Experimental Study And Optimization Of Adsorption Materials For Typical Hazardous Chemicals

Adsorption material is one of the effective measures to deal with the leakage of hazardous chemicals.It is crucial to determine the performance evaluation indexs of adsorption materials for hazardous chemicals and the corresponding test programs in order to select a suitable adsorbent material.In this research,styrene and acrylonitrile are respectively used as the representative of floating state and dissolved state hazardous chemicals for doing experimental research and optimization of adsorption materials.Six performance evaluation indexes and their corresponding test schemes for adsorption materials of floating hazardous chemicals are established.The six evaluation indexes are oil absorption rate,water absorption rate,oil absorption speed,oil holding rate,gravity retention rate and evaporation rate.A comprehensive performance evaluation system for adsorption materials of hazardous chemicals is established based on the principal factor method and the analytic hierarchy process.Based on that,the properties of 58 kinds of adsorption materials existing on market are tested.Three kinds of styrene adsorption materials with excellent properties are selected adopting the method of two steps screening.The three kinds of adsorption materials are PP-1 oil absorbent felt,dens absorbent cotton and feather velvet.The three kinds of materials are tested on the experimental device for simulating damming and adsorption experiment of floating hazardous chemicals.The experimental results indicate that the recovery rate of zero number of diesel oil and styrene in different conditions are all above 50%.And with the increase of oil film thickness and water flow rate,recovery rate of hazardous chemicals increases first and then decreases.Taking the case of styrene leakage in Lanzhou section of Yellow River as an example,we calculate the minimum storage quantity of emergency materials.The results indicate that during dry season,the minimum storage quantity of PP-1 oil absorbent felt,dens absorbent cotton and feather velvet are respectively 13.43 tons,12.74 tons and 14.46tons,and during wet period,the minimum reserve amount of PP-1 oil absorbent felt,dens absorbent cotton and feather velvet are respectively 15.83 tons,16.66 tons and17.55 tons.The performance evaluation index of adsorption materials for soluble hazardous chemicals is established,which includes oil absorption rate and removal rate.Firstly,the feasibility and applicability of three kinds of quantitative analysis methods for dissolved acrylonitrile are investigated,which includes refractive index method,UV spectrophotometry and gas chromatography.Refractive index method is preferred especially when the concentration of acrylonitrile is higher than 10000 mg/L,which is simple,fast and high accurate.Then different kinds of adsorption materials are screened.Coconut shell activated carbon is found to be the best.Its removal rate is about 75%and its adsorption speed is fast,which can reach adsorption equilibrium at 1.0 h.Effects of addition amount of adsorption materials,adsorption time,temperature and water flow rate on adsorption performance of dissolved acrylonitrile are investigated by self-developed simulated damming experiment equipment.It turns out that with the increase of amount of adsorption materials,extension of adsorption time and decrease of water flow rate,the removal rate of acrylonitrile increases gradually,but temperature has little effect on adsorption effect.At the same time,the quantitative relationship among initial concentration of acrylonitrile,water flow rate,addition amount of adsorption materials and removal rate is established.Coconut shell activated carbon is taken as an example to calculate the minimum storage quantity of emergency materials.The results show that when flow rate is 5 m~3/min,the minimum storage quantity is 9.35 tons and when flow rate is 400 m~3/min,the minimum storage quantity is41.86 tons.