Effect Of Iron-based Nanomaterials On Anaerobic Degradation Of Phenol And Benzoate

Phenol and benzoate are common industrial wastewater pollutants,which is also an important intermediate metabolite in the anaerobic degradation of monocyclic aromatic hydrocarbons and lignocellulosic wastes.Aromatic compounds such as phenol,as a kind of carcinogenic,teratogenic and mutagenic organic matter,will cause serious effects on organisms at very low concentrations.Therefore,the removal of phenol and benzoate from wastewater is essential for the environment and human health.As a simple and biocompatible material,iron-based nanomaterials can improve the stability and methane production of wastewater and waste anaerobic system.In view of the problems of long reaction time and incomplete treatment in the practical application of phenol anaerobic degradation,this study have been added different concentrations of iron-based nanomaterials to explore the impact of the anaerobic degradation of phenol and benzoate.The specific content is as follows:(1)First,a gas chromatography method for the simultaneous determination of phenol,p-cresol and volatile fatty acids(VFAs)has been established.The SP-7820 gas chromatograph was used to optimize the chromatographic conditions,and the optimal split ratio was confirmed to be 16:1.When phenol,p-cresol and 7 VFAs were detected simultaneously,All components were determined within 8 min.The problem of VFAs residue and unstable induction value could be solved by adjusting the sample with 1%formic acid.(2)Effect of iron-based nanomaterials on anaerobic degradation of phenol.In this study,the phenol anaerobic degradation culture system(NP)was obtained by using the sludge of the anaerobic treatment reactor containing phenol wastewater as the inoculation source.The effect of adding iron-based nanomaterials on NP anaerobic degradation of phenol has been studied.The addition of 10?200 mg/L Fe₃O₄ NPs and 50?200 mg/L Fe₂O₃ NPs had no effect on the anaerobic degradation of phenol,while the addition of300 mg/L Fe₃O₄ NPs and Fe₂O₃ NPs inhibited the anaerobic degradation of phenol.Adding 10 mg/L and 20 mg/L Fe₂O₃ NPs promoted the anaerobic degradation of phenol,and the cumulative methane production concentration increased by 32.08%and 20.13%,respectively.The effect of adding iron-based nanomaterials on the microbial community structure in the cultures was investigated by using high-flux sequencing technology.It was found that the main bacteria belonged to four phyla,including Desulfobacterota,Firmicutes,Synergistota and Spirochaetota.In cultures adding Fe₂O₃ NPs,Cryptanaerobacter of Firmicutes and Spirochaetaceae of Spirochaetota were the bacteria that mainly affected the anaerobic degradation of phenol,and Methanospirillum of Halobacterota were the archaea that mainly affected the anaerobic degradation of phenol.(3)Effects of iron-based nanomaterials on anaerobic degradation of benzoate in Sporotomaculum syntrophicum co-culture with M.Hungatei.Adding 10?500 mg/L Fe₃O₄NPs and 10?1000 mg/L Fe₂O₃ NPs had no significant effect on the degradation rate and methane production of benzoate.However,high concentration of Fe₃O₄ NPs significantly inhibited the degradation of benzoate.When the concentration was 600 mg/L,800 mg/L and 1000 mg/L,methane production decreased by 24.29%,44.13%and 61.54%respectively.