Constructing Polyamide/Ceramic Composite Membranes for Highly Efficient and Selective Separation towards Dye/salt Solution

Abstract

Membrane separation technology has been recognized as an effective approach to remove dyes from dyeing wastewater that are crucial for improving the quality of pigmentation effect in the printing and dyeing industry. However, the trade-off relationship between membrane permeability and selectivity is an inherent pain point for molecular separation membrane, which hampers the development of large-scale applications of membrane separation process. In this work, we provide a facile approach to construct highly selective polyamide (PA) layer on ceramic membrane by interfacial polymerization of branched Polyethylenimine (PEI) and Trimesoyl Chloride (TMC) for selective separation towards dye/salt mixed wastewater. With high positive surface zeta-potential (100 mV) and excellent hydrophilicity, the PA/ceramic composite membranes exhibit ultra-high solution permeance (496.4 L·m-2·h-1·bar-1) when treating simulated dye/salt aqueous solutions containing 40 ppm Congo Red (CR) and 1 g L-1 NaCl, which is 30 times higher than that of commercial polyamide nanofiltration membranes. Interestingly, the separation factor of NaCl to CR of the PA/ceramic composite membranes reaches above 980, which is far superior to the state-of-art nanofiltration membranes reported recently. Moreover, PA/ceramic membranes possess a relatively ideal long-term stability, with their flux remaining at 280 L·m-2·h-1·bar-1 after 10 h of testing. Taken together, the PA/ceramic composite membranes show strong promise in dye desalination and purification.