Performance of a hybrid coagulation/flocculation process followed by modified microfiltration membranes for the removal of solophenyl blue dye

The presence of textile dyes in waters and effluents is still a global concern since the conventional methods of treatment are not sufficient to completely remove these contaminants. Given this scenario, this study evaluated a hybrid system of coagulation/flocculation (CF) followed by microfiltration (MF) for solophenyl blue (SB) dye removal. The combination of these processes using potato starch (PS) as a natural coagulant and TiO2 to modify the membrane surface is innovative and efficient. The results showed that the processes, when applied separately, were not effective. The pretreatment by CF favored the removal of particles and colloids from the dye. The modification of the membrane surface allowed the mitigation of fouling in the MF process. Thus, the association of CF/MF showed excellent results, achieving a 100% SB removal and a considerable reduction in the fouling rate. The modified membrane preceded by CF, for example, has substantially improved the rejection of SB, as the removal rate has increased by about 57% compared to the pure membrane. Therefore, the proposed hybrid process demonstrated a significant improvement in the quality of the permeate, with high potential for application in the treatment of dye wastewater from textile industries, besides sustainable and economical characteristics.