การเตรียมวัสดุเชิงประกอบชีวภาพฐานพอลิแลกไทด์เพื่อประยุกต์ใช้ในการบำบัดน้ำเสีย ; Preparation of Polylactide-based Biocomposite Applied to Wastewater Treatment

วิทยาศาสตรมหาบัณฑิต (วิทยาศาสตร์และเทคโนโลยีพอลิเมอร์), 2566 ; Powder adsorbents are widely used due to their high adsorption efficiency, but they are inconvenient for practical use. In this work, polylactide (PLA) - based biocomposte adsorbents were developed for easy use, and environmental friendliness. Biocomposite adsorbents were prepared in membrane and bead forms using phase inversion method for cationic dye removal from water. To prepare biocomposite adsorbent, the cellulose fiber from agricultural waste such as oil palm empty fruit bunch (EFB) and lemongrass leaf (LGL) were firstly modified using maleic anhydride (MAH). The presence of carboxyl groups in MAH-modified EFB (MEFB) and LGL (MLGL) provided an excellent binding tocationic methylene blue (MB).The second step is the combination of modified fiber with biopolymers to produce adsorbents in membrane and bead forms. The biocomposite membrane from the PLA/ Poly(butylene adipate-coterephthalate) (PBAT) polymer blend added with MEFB was prepared by phase inversion method. The PLA/PBAT-MEFB biocomposite membrane could be twisted or bent. Moreover, the biocomposite membrane showed higher porosity and water absorption and more hydrophilicity than the PLA/PBAT blend membrane. Based on these results, by batch adsorption process, the biocomposite membrane showed higher adsorption capacity than the blend membrane. By filtration adsorption test, the pure water flux of biocomposite membrane was much higher than that of blend membrane and the separation efficiency of biocomposite membrane was 97.2% while blend membrane removed only 58.7%. The existence of MEFB in polymer matrix improved the adsorption efficiency of biocomposite due to the electrostatic binding between the carboxyl groups in MEFB and cationic MB. By filtration the mixed dye solution of cationic MB and anionic dye methyl orange (MO) through the PLA/PBAT MEFB membrane, cationic MB was almost completely absorbed by the negatively charged membrane. Whereas the negatively charged MO molecules passed ...