Per- and polyfluoroalkyl substances (PFAS) are a large class of chemicals widely used for many commercial and industrial applications and have resulted in contamination at sites across globally. Pump-and-treat systems, groundwater extraction, and ex situ treatment using granular activated carbon (GAC) are being implemented, either in full or pilot scale, to treat PFAS-impacted groundwater and drinking water. The only current method of regenerating spent GAC is to reactivate it at temperatures greater than 1000 °C, which requires large amounts of energy and is quite expensive. This research focused on development and demonstration of an effective GAC regeneration technology using a solvent-based method for PFAS-laden GAC used in water treatment. Two different organic solvents (ethanol and isopropyl alcohol) with 0.5% and 1.0% ammonium hydroxide (NH₄OH) as a base additive were tested to determine the most effective regenerant solution to remove PFAS from the contaminated GAC. Based on column tests using laboratory-contaminated GAC with perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), the solvent-base mix (SBM) of ethanol with 0.5% NH₄OH was found to be the optimum performing regenerant solution. The GAC life span assessment showed that solvent-regenerated GAC performed similar to virgin GAC without losing its optimal performance of PFAS sorption. Further, the solvent-regenerated GAC showed optimal performance even after four cycles of solvent regenerations tested using the optimum SBM. Average percent removal in laboratory-contaminated GAC using the optimum SBM was 65% and 93% for PFOS and PFOA, respectively. Four field-spent GAC samples were also regenerated using the optimum SBM. Percent removal from these samples was found to be in range of 55%–68%. The type of GAC used, level of contamination and type of PFAS present, water type and quality, and the presence of co-contaminants may have influenced the removal capacity. Distillation experiments have shown that it is feasible to concentrate the spent solvent prior to disposal, which reduces the amount of PFAS-contaminated solvent waste produced in regeneration cycles.

全氟烷基物质和多氟烷基物质（PFAS）是一类广泛的化学物质，广泛用于许多商业和工业应用，并已导致全球各地的污染。正在采用全规模或中试规模的抽水处理系统，地下水提取以及利用粒状活性炭（GAC）进行的异地处理，以处理受PFAS影响的地下水和饮用水。再生用过的GAC的当前唯一方法是在高于1000°C的温度下将其重新激活，这需要大量能量并且非常昂贵。这项研究的重点是开发和展示一种有效的GAC再生技术，该技术使用基于溶剂的方法处理水处理中含PFAS的GAC。两种不同的有机溶剂（乙醇和异丙醇），分别含0.5％和1.0％的氢氧化铵（NH测试了作为基础添加剂的₄ OH）以确定从污染的GAC中去除PFAS的最有效的再生剂溶液。基于使用实验室污染的GAC和全氟辛酸（PFOA）和全氟辛酸磺酸盐（PFOS）进行的柱测试，乙醇与0.5％NH ₄的溶剂基混合物（SBM）发现OH是最佳性能的再生剂溶液。GAC寿命评估表明，溶剂再生的GAC的性能与纯净的GAC相似，而没有丧失其PFAS吸附的最佳性能。此外，即使在使用最佳SBM测试的四个溶剂再生循环之后，溶剂再生的GAC仍显示出最佳性能。使用最佳SBM，在实验室污染的GAC中，PFOS和PFOA的平均去除率分别为65％和93％。使用最佳SBM还可以再生出四个用过的GAC样品。从这些样品中去除的百分比被发现在55％至68％的范围内。所使用的GAC的类型，污染程度和所存在的PFAS的类型，水的类型和质量以及共污染物的存在可能会影响去除能力。