Preparation Of Carbon Materials By Mechanochemical Reaction Of CaC₂ And Halogenated Hydrocarbon

Because of their excellent physical and chemical properties,carbon-based nanomaterials have been widely used in electrochemistry,adsorption and catalytic properties.The commonly used preparation methods are thermal decomposition,arc discharge,laser evaporation,chemical vapor deposition and so on.These methods have many disadvantages,such as complicated equipment,high energy consumption,high investment cost and low yield,thus limiting the development of carbon materials.This paper is based on the use of calcium carbide and halogen compounds as carbon source.A new type of carbon material was prepared by mechanochemical reaction in the stirring ball mill.It has important practical significance and industrial production prospect,the application of carbon materials in supercapacitors and adsorption desulfurization and mercury removal were also investigated.In this paper,six kinds of carbon materials(labeled ACM-1,ACM-2,ACM-3,ACM-4,ACM-5,ACM-6)were prepared by mechanochemical reaction of the industrial grade calcium carbide and polyhalohydrocarbon(C6CO6,C2CO6,C6Br6,C14H4Br10,C2Cl4,CC14),one was selected and the effect of KOH activation was investigated.Their composition,structure and morphology were characterized by XRD,Raman,elemental analysis,XPS,SEM,TEM,BET and so on.According to the properties of the prepared carbon materials,the following two aspects were studied.(1)electrochemical application,(2)adsorptive application for sulfur and mercury.The electrochemical properties of the seven materials were investigated.The results show that ACM-2 has excellent reversibility,stability and cycling performance,but its specific capacitance is not high.The ACM-1 has a higher specific capacitance,and the specific capacitance is 199.5 F·g-1 at current density of 0.1 A·g-1,but its stability and cycle performance are not satisfactory.Although the surface area of ACM-1-KOH obtained by high temperature treatment was increased,the specific capacitance was not significantly improved.As a result,these carbon materials do not seem to be suitable for use as ideal supercapacitors.The order of the adsorption desulfurization ability is:ACM-1>ACM-5>ACM-3>ACM-6>ACM-2>ACM-4.The adsorption isotherm of ACM-1 accords with the Langmuir model,and the maximum adsorption capacity is 24.43 mgS·g-1,which belongs to the middle and upper level in the non-modified carbon materials.The order of the adsorption removal of mercury ability is:ACM-1>ACM-5>ACM-3>ACM-6>ACM-2>ACM-4.The adsorption isotherm of ACM-1 can be well fitted by Langmuir model and the maximum adsorption capacity is 514.67 mg·g-1,which is one of the best mercury sorbents currently.Finally,the reaction of calcium carbide with mono halides,acetyl chloride and halogen were carried out.The results show that under the mechanical ball milling,oil bath and ultrasonic,there is no chemical reaction between calcium carbide and n-butyl chloride,n-butyl bromide,bromine and acetyl chloride.In DMF or chloroform solvent,calcium carbide and halogen(Cl2,Br2)all formed carbon materials and calcium halide,reflecting the oxidation properties of halogen and redox properties of calcium carbide.