Preparation And Adsorption Properties Of Graphene-based Materials

Graphene is a new type of two-dimensional atomic crystal,which has a wide application prospect in nano-electronic devices,catalysts,batteries,capacitors,new composites and sensing materials.In addition,the preparation process is simple,the theoretical specific surface area is large,the price is cheap and easy to be popularized and applied,so it has high application potential in adsorption and purification treatment.Its unique surface adsorption characteristics have high adsorption speed and capacity for organic compounds containing aromatic benzene rings.Cigarette smoke contains a large number of tobacco-specific aroma components and harmful substances,coke reduction and harm reduction is the main problem in the tobacco industry,but the composition of cigarette smoke is complex,the adsorption study of a single component can not meet its process.In this paper,graphene-based materials are used as adsorbents to reduce coke and damage,and their adsorption properties were analyzed from the selective adsorption of many components.The specific research and results were as follows:(1)The modified Hummers method was used to prepare GO,and graphene-based materials were prepared by the redox method with L-ascorbic acid,hydrazine hydrate,and Na BH₄ as reducing agents,the three main factors of reduction temperature,reduction time,and p H of the reduction process system were selected;and KOH activation with L-ascorbic acid and hydrazine hydrate as reducing agents.Three main factors were selected KOH/GO mass ratio,reduction temperature and p H of the reduction process system.Investigate the pore structure change of L-rGO?S-rGO?N-rGO?LK-rGO?SK-rGO under different horizontal conditions.The results show that the specific surface areas of the graphene-based materials L-rGO,S-rGO and N-rGO prepared by the redox method are:501.3 m²/g,775.6m²/g and 277.6 m²/g,respectively;Graphite prepared by the KOH activation method the specific surface area of the alkenyl materials LK-rGO and SK-rGO were:577.7 m²/g,655.1m²/g;the pore volume was 1.021 cm³/g,1.069 cm³/g.By FT-IR?XRD?SEM analysis,the results show that the graphene based material was amorphous and the surface of the material was rich in oxygen functional groups.(2)Using graphene-based materials with different structures as cigarette filter additives,the effects of graphene-based materials on seven main harmful substances in mainstream cigarette smoke were studied.The pore structure characteristics of graphene-based materials were the main factors affecting the reduction rate of harmful components in cigarette smoke.The adsorption performance of graphene-based materials with rich pore structure on harmful components of cigarette smoke was better,among which S-rGO had the best selective adsorption effect on 6 main harmful components of cigarette smoke B[a]P?HCN?NH3?crotonaldehyde?phenol?CO,and the reduction rates were 59.24%?75.32%?44.33%?42.58%?77.73%?66.48%,respectively.(3)The adsorption of phenol wastewater by different structure graphene-based materials was investigated by single factor experiment,response surface optimization and orthogonal test.The adsorption properties of phenol by the LK-rGO?SK-rGO prepared by KOH activation were significantly improved compared with those prepared by redox method.Effect of time,rotational speed,initial concentration of phenol solution and solution p H on the adsorption properties of phenol was studied by using single factor experiment to optimize the adsorption process conditions of phenol.The surface of graphene-based materials prepared by two methods had abundant basic groups.Therefore,under the condition of partial acidity,the adsorption of phenol by graphene-based materials reaches the adsorption equilibrium after 200 min,q_e increases with the increase of initial concentration of phenol.When the rotational speed was 180 rad/min,the adsorption performance of graphene-based materials to phenol was relatively good.(4)The adsorption behavior of phenol by graphene based materials was studied and the experimental data were fitted linearly.The results show that high temperature was not conducive to the adsorption of phenol by graphene based materials.For the S-rGO?SK-rGO,Langmuir model can better describe its isothermal adsorption equilibrium data,the equilibrium process was closer to monolayer adsorption;For the L-rGO?N-rGO?LK-rGO,Freundlich isothermal adsorption model,the adsorption equilibrium data of phenol can be better described.The graphene-based materials can be carried out quickly in the early stage and controlled by both physical adsorption and chemical adsorption.The active sites and structures on the surface of graphene-based materials have a great influence on the adsorption of phenol.The pseudo-second-order kinetics can better describe the adsorption kinetics of phenol by graphene-based materials.