Mechanical Activation Of Calcium Carbide And Preparation And Application Of Novel Alkynyl Carbon Materials

Calcium carbide (CaC2) is an important resource for coal chemical industry. For a long time, CaC2 industries have been faced with problems such as high energy consumption, serious pollution and single down-stream product. Hence, to study the chemical properties of CaC2, to explore ways to improve the reactivity of CaC2 and to develop high value utilization technologies of CaC2 are of great significance for the healthy development of CaC2 industry.This paper argues that the lattice energy has been a principal factor which binds the chemical reactivity of CaC2. Then the scheme of employing ball mill mechanical force to destroy the lattice of CaC2 is proposed and proved by reactions of CaC2 with polyhalogenated hydrocarbons. Alkynyl groups in CaC2 enable chemical reactions of CaC2 with several polyhalogenated hydrocarbons; corresponding products are alkynyl carbon materials (ACMs). Among the prepared ACMs, ACM-7 and ACM-8 were characterized emphasically in this article by SEM, TEM,BET, EA, XPS, XRD and Raman. ACM-7 is a micro-mesoporous material with high carbon content (82%), large specific surface area (504 m2·g-1 ), high graphitization degree (R=1.24), and proved to haveC(sp )-C=C-C(sp ) structural units. In addition, ACM-8 is a Si-doped micro-mesoporous ACM with larger SSABET of 570 m2·g-1 and higher graphitization degree (R=1.13). The atomic ratio of C/Si 4.1 is close to the theoretical value 4. Moreover, -C?C-, Si-C and crystal structures of a cetain kind of SiC material are proved to exist in ACM-8.Experiments were carried out to study the absorption of thiophenic sulfurs in fuel oil onto ACMs. Results show that the prepared ACMs are of favorable adsorption performance for polycyclic aromatic sulfur heterocycles (PASHs). ACM-6 particularlly possesses the highest adsorption capacity of 21.1 mg·g-1 for DBT in octane and a certain selectivity for PAHs in real oil. The used ACM-6, which is easy to be regenerated by using a solvent-washing method, can be recycled with high adsorption stability. As for the adsorption removal of Hg2+ in water,ACM-7 exhibits excellent performance including rapid adsorption rate,excellent adsorption capacity of 175.1 mg·g-1, stable cyclic-adsorption ability, and easy desorption. The adsorption process of the ACMs is basically dependent on physical interaction, however, chemical adsorption sites such as -C?C- inside the materials work simultaneously.The prepared ACM-7 also possesses outstanding electrochemical performance of charge-discharge reversibility, charge transfer and ion diffusion ability, cycle, current desity and scan rate stablility. In general,this study provides a new idea for the further study of CaC2 chemistry,and the preparation and application of novel ACMs.