Department of Chemical Engineering, Siirt University, 56100, Siirt, Turkey.
Department of Electrical &Electronics Engineering, Siirt University, 56100, Siirt, Turkey.
Environ Sci Pollut Res Int. 2020 Jul;27(21):26191-26210. doi: 10.1007/s11356-020-08848-4. Epub 2020 May 2.
In recent years, volatile organic compounds (VOCs) have become a group of major pollutants that endanger human health and the ecological environment. The main purpose of this study was to investigate the gas-phase adsorption processes of benzene and toluene, which are important VOCs, on the activated carbon (AC) produced from Elaeagnus angustifolia seeds by physical activation method. In this context, the central composite design (CCD) approach-based response surface methodology (RSM) was applied to examine and optimize the effects of process parameters on the adsorption of benzene and toluene by AC adsorbent. The characterization of the produced AC was performed by the Brunauer-Emmett-Teller surface area, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. The optimum process parameters were achieved (adsorption time of 74.98 min, initial benzene concentration of 16.68 ppm, and temperature of 26.97 °C, and adsorption time of 73.26 min, initial toluene concentration of 18.46 ppm and temperature of 29.80 °C) for benzene and toluene, respectively. The maximum adsorption capacities of benzene and toluene on AC were determined to be 437.36 and 512.03 mg/g, respectively, under optimum parameters. The adsorption process kinetics and equilibrium isotherms were also evaluated. Besides, AC reusability studies were performed five times for the gas-phase adsorption and desorption of benzene and toluene. After five cycles, it was observed that the benzene and toluene adsorption capacity of the AC decreased slightly by 8.10% and 7.42%, respectively. The results revealed that the produced AC could be utilized successfully for the removal of benzene and toluene in the gas-phase adsorption systems because of its high surface area, high adsorption capacity, and high reusability performance. Furthermore, the adsorption processes of benzene and toluene were investigated, both sole components and in a binary mixture. It was concluded that the adsorption behaviors of benzene and toluene against AC were quite different when they were in the competition (in a binary mixture) and without competition (sole components). Graphical abstract.
近年来，挥发性有机化合物（VOCs）已成为危害人类健康和生态环境的主要污染物之一。本研究的主要目的是研究通过物理活化法从沙枣种子中制备的活性炭（AC）对重要 VOC 苯和甲苯的气相吸附过程。在此背景下，采用中心复合设计（CCD）法-响应面法（RSM）研究和优化了工艺参数对 AC 吸附剂吸附苯和甲苯的影响。通过比表面积、扫描电子显微镜、傅里叶变换红外光谱和 X 射线衍射分析对所制备的 AC 进行了表征。得到了苯和甲苯的最佳工艺参数（吸附时间 74.98 min，初始苯浓度 16.68 ppm，温度 26.97°C；吸附时间 73.26 min，初始甲苯浓度 18.46 ppm，温度 29.80°C）。在最佳参数下，苯和甲苯在 AC 上的最大吸附容量分别为 437.36 和 512.03 mg/g。还评估了吸附过程动力学和平衡等温线。此外，还对苯和甲苯的气相吸附和解吸进行了 AC 可重复使用性研究，共进行了五次。经过五次循环，发现 AC 对苯和甲苯的吸附容量分别略有下降 8.10%和 7.42%。结果表明，由于其具有高比表面积、高吸附容量和高可重复使用性能，所制备的 AC 可成功用于气相吸附系统中去除苯和甲苯。此外，还研究了苯和甲苯在单一组分和二元混合物中的吸附过程。得出的结论是，当苯和甲苯在竞争（二元混合物）和无竞争（单一组分）时，它们在 AC 上的吸附行为有很大的不同。
