Study On The Adsorptive Property Of Graphene And Its Composites

As the pillar of national economy,petrochemical industry provides indispensable petroleum and chemical products.However,the rapid development of petrochemical industry has also brought serious environmental problems,the emissions of volatile organic waste and oily wastewater has increased dramatically,the harm to the environment is becoming more and more serious.How to deal effectively with volatile organic waste and oily wastewater is one of research hotspots today.Significant scientific and technological efforts have been dedicated regarding organic compounds and oily wastewater removal.The most extensively used method is adsorption.adsorbent is the key to the adsorption method.But the common adsorbents such as activated carbon adsorption capacity is limited,there is still a desorption problem,therefore,to develop a good pertinence,high efficiency and easy adsorption model of adsorption agent is particularly important.The article was maily introduced the synthesis of graphene and magnetic graphene adsorbent and its adsorption of toluene and oily wastewater.The main contents include:?1?Graphene and magnetic graphene composites were prepared by graphite oxide reduction method and chemical coprecipitation method,and their physicochemical properties were characterized.?2?Graphene was used as adsorbent to study the adsorption property of toluene under different toluene inlet concentration,adsorption temperature and bed height.?3?Magnetic graphene was used as adsorbent to study the adsorption property of oily wastewater under different amounts of magnetic graphene,adsorption time,solution pH,adsorption temperature and cycle times.The conclusions obtained from the experiment are as follows:?1?the specific surface area of graphene which was prepared by reduction of graphite oxide was 427.72m²/g,the average volume was 0.305702cm³/g,the average pore size was 3.29936nm.The equilibrium adsorption amount by graphene was 86.5mg·g^-1,when the toluene concentration is 1150mg·m^-3,adsorption temperature is 25?,bed height is 10mm,and gas speed is 200mL·min^-1.?2?With the increase of initial toluene concentration,the less time to reach the adsorption breakthrough point and saturation point,the higher of equilibrium adsorption capacity.With the increase of bed height,the more time to the breakthrough point and saturation point,the higher of equilibrium adsorption quantity;with the increase of adsorption temperature,the time of adsorption saturation decrease and the equilibrium adsorption capacity increased.?3?The fitting results of Langmuir and Frenudlich equation show that adsorption isotherms of toluene on graphene fit Frenudlich Isotherm better.Kinetic data analysis show that The pesudo-second adsorption kinetic model is more suitable for the analysis of adsorption mechanism.?4?The specific surface area of magnetic graphene which was prepared by chemical coprecipitation method was306.8m²/g,the average volume was 0.2045cm³/g,the average pore size was 4.4893nm.The equilibrium adsorption amount by magnetic graphene was 335.85mg·g^-1,when the emulsified oil concentration is 150mg/L,adsorption temperature is 35?,quality of the adsorbent is 20mg,and adsorption time is 60min.?5?The fitting results of Langmuir and Frenudlich equation show that adsorption isotherms of emulsified oil on magnetic graphene fit Langmuir Isotherm better.Kinetic data analysis show that The pesudo-second adsorption kinetic model is more suitable for the analysis of adsorption mechanism.Adsorption process is accompanied by chemical reactions?6?Compared with oil absorption material such as activated carbon,expanded graphite,magnetic graphene has larger adsorption capacity.After six times cycle experiment,magnetic graphene still can keep the higher adsorption efficiency.And adsorbent can be easily recycled under the condition of magnetic force.