FABRICATION OF GRAPHITIC CARBON NITRIDE-BASED FLOATING PHOTOCATALYST USING POLYURETHANE FOAM AS SUPPORT MATERIAL FOR THE DEGRADATION OF SYNTHETIC DYE WASTE

• Main Author: Jaya Budiarso, Indra
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/73020
• Institution: Institut Teknologi Bandung

Advanced oxidation process (AOPs) is a suitable option for synthetic dye-contaminated wastewater which is classified as persistent organic pollutants (POPs) due to its ability to degrade pollutant into less harmful products. Graphitic-C3N4 (GCN) has gained interest in photocatalytic treatment of synthetic dye-contaminated wastewater because it could be activated by visible light and metal free in nature. However, the sinking of GCN in water and fast electron-hole (e-h) recombination limits the GCN application as photocatalyst. Immobilization of GCN on floatable support is a possible solution to keep GCN floating on the water surface and the addition of electron acceptor agent could enhance e-h pair separation. In this work, GCN was synthesized with thermal polymerization route using urea as the precursor. The photocatalyst specimens were made by immobilizing GCN on polyurethane foam (PUF) with the help of polydopamine (PDA) as electron acceptor and adhesive. Immobilization of GCN to PUF was done with two step method (PUF/PDA/GCN-2) and one-step method (PUF/PDA/GCN-1). PUF/PDA/GCN-2 was made by coating PUF with PDA through dopamine autoxidation and subsequently depositing the GCN. PUF/PDA/GCN-1 was made by dopamine autoxidation in the presence of PUF and GCN. To investigate the effect of PDA addition, one specimen consisting of GCN deposited on PUF (PUF/GCN) was also fabricated. Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and diffuse reflectance Ultraviolet-Visible light spectroscopy (DR UV-Vis) show that GCN with heptazine-based structure and bandgap of 2.75 eV was successfully synthesized. The synthesis process of PUF/PDA/GCN-1 is preferable because GCN was evenly distributed on PUF that confirmed by SEM. Thermogravimetric analysis (TGA) result shows that GCN content on PUF/PDA/GCN-1 is 5.02 wt% which far exceeds PUF/PDA/GCN-2 (1.35 wt%). However, PUF/GCN has the highest GCN content of 7.75 wt% due to GCN agglomeration. Photocatalytic performance test with visible light shows that PUF/GCN has degradation efficiency of 10.06% whereas the non-immobilized GCN has only 5.26%. The addition of PDA also increases the degradation efficiency of PUF/PDA/GCN-1 two-fold from 10.06% (PUF/GCN) to 21.07%. This phenomenon is attributed due to uniform GCN distribution which leads to rich active sites in PUF/PDA/GCN-1.