Ultrafiltration/complexation process for metal removal from pulp and paper industry wastewater

A process for metals removal from totally chlorine free (TCF) wastewater using water-soluble polymeric ligands (WSPL) in combination with ultrafiltration is described. The polymeric ligands addition, contact time between the polymeric ligands and the wastewater, and pH were evaluated. The UF experiments were carried out in dead-end stirred cell and the pressure applied was controlled by nitrogen gas. The membranes used were made from polyvinilidene fluoride (PVDF) by the phase inversion method. Wastewater from Klabin Pulp and Paper Industry was used. The performance of water-soluble polymeric ligands poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) was evaluated by determining metal, color, turbidity and chemical oxygen demand (COD) removal. In general, the complexation/ultrafiltration process was efficient in the removal of those parameters from wastewater, leading to a better effluent quality when compared to ultrafiltration without any ligands addition.