Removal of nickel and vanadium from ammoniacal industrial wastewater by ion exchange and adsorption on activated carbon

Nickel and vanadium were removed from real ammoniacal industrial wastewater (Ni 2–4, V 40–50 mg/L) obtained from a synthesis gas scrubber. The aim of the study was to develop an industrial application for simultaneous removal of nickel and vanadium. The studied methods were adsorption (activated carbon (AC), AquaSorb® 2000), anion exchange (Amberjet™ 4200 Cl) and cation exchange (Amberjet™ 1200 H). AC removed > 95% of nickel at pH 5.5–9 (dose > 2 g/L) but the vanadium uptake remained poor. In batch cation exchange, all nickel was removed (optimum pH 4–7) and 70–75% of vanadium was removed at pH 7 (5–10 g/L). All nickel was removed in batch anion exchange (optimum pH 5.5–9, 2–10 g/L). Over 89% of vanadium was removed in batch anion exchange at pH 7 (1–10 g/L). Adsorption capacities of 4.36 and 48.9 mg/g were obtained for nickel and vanadium in anion exchange at pH 7. In column anion exchange, all nickel and 92–98% of vanadium were removed in all three ion exchange cycles at pH 7–9. In regeneration, 72–96% of vanadium was eluted from the resin with 2.5 M NaOH. However, the elution of nickel with 2.5 M NaOH was not successful. An acid rinse (1 M H2SO4) enhanced nickel recovery up to 94%. Anion exchange proved to be the most effective method for simultaneous removal of nickel and vanadium from industrial wastewater.