Removal of Organic Pollutants with Polylactic Acid-Based Nanofiber Composites

Abstract

In the process of using nano-titanium dioxide (TiO2) photocatalytic treatment of organic polluted liquid, the easy aggregation and recycling difficulty of nano-TiO2 particles are important problems that cannot be avoided. Anchoring nano-TiO2 to the substrate not only limits the aggregation of nano-TiO2, but also facilitates the easy removal and reuse of nano-TiO2 after processing. Herein, coaxial electrospun nanofibrous (NFs) made of L-polylactic acid (PLLA) and chitosan (CS) are coated with graphene oxide (GO) and TiO2 for the enhanced oxidation of organic pollutants. The adsorption and photocatalysis experiment results show that, for methyl orange (MO) dye solution, the saturated removal of MO by PLLA/CS, PLLA/CS-GO and PLLA/CS-GO/TiO2 nanofibers are 60.09 mg/g, 78.25 mg/g and 153.22 mg/g, respectively; for the Congo red (CR) dye solution, the saturated removal of CR by PLLA/CS, PLLA/CS-GO and PLLA/CS-GO/TiO2 nanofiber materials were 138.01 mg/g, 150.22 mg/g and 795.44 mg/g, respectively. These three composite nanofiber membrane materials can maintain more than 80% of their adsorption capacity after four repeated cycles. They are environmentally friendly and efficient organic pollution remediation materials with promising application.