Study On Degradation Of Indomethacin With Sodium Hypochlorite In Water

Indomethacin (IM) has a good effect in diminishing inflammatory and correcting the pain, and therefore, it’s widely used. As a drug into the body, a small amount of active ingredients of IM can be absorbed by the body. Most of IM return to the environment and accumulate constantly, which leads to its content continuing to increase in the water environment. IM belongs to a common class of drug pollutants among PPCPs. But the traditional process can remove the low concentration of IM very limitedly.The main methods to treat indomethacin include microbial activated sludge method, active carbon adsorption, membrane filtration, ozone oxidation, photocatalytic oxidation and so on. Sodium hypochlorite is a strong oxidant which exists not naturally. Because of its strong oxidation ability, Sodium hypochlorite can react with organic radical, resulting in the destruction of the structure of organic compounds to achieve the effect of processing. Therefore, sodium hypochlorite is widely used in all kinds of wastewater treatment. Because the sodium hypochlorite has the advantages of low cost and obvious effect, it is necessary to further study.Sodium hypochlorite system was applied in this experiment to treat IM wastewater. In this experiment, the effect of dosage of sodium hypochlorite, temperature, initial pH value were studied, At the same time, degradation of IM and TOC changes were explored when bromide ion exists in the sodium hypochlorite system.Meanwhile, the changes of the product and toxicity of the sodium hypochlorite and sodium bromide system were examined. In addition, the treatment of residual indomethacin (IM) in water through sodium hypochlorite solution can be affected by other substances. In order to investigate the effect of humic acid and different nitrogen forms on the degradation of indomethacin by sodium hypochlorite, different concentrations of humic acid (HA)、NH4+、NO3- and NO2- were added into different indomethacin solutions to test the degradation of indomethacin. Results showed that when the reaction temperature was at 30℃, the initial pH was at 4.6, indomethacin concentration was 30μM/L and NaClO solution concentration was 75 μM/L, both humic acid and NH4+ showed competitive degradation with indomethacin, which reduced the removal rate of indomethacin; NO3- and NO2- promote the degradation of indomethacin and NO3- is easier to promote the degradation of indomethacin than NO2-.