Catalytic removal of nitrates from waters in a continuous flow process: The remarkable effect of liquid flow rate and gas feed composition

▶ Composition of support affects behaviour of Pd-Cu catalysts towards NO3−/H2/O2. ▶ NH4+ selectivity decreases by 3 times when 4% O2 is added in the feed. ▶ 20 times less NH4+ is obtained when increasing liquid flow from 2 to 6 mL/min. ▶ 5 times less NH4+ is obtained when input CNO3− increases from 10 to 100 mg/L. ▶ The presence of Cl− ions in the feed slightly increases catalysts activity.