高硫石油焦分级多孔炭的制备及电容脱盐性能研究

Preparation and capacitive deionization performance of high sulfur petroleum coke hierarchical porous carbon

电容脱盐是基于双电层原理的新兴脱盐技术,由于其具有所需电压低、能量消耗小和无二次污染等优点受到研究学者的广泛关注。多孔炭具有较高的比表面积、孔结构可调、物理和化学性质稳定等优点,常被用于电容脱盐的电极材料。多孔炭中非炭材料的引入,能为材料提供一定的赝电容,提高材料的电容脱盐性能。本文探究了含硫多孔炭对电容脱盐的影响,实验以高硫石油焦为炭前驱体,KOH为活化剂,在高温下一步活化得到分级多孔炭,并对多孔炭的电容脱盐性能进行了测定。结果表明,高硫石油焦KOH活化后,孔体积和比表面积得到很大的提高,而硫含量随着KOH添加量的增加逐渐降低直至为零。通过分级多孔炭电容脱盐的测试,发现微孔不利于电容脱盐,介孔更利于电容脱盐。与不含硫官能团的ACs进行对比,含硫官能团对脱盐具有增益效果,AC-2电极单循环脱盐量达到5.00 mg/g,单位比表面积的脱盐量达到0.015 mg/m^2。

Capacitive desalination is an emerging desalination technology based on the principle of electric double layer. Due to its low voltage requirement, low energy consumption and no secondary pollution, it has received extensive attention. Porous carbon is often used as electrodematerial for capacitive desalination due to its high specific surface area, adjustable pore structure, and stable physical and chemical properties. Introduction of non-carbon materials in porous carbon can provide a certain pseudocapacitance and improve the capacitive desalination performance of the material. In this work, the effect of sulfur-containing porous carbon on the capacitive desalination was investigated. The experiment used high-sulfur petroleum coke as the carbon precursor and KOH as the activator. Hierarchical porous carbon was obtained by activation at high temperature, and the capacitance desalination performance of porous carbon was measured. The results show that the pore volume and specific surface area are greatly improved after the activation,and the sulfur content gradually decreases to zero with the increase of KOH addition. Through the desalination test, it is founded that micropores are not conducive to capacitive desalination, and mesopores are more conducive to capacitive desalination. Compared with the sulfur-free functional ACs, the sulfur-containing functional group has a gain effect on desalination, the single cycle deionization capacity and deionization capacity of per specific surface area of AC-2 reach 5.00 mg/g and 0.015 mg/m^2, respectively.