Research On Adsorption Of VOCs Using Modified Activated Semi-coke

Due to ubiquity in the environment and risk to human health, volatile organic compounds (VOCs) have received great attention in the field of environmental control. The main sources of VOCs is painting, printing, petroleum refining,pharmacy, plastic materials and gum polymer process.Treatment of VOCs is veryimportant and difficult in most actual occasions.Treatment methods of VOCs were also various, including adsorption,condensation, membrane and biochemical method,etc.This thesis focus on the preparation of activated semi-coke applied to remove VOCs. Semi-coke is the pyrolysis product of coal.At present, activated semi-coke is mainly used to remove the SO2 in gas.There are no reports about the activated semi-coke used in the treatment of VOCs.In this paper, experiments including single-species and multi-species (toluene,benzene, ethyl acetate and normal hexane) VOCs were conducted to observe the behavior of adsorption onto activated semi-coke.Further, the modification of activated semi-coke using H₂O₂ was done to change the adsorption efficiency of activated semi-coke towards VOCs.All of these were done to find the affection between different VOCs and determine the feasibility using activated semi-coke to treat multi-component VOCs.Also,the modification of activated semi-coke was to observe the effect of surface characteristic to the adsorption of VOCs.The research results show that when the VOCs is adsorbed by the activated semi-coke on the fixed bed,the exit concentration of VOCs is below the national standard.The combination order of these four VOCs are that: toluene＞ethyl acetate＞benzene＞normal hexane. At the condition of multi-species,the one with the high combination ability can replace the one with the low combination ability in a certain degree but not completely.Modification using the 30% H₂O₂ is the best way to activate the semi-coke.The modification improve the adsorption efficiency of the semi-coke to all the four VOCs especially to toluene. The study also indicates that single component adsorption equilibrium is good fit with Langmuir equation. For znulticomponent adsorption, The total capacity calculated by E-L equation is good tit with the conclusions of experiments.But the capacity of single component adsorption calculated by E-L equation has some deviation.Using the activated semi-coke to adsorb VOCs can not only solve the problem of how to deal with the semi-coke but also provide a cheap and good sorbent for the adsorption way to treat the VOCs in the industy.