Cyclic Chelation–Nanofiltration Process for High‐Efficiency Removal of Cu(II) Ions From Wastewater Using EDTA

ABSTRACT In this study, a hybrid nanofiltration (NF) process was developed using ethylenediamine tetraacetic acid (EDTA) as a chelating agent. EDTA binds with metal ions at lower pH levels, which can be easily removed from the effluent using NF with enhanced rejection. Later, EDTA from the concentrated retentate can be precipitated and recycled by adjusting the pH. This study investigated the removal of copper ions (Cu +2 ) from a model effluent. Experiments were conducted in a membrane test cell using a polyamide NF membrane with a 150 Da cutoff. Membrane performance was studied with and without EDTA. High transmembrane pressure, high feed flow rate, and a feed pH of 5 were optimal operating parameters for achieving higher water flux and rejection. The modified process achieved a maximum flux of 11.82×10 −6 m 3 /m 2 s and a maximum rejection of 99.88%. Results confirm that applying the chelating agent improves the rejection and removes nearly all Cu +2 ions from the effluent stream.