Research On The Mechanism Of Straw Activated Carbon To Accelerated Anaerobic Degradation Of Azo Dye

Azo dye wastewater because of its complex composition,poisonous,large water and other characteristics,the degradation of Azo dye was slowly by the traditional biological treatment.Carbon material has a developed pore structure and specific surface area,and the structure contains more functional groups,so that it has excellent physical and chemical properties.it has been the focus of the majority of scholars.In this study,straw-activated carbon?SAC?and modified straw activated carbon?SAC_M?were prepared by straw straw.The Orange G?OG?substances in the simulated dyestuff wastewater were studied.The effects of SAC and SAC_M on the catalytic activity of degradation of OG was study by Na₂ S and anaerobic granular sludge?AGS?system.The influencing factors of OG degradation and the possibility of the practical application of UASB continuous flow were also study.The physical and chemical properties of SAC prepared by?NH₄?₂HPO₄ as activator and SAC_M modified by phenols were analyzed by means of characterization.The results showed that both SAC and SAC_M had developed pore structure and specific surface area,andhe internal pore size was mostly microporous.The surface area of SAC_CT-1.0 and SACHQ-1.0 modified by catechol and hydroquinone was significantly decreased,while the specific surface area of SAC_PH-1.0 modified by phenol was increased.The results show that there are many functional groups in the structure of SAC and SAC_M,and the oxygen-containing functional groups in the SAC_M structure after phenolic modification are obviously increased.Raman spectroscopy results show that the SAC and SAC_M structure Atomic or structural defects were less.The p Hpzc of SAC₃ and SAC_PH-1.0 were determined by drift method.The pH_pzc of SAC₃ and SAC_PH-1.0 were 2.62 and 2.21 respectively.Then,the chemistry degradation process of OG was studied.The 49% decolorization of OG under the condition of Na₂ S concentration was 10mmol/L,temperature was 37? and the initial pH was 7.2.The decolorization rate of OG was preferably in the pH value was 7.2 8.4,the degradation efficiency of OG was slowly in the pH> 8.4,and the OG is basically no degradation in the pH=6.And the degradation rate of OG was significantly increased after adding SAC and SAC_M,and the effect of adding SAC_M was better than SAC.In the study of SAC promoting Na₂ S degradation of OG,30%?Wt??NH₄?₂HPO₄ was found best for the preparation of SAC₃,when the SAC₃ dosage was 0.3g/L,Na₂ S concentration was 10mmol/L,the temperature was 37? and the initial pH was 7.2,with 90 min the decolorization rate of OG reached 100%.The degradation rate of OG was positively correlated with the dosage of SAC₃,Na₂ S concentration and temperature,and negatively correlated with pH.Phenol concentration is 1.0 mmol/L was preferably for preparation SAC_PH-1.0,when SAC_M promoted the degradation of OG by Na₂ S.The dosage of SAC_PH-1.0 was 0.3 g/L,the concentration of Na₂ S was 10 mmol/L,the temperature was 37? and the initial reaction time pH was 7.2,with 30 min the decolorization rate of OG reached 100%.And the degradation rate of OG was positively correlated with the amount of SAC_PH-1.0,Na₂ S concentration and temperature,and negatively correlated with pH.Analyzed the TOC and UV-Vis spectroscopy of OG,found that the mineralization rates of OG were 22.8% and 34.2% respectively by SAC₃/Na₂ S and SAC_PH-1.0/Na₂ S systems.And the characteristic absorption peaks of azo bond and naphthalene rings in OG structure with the progress of the reaction continues to decline,and finally completely disappeared.Finally,the biodegradation process of OG was studied.It was found that the degradation efficiency of OG was lower in AGS system.When the concentration of AGS was 30mmol/L,the temperature was 37? and the initial pH was 7.2,with 48 h the decolorization rate of OG was only 53.7%.Is far less than the decolorization rate of OG was 72.2% and 90% after addition SAC₃?0.3g/L?and SAC_PH-1.0?0.2g/L?,respectively.The degradation rate of OG was positively correlated with SAC₃ and SAC_PH-1.0 dosage,AGS concentration,temperature,nutrient concentration,and negatively correlated with pH by the SAC₃/Na₂ S and SAC_PH-1.0/Na₂ S system.In the UASB continuous flow system,when the concentration of influent OG increased to 150mg/L,the OG concentration of effluent was about 46mg/L after 60 days.And the carbon material was fed for 40 days,the concentrations of OG in SAC₃/UASB and SAC_PH-1.0/UASB continuous flow systems were reduced to about 25mg/L and 16mg/L,respectively,and remained stable.It is shown that SAC₃ and SAC_PH-1.0 not only have excellent decolorization rate of OG in AGS serum bottle experiment,but also play a better effect in the UASB continuous flow model,which makes the practical application of this environmentally friendly material become may.In summary,As Redox Mediators the SAC₃ and SAC_PH-1.0 have a larger specific surface area and more oxygen-containing functional groups in the structure.On the Na₂ S or AGS and OG has played an accelerated role in the electron transfer.The effect of SAC₃ and SAC_PH-1.0 as RM transfer electrons is mainly related to their physical and chemical properties,which can be summarized as two points:?1?SAC₃ and SAC_PH-1.0 adsorption properties;?2?SAC₃ and SAC_PH-1.0 surface oxygen content of functional groups.And the products and pathways of OG chemical degradation and biodegradation were analyzed by GC-MS.