Revisited Coagulation-Flocculation-Nanofiltration for Dye Removal

Wastewater generated from industrial processes that contain dyes presents a significant environmental challenge, and traditional treatment methods often struggle to efficiently eliminate these harmful substances. Nanofiltration (NF) plays a crucial role in addressing dye wastewater treatment, but it encounters a major drawback in the form of fouling. To mitigate the fouling and improve the performance of NF for water reuse, coagulation-flocculation (CF) is suggested as a pretreatment step before NF. This review explores advancements after year 2011 in coagulation-flocculation-NF techniques for dye removal. Aluminum sulfate and ferric sulfate have been used as coagulants while polydiallyldimethyl ammonium chloride and anionic polyacrylamide have been used as flocculants. Application of natural coagulant-NF technique for dye containing wastewater treatment has potential to generate less sludge in comparison to alum, potentially reducing overall costs and promoting environmental sustainability. Moringa oleifera has potential as an alternative to the conventional coagulant. Synthesizing a natural coagulant through plant extraction for excellent coagulating agent needs to be explored in the future.