Gagliano Erica, Falciglia Pietro P, Zaker Yeakub, Karanfil Tanju, Roccaro Paolo
Department of Civil Engineering and Architecture, University of Catania, Catania, 95125, Italy.
Department of Environmental Engineering and Earth Science, Clemson University, Clemson (SC), 29634, United States of America.
Water Res. 2021 Jun 15;198:117121. doi: 10.1016/j.watres.2021.117121. Epub 2021 Apr 5.
This study investigated the regeneration of PFAS-saturated granular activated carbons (GACs) by microwave (MW) irradiation. Two commercially available GACs (bituminous coal based GAC [BCGAC] and lignite coal based GAC [LCGAC]) were saturated with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and then irradiated at different MW conditions (applied power = 125 - 500 W, irradiation time = 3 - 12 min). The performance of MW regeneration for PFOS- or PFOA-saturated GACs was assessed by evaluating the variation of GAC adsorption capacity (regeneration efficiency, RE) and weight loss percentage (WL). Moreover, the effect of MW irradiation on GAC textural properties (e.g., surface area and pore volume) was examined through N adsorption isotherms. Additionally, five successive adsorption/regeneration cycles were carried out at the MW operational condition that allowed to reach the target temperature (T>600°C) while minimizing the WL. Both GACs exhibited a strong ability to convert MW irradiation into a rapid temperature increase (150°C min at 500 W). The highest values of RE (>90%) for both PFOA- and PFOS-saturated GACs were obtained at MW irradiation conditions that employed short regeneration time (3 min) and optimal temperature. Indeed, the highest RE did not occur at the highest temperatures (>750°C) due to the damage of GAC porous structure, particularly for LCGAC. After five cycles, the observed values of RE (65%) and a moderate weight loss (<7%) demonstrated the good performance of MW irradiation for regenerating PFOA- and PFOS-saturated BCGAC. The obtained findings pointed out that MW irradiation is a promising alternative regeneration technique for PFAS-saturated GAC.
本研究考察了微波（MW）辐照对全氟和多氟烷基物质（PFAS）饱和颗粒活性炭（GAC）的再生效果。将两种市售GAC（烟煤基GAC [BCGAC]和褐煤基GAC [LCGAC]）用全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）饱和，然后在不同微波条件下（施加功率 = 125 - 500 W，辐照时间 = 3 - 12 min）进行辐照。通过评估GAC吸附容量的变化（再生效率，RE）和重量损失百分比（WL）来评价MW对PFOS或PFOA饱和GAC的再生性能。此外，通过N吸附等温线研究了MW辐照对GAC织构性质（如表面积和孔体积）的影响。另外，在能达到目标温度（T >600°C）同时使WL最小化的MW操作条件下进行了五个连续的吸附/再生循环。两种GAC均表现出将MW辐照转化为快速升温（500 W时约150°C/min）的强大能力。PFOA和PFOS饱和GAC的最高RE值（>90%）是在采用短再生时间（3 min）和最佳温度的MW辐照条件下获得的。实际上，由于GAC多孔结构的破坏，最高RE并非出现在最高温度（>750°C）下，尤其是对于LCGAC。经过五个循环后，观察到的RE值（约65%）和适度的重量损失（<7%）表明MW辐照对再生PFOA和PFOS饱和BCGAC具有良好性能。所得结果指出，MW辐照是一种用于PFAS饱和GAC的有前景的替代再生技术。
