Evolution of Membrane Performance During the Ultrafiltration of Reactive Black 5 Solutions: Effect of Feed Characteristics and Operating Pressure

Abstract

In the present work, the feasibility of the ultrafiltration (UF) technology for the removal of a hazardous azo reactive dye, Reactive Black 5 (RB5), was studied. A tubular UF ceramic membrane was used to filter RB5 aqueous solutions. Solutions at different feed concentrations (50, 100, 500 mg/L) and temperatures (25, 30, 35, 40 oC) were tested in order to observe the influence of these two parameters on the evolution of permeate flux and dye rejection with operating time. Moreover, the effect of transmembrane pressure (TMP) was also studied by performing essays at different operating pressures (1, 2, 3, 4 bar). Additionally, membrane performance was also evaluated by means of the average permeate flux and the cumulative flux decline. The results showed that both the productivity and the permeate quality improved by increasing feed temperature and decreasing feed concentration. On the other hand, an increase in TMP led to an increase in permeate flux. However, in this case the flux decline was more pronounced and the retention of dye decreased. Finally, the relatively high dye rejections obtained are an indicator of the suitability of UF technology for the removal of RB5 from aqueous solutions as a pretreatment of other membrane processes to textile water reuse.