Simulation Study On The Effect Of Nitrobenzene Double Mode Blocking On The Transmission Kinetics In The Sediments Of The Weihe River

Nitrobenzene is widely used in industry,and its toxicity is strong.Once it enters river water,it will pose a potential threat to human health.In this paper,the adsorption-desorption experiment of p-nitrobenzene in the sediments of Weihe River was carried out by batch balance method.The experimental study on the kinetics of nitrobenzene transmission was carried out through an indoor seepage tank.The transmission kinetics model under the influence of nitrobenzene blockage was established,and the transmission kinetics of nitrobenzene was simulated by the model.Experimental results show:1.The adsorption characteristics of nitrobenzene show that the adsorption kinetics of nitrobenzene accords with the Elovich equation.The adsorption equilibrium time was 12 h.The isothermal adsorption process of nitrobenzene accords with the two-mode isotherm adsorption model of Liner+Langmuir,and the expression of the double-mode retardation factor under the double mode adsorption of Liner+Langmuir is obtained.2.Influencing factors of adsorption The experimental results show that under the same conditions,the smaller the particle size of the sediment,the stronger the adsorption capacity of nitrobenzene.The increase of ionic strength is not conducive to the adsorption of nitrobenzene.The higher the organic matter content,The stronger the adsorption capacity of the sediment,the acidic conditions favor the adsorption of nitrobenzene by the sediment.3.The adsorption thermodynamics experimental results show that the adsorption of nitrobenzene in the sediments of the Weihe River is an exothermic reaction,and the increase of temperature is not conducive to the adsorption of nitrobenzene.The main force of the adsorption process is the dipole bond force,and there is also a hydrogen bond force.At the same initial concentration of nitrobenzene,the double-mode retardation factor decreased with increasing temperature,indicating that the higher the temperature,the less obvious the adsorption retardation effect of the sediment on nitrobenzene.4.The desorption experiment of nitrobenzene showed that the desorption process accorded with the pseudo first-order kinetic equation.The equilibrium time of desorption of nitrobenzene was 12h,and the hysteresis coefficient HI of the initial concentration of 10nitrobenzenes was greater than zero,indicating that there is hysteresis in desorption.5.The seepage experiment of the seepage trough showed that the permeability coefficient of the tracer experiment was 29.8m/d,the percolation velocity was 23.18.cm/d,and the diffusion coefficient Dx=0.0572cm~2/min.The experiment of migration of nitrobenzene showed that the concentration of nitrobenzene gradually decreased in the horizontal direction,and the percolation flow rate of nitrobenzene in the horizontal direction was 11.6 cm/d.The concentration of nitrobenzene increased in the vertical direction with increasing depth.The value of the dynamic retardation factor was calculated to be 1.9983 by the migration rate of nitrobenzene and the migration rate of the tracer.6.According to the nitrobenzene adsorption characteristic parameters and the experimental parameters of the seepage trough transmission law,the mathematical model of the coupling of the transmission kinetic model and the groundwater flow model under the influence of the nitrobenzene double-mode retardation is constructed,and the model is verified and corrected.It is found that the Liner+Langmuir dual-mode blockade effect expression is better in the mathematical model of the coupling.7.The expressions of different retardation factors and dynamic retardation factors established by different adsorption characteristics of nitrobenzene in the sediments of Weihe River were introduced into the kinetic model of nitrobenzene transfer respectively to carry out the nitrobenzene in the sediments of the Weihe River.The simulation study of the transmission law,through the analysis of four error functions,found that the simulation error of the adsorption model under the influence of the Liner+Langmuir dual-mode retardation factor is the smallest.Therefore,the transmission dynamics model under the influence of the Liner+Langmuir dual-mode retardation factor established in this paper can better carry out the risk assessment and simulation prediction of nitrobenzene pollution in the sediments of the Weihe River.