koefisien permeabilitas tertinggi juga ditunjukkan oleh N3, yaitu 16,88 L/m²·jam·bar. Meskipun N4 memiliki nilai rejeksi Fe tertinggi sebesar 99,24%, membran N3 tetap dipilih sebagai yang terbaik karena menunjukkan kinerja paling seimbang antara rejeksi (92,92%), fluks tinggi, dan struktur pori yang optimal. Dengan demikian, kombinasi PES/PVA dengan silika dari abu sekam padi terbukti efektif meningkatkan efisiensi penyisihan Fe dari air limbah quarry tambang batu bara.
Kata Kunci : Logam Fe, Silika, Polieter sulfon, PVA, Membran, Ultrafiltrasi

Heavy metals such as iron (Fe) are one of the main pollutants in toxic mining wastewater, which is not biodegradable and easily settles at the bottom of water bodies. Membrane technology is a potential solution for direct wastewater treatment. Polyethersulfone (PES) is one of the polymers commonly used in membrane production due to its thermal stability, chemical resistance, and high mechanical strength, despite its hydrophobic nature. To address this limitation, PES membranes were modified by adding polyvinyl alcohol (PVA) and silica extracted from rice husk ash via the sol-gel method. The extracted silica had a purity of 92.52% and was amorphous with a crystal size of 0.15 nm, confirmed by XRF, FTIR, and XRD tests. The membranes were prepared using the phase inversion method, with variations in composition: pure PES, PES/silica 1%, PES/PVA 1%/silica 1%, PES/PVA 3%/silica 3% (N3), and PES/silica 3%. Characterization results showed that the addition of PVA and silica significantly improved the membrane's hydrophilicity, pore morphology, tensile strength, and porosity. The N3 membrane had the highest porosity of 39.99%, an average pore size of 69.27 µm, and the highest pure water flux of 37.77 L/m²·h. In filtration performance testing, the highest permeability coefficient was also demonstrated by N3, at 16.88 L/m²·h·bar. Although N4 had the highest Fe rejection rate of 99.24%, the N3 membrane was selected as the best option due to its balanced performance between rejection (92.92%), high flux, and optimal pore structure. Thus, the combination of PES/PVA with silica from rice husk ash has proven effective in enhancing the efficiency of Fe removal from coal mine quarry wastewater. Keywords: Fe metal, Silica, Polyether sulfone, PVA, Membrane, Ultrafiltration