Development of advanced floating poly(lactic acid)-based materials for colored wastewater treatment

Abstract

The release of industrial wastewater into the ecosystem prompted our research on the development of an efficient and biodegradable material that can be used for wastewater treatment. We optimized preparation of porous material from poly(lactic acid) (PLA) by variation in solvents and drying methods (air-drying vs. supercritical CO2-drying). In addition, we optimized the method of TiO2 nanoparticles immobilization (in situ vs. ex situ) onto porous PLA. The material properties and functionality were verified by SEM, water displacement, gas adsorption-desorption, Hg-intrusion porosimetry, dye degradation, FTIR, TGA/DSC, and water contact angle analysis. We showed that the morphology of PLA material could be controlled by variation in process parameters resulting in porosity from 43% to 73%. The prepared material sustained floatability for longer than 4 weeks and provided complete discoloration of dye C.I. Acid Orange 7 after 240 min of illumination. The high photocatalytic activity was preserved within three repeated cycles.