Removal of nitroderivates from synthetic wastewaters by electrochemical reduction

The electrochemical reduction of 4-nitrophenol (4-NP) and 2,6-dinitrophenol ( 2,6-DNP) in different conditions (0.2N H(2)SO(4) and 0.1 M NaCl aqueous solution) were studied in this work. In the case of 4-NP the cathodic materials were nickel and graphite, and the electrochemical reduction processes were performed in two different reactors ( two compartment reactor type filter-press, and undivided electrochemical reactor, both with electrolyte recirculation). In the case of 2,6-DNP the cathode was made from graphite using two compartment reactor with electrolyte recirculation. The experimental processes were pursued by different methods: cyclic voltammetry (BAS100), and spectrophotometry in UV-Visible (Unicam Helyos B and DR/2000 HACH); lambda(max) = 318 nm for 4-nitrophenol and lambda(max) = 440 nm for 2,6-DNP. The experimental determinations demonstrated practically 65-99% removal yield for the both nitro derivatives, depending on the experimental conditions. The best result have been obtained, in the case of 4-NP, in undivided electrochemical reactor with graphite electrode (90% of 4-NP removal), and in the case of 2,6-DNP the final removal was of 99% in two compartment reactor with graphite cathode.