Preparation Of Porous Materials And Study On Their Adsorption Properties Of VOCs

With the in-depth study of the characteristics of steel sintering smoke pollution in the society,the state began to increase the emission limits of VOCs for steel companies,which has inevitably increased environmental pressure on steel companies.How to improve the level of air pollutants and meet the national emission standards for steel industry pollutants is a common problem faced by steel companies.The VOCs emitted during the sintering process not only seriously endanger the health of the workers but also hinder the coordinated development of the regional economy and environment.Accelerating the research and development of advanced technologies for sintering flue gas pollutants to control the emission of flue gas pollutants in the sintering production process is the focus of pollutant treatment in iron and steel enterprises.Adsorption is a highly efficient exhaust gas treatment technology commonly used in industry,and its core is the adsorption performance of adsorbents.Based on this,this paper focused on the preparation process of activated carbon with high adsorption capacity and improved the adsorption performance of metal organic framework materials.Three adsorption materials with good adsorption performance were successfully prepared,and the adsorption properties of the prepared materials were explored.The specific research process is as follows:The metal-organic framework MIL-101 was prepared by hydrothermal method with sodium acetate as mineralizer.The material was characterized by X-ray diffraction,scanning electron microscopy,infrared spectroscopy and gas adsorption instrument.The adsorption properties of benzene,methanol,toluene and water were studied by static adsorption method.The results show that the prepared MIL-101 has octahedral morphology and particle size of about 500 nm.Its VOCs adsorption properties are similar to those of MIL-101(HF)prepared at 220?.It is superior to those of commercial activated carbon prepared at 210?and 200?.At 25?,the adsorption capacity of benzene,methanol and toluene reaches 1300 mg/g,1127.7 mg/g and 750 mg/g,respectively.By comparing the initial slope of adsorption isotherm,it was found that toluene/water had the best adsorption selectivity,followed by benzene and methanol.In the process of hydrothermal preparation of Uio-66,the adsorption of benzene and toluene was improved by adding appropriate acetic acid to cause structural defects.The study found that the addition of acetic acid had little effect on the thermal stability of the material.The material was 500°C begins to decompose and has good thermal stability.In the one-component adsorption system,the Langmuir isotherm adsorption model can better describe the adsorption equilibrium curve of Uio-66 material for benzene and toluene.When the amount of acetic acid added was 1ml,the adsorption performance of the material to benzene was the best.Under the environment of 25°C,the adsorption amount of benzene was 367.13 mg/g,which was 41.9%higher than that of the original material.When the addition amount is 2ml,the adsorption performance of the material to toluene is the best,the adsorption amount is 410.21 mg/g,which is 93%higher than the original material performance,which is attributed to the structural defects increasing the unsaturated adsorption site and specific surface area of the material,thereby improving Adsorption performance.In the DIH equation,the maximum adsorption selectivity of Uio-66-1ml material to benzene and toluene was 27.2 and 7.52,respectively.In the mixed atmosphere of water and steam,the material still has a lot of work to do in hydrophobic modification..A series of activated carbons were prepared by using two-step high-temperature method using grapefruit peel as raw material,and different ratios of activators were added.Then,the adsorption performance of benzene,toluene and water was tested.The results show that the activated carbon has rich porous structure under the action of activator,and has excellent adsorption performance for benzene and toluene.The ratio of potassium hydroxide is 4,and the low pressure adsorption effect is best when the activation temperature is 800°C.The adsorption amounts of benzene and toluene were 1295.3 mg/g and 1427.9 mg/g at a relative pressure of 0.6 at 25°C,respectively,and the adsorption process was reversible.The adsorption isotherm of water vapor at 25°C shows that when the relative pressure is lower than 0.6,the amount of water vapor adsorption is very low,which is an important factor for the industrial application of grapefruit skin activated carbon materials in the future.In the DIH equation,the highest adsorption selectivity of benzene and toluene to benzene and toluene was 1671.17 and 12399.9,respectively,and the adsorption selectivity was better.The non-degradable cigarette butts in life were used to prepare activated carbon porous materials by hydrothermal pre-carbonization and chemical activation methods,which were used for industrial VOCs exhaust gas adsorption treatment,and tested by correlation characterization and adsorption performance of benzene and toluene.It is found that under the high temperature activation of potassium hydroxide,the surface of the carbon material after hydrothermal formation forms abundant micropores and mesoporous structures.The higher the activation temperature,the higher the aromaticity and the better the thermal stability of the material.The material decomposes in an air environment of 400°C and has good thermal stability.It has been found that the material prepared at 800°C has good performance.The specific surface area of CF-800 material reaches 3088.1 m~2/g,and the pore type is mainly microporous.At 25°C,the adsorption capacity of benzene and toluene at relative pressure of 0.6 respectively 1268.1 mg/g and 1181.6 mg/g.Comparing the properties of materials prepared under the same conditions with waste cigarettes,it is found that the materials prepared at 800°C are also the best,and the adsorption properties are similar to those of the materials prepared from pure raw materials.The adsorption amounts of toluene and toluene were 1250.8 mg/g and 931.26 mg/g,respectively.In the water vapor environment,the choice range of benzene is 3~21.544,and the choice range of toluene is1361.42~10070.1.The material has good selectivity in the mixed gas of toluene and water.This provides a good idea for the future recycling of cigarette butts and the preparation of high performance activated carbon.