Characteristics Analysis Of Denitrification Degradation With Pyridine

Nitrogen heterocyclic compounds are toxic, carcinogenic and mutagenic, and they can be accumulated in the biosome, which were harmful to human’s health. Meanwhile, most of these compounds are difficult to be degraded due to the high stability. With the rapid development of coal, oil industry etc., the produced nitrogen heterocyclic compounds may cause water pollution and attract much attention all over the world. Currently, microbial transformation and degradation is one of the most promising methods for the removal of nitrogen heterocyclic compounds due to its economical and high efficiency. The influence of condition and environment of reaction on the ability for microbial degradation of pollutants can not be ignored. Therefore, pyridine as the typical nitrogen heterocyclic compound is set as the research object in this paper to study the denitrification degradation characteristics and metabolic properties in a single matrix and in the presence of phenol. Meanwhile, photodegraded products of pyridine in denitrification were tested to investigate the influence of the optimal reaction conditions and other coexisting substances on the degradation of pyridine and intermediate products. In previous studies, the research target was just qualitative detection. A quantitative measurement of intermediate products was made for the first time in this paper. And the photodegraded product was set as indicator to study the denitrification of pyridine in another angle. The main methods and conclusions are shown as follows:(1)The concentration of pyridine, NO-3-N and NO-2-N in the process of denitrification, were set as indicators to study the denitrification degradation under different concentrations of pyridine through parallel experiments. 80 mg / L is identified as the most appropriate pyridine concentration.(2)Photodegraded products of pyridine in denitrification were extracted by liquid extraction under the optimum conditions. And an important intermediate product – glutaraldehyde was detected by GC-MS. Meanwhile, the varying pattern of glutaraldehyde was summarized by detecting the change of the concentration and the denitrification degradation characteristics can be further studied using glutaraldehyde as the indicator of denitrification.The concentration of glutaraldehyde was measured by UV spectrophotometry. And the concentration curve of glutaraldehyde shows that peak value reached 9.8mg / L at 32 h.(3)In the initial experimental conditions, the effects of phenol on the denitrification degradation of pyridine was studied by adding phenol with different concentrations, which makes the denitrification research of pyridine more fitting for treatment of wastewater. It was found that phenol could inhibit the denitrification of pyridine, and the inhibition effect was strengthened with increasing phenol concentration, and the inhibition effect was the strongest when the concentration of phenol was 30 mg / L.(4)The concentration and the degradation rate of NO-3-N and glutaraldehyde, were set as indicators under the optimum degradation conditions to study the denitrification degradation. And it was compared with that under a single matrix to further study the pyridine denitrification characteristics in the presence of phenol and obtain a reasonable inference mechanism for inhibition effect of phenol. It was analyzed that phenol or the degradation products of phenol can inhibit the enzyme system,which may act on the ring opening stage of pyridine in denitrification degradation.