Simulation Experiment Research On Removal Technology Of Volatile Organic Pollutants In Sandy Soil

A method of air stripping-catalytic oxidation coupling repair is proposed for the treatment of volatile organic pollutants in sandy soil.Taken the toluene as the model pollutant,this paper analyzes the stripping laws and the effects of three factors:soil particle size,ventilation rate,and temperature on the stripping effect,through one-dimensional soil column simulation device experiments,Metal element and activated carbon catalysts with different loading-rate?1%,3%,5%and 10%?are prepared with the help of equal-volume impregnation methods,the effects of different adsorption conditions on the adsorption performance of activated carbon on toluene were studied,including metal loading,temperature,and number of regenerations.Through the programmed temperature oxidation experiment,the catalytic performance of the catalyst under different metal loadings and toluene inlet concentration conditions was analyzed.The conclusions are as follows:?1?By monitoring the change of the toluene concentration in the tail gas of the stripping device,it was found that three elements:the soil particle size,ventilation rate and temperature,influence the toluene stripping effect a lot in the soil.Under the same experimental conditions,the larger average particle,the higher ventilation rate and soil temperature,leading to the higher the initial concentration of toluene in the tail gas and removal rate.On top of that,these favorable factors contribute to shorter time to enter the tailing stage with the better treatmet.?2?After loading copper oxide,the performance of activated carbon to abs orb toluene is affected.Impregnation of activated carbon in a low charge number can enhance its adsorption performance,while that in a high charge number will lead to the counteraction.When the regeneration temperature is 300?,1wt%Cu/AC has the best regeneration adsorption performance,whose capacity is 300.1 mg/g-------96.3%of the initial adsorption capacity,which is still stable and greater than 90%after6 consecutive regeneration and adsorption cycle experiments.?3?When the toluene gas concentration is 2000 mg/m³,the flow rate is300 m L/min,and at the same time 5%O₂/Ar with a flow rate of 30 m L/min is used as the reaction atmosphere,the catalytic activity of 10wt%Cu/AC is the best,and T_50%and T_90%are 184.6?and 275?respectively.The toluene conversion rate improves with the increase of copper oxide loading.When the toluene concentration increased from 2000 mg/m³to 8000 mg/m³,the reaction temperature T_50%and T_90%of 10wt%Cu/AC catalyst for toluene increased 121.7?and 125?respectively.