Research On Structure-activity Relationship (QSAR) And Enhanced Separation Of Phenolic Pollutants In Weak Oxidation Process

In view of the current situation that organic pollutants in heavy industry,pharmaceutical and other industrial wastewater are difficult to treat phenolic small molecule pollutants under common process conditions,the conversion path of soluble micro-pollutants in nature has proposed a feasible solution for us-weak oxidation mixed Condensation coupling combined technology.（1）This article first summarizes the reaction kinetic rate constants of the 24 organic pollutants in the manganese oxide system and the 14 organic pollutants in the enzyme-catalyzed oxidation system through the literature system,and calculates the electronic structure characteristic parameters of different organic pollutants based on density functional theory（DFT）,and further uses nonlinear regression and multivariate The linear regression method constructs a quantitative structure-activity relationship（QSAR）model between the electronic structure characteristics of different organic pollutants and the reaction rate constant of single-electron oxidation,and finally uses the leave-one-out method to internally verify the constructed model;and supplement it through experiments The single-electron oxidation reaction rate constant of organic pollutants is used to verify the predictive ability of the QSAR model.The results show that the optimal QSAR models constructed and screened based on 91 groups of manganese oxide quasi-first-and second-order kinetic reaction systems have shown a good degree of fit（R₁²=0.845,R₂²=0.928）,and After experimenting to summarize 18 sets of data,internal and external verification confirmed its stability(Q²_LOO1=0.801,Q²_LOO2=0.990)and good predictive ability(R²_ext1=0.813,R²_ext1=0.852).At the same time,it summarizes the optimal QSAR model constructed and screened by 60 groups of enzyme-catalyzed quasi-first-and second-level kinetic reaction systems,and has a certain degree of fit（R₁²=0.770,R₂²=0.943）.The results of the study also found that the mutual influence of different factors on whether organic matter can be oxidized by manganese oxide and enzymes is more prominent;among them,the dosage of organic matter is C organic matter,the number of active functional groups N,and the energy gap value E_GAPFactors such as the use of manganese oxide and enzymes for single-electron oxidation have a greater impact.（2）Based on the second chapter,the characteristic parameters E_LUMO,E_GAP,electrophilic index,dipole moment,etc.that can characterize the stability and separation properties of the phenolic pollutants before and after the weak oxidation reaction are screened out,and combined with the weak oxidation and coagulation process.Taking removal efficiency of COD as the dependent variable,and its different characteristic parameters as independent variables,the method in Chapter 2 is used to establish a QSAR that simulates the COD removal effect of pollutants,the electronic structure characteristics of the pollutants at the micro level,and the weak oxidation-coagulation conditions at the macro level.model.The results show that the optimal QSAR model constructed and screened based on the 114 sets of experimental data showed a certain degree of fit（R²=0.761）,and the remaining 20 sets of experimental data were verified internally and externally(Q²_LOO=0.992,R²_ext=0.754)Shows good stability and predictive ability.It shows that the electrophilic index EI,the lowest unoccupied orbital energy E_LUMO,the number of active functional groups N,the oxidation time T,the amount of oxidant C,oxygen,etc.have important effects on the removal of phenolic pollutants COD.The research results also found that,corresponding to the predicted results,the selected characteristic parameters EI,E_LUMO,etc.can effectively characterize the changes in the separation properties of phenolic pollutants after the weak oxidation reaction.（3）The weak oxidation-coagulation coupling process is used to treat the actual coal chemical industry wastewater.Through the optimization of the weak oxidation-coagulation conditions,the degradation treatment of phenolic pollutants by the weak oxidation-coagulation coupling process in the actual complex system is explored.The results showed that under the optimal weak oxidation-coagulation conditions(p H=5-9,0.8g·L^-1manganese dioxide,oxidizing for 1.5 h,and g·L^-1PFS coagulant),the actual Almost all of the five main phenolic pollutants in wastewater are converted.The degradation of total organic matter in the actual wastewater was measured by COD and TOC,and it was found that under only oxidation conditions,the removal rates of COD and TOC were14.5%and 13.6%;under only coagulation conditions,the removal rates of COD and TOC were 33.6%and 41.1%;Under the weak oxidation-coagulation coupling process,the removal rates of COD and TOC are 54.4%and 63.8%.The weak oxidation-coagulation coupling process can significantly improve the COD and TOC degradation effects of phenolic pollutants.