Study Of Release Characteristics Of Aniline And Nitrobenzene Compounds In Sludge Drying Process

Aniline and nitrobenzene compounds are priority-controlled pollutants, which have strong toxicity to ecological environment. Sludge drying process is significant in utilization of sludge. However it may cause some environmental risks in the process of sludge drying. This experiment, which is carried out in laboratory scale, has studied the release characteristics of these two chemical compounds in the drying process of 6 different kinds of sludge at the temperature of 100-300℃. Meanwhile, combined with their original background value in the sludge samples, this experiment has also analysised the impact of temperature on the release of these two chemical compounds in sludge drying process. The results show that, in sludge drying process, the release amount of aniline and nitrobenzene compounds increases gradually as the drying temperature increases. When the drying temperature is 100℃, the release amount of aniline and nitrobenzene compounds is very small, which is about 11% and 2.95% of that when the drying temperature is high, respectively; when the drying temperature is between 150-250℃, the amount of two compounds released increases rapidly, and at about 225℃, it balances the background value of sludge itself has; when the sludge drying temperature is greater than 250℃, the release amount is close to their peak value. In the dyeing sludge drying process, all kinds of sludge release the largest amount of aniline and nitrobenzene compounds; the release characteristics of these two compounds in the papermaking sludge drying process present a polarization trend; the release amount in the tannery sludge drying process is in the middle level. In the drying process at high temperature, the release amount increases in the papermaking sludge and tannery sludge, while decreases in other kinds of sludge, as the drying temperature increases. In the drying process at low temperature, especially below 150℃, the release amount of aniline and nitrobenzene compounds can be effectively controlled, thus reducing environmental risks.