Recovery of chromium from plastic plating wastewater by cetyltrimethylammonium bromide MEUF and electrodialysis

Abstract

AbstractTo study the recovery of chromium for micellar-enhanced ultrafiltration (MEUF) process, a two-stage process was designed to concentrate chromium by MEUF with cetyltrimethylammonium bromide (CTAB), then recovered by electrodialysis (ED). Wastewater from full-scale plant containing heavy metals, including chromium, copper, and nickel, with pH < 2 were tested to investigate the effects of pH, surfactant/metal (S/M) ratio, and operating pressures. The results showed the removal efficiencies of chromate were increased at lower pH and higher CTAB concentration. The micellar hydrodynamic diameters (Dhs) gradually increased with the concentration of CTAB as Cr(VI) of 1.0 mM, and ranged from 3.1 to 4.7 nm. The zeta potentials gradually increased with the concentration of CTAB, but reached plateau for concentration higher than critical micelle concentration. The experimental results indicated that the removal of Cr(VI) by MEUF exceeded 96% for operating parameters of pH 1.53, ΔP = 30 psi, and S/M = 2. For E...