Mechanism And Simulation Prediction Of The Effect Of Nitrobenzene Double Mode Block On The Transmission Kinetics Of Weihe Sediments

The Weihe River plays an important role in the development of the Guanzhong area of Shaanxi Province.However,with the occurrence of industry,pollution often occurs.Nitrobenzene is an important chemical raw material,with high toxicity and difficult to degrade characteristics,once into the river will cause great harm to human health and water ecological environment.It has been reported that the Weihe River has been contaminated by nitrobenzene,so it is important to study the transmission law of nitrobenzene in the sediments of the Wei River and to establish a dynamic model that reflects its transmission characteristics to understand the pollution status and risk assessment of nitrobenzene.In this paper,the migration law of nitrobenzene in the sediments of the Wei River is studied by batch balancing experiment,sand column migration simulation experiment and numerical simulation method,and the transmission dynamics model is established for simulation prediction.The results of the study are as follows:(1)The best adsorption soil and water ratio of nitrobenzene shows that the adsorption effect is better when nitrobenzene is selected with sand sample.(2)The quasi-secondary dynamic rate equation can better describe the dynamic process of adsorption and desorction of nitrobenzene.In the study of the isometric balance adsorption experiment of nitrobenzene,it is found that the linear and Langmuir dual-mode adsorption model has the best degree of preparation of its adsorption data,and the two-mode blocking factor expression and the double-mode blocking factor decrease with the increase of the initial concentration of nitrobenzene.(3)In the sediment particle size,nitrobenzene initial concentration,temperature,pH to nitrobenzene adsorption effect study shows that: sand sample particle size is smaller to nitrobenzene balance adsorption,in the initial concentration of nitrobenzene 0.912 to 30.832 mg/L range,nitrobenzene adsorption with the initial concentration increase;In the temperature range of 20 to 40 degrees C,the adsorption of nitrobenzene decreases with the increase of temperature,and the change of pH has little effect on its equilibrium adsorption.(4)The equal temperature desigenating experiments of nitrobenzene show that the desorption process of nitrobenzene is not the inverse process of adsorption,there is a certain lag in the desorption,the solution of its lag coefficient is found that the lag coefficient decreases with the increase of the initial concentration of nitrobenzene,and the coefficient of bi-mode blocking of nitrobenzene is found to have a positive correlation between them.(5)The results of the desigenol factors of nitrobenzene show that: the sand-like particle size in the range of 0 to 1mm,the smaller the particle size to nitrobenzene desorption rate is smaller;The amount of nitrobenzene is increased with the increase of temperature in the temperature range of 40 degrees C.The change of pH had little effect on the equilibrium desorption of nitrobenzene.(6)The migration process of nitrobenzene in the sediments of the Wei River was simulated by indoor sand column experiments,the dispersion coefficient and average gap flow rate were obtained by the tracer experiment,and a mathematical model of nitrobenzene in the double migration mode of the sand column was constructed based on the parameters obtained from the tracer experiment and the adsorption experiment.The migration pattern of nitrobenzene in the sand column is simulated,and it is found that the simulation value is in good agreement with the actual value,and the model can be used to study the transmission process of nitrobenzene in sediment.(7)By predicting the study area,it can be seen that when the initial concentration of 8.68 mg/L of nitrobenzene solution continues to be transmitted in the sediments of the Weihe River bed,the concentration of nitrobenzene at 150 h sampling from the source of pollution is 4.85 mg/L,and the concentration of nitrobenzene at 180 h sampling is 6.93 mg/L,The concentration value of nitrobenzene at 150 h at 30 m from the source of contamination was 0.25mg/L,and the concentration value of nitrobenzene at 180 h sampling was 0.56mg/L.