Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry, Nanjing 210042, China.
Key and Open Laboratory on Forest Chemical Engineering, State Forestry Administration of the People's Republic of China, Nanjing 210042, China.
Molecules. 2018 Jan 2;23(1):96. doi: 10.3390/molecules23010096.
Carbon spherules from ginkgo seed starch were prepared through stabilization and carbonization processes. The ginkgo seed starch was first stabilized at 195 °C for 18 h, then carbonized at 500 °C for 2 h under an N₂ atmosphere. The characterization results confirmed that carbon spherules were in the size range of 10-20 μm. Experimental data were also evaluated to find out the kinetic characteristics of phenols on the carbon spherules during the adsorption process. Adsorption processes for phenol, -nitrophenol and -chlorophenol were found to follow the pseudo-first order kinetic model with ² values of 0.995, 0.997 and 0.998, while the rate constants ₁ = 0.014, 0.009 and 0.011 min showed that the adsorption is mainly controlled by adsorbate diffusion. The equilibrium data were analyzed with the Langmuir, Freundlich and Temkin-Pyzhev models and the best fit was observed with the Freundlich isotherm, suggesting the physical adsorption of phenols. From the thermodynamic functions, ∆G, ∆H, and ∆S were calculated, which showed that adsorption is more favorable at low temperature and is an exothermic process, and the adsorption of -nitrophenol and -chlorophenol were more advantageous than that of phenol.
通过稳定化和碳化过程制备了来自银杏种子淀粉的碳球。首先将银杏种子淀粉在 195°C 下稳定 18 小时，然后在 N₂气氛下于 500°C 碳化 2 小时。表征结果证实，碳球的尺寸范围为 10-20 μm。还评估了实验数据，以找出酚类物质在吸附过程中在碳球上的吸附动力学特征。发现苯酚、-硝基苯酚和-氯苯酚的吸附过程遵循准一级动力学模型，² 值分别为 0.995、0.997 和 0.998，而速率常数 ₁ = 0.014、0.009 和 0.011 min 表明吸附主要受吸附质扩散控制。用 Langmuir、Freundlich 和 Temkin-Pyzhev 模型分析平衡数据，观察到最适合 Freundlich 等温线，表明酚类物质的物理吸附。从热力学函数中计算出 ∆G、∆H 和 ∆S，结果表明吸附在低温下更有利，是一个放热过程，-硝基苯酚和-氯苯酚的吸附比苯酚更有利。
