Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environment, South-Central Minzu University, Wuhan, 430074, China.
Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environment, South-Central Minzu University, Wuhan, 430074, China.
Chemosphere. 2024 Sep;364:143161. doi: 10.1016/j.chemosphere.2024.143161. Epub 2024 Aug 22.
Activated carbon (AC) has been widely used in volatile organic compounds (VOCs) treatment of industrial exhaust gases. Rather than modifying specific pore size distributions and surface properties, altering the shape of AC offers a more feasible approach to enhance its adsorption performance. This study investigates the adsorption-desorption performance of two different shaped ACs with highly similar properties for the removal of VOCs. The clover-shaped AC (CSAC) has a 27.46% lower internal void fraction and a 39.10% higher external void fraction compared to cylindrical AC (CAC), resulting in denser packing and longer contact time with VOCs. Adsorption experiments showed the CSAC has 40% longer adsorption breakthrough (BT) times for ethanol, ethyl acetate, and n-hexane on average, and 20% higher saturation adsorption capacity per unit volume. CSAC also has higher partition coefficients, with the highest values for ethanol, ethyl acetate, and n-hexane being 0.0187, 0.0382, and 0.0527 mol kg·Pa, respectively. The desorption process for selected VOCs is non-spontaneous and endothermic. Optimal desorption conditions were identified as an inlet space velocity of 3535 h, a desorption temperature of 150 °C, and a pulsed inlet method. To investigate the possibility of the application of CSAC in real-world scenarios, xylene was chosen as a representative industrial VOC. Results showed CSAC has 20% higher BT time and saturation adsorption capacity for xylene compared to CAC under different bed heights. The desorption efficiency for xylene on both ACs is below 40%. With increasing xylene inlet concentration, the mass transfer zone (MTZ) height initially increases but stabilizes beyond 1704 mg m. At identical bed heights, the MTZ height of CSAC is 29% shorter than CAC, indicating a higher bed utilization efficiency.
活性炭（AC）已广泛应用于工业废气中挥发性有机化合物（VOCs）的处理。与改变特定的孔径分布和表面性质相比，改变活性炭的形状提供了一种更可行的方法来增强其吸附性能。本研究探讨了两种具有高度相似性质的不同形状的活性炭（CSAC 和 CAC）对 VOCs 去除的吸附-解吸性能。与圆柱形活性炭（CAC）相比，三叶草形活性炭（CSAC）的内部空隙率低 27.46%，外部空隙率高 39.10%，导致其更紧密的堆积和与 VOCs 更长的接触时间。吸附实验表明，CSAC 对乙醇、乙酸乙酯和正己烷的平均吸附穿透时间长 40%，单位体积的饱和吸附容量高 20%。CSAC 还具有更高的分配系数，对于乙醇、乙酸乙酯和正己烷，其值分别为 0.0187、0.0382 和 0.0527 mol kg·Pa。选定 VOCs 的解吸过程是非自发的和吸热的。确定了最佳解吸条件为入口空速为 3535 h、解吸温度为 150°C 和脉冲入口方法。为了研究 CSAC 在实际场景中的应用可能性，选择二甲苯作为代表性的工业 VOC。结果表明，在不同的床层高度下，CSAC 对二甲苯的穿透时间和饱和吸附容量比 CAC 高 20%。两种活性炭对二甲苯的解吸效率均低于 40%。随着二甲苯入口浓度的增加，传质区（MTZ）高度最初增加，但超过 1704 mg m 后稳定。在相同的床层高度下，CSAC 的 MTZ 高度比 CAC 短 29%，表明其床层利用效率更高。
