Study On Carbon Disulfide Adsorption And Desorption Behavior Of Activated Carbon

CS₂is an important chemical solvent with a wide range of applications,but it is volatile,emits a foul odor,is highly toxic,and seriously harms the environment and human health.Activated carbon is a green and environmentally friendly adsorbent,which has the characteristics of easily available raw materials,low cost,simple operation and good adsorption effect.It is widely used in environmental protection fields such as solvent recovery and treatment and purification of waste gas and wastewater.In this paper,the current commercial activated carbon has low adsorption efficiency for CS₂,low adsorption capacity,high residual rate,and unclear adsorption conditions,and carried out research on the adsorption and desorption behavior of activated carbon on CS₂.The main research contents and results of the thesis are as follows:1.The relationship between the pore structure and surface chemistry of activated carbon and the adsorption and desorption of CS₂The dynamic experiments of CS₂adsorption and desorption on five different types of activated carbon were carried out to study the effects of pore structure and surface functional groups on the adsorption and desorption of CS₂.The experimental results show that:the effective adsorption pore size of activated carbon for CS₂is 3-5 times the molecular diameter of CS₂.The adsorption capacity of activated carbon for CS₂depends on the pore volume distributed between 1.48～1.85nm.The larger the pore volume,the higher the adsorption performance of activated carbon for CS₂;The desorption capacity of activated carbon for CS₂depends on the pore volume distributed between 2.59～3.33nm.The larger the pore volume,the higher the desorption performance of activated carbon for CS₂.Under the same adsorption conditions,the adsorption capacity of activated carbon for CS₂is closely related to the type and content of functional groups on the surface of activated carbon.The content of phenolic hydroxyl and acidic groups on the surface of activated carbon is reduced,which is conducive to the adsorption of CS₂by activated carbon.2.The effect of activated carbon on the adsorption and desorption of CS₂under different working conditionsThe dynamic experiments of CS₂adsorption and desorption on five different types of activated carbon were carried out to screen for activated carbon with high adsorption capacity and low residual rate for CS₂,and the activated carbons were studied at different temperatures（15,25,35,45°C）and flow rate（500,625,795m L/min）,concentration(765,954,1 215mg/m³)and humidity（dry,RH=25%,RH=50%）and other conditions on the adsorption and desorption of CS₂.The results show that the best process conditions for activated carbon to adsorb and desorb CS₂are in a dry state,the adsorption temperature is 25℃,the flow rate is 625m L/min,and the CS₂ concentration is 954mg/m³.3.The relationship between activated carbon modification and CS₂adsorption and desorptionActivated carbon with high adsorption capacity and low residual rate for CS₂was screened out,and then modified by H₂O₂ solution,high temperature ammonia gas,NH₃·H₂O and Cu（NO₃）₂ solution,Study the effect of modified activated carbon on the adsorption and desorption of CS₂.The results showed that:（1）After the four methods of modification treatment,the adsorption capacity of activated carbon on CS₂ was increased by 4.3%,0.4%,1.8%and 2.3%,respectively,which shows that the modified activated carbon is beneficial to the adsorption of CS₂.（2）After modification with H₂O₂ solution and high temperature NH₃,the residual rate of activated carbon on CS₂ was reduced by 1.9%and 0.4%,respectively,indicating that the modified activated carbon is beneficial to the desorption of CS₂;After modification with NH₃·H₂O and Cu（NO₃）₂ solutions,the residual rate of activated carbon on CS₂was increased by0.3%and 2.5%.Respectively,which shows that the modified activated carbon is not conducive to the desorption of CS₂.4.Study on the kinetics of activated carbon adsorption of CS₂Activated carbon adsorption kinetics of CS₂By fitting four kinetic models of the quasi-first,quasi-second,Elovich equation and Bangham equation on the adsorption behavior of activated carbon on CS₂before and after modification,the results show that the adsorption behavior of CS₂before and after the modification of activated carbon conforms to the Bangham kinetic equation.