Discolouration of contaminated water with textile dye through a combined coagulation/flocculation and membrane separation process with different natural coagulants extracted from Moringa oleifera Lam. seeds

Abstract

AbstractThe removal of reactive black 5 (RB5) dye present in aqueous solution was studied by applying individual coagulation/flocculation (CF) and microfiltration (MF) processes as well as the combination of both processes (CF‐MF). In the CF process, three natural coagulants produced from Moringa oleifera Lam. seeds (MOS) were used: saline extract (ES) and the purified protein fractions of albumin (ALB) and globulin (GLO). In the MF process, a commercial polyethersulfone (PES) membrane was used. It was noticed that without the combination of both processes, the obtained RB5 removal was only 20.38% for ALB, 52.38% for GLO, and 12.50% for ES. However, when the CF process was combined with a microfiltration process, it was possible to achieve a higher textile dye removal, due to the formation of aggregates in the CF process larger than the pores of the microfiltration membrane. Especially with the ALB coagulant, the combined CF‐MF process achieved a removal greater than 95%. The results demonstrate the potential use of the purified proteins fractions of Moringa oleifera Lam. coagulant in combination with microfiltration process for water treatment.