Study On Behavior Of Ibuprofen Oxidative Degradation By Simulating Disinfection Of Drinking Water

As a new generation of non-steroidal anti-inflammatory drugs, ibuprofen is widely used because of low toxicity, curative effect and side effects which are is superior to aspirin and paracetamol. Ibuprofen enter water environment and pose a threat to the aquatic ecosystem through various means, this affects human health at the same time. In recent years, trace amounts of organic pollutants such as ibuprofen have been detected in the source of drinking water in several country. So it is necessary to study on environmental behavior of ibuprofen in drinking water. The way of ozone disinfection is commonly used in drinking water disinfection, and it is able to oxidize and degrade organic pollutants effectively. This paper mainly studied on the oxidation kinetics, oxidation mechanisms, oxidation pathways and products of ibuprofen in simulation of water ozone disinfection to better understand the transform disciplinarian in drinking water.Firstly, this paper investigated on the oxidative degradation of ibuprofen by different ozone concentration and other environmental factors, and deduced the oxidation kinetics, oxidation mechanisms and products toxicity change rule. The experimental results showed that, ibuprofen could be degraded by ozone, and the process of oxidative degradation of ibuprofen could be fitted by the pseudo first-order kinetics model. On the basis of quenching experiments with reactive oxygen species (ROS), the results showed that, in simulation of water disinfection, ibuprofen’s oxidation included direct oxidation and indirect reaction which ROS involved in, and the indirect reaction contributed to the main degradation of ibuprofen. The toxicity test using luminous bacteria indicated that oxidative degradation products of ibuprofen had certain toxicity, and intermediate products with a higher risk than ibuprofen had been generated during this process.We also studied the different influences on the oxidative degradation of ibuprofen with different concentrations of nitrate, nitrite, ammonium ions, metal ions such as ferrous ions and cupric ions, and surfactant which exist alone. The result showed that nitrate and nitrite inhibited the degradation of ibuprofen, and the higher the concentration, the more pronounced the inhibitory effect. Ammonium ions have no effect on the oxidative degradation of ibuprofen. Ferrous ions and cupric ions stimulated the degradation of ibuprofen, and the higher the concentration, the more pronounced the stimulative effect. Cationic and nonionic surfactants promoted the degradation of ibuprofen, while anionic surfactant inhibited the degradation of ibuprofen. It can react with ozone and with the OH-competitive effects, thus inhibiting the oxidation of ibuprofen. It was mainly because nitrate and nitrite restrained the oxidative degradation of ibuprofen by generating quenching agent which is easier to react with hydroxyl radical. With the ferrous ions catalyst, ozone decomposed into hydroxyl radical and (FeO)2+that had strong oxidation, which promoted oxidation reaction of ibuprofen. Cupric ions react with ozone to form hydroxyl radical which was conducive to oxidation reaction of ibuprofen. Cetyl tri methyl ammonium bromide (CTMAB) could stimulate the degradation of ibuprofen by electrostatic effect with ibuprofen. Sodium dodecyl benzene suffocate (SDBS) could inhibit the degradation of ibuprofen by competing for hydroxyl radical with ibuprofen and generating the medium effect. And concentration effect caused by nonionic surfactant could influence on the degradation.In the end, ibuprofen oxidative degradation products in simulation of water disinfection were studied by HPLC/MS/MS.According to spectrogram, six oxidized products were detected, which were4-ethylbenzaldehyde,2-[4-(1,2-dihydroxypropyl)-2-hydroxyphenylpropionic acid,1-(4-ethyl-phenyl)-2-methylpropanol,1-(4-ethyl-phenyl)-2-methylacetone,2-[4-(1-hydroxy-2-methyl-propyl)-phenyl]-isopropyl acid,4-ethylisobutylbenzene. Moreover, speculated degradation pathway for ibuprofen under simulated disinfection.