Electronic Theses and Dissertation

Pencemaran air akibat limbah industri tekstil yang mengandung zat warna seperti methylene blue (MB) merupakan salah satu permasalahan lingkungan yang serius. Teknologi membran menjadi solusi potensial dalam pengolahan air, terutama melalui pengembangan membran thin film nanocomposite (TFN) yang dapat meningkatkan efisiensi pemisahan. Penelitian ini bertujuan untuk mensintesis dan mengevaluasi kinerja membran TFN berbasis nanokristal selulosa (NCC) dari limbah daun nanas. Membran ultrafiltrasi dibuat dari 17% polimer polietersulfon (PES), 1% aditif polivinilpirolidon (PVP), dan 82% pelarut dimethyl sulfoxide (DMSO). Membran TFN disintesis melalui metode interfacial polymerization dengan variasi konsentrasi NCC sebesar 0; 0,1; 0,5; dan 1 wt%. Karakterisasi NCC menunjukkan struktur berbentuk nanowhisker dengan kristalinitas tinggi dan gugus fungsi karakteristik seperti hidroksil, karbonil, dan eter. Hasil karakterisasi membran menunjukkan bahwa penambahan NCC meningkatkan hidrofilisitas, stabilitas termal, dan kekuatan mekanik. Analisis scanning electron microscopy (SEM) menunjukkan bahwa membran ultrafiltrasi memiliki pori-pori yang lebih besar dibandingkan membran TFN. Pengamatan penampang mengungkapkan bahwa membran ultrafiltrasi tidak memiliki lapisan atas tipis, sedangkan membran TFN memiliki lapisan tipis di permukaan. Analisis fourier transform infrared (FTIR) mengkonfirmasi keberhasilan penggabungan NCC dengan mengidentifikasi gugus fungsional karakteristik, termasuk ikatan hidroksil (-OH), karbonil (C=O), dan eter (C-O-C). Analisis Thermogravimetric Analysis (TGA) dan Differential Thermal Analysis (DTA) mengindikasikan peningkatan stabilitas termal dengan peningkatan NCC. Analisis mekanik memperlihatkan bahwa penambahan NCC meningkatkan kuat tarik membran. Membran M4 (0,5% NCC) menunjukkan nilai kuat tarik tertinggi sebesar 5,22 MPa dibandingkan dengan M1 (tanpa NCC) sebesar 3,47 MPa. Membran TFN dengan kandungan 1 wt.% NCC (M5) menunjukkan efisiensi penolakan MB tertinggi sebesar 92,45%, sedangkan membran dengan 0,5 wt.% NCC (M4) memberikan keseimbangan terbaik antara permeabilitas (1,59 L/m2 .h.bar) dan selektivitas (85,07%).

Kata kunci: membran, nanofiltrasi, nanocomposite, nanoselulosa, methylene blue

Water pollution caused by textile industry waste containing dyes such as methylene blue (MB) is a serious environmental issue due to MB’s toxicity, stability, and resistance to degradation. Membrane technology offers a promising solution for water treatment, particularly through the development of thin film nanocomposite (TFN) membranes that enhance separation efficiency. This study aimed to synthesize and evaluate the performance of TFN membranes based on nanocrystalline cellulose (NCC) derived from pineapple leaf waste. The ultrafiltration membrane was fabricated using a solution of 17% polyethersulfone (PES) polymer, 1% polyvinylpyrrolidone (PVP) additive, and 82% dimethyl sulfoxide (DMSO) solvent. TFN membranes were synthesized via interfacial polymerization with varying NCC concentrations of 0, 0.1, 0.5, and 1 wt%. Characterization of NCC revealed a nanowhisker morphology with high crystallinity and functional groups such as hydroxyl, carbonyl, and ether. Membrane characterization results indicated that the addition of NCC improved hydrophilicity, thermal stability, and mechanical strength. Scanning electron microscopy (SEM) analysis showed that the ultrafiltration membrane exhibited larger pores than TFN membranes. Cross-sectional observations revealed that the ultrafiltration membrane lacked a thin top layer, whereas TFN membranes exhibited a distinct thin layer at the surface. Fourier transform infrared (FTIR) analysis confirmed successful NCC incorporation by identifying characteristic functional groups including hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C) bonds. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) indicated increased thermal stability with higher NCC content. Mechanical analysis demonstrated that the addition of NCC enhanced the tensile strength of the membranes. The M4 membrane (0.5% NCC) exhibited the highest tensile strength of 5.22 MPa, compared to 3.47 MPa in M1 (without NCC). The TFN membrane containing 1 wt% NCC (M5) achieved the highest MB rejection efficiency of 92.45%, while the 0.5 wt% NCC membrane (M4) offered the best balance between permeability (1.59 L/m²·h·bar) and selectivity (85.07%). Keywords: membrane, nanofiltration, nanocomposite, nanocellulose, methylene blue