Utilization of Biodegradable Nanofiltration Membrane for Efficient Removal of Anionic Textile Dye

Dye pollution has a major adverse effect on ecosystems and human health since it comprises complex pollutants containing dyestuff and chemicals. During the last period, some promising solutions to remove dyes from textile wastewater have come through separation technologies that are based on membranes. However, limitations have been identified with polymeric membranes due to their non-biodegradability and environmental impact. Chitosan-based membranes are getting more attention mainly because they are biocompatible, sustainable, and can be tailored for specific applications. Chitosan (CS) is a sustainable and biodegradable membrane material. In this study, a flat-membrane sheet of neat chitosan (CS) was fabricated using a solvent-casting process on nonwoven support (polyester) to prepare a multilayer composite nanofiltration membrane. The composite CS membrane was investigated by scanning electron microscope (SEM), contact angle measurements, atomic force microscopy (AFM), and mechanical testing. The characterization results showed improvements in surface roughness, hydrophilicity, tensile strength, and overall surface structure. By utilizing the multilayer technique during membrane fabrication, the membrane surface was transformed from a rough texture with large pore radii to a smooth surface featuring a refined pore structure. Furthermore, it exhibited a high rejection efficiency of 100 % for anionic direct blue 78 dye with permeation flux 9.3 Lm-2h-1 and excellent antifouling performance for a 600 min filtration test. These results showed that the CS nanofiltration membrane has a promising application for hazardous contaminants removal from textile dyeing effluent.