Tubular SiC membranes in brine purification: Effects of operational parameters towards low energy consumption process

Abstract

Brine purification process using ceramic membrane has the advantages of short process, high filtration precision, low cost and long life. Silicon carbide (SiC) ceramic membranes are featured by excellent hydrophilicity and unique negatively charged surface. This work focused on the application of low-temperature reaction bonded SiC membranes in brine purification, and commercial SiC membranes prepared by the recrystallisation method were also adopted for comparison. Under low-energy conditions (transmembrane pressure ≤ 0.1 MPa, crossflow velocity ≤ 2 m·s^-1), the low-temperature reaction bonded SiC membranes exhibited higher stable flux and superior antifouling performance (i.e., lower flux decline), attributed to the formation of a cake layer on the membrane surface. However, at high pressures (>0.1 MPa) and velocities (>2 m·s^-1), some precipitated particles entered the pores of reaction bonded SiC membranes, resulting minor pore blockage, reducing permeability. Interestingly, the gradually increased initial permeate flux observed in cycling filtration was attributed to the increased surface hydrophilicity of SiC membranes. Therefore, low temperature reaction bonded SiC membranes can provide a high-efficient and energy-saving brine purification process in the chlor-alkali industry.