Study On Treatment Of Diazodinitrophenol Wastewater By Iron-Carbon Or Iron-Copper Internal Electrolysis

Because of the characters of fine explode, abundant raw materials, safe production, Diazodinitrophenol (DDNP) is used to product industrial detonator instead of mercury fulminate. Recently, there are nine processes to product industrial detonator with DDNP. Although, the wastewater of detonator production is harmful to the environment and health of people. So, the wastewater has to be treated.Internal electrolysis (micro electrolysis or iron chips filtration) was developed from 70s 20th century with the iron used in wastewater treatment. Basic on the principle of electrochemical oxidation reduction, it is used to treat wastewater by enrichment, oagulate, adsorption and filtration. At present, internal electrolysis usually is used to treat the wastewater treated by microbiology process difficultly. There are many papers on the principle and projects of internal electrolysis. But, using internal electrolysis process to treat DDNP wastewater is few.In this paper, Internal electrolysis is used to treat DDNP wastewater, and orthogonal experiments are used to confirm optimum conditions of the process. And the influences of pH, reaction time and ratio of iron and activated carbon /iron and copper on the removal effect are researched. The optimum conditions of four processes are respectively: 1) Fe/C internal electrolysis process in acid: pH=4, reaction time(RT)=2d, Fe(V):C(V)=1.2, reaction temperature(T)=25℃, and the removal efficiencies of COD, S2-, SS and color index are respectively 85.65%,91.6%,100% and 9.63%; 2) Fe/C internal electrolysis process in basic: pH=10, reaction time(RT)=2d, Fe(V):C(V)=1.2, reaction temperature(T)=25℃; and the removal efficiencies of COD, S2-, SS and color index are respectively 90.13%, 99.73%, 100% and 99.63%;3) Fe/Cu internal electrolysis process in acid: pH=1, reaction time(RT)=2d, Fe(m):C(m)=1.0, reaction temperature(T)=30℃; and the removal efficiencies of COD, S2-, SS and color index are respectively80.56%,96.47%,96.8%and 87.5%;4) Fe/Cu internal electrolysis process in basic: pH=8, reaction time(RT)=3d, Fe(m):C(m)=1.2, reaction temperature(T)=35℃; and the removal efficiencies of COD, S2-, SS and color index are respectively 31.5%, 49.55%, 95.2% and 37.5%.Simultaneously, the mechanism and kinetics of internal electrolysis and absorption by activated carbon are researched. The results of cyclic voltammetry show that the internal electrolysis reaction is not straight-out, and according to the conclusion, the reaction mechanism of DDNP is extrapolated. The basic reaction mechanism is as follow,nitrophenol to nitrosobenzene to phenylhydroxylamine to aniline phenylamine. The results of kinetics analysis show that removing of COD by Fe/Cu internal electrolysis process in acid is in accord with the 1.0 or 1.8 stage reaction kinetics; the internal electrolysis reaction of Fe/C internal electrolysis process in acid is main, and the absorption by activate carbon of Fe/C internal electrolysis process in basic is main. Therefore, the Fe/C internal electrolysis process and Fe/Cu internal electrolysis process in acid are useful in the project.Additionally, the wastewater treatment cost per cubic meter of the Fe/C internal electrolysis process and Fe/Cu internal electrolysis process in acid is calculated. The results show that the cost of Fe/C internal electrolysis process in acid is lower than the Fe/Cu internal electrolysis process in acid. So, the Fe/C internal electrolysis process in acid is more useful in the project.