Process for automatically controllable lowering the nitrite content in nitrite containing aqueous solutions to a concentration of less than 1 mg/l

摘要

The lowering of the nitrite content of aqueous solutions by treatment using hydrogen peroxide in the acidic pH region can be controlled by measuring the redox potential. In contrast to the teaching of the prior art, in the process according to the invention, the addition of the hydrogen peroxide is not terminated in the region of the highest redox potential but only after lowering the potential to a value of 650+/-10 mV. In this manner, nitrite contents below 1 mg/l can be obtained even when the solutions additionally contain varying amounts of various constituents which can be oxidised by H2O2.